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Showing content with the highest reputation since 07/12/2020 in Posts

  1. 38 points
    If you choose to sell the bike be honest on what the problems are. Me I would rebuild the bike and no what I really had in the end. The joker who sold it to you wasn't up front on the problems. Don't choose to be the same.
  2. 25 points
    Or you could try being honest and just take a hit when you go to sell it... or just fix it, it may not be as bad as you think
  3. 24 points
    TT is a man down, a good man down. Micheal, better known as @irme42day, proprietor of the world renowned Swine Lake Resort has past peacefully on to the desert in the sky. He lost a righteous battle with the Brain Sucking Spiders from Mars. He never lost his sense of humour no matter how bad he was feeling. How many of us could make jokes while throwing up. Well he certainly did, and they were good ones. I'd like to quote IRME for y'all... He came in with a splash... First post - thought I would introduce my self - I have been a Yamaha fan from the DT1 - I currently have an 01 RoadStar and 03 WR250F - and I'm here in NW AZ, Golden Valley to be exact which is between the Black Mts and the Cerbat Mts. - also have some goats (13 to expand in june) 1 Llama, 2 Alpacas, 2 potbelly pigs, 1 cat and 2 TOTALY PAYED FOR EX-WIVES. Please barewith me and let me know if EYE step out of line or add too many BAD JOKES. I will post pictures as soon as I figure out how to do it. Thanks Michael G & H Acres Beautiful Golden Valley AZ Garden Spot of the Galaxy Vacation Destination of the Universe ...one of his last posts... Well it happened, I was amazed to the point of B-wilderness-ment-ed-dud! Air! 50 foot of it! And I was ride'n Red the Alien Hunter! The Set Up - I was out and about check'n the price of goat hay and catching up with a friend or two this morning and was on my way back home. I was ride'n the trail on the north side of hwy68 come'n up to the clinic. I was still a bit stressed from the trip to the principals office yesterday, no I didn't get kicked out of school (radiation treatment), and I was un-stressing a bit. Well I was in 5th do'n alot of right hand math when I remember the 3 foot tall berm of dirt, OH SHIT!!!!! No time to stop and regroup so wooo-ha!!!!!!!!!! I must have been 50' in the air, well maybe 5', but that's a whole bunch and a half on red (04 crf230f). I'm in the air things are look'n like they should from my point of view, I'm try'n to make sure my size 12's are on the foot pegs and then I touch the ground AND to my suprise when I did touch earth it was actualy some what controled! Amazed the live'n daylights out of my self and what's even better I have that in my bag of tricks if I need to use it. On one visit to the doctor, when asked about a broken rib he had to explain to her about his run in with Sand Aliens and Silt Suckers. Well she didn't find it as humours as the rest of us did. ...that was him right up to the end. His last ride out to do battle with the Sand Aliens and Silt Suckers. I'd say he kicked their butts that day. I'll miss you my friend and hope to kick some Sand Alien butt for you. RIDE ON always IRME.
  4. 18 points
  5. 17 points
    We found her a leftover 150xcw. Going from a crf150R to the full frame Ktm she looks way more comfortable while riding. She had no idea when she woke up this morning that she was getting a new bike. I ordered a lectron for it Wednesday when we bought it for her and I can’t wait for it to arrive. I’m not even going to bother messing with this carb. lol
  6. 16 points
    Thought I would share a few pictures of my son's YZ250 refresh. We are all quite busy so things seem to move really slow and since we have plenty of bikes to ride there was no urgency to get this one back together. The COVID gave me a little spare time but then parts shipments had me waiting.....ugh!! Here was the bike when my son bought it in 2017 with his money working at Papa Johns while going to high school. Bike looks good in the back of his '87 Toyota 4x4. The bike was halfway decent and ran great so he rode the crap out of it. The old "rode hard and put away wet" 😜 Fast forward a couple of years and it was needing some attention. Swingarm weld had a crack, swingarm and linkage bearings were shot, shock and fork seals leaking, tires shot, pipe beat up, cylinder plating worn thru, etc. You get