Jump to content

Search the Community

Showing results for tags '2-stroke'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Dirt Bikes
    • General Dirt Bike Forums
    • Make / Model Specific
    • Dirt Bike Technical Forums
    • Special Interest Forums
    • Dirt Bike Regional Discussion
  • General
    • General Forums
  • ATV / UTV
    • General ATV / UTV Forums
    • Make/Model Specific
    • ATV / UTV Regional Discussion
  • Inside TT
    • Advertise
    • Community Sponsors
    • Site Usage & Functions
    • Bug Reports & Suggestions
  • ThumperTalk Clubs FAQ & Help's FAQ/Help & Discussion
  • RokFox's Current Kit
  • RokFox's What's New
  • So Cal Flattrack's Club Forum
  • Pittsburgh Area Off-Road N@'s Welcome!
  • Thumperjunkies - Ottawa & Eastern Ontario Riders's Discussion
  • Jersey MX and offroad's Places you ride
  • Jersey MX and offroad's Discussion
  • Sonoma Coast Skinny Twisties's Discussion
  • Sonoma Coast Skinny Twisties's Topics
  • New Mexico Trail Riders's Discussion
  • Okanagan Off Road Motocycle Club's Club Forum
  • Redwood Riders's Club Forum
  • jack graybill's Club Photos
  • TAS trail/Enduro riders's Club Forum
  • The official Aussie 2 Stroke club's Favourite riding places
  • Folsom Trail Riders's Topics

Categories

  • Universal Parts & Accessories
  • Parts & Acc. - Japanese Bikes
    • Honda Parts & Accessories
    • Kawasaki Parts & Accessories
    • Suzuki Parts & Accessories
    • Yamaha Parts & Accessories
  • Parts & Acc. - Euro Bikes
    • Beta Parts & Accessories
    • Husqvarna Parts & Accessories
    • KTM Parts & Accessories
    • Other Euro Parts & Accessories
  • Motorcycles
    • Off-Road Motorcycles
    • Dual Sport Motorcycles
    • Street Motorcycles
  • Powersports Gear & Apparel

Products Categories

Vehicles Categories

Garages

Blogs

There are no results to display.

There are no results to display.

Calendars

  • ThumperTalk Clubs FAQ & Help's Club Calendar
  • RokFox's Enduro Ride Schedule
  • So Cal Flattrack's Club Calendar
  • So Cal Flattrack's Events
  • Thumperjunkies - Ottawa & Eastern Ontario Riders's Club Calendar
  • Thumperjunkies - Ottawa & Eastern Ontario Riders's Events
  • Sonoma Coast Skinny Twisties's Calendar
  • New Mexico Trail Riders's Events
  • Okanagan Off Road Motocycle Club's Club Calendar
  • Redwood Riders's Club Calendar
  • jack graybill's Club Calendar
  • TAS trail/Enduro riders's Club Calendar
  • Folsom Trail Riders's Ride & Event calendar

Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Interests

Found 38 results

  1. Recently picked up a brand new YZ250x 2017 and this is my log on why i think this is the best Motocross and Endrocross 2 stroke out there! Currently the bike is all stock! I've made a few adjustment for my carb such as a 172main and a 48 pj. right on the mark for main jetting in Colorado. Power is nothing but smooth and predictable one of the best 2 stroke iI've ever rode! As time goes on i will add parts to this bike and keep you guys updated on what they do! hope everyone's excited! If you like to sponsor the bike or have a product you like tested please contact me at tatmanjosh@gmail.com
  2. Recently picked up a brand new YZ250x 2017 and this is my log on why i think this is the best Motocross and Endrocross 2 stroke out there!
  3. ExtremePolyAthlete

