Jump to content

Search the Community

Showing results for tags 'tuning'.



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
  • LCV Trail Riders's Local Information
  • LCV Trail Riders's Planning
  • KJRRC - Krannie's Just Right Ride Club's Club Forum
  • Long Island Moto X-Change's Trail Riding
  • Long Island Moto X-Change's Enduro Racing
  • Long Island Moto X-Change's Motocross Racing
  • Long Island Moto X-Change's Harescramble Racing
  • Long Island Moto X-Change's Dual Sport
  • So Cal Flattrack's Club Forum
  • Sonoma County,Mendocino County,Lake County & Napa County 707 Trail riders's tell us about your self and about your bike, what type of ridding you like to do,
  • Sonoma County,Mendocino County,Lake County & Napa County 707 Trail riders's 707 Trail Riders Group ride 11-25-18 at Knoxville Northern Trail head AKA UPPER CAMP area meet up about 10 am
  • Couple Riders of Stanislaus'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

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
  • LCV Trail Riders's Ride Calendar
  • KJRRC - Krannie's Just Right Ride Club's Club Calendar
  • So Cal Flattrack's Club Calendar
  • So Cal Flattrack's Events
  • Sonoma County,Mendocino County,Lake County & Napa County 707 Trail riders's Club Calendar
  • Couple Riders of Stanislaus's Club Calendar
  • Couple Riders of Stanislaus's Club Photos
  • 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

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 24 results

  1. Hello all, new to the forums! I have a few questions reguarding an 09 kx450f i recently picked up. The previous owner had done a bunch of work to it, actually heres the list Tusk hand guards Sunline unbreakable levers. Clutch & brake Tag Stewart bend fat bars 1-1/8 Tag bar mounts Tag grips 2012 kx 450 triple clamp adjustable Sunline shifter Sunline wide & arched foot pegs Tusk chain guide Tusk swing arm chain guide Tusk rear brake lever Yosimura oil plug Works holeshot device Sunline anodized rim locks FMF power bomb header K & N air filter BIG GUN Eco system silencer Rekluse clutch w/tusk clutch Primary drive steel sprockets w/gold x-ring chain Tusk axle blocks Acerbis X-seat Kayaba lowering link Tusk front fork bleeders 2013 kx front fender Tusk 1.6 radiator cap Brand new front & rear brakes Mosimoto green hose kit Yosimura pim fi controller Ultra heavy duty tubes Maxxis desert it tires Tusk case saver Green spoke skins Boyesen clutch cover Pro filter oil filter cover Tusk front brake rotor Tusk rear brake rotor This thing is an animal! I love it! He currently has a tune to run 110 race gas and im not interested in racing this untill im completely comfortable with it. That being said, with the yoshimura pim2 how would i change the tune to run on pump gas so i dont spend a small countrys income on fuel? Thanks again for any input!
  2. I have a 1995 yz125 2t and the thing runs pretty good, well at least it seems to have no issues but it does not need the choke to start the bike. I changed the main, idle, and needle jets all to factory specs for my temperature and altitude. The bike will start first kick when 100% cold and will start first kick when warm but it just does not need the choke. So I'm wondering if I'm hindering my bikes performance in a way because it does not need the choke. Suggestions?
  3. Anyone running a Vortex ignition on a YZ250F 2014-2018, or 450 for that matter? What advantages does it have over tuning FI/IG with the GYTR power tuner, and are there maps readily available for stock or mod and race fuel? I've messed around with the GYTR tuner on one of my bikes- 2017 YZ250F with bolt ons and VP racing fuel, but there is a lack of maps to run and I've heard there is more power to be had with the Vortex Ignition. I'm aware there are other less costly avenues to add horsepower.
  4. I bought a 1997 YZ250 a little while ago knowing it needed some work. Clutch was bad but it ran fine. It got into the powerband great and it idled fine. I replaced the clutch plates and basket and I rode it a few times and then it just bogged out and fouled a plug. I went through the carb multiple times, rejetted it, tuned it, and still no fire. Has great compression and spark, but it is getting too much fuel. I flipped the reeds over as a test and it fired right up. I put in new reeds and now it wont start again. Same issues. I am thinking reeds yet but was not too sure. Any suggestions or help would be greatly appreciated. Thanks, Kyle.
  5. i got a mint cr500 that was set up for low end.. i feel pretty slow on the bike because the front tire never really touches the ground. I run a lot faster times on my 250 4stroke anyways thats not the point. The top end feels pretty flat on the cr500 and was thinking of changing the carb and the pipe. It had a pj carb on it now with a fmf gnarly on it btw its a 96 motor. I have a cr500 parts bike i got for $100 as part of a deal and it had a 38 or 39mm airstriker carb and a brand new pro circuit pipe. If i changed the carb over and the pipe what adjustments will need to be made to the carb. Does anyone think it could keep that front tire a little more on the ground and give me more rev out on the top end. I do not wanna change the sprockets. I def want to have more of a top end was planning on doing a super moto but i might just make the parts bike the super and have 1 dirt 1 street any help would b appreciated
  6. Benjamin.ku