the idea. Stripped the bike down, re-welded the swingarm weld and then sent it to get powder coated. I have mentioned it before but the color, Illusion Royal, ended up being a little too purple but I really like the color. New Pro-X "A" piston, crank, and bearings/ seals, plus a cylinder re-plate from PowerSeal USA. Lots of other small OEM parts, seals, fasteners etc. to button the engine back up. @218 cut and re-shaped the head for me to 0.046" squish. Head looks awesome and the bike runs phenomenal. Thanks @218 👍 Rebuilt the rear shock and new fork seals/ bushings, etc in the forks with some OEM .43kg/mm springs I picked up from @218 The springs in it were much too stiff for my son and we had previously installed a stock rear spring. Laced up an 18" rear Tusk wheel to run instead of the 19" that was on it. Decided to try the Shinko 525 Hybrid Cheater on the rear and 90/90-21 Shinko MX216 on the front. New Polisport plastic kit and then had a local Texas girl MXG Designs https://www.facebook.com/mxgdesigns/ that had done the graphics on the bike when my son bought it, make a new set of the same graphics. My son has been super busy with college and taking a bunch of summer classes and working so the bike sat done waiting for him to do a heat cycle. Finally did that a few weeks ago and then a couple of weeks ago finished breaking it in and got out this past weekend for a good ride. Bike is working awesome and it rips again 😁 Compression is 220-225 PSI after break in. Sorry for the long post and a few glamour shots before he took it out and started beating it back up. The rocks and terrain we ride in are not real kind to the bikes and it already has a few new scares 🙃 Thanks for checking it out and thank you to all that have answered my questions along the way. The likes of @Motox367 @Smoking 2's @YZDOC @218 and others 👍 P.S. '99 is the year the kid was built, I mean born...haha and figured the bike being a 2000 was also built in '99 so it seemed fitting.
  7. 14 points
    Howdy all, Shortly after purchasing my second DR-Z last winter, I decided I wanted to convert it to fuel injection. Fuel injection has always intrigued me since I helped my father convert a Chevy 383 stroker engine to fuel injection when I was in middle school. I wasn't smart enough to grasp the concepts at the time, but ever since then I have wanted to play around with it more and more. Now after lots of research, some very helpful conversations with roleyrev, and about 7-8 months of slowly acquiring parts I'm about to jump head first into the conversion. If you haven't checked out roleyrev's threads on converting of his bikes, I highly recommend you check it out. I'll link to them below. I will be following roleyrev's 2nd fuel injection recipe that only requires simple modifications to the flywheel. With that some of the key components are: Microsquirt ECU - the brains of the operation Oxygen sensor and controller - I went with the 14point7 Spartan 2 controller and Bosch LSU 4.9 sensor RMZ 450 throttle body - complete with fuel injector, MAP sensor, and TPS sensor Extra DRZ 400 flywheel - so I don't stuff up my original one when modifying it Ignition coil with internal igniter - From a Nissan Silvia S15 SR20DET engine. Only requires +12V power, ground, and a logic level signal from the ECU. Fuel pump with integrated pressure regulator I've removed about 11 wires not needed for this conversion, and installed sealing plugs in the connector housing to keep things water tight. Hmmm, it's looking like I need to vacuum my carpet. Dog hair everywhere... I've done about all I can do from the comfort of my living room, and will begin to tear into the bike tomorrow. I'll keep this thread updated with my progress.
  8. 14 points
    Great Teanaway ride! West Fork, Yellow Hill, Middle Fork, Jolly Creek, de Roux, Elsinore, Johnson Medra, Jungle Creek, Way Creek. I’m tired!
  9. 14 points
    Have our spot looking Northwest waiting for the sun to go down and hopefully get to see C/2020 F3 Neowise! 2 pictures of the comet from last Saturday.
  10. 13 points
    K&N filters suck. The end.
  11. 13 points
    Ever hear of the Penny Trick? Bend the spring to open the coils, stick pennies in the openings causing the spring to be longer. With the KS up, drop the spring onto the pins. Now move the KS to the down position. This will stretch the spring and the pennies will fall out, and you're all done.