    bikewontstart Bike won't start

    I just bought a 1998 Kawasaki kx80, and I'm gonna need some help getting it running, so any help that anyone could provide would be great. The bike had a little bit of fuel in it, but it mostly looked like oil, so i'm guessing that the gas evaporated. It was looking very blue inside there. I put in some mixed fuel but not a lot, i'm not actually sure if it was the right mix. I tried kick starting it and it has some compression, but it wouldn't start at all. I tried push starting it and kicking it into second, and it got a lot closer to starting, but still would not fire up. Then I realized that the clutch was not engaging. When I pull the lever, I can see the cable moving, so I think it is something inside the bike. Also, when I pull the lever, I know its supposed to have some tension as you pull it in farther, but the tension does not change at all, like its not doing anything. I know I probably need to get inside the clutch side of it, but what is wrong with it, and what do I need to do? I'm going to clean the carburetor because that is probably one of the main problems, and I will also try cleaning the air filter. I know that it also has a blown head gasket, which is pretty easy to fix, and I can do that by myself. I also checked the spark plug, and it was super oily, and I cleaned it quickly, and made sure it was getting spark. It was sparking, so I put it back, and tried push starting some more times, and it got a little closer, but it still isn't starting. The bike is also super oily/greasy all over, and I have no idea why, is there a specific reason for this, or just because it has been sitting? One other thing that is wrong with it is that the rear brake works, but is super stiff, and when I push it down, it doesn't want to come back up so I have to pull it back up. The return spring does look a little rusty, and everything around the rear brake system does look a little rusty. I'm going to take it apart and lubricate it and see if that helps at all. What I know I need to do: Clean carburetor, clean air filter, replace head gasket, drain all the fuel in the tank and put the correct mixture in, check the oil and all the fluids, What I need answers to: Why isn't the clutch engaging, and what do I need to do to fix it. Should I get a new spark plug just in case, and why is it so oily in there? What else do you guys think could be wrong with it, and what do I need to do to it? Thanks for the help, I really appreciate it.
  4. Hey All, I have a two-stroke KTM. I've never had an issue with running out of gas thus far, but will be taking some long runs down in Ouray this weekend. I'm not comfortable carrying pre-mix gas on my person, and don't have much room in my pack that consists of hydration pack, snacks, and tools. Instead want to carry some 2T oil in a tall thin cylindrical container of sorts. I'll mark the container to reflect amount to add to 1/2/3 gallons. What types of containers are you guys traveling with? Maybe I'm overthinking this, but I like to be prepared...
  5. https://www.gofundme.com/my-dads-brain-tumor-surgery Please do all that you can do for my friend Paul Santoro aka Syco, who's been diagnosed with a brain tumor. For those of you who know him you all have stories to tell without a doubt and for those who don't, he is one of a kind beyond his incredible talent and passion for adventure on a dirt bike let alone mountain bike and surfing he really does have a heart of gold! Paul has two boys one of which is responsible for setting up the above fund for his father and a daughter whom all are by his side supporting him in these challenging times and his girlfriend Chardel too is beyond words lovingly by his side. So again, I'm asking for your support whether it be donating to his fund and/or spreading the word/link around so people can contribute. My deepest gratitude to all that take time to read this post and for those who help in any way you are awesome! Thanks, Brian
  6. ross_co

    Clutch not engaging

    Hi, I have a CR250 and went to get it out for the season to find when I pull the clutch lever in, the gears are still engaged. I tried adjusting the cable with no luck, so I trained the bottom end oil out and removed the clutch cover and plates to inspect it. There are some grooves in the clutch basket, but they don't look too bad (see attached). Any ideas on how to trouble shoot this issue ? Thanks
  7. So I'm looking for some pivot levers for my clutch and hand brake on my '99 KX 250, I found these ones on amazon that say they will fit an '00 to '04 kx250, do you guys think these would fit my '99? if not do you know any that I can buy online, Im looking for green ones specifically, Thanks. https://www.amazon.com/MZS-2000-2017-2001-2017-2000-2005-2000-2004/dp/B01E6XQDFM/ref=wl_mb_wl_huc_mrai_1_dp
  8. So I bought this bike about 2 months ago .. noticed a small leak where the exhaust manifold and expansion chamber meet the head mounting studs.. seems to progressively get worse as I ride as I notice more smoke. so I pulled off my pro circuit pipe and my exhaust manifold and I noticed the top stud is super stripped (the nut just keeps spinning on the stud). I am wondering how I can get this stud out because it seems to just be a stripped stud and it will not just turn out with vice grips.. and are there any recomended studs or sealers I can use ? Also how am I going to screw in the new stud without damaging the threads ? As you can see I don't have enough room to put 2 nuts on and screw it out as I tried that !
  9. Henry Nichols