    Yamaha xt 250 Supertrapp Discs

    Hey there I'm from France. I installed a Supertrapp 4” exhaust on my Xt 250 1980. Now I’m trying to find the right among of discs but its quiet difficult. Carbs, main jet, settings are original. I tried from 4-8 discs, it run quiet well but not as good as the stock exhaust. It feels like the stock exhaust has better acceleration and low end. Should I try with more discs? If I’m using more discs how much bigger should the main jet be? ( I think it’s 165 stock ) Thanks for your help Lionel
  7. I'm trying to tune the mixture. I removed the welch plug. I turned the mixture screw out (left) about 1 quarter of a full 360. Situation: Bike starts up way faster now, bike runs good and a lot less decal pop, sounds fine. Only problem is now I will warm up the bike with choke, I close the choke and then do small revs at 3k rpm and it will sputter/hesitate. The problem goes away after I just drive around the block for three blocks or so. Assumptions: installed the float plastic thing and needle wrong? can it be the carb rubber boots leaking? ..pretty sure I checked them good. throttle cable no installed correct? ...it looks theres no play when I pull the throttle (almost instant cable tension) Bike details: KLX 250s all stock factory, new oil filter, cam timing marks lined up, manual CCT, oldish air filter
  8. Hello, My name is Dan. I recently bought a 2001 yz125. I have been having jetting issues that i cant seem to fix. I have rebuilt the carb, tried a JD Jetting kit, and new reeds and nothing is working. I am looking for someone in the Central Jersey area who is willing to help me work on my bike and get it running strong. I have all tools necessary. I would pay $25 dollars per hour. This is completely legitimate. Feel free to text me at 908-448-9639. Located in Central New Jersey
  9. skiwithnoskis

    Carb tuning HELP!!!!

    Back story. Just finished complete rebuild new head, valves, crank, bearings seals, and muffler bearing. I've checked, double checked ,and checked again timing. Exhaust valves are .011 and the intake are. .007 (I know a frog hair loose). It will fire right up when towed and it will stay running. So I am assuming ( I know) the carb probably needs some help. Can you guys point me in the right direction as I am baffled by carburetor theory and function. By the way happy Mother's Day to any that are reading brad
  10. Hey guys I need some input on tuning my suspension for freeride/enduro. -------------------------------------------------------------------------------------------------- Here's my stats for reference: Bike: 2017 KTM 500 EXC Riding weight: 170lb Tire pressure: 10psi Sag: 115mm Current Settings: -Fork: compression stock, rebound -2 clicks slower -Shock: Low speed stock, High speed stock, Rebound -2 clicks slower -------------------------------------------------------------------------------------------------- Current Issue: The other day I did a hillclimb 3rd gear dicked a couple times. When my front wheel hit the rock outcroppings the front end really spanked into the rocks, I felt really hard hits in the bars, like the rim hit the rock. Same feeling when I hit potholes rippin 4th hard, the front end really bangs hard and the bike gets hucka bucka. Anyone with some experience have any suggestions what needs to be done here?
  11. wild-billy