  12. 12 points
    As an introduction, I'm the "trail manager" who wrote the Facebook post getting all this attention. Name is Reid Brown. Been riding motorcycles for 30 years, represented the USA at the ISDE two times, and spent my entire life riding, building trails, and now working in the Tillamook State Forest as the Off-Highway Vehicle Specialist. I know it's a little tough to follow along with the original thread because it's a re-post from Facebook, but I feel I should provide some clarifying comments to help put people's mind at ease. Firstly, the talk of closing trails and riding areas isn't coming from me. These discussions happen higher up after other field staff and management have received complaints, or observed issues (perceived or otherwise) first hand out in the forest. At this point, I get called into an office, told what the problem is, and that if I can't come up with a solution, then other, more aggressive measures will need to be taken. The point of my post on my personal Facebook page was to help make people aware of the REAL threats our sport faces on a daily basis around the country from OHV-enemy land managers, environmental groups, and others who would rather dirt bikes not be used on public lands. The second point I want to provide context to are the specific situations I was referring to when I made the post. For those who aren't familiar with the Tillamook State Forest, it's steep. We also get 100+ inches of rainfall per year. This is a recipe for erosion. Part of the uniqueness of our trail system, and something you wont find in nearly any other place in the United States, are downhill-only trails that are steep enough that only the best riders in the country can stay on the bike to ride down (for context, last year we held an ISDE style event that used some of these trails, and of the 24 pro level riders who entered the AA class, only 3 were able to stay on the bike to ride all the way down the hills). The Tillamook Forest has lots of trails like these, and others that are less steep, but still no where near flat enough to climb for even the most advanced A level rider. The problem lies in riders who don't have enough skill to make it to the top of the hill who make a game each week of seeing how far they can make it up before they get stuck. Problem is, as you can imagine, these attempts aren't graceful. They're full throttle, rear wheel spinning, creating deep ruts, and getting stuck on roots until they finally lose momentum and come to a stop. But the damage doesn't stop there. Rather than backing down the hill, they'll try to start mid-slope. Again, rear tire spinning, digging big holes, creating massive root step ups, and loosening the soil beneath them. That's all fine and good until the winter months come and the massive rainstorms we get washes all that loose dirt away. This creates a rut all the way down the trail. That rut then channels water forever, and each year, it gets deeper, and deeper, and deeper until finally the top of the rut is to the top of the seat, and 4-5' wide at the top. So what was once a nice smooth downhill for every rider, and a make-able challenge for the most advanced rider, is now a trail people don't like riding, and also an environmental issue. My Facebook post isn't concerned with people riding trails responsibly and the sport of dirt bike riding that inevitably causes some wear and tear on the trails. It is acutely directed at a growing number of people who watch hard enduro helmet cam videos from Romaniacs, Erzberg, TKO, and other hard enduro races where Graham Jarvis and the other TOP RIDERS IN THE WORLD can ride like a mountain goat and traverse the steepest terrain without barely breaking the tire loose, then try to emulate those same moves over the same type of terrain, but don't have the skill to do it. Lastly, I saw some comparisons to logging and the amount of damage caused by that activity compared to dirt bike riding, even in these most extreme cases that I'm talking about. First off, you're preaching to the choir. I've grown up around logging my entire life (my family owns a timber farm), and I'm well aware of the environmental impacts that activity causes to the land. The best answer I have for you is that on the forest where I work, timber harvesting generated nearly $20 million for Tillamook County last year. That's pretty big money. Most politicians and members of the public see that revenue as a big enough reward that they're willing to sacrifice some level of environmental quality. Right or wrong, dirt bike riding doesn't have that same perceived benefit to local communities. I beat the drum almost every day in my office about the positive economic impacts of outdoor recreation, specifically dirt bike riding, brings to local communities, but it's not a tangible deliverable like seeing a fully loaded log truck being driven out of the woods. Thankfully, organizations like NOHVCC have produced literature that highlights the massive economic benefits of off-highway vehicles, and are working hard to distribute to elected officials around the country. Expanding on this topic, to assume logging is getting a free pass while dirt bikes take all the blame is naive. Right now, the Oregon Department of Forestry is being sued by the Center For Biological Diversity. This suit aims to make logging environmental safeguards so expensive and out of reach that it effectively shuts down timber harvesting on the state forest. They are under a lot of scrutiny right now, and the agency is taking active measures in an attempt to head off that suit. Thankfully for us dirt bike riders, logging has taken the VAST majority of the environmental groups' focus, energy, and resources while OHV use had generally slid under the radar. However, if there comes a time when the environmental groups win that fight, you want to guess where their attention will be drawn to next? You guessed it, OHV use. So in an effort to get our house in order before it gets to that point, my post aimed to help aim awareness to the issue in hopes that we can make some changes before it's too late. Since I hit the send button yesterday, I've received a lot of good feedback and ideas on how we can solve this issue. Signage is important. Our trails have to be adequately signed in order for people to know where they are and if a trail is above their skill level. We have a lot of problems with sign theft, but we're working on some strategies as we speak to help keep our sign inventory at 100%. Next is education. Getting the word out to riders about trail etiquette and how to have fun out there without causing trail damage is the single most important thing we can do. That will come in the form of official literature from land managing agencies like the ODF, to the USFS, and the BLM, and also peer to peer engagement out on the trails. There is no more effective communication and education than one group of riders talking to another group about why it's important to take care of the trails. People are wary of the government, but they trust their fellow rider, so that rider to rider communication is critical. Lastly, we need to raise the level of riders who enjoy recreating on state lands. These trails are for everyone, but in order for everyone to enjoy them, we need to make sure everyone has the skill to ride without tearing things up too much. Sorry for the long post, but after reading through this thread, it was clear I needed to chime in clarify a few things. If you have some ideas or want to chat with me, feel free to shoot me a message on Facebook or Instagram anytime. Also, my work email is reid.a.brown@oregon.gov. Happy Riding! Reid
  13. 12 points
    It doesn’t get any simpler than using the no toil cleaner. It’s wife approved and won’t leave any residue in the kitchen sink. It blows me away that people would willingly play in gasoline to clean a filter.