    Kx 250

    Okay guys, I have a 1997 kx250 frame and I wanna know(if even possible) if there are any 2 stroke engines besides the original that will Bolt onto the frame without any modifications.
  10. So basically. I got this yuuuuggeee RM250 in a trade. It is a really nice bike. I really didn't know much about it when I got it, except that it was very pretty and extremely fast. Anyways, I look it up and find that its the only year of air cooled engine w/ mono shock suspension. Anyways I have been storing the bike ever since on inside of my house and I think its time to make some space. The bike deserves to be ridden more... Honestly, I am a little afraid of how fast it is! And in case you can't tell where this is going... I decided to sell the bike and thought maybe you would be interested. I know its not from the best era or the coolest bike you've ever seen... But it is clean, fast, and pretty dang rare. If you appreciated that I didn't just throw this at you and say BUY MY BIKE and instead wrote a semi-thoughtful write up about it and then hooked in the advertisement at the end. You should check out the bike on Ebay. Ill put the link below. It deserves a good home. Someone like you. Someone like your son who's birthday is coming up. If someone wants it come and get it. No reserve, I sell to highest bidder no questions asked. I will help with shipping, provide more info, etc at jonahdeich@gmail.com. The bike is located in Savannah, Georgia http://www.ebay.com/itm/222475245091?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
  11. Kangaroo_Smasher

    Help! cr125 bogs!

    Backstory: 2003 cr125 piston siezed during mud race. cylinder replated, fresh top end, all back together and bike rips well but looses coolant out exhaust. Fast forward 3 years and 3 complete gasket sets later and found out that the replated cylinder had a crack behind the inner power valve axle stay, so it was loosing coolant out the power valve. Now: new oem cylinder and head, fresh wiseco piston, carb rebuild, air filter, fresh silencer packing, and now the bike starts and runs well but bogs soooo badly off idle and when i crack it WOT. feels like its misfiring. it rolls on power okay if i roll onto the throttle slowly. Im at a loss. So far I have changed out spark plug, checked correct piston orientation, checked correct PV operation, Jetting is currently 410 main, 37.5 pilot, needle 2nd cip, AS 1.5 out. I don't know what to do with this bike. Can anybody suggest anything that I haven't tried yet? I want to get this bike back on the trail
  12. AMM888