    Exhaust soot

    My 2011 TE-250 has a sooty exhaust (black powder) both at the pipe sleeve prior to the silencer and at the discharge. Does this indicate to rich, timing off? Starts and runs great, some low end bog...
  12. Hello all, Some time ago i made double exhaust in my DRZ 400 SM, it was modifited since year and now its completly ready. I record a movie with some explanation "how its made" and soundcheck after all - english version is in description ( i will do my best to repair it becouse my english is not too good ) . It cost me a lot of work and time to make it good and now i want to show it to the world xD So, what you think about it ?
  13. I am playing around with my suspension finding a solid set up for fast desert and logging road style riding. I have always wondered what makes a suspension tech so great. I have ridden bikes with pro tech'd suspension and it makes a world of difference. I want to know what they do that we as weekend warriors cannot in our own garage.
  14. PitRipper

    Mikuni carburetor tuning guide

    I think this could be a useful sticky. http://www.mikuni.com/pdf/vmmanual.pdf This is a free tuning and carburetor knowledge manual that is very informative and easy to read. Most of all carb problems are addressed in this PDF file. Since a large portion of our forum topics are carburetor problem related, I think this could be very useful and lead more people to be able to help others, effectively making more question answerers as opposed to question askers, which is good for everyone. Just an idea...
  15. I put an aftermarket FMF factory 4.1 exhaust on my bike love the sound and the pipe however on the decel get some popping, was advised to get the jd jetting kit. I installed the kit very easy plug and play however I need some help with the modes and how to tune can't find any videos online anyone with experience with this kit your input is greatly appreciated. Thanks
  16. roleyrev