  14. 12 points
    I thought I should a least post a photo, I sold all previous bikes and this is what we have ended up with😎 I do have review information, but this is all I have time for right now. Oh ya, out of the three, if only one bike the 350 is TOPS !!! so much fun ⭐⭐⭐⭐⭐
  15. 11 points
    What a rush. Been street riding for 33 years , dabbled with dirt 10 or so years ago with the kids but never serious. Recently bought my drz400 and having a blast
  16. 11 points
    You need to use the No Toil cleaner or something similar and NOT petrol etc. Go to their web site to learn how to clean/oil No Toil correctly
  17. 11 points
  18. 11 points
    You want that tig welded. Try and find a shop that works on roll cages for race cars. They will have that better than new.
  19. 11 points
  20. 10 points
    Its says right on the K&N website " a performance upgrade for CFM, based on a reduction of laminar interference' . Flows better, filters less. Like a lot less. N95 - .125 microns Twin Air - 25 micons properly oiled Uni filter - 15 microns properly oiled DT-1 dual layer filter - 10 microns properly oiled K&N filter - 85 mircons properly oiled
  21. 10 points
  22. 10 points
    The arrival of your new-to-you bike! The guy I found through uShip sent a pic of it being loaded up yesterday and now I wait until Friday afternoon for it to get here. It's a 2019 250 RR Race Edition. Looking forward to start learning all I need to know form all of you in making the leap into the Beta world.
  23. 10 points
    Its a KTM thing. They do it to make sure the bike isn't spitting little bits of the engine out of the exhaust.
  24. 10 points
  25. 10 points
    Well fellas- here she is. 2017 yz125. Factory Connection Suspension set up for woods and spung for my weight, FMF fatty, 18inch rear, Vforce reeds, JD jet kit. I got the bash plate and hand guards in a box - going on today. All for about $$1/2 the price I could get an X for OTD. This thread was 99% influence on this buy. I’m putting the 3.2 tank on and racing it as is. Over time I will slowly do The full X conversion. Thanks guys for all the advise - best thread around.
  26. 10 points
    If I'm not mistaken, BOTH halves of the clamp should be on the SAME side of the mounting flange. The flange should not be between the clamp halves; it will keep the clamp from squeezing the brakeline. Something like this: Instead of this:
  27. 9 points
    This probably wont be a popular opinion here but I don't get he "inexperienced riders ripping stuff up" thing. Yes there will be trenchers and idiots out there, but even the pros are spinning their tires and tearing stuff up at times. I am definitely guilty of doing this sometimes, especially when I am dead tired or don't get a good run up to an obstacle. I feel like its just part of the sport. Any trail with too much pressure is going to get damaged. Most of the reason I enjoy dirt biking is because it's challenging. Riding things that are over your comfort or skill level is how you get better. I don't think we should necessarily blame new inexperience riders for their inexperience. It seems like 99% of the issues we face have to do with overcrowded trails. Which is a direct result of a ridiculous amount of regulation that makes following all of the laws practically impossible and makes new ORV trails cost in the hundreds of thousands of dollars a mile. They really need to make their own set of regulations for single track moto trails that allows for more miles of true single track. Let the quads and SxS do doughnuts in a gravel parking lot and tear up the tiny ORV park, and let single track users disappear into the woods and not bother anyone.