    99 YZ125 v 03 YZ125

    I am looking for a YZ125 and have found a 99 for 1300 and an 03 for 1600 both in pretty nice condition. Obviously going to negotiate the prices down however I was wondering which one you guys would suggest. Ive been doing research and know that the 03 is lighter with a modified frame though it has a 5 speed. The 99 motor is well liked for the power and reliability. I will be doing strictly trail riding so whats the better option here?
  13. This week I want to talk about two-strokes. To kick off this post I have some awesome news. The Two Stroke Dirt Bike Engine Building Handbook is off to the printers and will be available for pre-sale very soon! Getting the book off the ground has been no cake walk. It's been two years coming and we are so thankful our riders and fans have been patient with us! At the end of this post I'll give you instructions on how you can stay updated on the launch. With that said, let's get started. Today's post aims to provide an overview of the important aspects of the two-stroke cylinder and answers a couple commonly asked questions relating to cylinder modifications. The ports found within a two-stroke cylinder in combination with the exhaust system have the greatest influence on power, torque, and the RPM at which maximum power is created out of the various engine subsystems found within a two-stroke engine. Typically when a new engine is designed the port characteristics are one of the first parameters to optimize. With this being the case they are also one of the first things anyone planning on altering an existing engine should consider improving or tailoring to their specific application. A two-stroke cylinder consists of exhaust, transfer, and occasionally inlet ports (true inlet ports are only found on piston or rotary valve controlled engines). The port heights, widths, areas, directions they flow, and relationships to one another all have a significant influence on how the engine will behave. The cutaway of the cylinder shown details the port arrangement and common nomenclature. The inlet port/passage delivers air into the engine’s crankcase, most commonly through a reed valve, on a dirt bike engine. On older engines, a rotary valve or the piston may also be used to control the opening and closing of the inlet port. On modern machinery, the inlet simply connects the reed valve to the cylinder or crankcase. In this case, the primary restriction in the inlet port is the reed valve and as such the valve’s geometry and flow capabilities often dictate the inlet port's performance. The transfer ports are responsible for moving fresh air and fuel up from the crankcase into the cylinder. This occurs as the piston travels downward after the cylinder has fired. Once the piston uncovers the tops of the transfer ports the blowdown phase is complete, at which point much of the exhaust gas has been expelled from the cylinder. As the transfer ports begin to open, the exhaust pipe sucks fresh mixture up through the transfer ports into the cylinder. To a lesser extent, the downward motion of the piston also aids in creating a pressure differential between the crankcase and cylinder. The shapes and flow capabilities of the transfer ports play a big part in how effectively the cylinder can be scavenged of exhaust gases and filled with fresh air and fuel. The transfer ports also help cool the piston. The exhaust ports dictate how much and how well exhaust gases depart the cylinder. Similar to the transfer ports, the duct shape, angle, length and volume have a large influence on how well gases can flow through the port. Typically, dirt bike engines commonly feature bridge port or triple port designs. General insights into a cylinder’s performance can be made by characterizing attributes such as the timing of the exhaust and transfer ports, the port widths, and the directional flow angles, but a deeper analysis is required to truly optimize a cylinder. Today, tuners and designers rely on computer software which computes a port’s specific time area (STA). As defined in the EngMod 2T software suite, “STA provides an indication of the effective port window area that has to be open for a certain length of time to allow enough gas to flow through the port to achieve the target power at the target RPM for the given engine capacity”. STA values are used to quantify the exhaust, transfer, and inlet port geometry as well as the blowdown phase of the two-stroke cycle. The blowdown phase occurs between exhaust port opening and transfer port opening and is one of the most important parameters in predicting engine performance. By manipulating STA values and subsequently the height, shape, and size of the exhaust, transfer, and intake ports, an engine’s power characteristics can drastically be altered. Port modifications can be made which allow more air to move through the cylinder, ultimately increasing the power of the engine. Conversely, ports can be filled or welded and reshaped which tame the engine and provide less peak power but a broader spread of power. Simple modifications to the ports can also be carried out which improves the air or exhaust gas flow through the port yielding better cylinder scavenging. Can I modify my own cylinders? Unless you have a deep passion for two-stroke tuning, are willing to spend money on software and porting equipment, and are comfortable throwing away botched cylinders, I would recommend having a reputable professional carry out any desired port modifications. Experienced tuners have developed a number of porting combinations that will work well for various makes/models and riding applications which will take the guesswork out of the situation and provide you with a good performing cylinder. Who should consider two-stroke porting modifications? For the sake of simplicity, I will lump porting modifications into two categories: major and minor. Major port modifications would include tasks such as significantly changing the port timings (by either removing or adding material), altering the shapes of the ports, or changing the directions the ports flow. Anyone drastically altering their engine, such as turning an MX engine into a road racing engine, should consider major porting modifications. Other examples of applications that may require or benefit from major port modifications include drag racing, hare scrambles, ice racing, or desert racing. Minor port modifications would include basic tasks such as removing casting flash, slightly altering the ports to achieve the stock port timing, and correcting areas that result in minor flow deficiencies. Just about everyone could benefit from these types of corrective actions; however, if the engine is already performing or producing adequate power, they often aren't considered. I hope you enjoyed this writeup on key features affecting the performance of two-stroke cylinders. To stay officially updated on The Two Stroke Dirt Bike Engine Building Handbook we created an email sign up for our readers. Click this link to see the new cover, the Table of Contents, and some sneak peek pages right from the book. Thanks for reading and have a great rest of your week! -Paul
  14. Karl Thibaudeau (Riffdis)

    Oil/coolant mix in crankcase

    Hello, So my buddy got a cheap broken down project bike (2001 Yamaha YZ 125) and we originally found that the piston had a hole on its side, and the side of the cylinder was all scratched up. We sent the cylinder to get nikasiled, got a new piston and head gasket and drained all fluids. We found that the crankcase was full of this brown milky oily substance that will not drain. We determined it's probably coolant that mixed with the oil, but we have no idea how to properly get it out. We're thinking that maybe the drain is clogged somewhere, but liquids have drained before... Has anyone ever seen this? How did you deal with it?
  15. I just recently did an exhaust repacking on my FMF Turbine Core spark arrestor pipe for my ‘98 CR250r and was able to repack and re-rivet the pipe from the end leading to the bike’s cylinder head and expansion chamber (two-stroke) without any problems. When I remounted the exhaust I noticed the tail end had an inner metal tube that was loose and could be moved around easily. I believe it was tack welded into place and he welds broke but just wondering if anyone has dealt with the exhaust outlet side when repacking the bike side and wether I didn’t assemle the exhaust correctly or whether the back part of the tubing just broke free?? Also how to fix? Here is a pic of the exhaust tip with the inner tube obviously out of place and not lined up with the outer.
  16. I recently bought a 1982 YZ125 and have been struggling to get it to start. Bike has very low compression, got a new piston ring but didn't help the issue. Has spark, and when I pull the plug out it's wet so gas is getting to it, but I still don't hear any pop or fire or anything when I try to start it. I'm no expert but if the plug was sparking inside the cylinder with gas I should hear something right? So I was thinking maybe the timing's off (although it would have to be really off for it not to even fire) or maybe the plug is sparking outside the cylinder but not inside? Anyways I'm not sure what to do next any suggestions appreciated!!
  17. Just came across this article: http://www.automototime.com/2017/10/mx-nationals-250-two-strokes-in-mx2-for.html According to the article 2 stroke are allowed back into MX2 although first in Europe Should be interesting.
  18. mxrook