    Fuel Injected DRZ

    Hi all, After some consideration about DRZ400SM carb choices (Pumper vs CV) I decided to that I would like to give fuel injection a go. This has been a project that I have had in mind for a few years thinking that I would be a great way to get the best out of a bike. At the time of inception I didn’t know that it was going to be a DRZ400SM. I did know that I was going to uses a Microsquirt to do the injecting. I have done a couple or car FI conversions – a 77 V12 Daimler Double SIX and a Mitsubishi RVR (4AG63) – Both started out life as FI vehicles making them easy to convert to aftermarket – tuneable ECU’s. Both running MegaSquirt 2’s with outstanding results. Moving along – when I brought the bike I was a little underwhelmed with the performance off the showroom floor. I got a Yoshimura rs2 for a good price 2nd hand – cleaned it up and rejected the SM’s standard CV carb did the 3x3 mod and that was much better. Then I had a ride on an E – pumper carb -super snappy, so I started to have a look around for one to put on the bike. I was a bit overwhelmed with the price of said carbs new. I got to thinking about fuel injection and how good that would be, as well as fully programable ignition and the room for mechanical mods further down the track. It was an idea I couldn’t leave alone. So here we are – the bike is just back together and operational. It is still in need of some tuning but preliminary results are it is a success. It is much more “Stompy” than the CV carb’ed version and at the onset looks to be more fuel efficient. The throttle body come from an injected LTZ400 which is a very close relation in terms of motor to the DRZ. It is made by Keihin and 38mm. It has the same external diameter of the Keihin MX39 carb that it commonly fitted so the boot you buy for that carb conversion also works for the Throttle Body conversion. I made a bell mouth adaptor for the air box side to fit the standard SM air box boot. The throttle body has an integrated MAP and TPS sensors now used by the Microsquirt. Careful bench testing of the sensors enabled a calibration table to be made for each to enable the Microsquirt to read the sensors accurately. I’m not sure of the purpose but the LTZ had an axillary air plunger on a cable system (hot start / cold start?). I found Keihin spares had a choke plunger that fitted with no cable involved – so I now have an auxiliary air knob for fast idle situations. I also brought the LTZ flywheel with the view of fitting it to gain the required triggering for the ECU. The flywheel is subtlety different in too many ways to fit the DRZ, for one it is 1.5mm larger in diameter and has about 200grams more mass and the stator for the injected LTZ is also of bigger diameter. I liked the 18-1 tooth triggering arrangement though. So I had the existing flywheel modified, taken down by a couple of mm - removing the standard trigger teeth for the CDI unit and a ring made with the 18 – 1 triggers machined into it, and had that slipped on. I had considered the LTZ fuel system as they have an out of tank pump, but after a good look I decided that there was no room for the swirl tank / pump combo. Other considerations were the extra plumbing required for fuel, low pressure fuel, return fuel and high pressure fuel also the pressure regulator and fittings. I had a good hunt around and found a fuel pump with integrated regulator, this also helps keep the plumbing to a minimum as the fuel connections to the regulator are integrated in the pump. I designed printed some mounts to hang it in the space where the carb float bowel would normally be. There were a few minor hiccups along the way – the high pressure fuel barb aimed directly at the frame spar, this was rotated on its O-ring with the use of a bracket to become parallel to the frame. The cover for the throttle body interfered with the oil breather box. I split the oil box in two and designed and printed a new side with a scallop in to clear the throttle cover. I’m a firm believer in the right tools for the job too so I have fitted an innovate wideband O2 meter, while the end game is not to use the O2 for day to day use (i.e. have the bike tuned well) I need such a device to complete the initial tuning. The control box for the O2 sits in on the frame just forward of the tank rubber, in the place that the CDI coil used to sit, the O2 Probe can be seen on the side of the exhaust. The control box is connected directly to the ECU to provide feedback on mixture richness ETC. The CDI coil has been replaced with a Nissan S15 Coil on cap item. This has an integrated igniter that can be triggered directly from the Microsquirt. It needed a small amount of modification to fit, I had to cut about 10mm from the bottom of the plug cap so the conductor would reach the bikes spark plug. I also printed a spacer / dust cap for the top to make the system as waterproof as possible. The electrical system I tried to keep simple. One extra relay for fuel pump, injector and spark power and two fuses, one for fuel pump / injector and one for spark. The relay is mounted between the shock body and the back of the air box, the fuses are above it. I selected waterproof items where possible as I do have an 18/21inch wheel combo for off road / adventure riding. Cheers John