  28. 9 points
    The Boy catches the bird in flight and we saw The Old Jeezer blow.
  29. 9 points
    Pretty out here. Now Barbecue bear and beer time.
  30. 9 points
    So I got my 2018 KTM 250XC about a month ago, and the guy I bought it from had never done the proper fixes on the mikuni carb. I did lots of reading on this site and bit the bullet right away with a JD Jetting kit and jet block gasket kit. I live at 8000’ and ride up from there. All I can say is that the last couple rides after I fixed the jet block gasket, needle seat o-ring, and got the proper needle and jets in there, it’s a beast. I think this carb got a bad rap cause people didn’t fix the gaskets before playing with jetting. Anyways, just very psyched on this bike and how fun and nimble it is.
  31. 9 points
    I have never ran one on a bike, but the machine shop I used to work for saw it a lot, especially in dirt track cars. Our head machinist could pick out every engine that came in that had been running K&N with almost 100% accuracy. Even with street engines, we would see carburetors with a definite film of dust inside of them. They flow well, and the trade off is that they don’t filter well. He threatened me if I put one on my Mustang. Lol
  32. 9 points
    Rip .... just another reminder never take a day for granted and just a be an awesomely kind person.
  33. 9 points
    I f no-one else will say it, I'm gonna say it, what the hell were you thinking grinding down such a critical part of the bike! Take it to a GOOD engineer, and have the whole weld you ground down re-welded, and hope it doesn't pull everything too far off line. Then cut the plug off your grinder and get your mom to put it way up outta your reach. Any steering damper kit worth fitting will not need ANY part of the bike ground.
  34. 9 points
  35. 9 points
    you need a muffler pipe expander to fix. maybe run it by a muffler shop
  36. 9 points
  37. 9 points
    You think road riding would be a whole lot safer?? Joe
  38. 9 points
    I am 69 and I have been riding 56 years.
  39. 9 points
    Had another epic weekend, this time with Rev It Up Girls Riding Club near Palisades Resevoir in southern Idaho on the Wyoming border. Half of the gals were on quads or razors and the other half on dirt bikes. We did a ride Saturday up a rocky road with everyone, then two of us split off on singletrack. We rode up to a point with absolutely amazing 360 degree views. We could see one of the peaks in the Tetons. The trail was rocky, but not super technical. As we went down we went through the forest on some twisty fun stuff. We came out at the creek and the trail followed the creek the rest of the way out. We alternated crisscrossing the river about 6 times and following the trail up above on skinny exposed trail overlooking the creek for about 8 miles. This was where we got into trouble. My friend went off the downhill side of the trail three times! We managed to get her bike back up on the trail the first two times .... exhausting work for just the two of us. The third time she went down, she busted her chain. We had 4 miles to go to get back to the road. Thank God she didn't get hurt, but we didn't have a masterlink so couldn't fix it ourselves. It's too long of a story to tell, but the recovery included me riding out to get help, a guy double riding her out, double riding her back in on Sunday, a dunk in the creek and having to take out the plug, a guy getting oil shot in his face as we turned over the bike, a masterlink not fitting the chain, and another trip necessary tomorrow to recover the bike after the shops open. Throughout it all we were still joking and I returned to Montana with newly formed friends.
  40. 9 points
    Yon is still there. It was he who organized a shoveling party with a bunch of other dirt bikers so we could all get through the huge drift on Monarch Crest. Its hundreds of feet long and bypassing it isn't cool. If ya get any grief from MTBers up there (I found them and hikers usually grumpy) ask em if they know who cleared the drift and all the downed trees on all the trails every year....likely they don't know. Answer is, moto guys do it every year. Maybe that'll change their attitudes...a little anyway. Below are my pics of the drift from last week's trip. Amazing how much its shrunk in the 2 weeks!. My second pic is of it on the descent.
  41. 9 points
  42. 9 points
  43. 8 points
    Riding partners didn't show this morning... like usual. So did a great 55mi loop solo, like always.
  44. 8 points
    Also would it be a bad idea to ride it easy for like 20 minutes with the new filter and oil and see what the filter looks like after?