    clutch trouble

    hey guys, I'm new to the world of bikes and my uncle has experience with bikes and showed me a few simple things like brake pads and bleeding my brake lines, i just bought my first bike a 2006 rm125. first time i went to ride we started it up and went to put it in first gear, slammed first gear and stalled. figured out if i rev while putting it in gear it goes in fine with a little lurch (no problem just getting my bearings riding the bike for now).clutch plates are brand new, swapped in a new clutch cable hoping that was the only issue. so with a brand new cable I'm still having this problem it seems as though the fitment is off. i was wondering if anyone has an opinions on what might be wrong, i was told something might be missing on the inside (from when previous owner replaced clutch) because the arm that holds the clutch inside the engine (no idea the name of it) could be a little bit lower so that it engages sooner and better. again like i said i apologize I'm a newb with all this and just looking for opinions on what may be wrong. my question is, why wont a clutch cable made for my bike not fit right? could i be missing an internal component causing issues? and should i just go with a whole new clutch kit?
  19. Jesse T. Groth-kennard

    05 kx250 new rebuild running hot

    Just did a fresh build on the eng in my kx250 new crank and complete bearing set, bought a complete jug from someone that did a big boar kit when the bike was new, and new seal kit, it looks like the fluid that is flowing in the radiator is full of bubbles i switched to water and purple ice by royal purple an it didnt cool it down but it still looks frothy as it pumps by the cap, and in the exhaust port there was a few water drops on far right exhaust valve and the side of piston was milky looking, here is a pic threw the exhaust port. any one have any ideas one were i should start? i even put new oversize radiators on but still gets hot and starts running real sporadic high smooth idol with no ting so i shut it down. any help would be great!
  20. OK I am posting this because it has always intrigued me... and I have never done this but have often asked why people do. The topic is Ratio of premix why do people change it based on how the bike is running / or change in location IE Elevation? I have always gone with the oil's recommended mix ratio.. bell-ray MC1 was 50:1 some others 32:1 and such, but I have never changed the ratio based on where I ride or because of #spooge coming out of the exhaust, fouling plugs, lots of smoke out the exhaust ect. If I encounter any of those following issues I do 1 thing, I re-jet to the elevation or conditions. The reason I am asking this is that I try to be a nice guy and help out people, in doing so one of my neighbors recently acquired a CR250R and he isn't really a bike guy but at the deal he got it at he couldn't pass it up. It's a 2002, so I asked him what the PO was running for an oil and at what ratio, he said that the PO was running an oil I had never heard of but the ratio was depending on elevation he was 50:1 at one and 40:1 at the other. So I let this rattle around in my cerebral carcass all night... I am thinking what difference does the ratio of Oil have to do with elevation and less oxygen? I get the lean rich thing, but why run at a different ratio trying to compensate for less oxygen in the air? So please enlighten this OLD rider that doesn't understand this possibly simple problem.
  21. Photo: KTM 300 EXC TPI - Six Days ISDE Edition Two-strokes are still a hot button when it comes to talking about dirt bikes these days. The old "two-stroke vs. four-stroke" debate has been beat to death and many of us are sick of it, but it rages on regardless. OK!! So four-strokes won, the Japanese factories, AMA and EPA got what they wanted and it's over...two-strokes, once the powerhouses of motocross, have now been relegated to the shed, gone out of fashion and not used by any top racing team in MX or SX. But the two-stroke is still gasping for air thanks to KTM and maybe even Honda... who officially stated they'd converted to a four-stroke company years ago, so that's a surprise! Why is it still here? Because it's awesome that's why...two-stroke engines pack more horsepower per pound than four-stroke engines, and even if that statistic was equal, the number of complicated, fragile and expensive parts in a modern four-stroke will always cost more to replace. Granted the replacement interval for four-stroke motorcycle engines has gotten longer and longer but you'll always have the complication and expense factors to think about...and that's good for the manufacturers...a nice balance between reliability and the need to replace worn parts makes for a good bottom line, but that's another discussion. Obviously less moving parts and making more HP/lb are excellent attributes that appeal to motorcyclists and maybe not so much to the manufacturers at large. Three years ago, I wrote an article that talked about advances in two-stroke technologies and the possibility that these technologies (EFI, DFI, TPI) could help the two-stroke gain more market share. One of the conclusions was that EFI using DFI was too expensive, bulky and heavy to be a reality on off-road motorcycles and that has turned out to be the case when looking at how the technology is presenting itself in production form. KTM have been the leaders in two-stroke motorcycle engine design and accompanying technologies so it was only natural that KTM would be the first major motorcycle manufacturer to provide a viable cleaner-burning technology to the two-stroke arena. The first bikes to display this technology are the KTM 250 EXC TPI and the KTM 300 EXC TPI. Honda also has filed a similar patent but has not put any examples into production and looking at the patent drawings, it appears to be an industrial design featuring a pushrod, not suited for high-performance applications. What does this advancement mean, and is this the saving grace technology that two-stroke fans have been waiting for? No. But OK, it's a great advancement in terms of the accomplishment - but how does it impact the market as a whole? It's great if you ride enduro bikes in the EU...but will TPI bring two-strokes back to off-road