  17. So, I bought this bike a month ago. It ran in the guys garage but I never rode it, just paid the man and loaded it up and brougth it home. So it runs, but is very hard to start...won't idle, backfires, spits, I have to keep working the throttle to keep it running. The first time I started it the throttle cable/throttle tube, etc...wouldn't even return so I parked it for some clean and lube...I wasn't wearing a helmet...it was 11:00 at night, snowing, I'd never ridded a BRP before...didn't want to have to pry myself off a parked car down the street so anyway here I am today. I've had time now to clean and oil the air filter, new spark plug, drained the tank, and carburator bowl, fresh fuel, new throttle tube, lubed cables, new grips, (new AVS levers), and so I'm back to where I started...Yesterday, with a ton of effort, I finally fired it back up. I almost quit trying to kick it; but I'd then try one more time. I finally tried a shot of starting fluid, but only caused a fire in the airbox but it quickly was put out...I had the Uni Filter (freshly cleaned) out with the choke on half; and it finally came to life. I had to keep working the throtte...I quickly flipped the choke wide open and it ran better and I thought it was going to run fine...I put it in gear and ran it down the street...hoping it would just run fine...One Block, Two Blocks, Three Blocks...turn around...same thing on return...I wheelied a bit in second gear...I know I was smiling...anticipating a nicley running bike that I now could continue to dump tons of money into. But then I got back to the house and I was still pumping the throttle, and then I thought well lets see how she idles...and flatline...................... I'm thinking rebuild the carb...AGAIN...the one reciept the guy gave me was fron his local power sport store for a carb rebuild and tune for $408...labor/parts etc...I am assuming it ran good then...??? What'd ya'll do?
  18. Hey all! I have a 2011 Gio X31 250cc that is losing compression gradually. It had amazing compression when it was new...but now it's becoming a tiresome task to kick-start when my electric start is down. It's burning a small amount of oil, but I don't even have to top it up between oil changes (~10 hrs. per change). I'm thinking it just needs a valve adjustment to bring the compression back up. I'm surprised how good this engine has been. I ride it hard and it keeps up with bikes 2-3x the hp and refuses to die! I don't know how to adjust the valves on a 4-stroke, let alone a Chinese one. If any of you know how to adjust the valves on a Gio X31 250cc I would appreciate the help! Do I need to pull the engine for this? Thanks
  19. What is this Red Top Jet Needle without any other markings on it? When I bought my 2012 YZ250 a few months back it wasn’t long before I took the carb apart and noticed it had a JN with no markings on it. The only thing I could ID on it was that the top/Head was painted red. I tried replacing the JN with others (EW, EJ, CW) for ID reasons but nothing seem to work as good as the Red Top JN. It just seems to be the magic JN! Need to know for future reference and recommend it to anyone!!!
  20. Finally getting this 05 KX250F up and running. It's kicking over (most times) fairly quickly. However, when it gets going it's Idling at what seems to me to be high or will die out if I start adjusting the idle adjustment. I've done the recommended jetting from 40 to 42. My question is, I know where to start the air/fuel screw but when trying to find to sweet spot for idle where do you start with the idle screw and how do you work back and forth to find a nice idle? TIA
  21. I have a 2008 YZ450F with a stock header pipe and Pro Circuit T-4 Slip-On Exhaust. I'm 99% sure the slip on is shot because its loud as hell and when I take it off and shake it it rattles. I would repack it but the screws are all stripped ect. Anyways I've gone over the carb multiple times and I've got it running pretty well. The only issue I have with the bike is that it sputters and pops around 1/2 throttle when I hold it there. When I give it full throttle from any RPM it runs great or when I give it about 3/4 throttle it spins up like a top to redline. Initially the popping and sputtering was way worse I made the situation better by moving the pilot jet up in a few sizes from a 45 (stock) to a 62. The issue has gotten way better since then but I'm not super sure what to do from here. Should I keep moving my pilot jet up in size because that's a pretty large jump right? I tried changing my needle clip position but that didn't help much if anything it just made starting it worse and little to no impact on the ride. Any input on this would be helpful. I don't want to buy other slip on. Also as for the rest of the carb I'm very sure everything else in it is what it needs to be at. I've replaced all the gaskets and O-rings cleaned all the jets, valve holes ect. fixed the accelerator pump timing. I just thinks its strange that my pilot jet size is going so far from the stock 45, but all symptoms point to the bike running lean.
  22. I am stumped on what to do and looking for guidance. i have a 2018 Drz400sm. put it through the first service then went through with the 3x3 mod with JD jet and full FMF pipes. followed everything the jet kit said and tuned for sea level with blue needle in 3rd position 160 main and 25 pilot and fuel screw 2 1/2 turns out. Took the bike for a spin and it ran like crap. Idle is fine . But the bike just has no power anywhere and feels like a 50cc machine. Top speed was 95kmph on the road. So following this a took the carb apart and tried more jetting combos thinking it was just running lean. No success. Still slow with no response. I put the bike back to complete stock jets and exhaust and taped over the 3x3 hole to replicate the snorkel back in. And even then it ran the exact same no power and weak response. So currently the bike is sitting back at full fmf exhaust , blue needle in 4th position, 160 main 25 pilot and 2 1/2 turns out with 3x3 airbox standard air filter. All to which it runs slow like the throttle doesn't work but every now and then it surges in power for a second and dies away. i looked into the TPS ( throttle control sensor) and it is running the correct resistance of 5 at closed throttle and 3.9 open. What could be the problem? help would be much appreciated.
  23. Paul Olesen