bikes? Maybe, but motocross only bikes won't be included. Why not? Because the Japanese factories have a lot of time and effort invested in four-stroke technology and it's not going away. They influenced the sanctioning bodies and promoters to implement unfair displacement rules that favor four-strokes. So why did KTM do it? Because a lot of folks ride two-stroke enduro bikes and KTM sells a lot of them both in Europe and here in the USA! Although KTM doesn't make two-stroke streetbikes per se, they do have two-stroke enduros with plates and lights and these enduro models are homologated for use on EU public roads, which means they have to adhere to tough new Euro4 emissions limits, as well as be prepared for the upcoming Euro5 restrictions. I've spent a lot of time in the EU and small bikes matter...in fact small motorcycles are the norm not the exception. You see lots of small two-stroke bikes and scooters...but the EU impose restrictions on emissions so these bikes need to have some kind of emissions/clean air technology if they are to survive and prosper. Photo: New for 2018 KTM TPI Unit KTM has come to the conclusion that Transfer Port Injection (TPI) is the EFI delivery system that has won the war against its Direct Fuel Injection (DFI) rival which was the technology explored earlier by KTM. Why? DFI seemed good and had been proven on the street in a few smaller two-stroke applications and a bunch of four-strokes but when all the support hardware and electronics were installed on an off-road machine, things didn't play as well. Weight, expense and complexity all played into KTM abandoning the DFI technology. But they didn't stop looking for a cleaner burning two-stroke solution. TPI wins that war until something better comes along. TPI wins for now because of its unique new design which according to KTM features "two lateral domes, holding the fuel injectors supplying fuel into the rear transfer ports. Thus the loss of unburnt fuel is reduced for less emissions, a more efficient combustion and reduced fuel consumption. A little tube in the back of the cylinder is connected with an intake pressure sensor, which supplies pressure data to the control unit." KTM continued: "The TPI engine is fitted with a newly developed throttle body made by Dell`Orto. It features a diameter of 39mm. The airflow is regulated by a butterfly connected with a twin-cable throttle cam, which is operated by a new handlebar throttle assembly. A throttle position sensor provides airflow data to the control unit, while a bypass screw allows the regulation of the idle speed. The cold start device also opens a bypass supplying more air. Via an oil intake tube oil supplied from the oil pump is mixed with the incoming air to lubricate crankshaft bearings and cylinder/piston etc." Another great advantage is no more pre-mixing the fuel with oil, there is now an oil tank and metering system controlled by the ECU and this allows a very precise, variable and minimal mixture of oil to be burnt resulting in lower emissions. Photo: KTM 2-Stroke TPI Engine for 2018 Smaller niche companies that make two-stroke off-road machines in the same niche could be expected to follow this trend, possibly by licensing the technology from KTM or creating their own variants. This could include brands like Sherco, Ossa, Beta, TM, Gas Gas and the KTM-owned Husqvarna brand. So more cool bikes in Europe but what does it mean for riders in the USA? It could mean a little or a lot. Could this mean that KTM will be able to certify two-strokes with an emissions label indicating for "on-highway use"? This would be the hurdle to cross...once they've passed emission in places like Californis, the whole pie is up for grabs – here is what the California regulation says now: "Off-highway motorcycles must have an emission label affixed to the vehicle indicating certification by the manufacturer for on-highway use when converting to on-highway or dual registration. Registration guidelines for off-highway motorcycles converting to on-highway or dual registration require verification of the emission label." For KTM two-stroke riders, this technology would make sense to scale to the whole two-stroke lineup from EXC to SX. Imagine a version of the 250 EXC with lights that's legal for the streets here...and you ride it to work like the ultimate hooligan, or just be able to get a street plate to ride to your favorite riding destination. In conclusion, most people thought two-stroke was dead but maybe, just maybe, technology like TPI will make it feasable for KTM to expand their offerings using this technology. The first step it seems would be the ability to pass emissions both in the EU and USA, then maybe apply it to US market machines. If that happens we'll be first in line to try them. __________________________ ThumperTalk wants Your Comments On This Article: Is this a stopgap or a technological step forward? Would you ride a two-stroke street bike? Aren't those Six Day graphics awesome? Tell us what you think below!!
  22. So I recently found out that my power valve is hitting my piston on my dirt bike. The bike won't start right now lol so the piston is fine. Anyways I'm just not sure how to get the power valve out of the block and I was wondering if anyone knows? I have a YZ125 from '82.
  23. I need to know the difference between having a lean gas mix and a lean fuel/air ratio. I know that 100:1 is leaner than 50:1 which is leaner than 32:1, and I have an idea of what leaner fuel/air looks like, or too lean, but what are the signs of the gas mixture being too lean? I am currently switching my gas mixture from 32:1 to 50:1 and I ride a KTM 250sx and I will tune my carb, etc. I made a whole thread on this already and I'm pretty positive the bike will run 50:1 fine since the recommended is 60:1 without having to jet it due to the fact that the guy never jetted the carb for 32:1, it is still jetted for 60:1. I just need to know what the signs of lean gas or fuel/air mixture and the difference. I shouldn't even need to know the sign of lean gas, if there are any... I don't wanna &%$#@! up the bike. I would at least like to know the sign of lean air/fuel ratio so that I can adjust since idk the signs of what I would see if it is too lean or rich.
  24. dirtbagian