    Three Easy Ways to Improve Engine Cooling

    This month I want to discuss three easy ways to improve engine cooling for your dirt bike or ATV and explain why they are effective. As improvements are made to an engine that increase its power, the amount of heat the engine will create will also increase. Effectively removing heat from the engine and cooling it is very important as the power output of the engine goes up. The cooler an engine runs, the more power it can produce. There are three ways that the aftermarket attempts to improve the cooling system of a particular engine. 1. Increase flow through the cooling system. 2. Increase the cooling capacity of the radiators. 3. Increase the pressure of the cooling system. Let's dive in. 1. Increase flow through the cooling system The flow through the cooling system can be increased by installing a water pump impeller designed to increase the flow rate of the coolant. The reason increasing the flow rate of coolant works is because the rate of heat transfer from the engine to the cooling system is directly proportional to the mass flow rate of coolant. This is thermodynamics jargon, but there are two key parts to consider. First, how much coolant is flowing, and second, at what speed the coolant is flowing. The more coolant that flows and the faster it flows will reduce the temperature difference between the point where the coolant enters into the engine and where it exits. This next part is not quite as intuitive. When the temperature difference between the inlet and outlet is reduced, the average coolant temperature is lowered. When the average coolant temperature is lowered the engine will run cooler. This is why fitting a water pump, which increases the flow of coolant through the engine, improves cooling. 2. Increase the cooling capacity of the radiators Radiators consist of a series of tubes and fins which run from the top to the bottom of the radiator. These are often referred to as the radiator’s cores. As coolant enters the radiator it moves through the series of tubes and heat is transferred from the coolant to the fins. Air passes over the fins and heat is transferred from the fins to the air. This transfer of heat from coolant to air is how radiators reduce the temperature of the coolant. Coolant temperatures can be reduced by upgrading radiators in three ways, by increasing the frontal area of the radiators, by making the radiators thicker, or by using materials with better heat transfer properties for the cores. For all practical purposes, increasing the radiators’ frontal area and improving the core materials is rarely a viable option for dirt bike applications. This is because there is little room for the radiators to begin with and they are susceptible to damage, making the use of expensive core materials a risky affair. Unfortunately, both of these options are better improvements to make before resorting to increasing the thickness of the radiators. Increasing the thickness of a radiator is not as efficient of an improvement as increasing the frontal area of the radiator. In order for thicker radiators to cool more effectively than their stock counterparts, airflow past the radiators is key. When the thickness of a radiator is increased, air must travel a greater distance through the radiator before exiting. The speed the air is traveling plays a big role in determining how quickly the air heats up as it moves through the radiator. If the air is not traveling fast enough through the radiator, the air temperature will rise and equal the coolant temperature before reaching the end of the radiator. Once this happens, heat transfer stops and whatever portion of the radiator remains will not help with cooling. In order for a thicker radiator to be effective, air must flow quickly enough through it so that the exiting air temperature is at, or better yet, below the coolant temperature. In conclusion, benefits from adding thicker radiators will be more prominent in applications where speeds are relatively high. Whereas in applications where the bike is hardly moving, improved cooling may not be noticeable. 3. Increase the pressure of the cooling system The last alteration to the cooling system that can be made is to install a high pressure radiator cap. As coolant temperature increases, pressure increases inside the cooling system. The radiator cap is designed to be the pressure release point in the cooling system in the event that too much pressure builds up. This can occur as a result of overheating or a blown head gasket for example. By designing the radiator cap to be the weak link in the system, other parts of the system, such as seals, don’t end up getting damaged from being over pressurized. The radiator cap features a plug and spring on its underside. The spring is designed to compress once a certain pressure is reached, at which point the plug will move upwards and uncover a pressure release hole where excess pressure will be vented. The coolant’s boiling point and ability to conduct heat are necessary factors in understanding why a high