    1998 KX250 shifting problems

    Hi, this is my first post on TT! I recently traded my PS4 for a 1998 KX250 with a "broken shift lever" the bike was unable to start due to it being freezing cold and stuck in gear. The reason the shift lever was broke was because the splines were completely worn. So right away, I bought a new shift lever. The old one was a bitch to get off as he had snapped the end of the bolt off to tighten the lever to the shift shaft. I ended up using a pickle fork to pry it off. Bit anyway. After putting on a nice, new shift lever, I was ready to get it running, only to unable to get it into neutral. Which wasn't really an issue. I figured I'd just bump start it. After several attempts, it didn't start, but I got it into neutral. After getting it into neutral, I couldn't get it back into gear. It just clicks about 7 times up or down and nothing happens. Now, I am able to get it in and out of gear, but only by clicking it randomly up and down so many times. I have no idea what gear it's going into, and it has no pattern. I already have the bike mostly tore apart. I plan on splitting the cases, I am just curious if someone can help me diagnose the issue, before I split the cases. Possibly worn shift forks?
  25. Hello, For this summer, I was looking for a project. As a desert/trial, and occasionally single track rider from Southern California, any time of the year works for a build like this. I grew up riding two-stroke and after a couple years on four strokes, I want to return to the enduro king. However, KTM and Husky sell their bikes for quite a high price tag. So, I have decided I want to take an older two stroke motocross bike i.e. cr250, yz250, etc., and make it the ultimate desert bike for significantly less than a new KTM. I am not loyal to one brand, but I have always loved Honda and spent a grand a month ago on all new gear with Honda's name plastered all over it. I know all the mods I want to do the bikes to make them enduro/desert ready: heavy flywheel, 18 inch rear wheel, new exhaust, steering stabilizer, etc. What I need help in is I don't know what bikes I can install a wide ratio transmission in. I know yz250 can take a 400 or 426 transmission, but can any other brand? I would like to see a cr250 with the gears of a 450x rippin through the desert. I like the steel frame for off road use, and I just need some advice on the best bike for this conversion. Thanks
×