pressure radiator cap can help improve engine cooling. Water alone boils at 212°F (100°C) while a 50/50 mix of water and antifreeze boils at 223°F (106.1C). Radiator cap pressure designations are usually advertised in bar, with most stock radiator caps designed to withstand pressures up to 1.1 bar (16psi). The more pressure a fluid is under, the more difficult it becomes for the fluid to vaporize, and the higher its boiling point becomes. When water is under 1.1 bar of pressure, the temperature water will boil at is 260°F (127°C) while a 50/50 antifreeze mix will boil at 271°F (133°C). By installing a radiator cap designed to withstand higher pressures, an additional increase in the coolant’s boiling point will be seen. High pressure caps are usually designed to withstand 1.3 bar (19psi) of pressure. This 0.2 bar (3psi) increase in pressure over the stock system will increase the boiling point of water or antifreeze by 8.7°F (4.83°C). This will then bring the boiling point of pure water or a 50/50 antifreeze mix to approximately 269°F (132°C) and 280°F (138°C) respectively. While this small temperature increase alone won’t do a lot for your engine, coupling a high pressure cap and using coolants with better heat transfer properties can do wonders. Antifreeze (ethylene glycol) alone is not an inherently good conductor of heat. In fact, pure antifreeze conducts heat about half as well as water, while a 50/50 mix of antifreeze and water conducts heat approximately three quarters as efficiently as pure water. This means a cooling system using a 50/50 mix of antifreeze would have to flow faster than a cooling system filled with pure distilled water in order to achieve the same cooling efficiency. What this means for you is significant cooling gains can be made by using distilled water and an additive called “Water Wetter” in place of an antifreeze-water mix. Water Wetter is an additive that improves water’s “wetting” abilities (another whole subject), adds corrosion resistance, and slightly increases the boiling point of water. A high pressure radiator cap in conjunction with distilled water and Water Wetter as the coolant is by far the best route to go for high performance applications where freezing is not an issue. For applications which must still be resistant to freezing, the antifreeze-water ratio can be altered in favor of mixtures incorporating more water than antifreeze so that the cooling efficiency of the mixture is improved. Just bear in mind the freezing point of the mixture as it is thinned with water will be reduced, so you will need to pay close attention to the environment you are operating in so that the coolant is never susceptible to freezing. A frozen coolant system can ruin an engine and makes for a very bad day! I hope you enjoyed this post on three easy ways to improve your engine’s cooling. One more thing before I wrap up! April is Autism Awareness month, and here at DIY Moto Fix we couldn't be more excited to announce that we will be donating 15% of all profits made in April to AutismMX. If you haven't heard of AutismMX, this amazing non-profit brings Autism awareness to the motorcross community. Founder, Matthew Dalton, created this non-profit after finding that motorcross was an amazing way to connect with his autistic son. At DIY Moto Fix this non-profit also touches a chord with us. Our filmmaker and photographer, Kelsey Jorissen, loved dirt biking with her autistic brother throughout their childhood. The Autism MX Project focuses on four areas: Autism MX Day Camps are days for ASD kids and families to have the chance to ride AMX’s little dirt bikes and quads and enjoy the sport of motocross. Team Autism MX Sponsoring amateur MX racers, riders as well as sponsoring AMA pro racers. Through doing so, they are getting out the word on Autism Awareness to millions. AMX Puzzle Piece Apparel from shirts, graphics, goggles, to help stand out and support Autism Awareness. AMX Ride Days for Autism Awareness AMX celebrates Autism Awareness and is a fundraiser for The Autism MX Project. So for the entire month of April - if you buy a book, a video, even a poster - 15% of that purchase will go towards AutismMX and their amazing cause. Thanks for reading and have a great rest of your week!
  24. Hey Everyone, I have just recently gotten back into riding, and I have been trying to get my sag set on my bike. I have a 2005 RMZ 450. The manual calls for 104mm of rider sag. I am a bigger guy, 6ft and 320lbs. I know the spring that is currently on the bike is stiffer than stock, but I am not sure what the rating is on it. I currently have the bike set at 120mm rider sag, and 10mm static sag. I know this means that my spring is too soft, and I need to go to a heavier spring. However, I probably wont be able to switch out the spring for awhile. So for now, what is the best sag setting with my current spring? Should I try to get rider sag closer to 104mm, or should I worry more about raising my static sag? I do mostly trail riding and I am a novice. Will messing around with adjustments on the rear shock help?
×