  45. 8 points
    It is easy to hate on the “other”. Unless you are of Native American ancestry, you too are a son or daughter of an immigrant. Over the 4 centuries of European colonization of the Americas there have been many waves of immigration from different cultures. Each new batch got treated poorly and could only work the dirtiest and most dangerous jobs. Two of my grand uncles died working in the mines and forests of the PNW within the first year of their arrival from Sweden. Safety meant the Boss staying in town counting his money. When I came of age our country was involved in a long and bloody conflict with Viet Nam. We were raised to hate these people we had never met. Just 6 weeks ago the son of a Vietnamese immigrant, a cardiologist, saved my life. I am forever grateful and cannot hate the man because of his heritage. Something to consider.
  46. 8 points
    So............I am no expert but this is what I have been told........Dexcool is a GM developed coolant that works great in aluminum engines. It transfers heat well and another difference is that it runs clean in passage ways ( leaves behind no residue ). Glycol coolant ( the green traditional stuff ) leaves a small film in passage ways as it is being used. This works well in cast iron blocks to help prevent corrosion. Using Dexcool in a system that has been running Glycol ( green traditional coolant ) can cause that residue / film to break loose and has the possibility of clogging up the coolant system and causing issues. I know this as a buddy with an LSA ( super charged small block all aluminum chevy motor ) in his jet boat lost a sight glass tube out on the river one day..........we put in glycol and river water to get us back to the dock then learned of the things I mentioned above...........had to do a lengthy purge / clean of the entire coolant system and re-fill with Dexcool. Running Green for a bit in a system that has Dexcool is not the end of the world like what happend with the boat..........but the reverse putting the orange dexcool in a system that has been running Glycol can cause problems by breaking loose the protective film Glycol leaves behind. Just a heads up. If ya run it check your system a bit after running and make sure it isn't causing issues. Dave
  47. 8 points
    I will be needing to fit panniers to my DRZ in a sort of "half assed adventure bike conversion" way, but being a skinflint I thought I'd rather not spend £££ on a proper rack. So expensive! Decided to have a go at making my own... Bear with me, it's a work in progress. Surprising what you can do with a plumber's pipe bender and a few bits of mild steel tubing. If it ends up costing more than £50 I'll be amazed. So far, £12 plus welding / painting. I need to make a bracket to fix it to the bike's mounting points and finalise other aspects of the "design". All done by eye and trial and error. The only problem is that it is pretty soft mild steel tubing, 14mm, and thus won't be all that rigid. Maybe that is best? Drop the bike, bend the rack, pull it straight again? It seems likely I will need to add a transverse brace to go across the bike behind the number plate, and an extension to the right hand side that will support the pannier a bit better. But so far it is surprisingly low profile and once painted might be nearly invisible. If I'm lucky. I am also thinking of adding braces to locate on the pillion footpeg mounts, so as to hold some of the weight. And a heat shield needs to be made as well. All in all, a nice bit of fun so far.
  48. 8 points
    Hey, thanks for the kind words guys! Hey John, thanks for the invite! Wow, what a detailed thread! This actually is how I got to know Mixxer many years ago. I always enjoyed his intensively detailed threads about porting as well as any other aspect of an engine. At the time, I was looking to learn anything I could about engine performance, and John and I had quite a few discussions about various topics, which really opened up my mind to what really matters to the engine. When I first got into porting, it was purely to learn, and did I ever learn. I built my own flow bench, practiced on some junk, and took some of the concepts that I learned from Mixxer and some others, and went to work. I spent a lot of time hogging a head way too big getting the flow up (knowing it was too big) and using clay to change shapes and velocities in certain areas until I could get to the velocity that I wanted without hurting the air flow. I also tried to study fluid dynamics as much as I could comprehend in conjunction with that, looking to understand why things were or were not working for me. I still learn something pretty regularly. Sometimes it's useful, sometimes, not so much. My methods have definitely changed some over the years as I've had luck with this or that. I got a dyno last year, and now I get much better feedback. I've only done a handful of DRZ heads. It's been mostly the LT-Z (and it's clones), and most of the people that have consulted me, were building 462cc-510cc race engines in various configurations from XC to drag racing. Those charts posted above were 490cc drag builds. Definitely outside of what you want to ride down the highway for thousands of miles, but the biggest differences are in the cams and head. That said, the DRZ/LTZ 400 gets a lot of disrespect that it really doesn't deserve. This engine platform is right at home with the 450's if you build it right. The head is technology handed down from the GSXR, and is honestly better stock for stock than some of the 450 heads, but it still responds well to porting, and has enough meat to cut without compromise when needed. This is also the engine that really put a foot in the door for the rise of the 4-stroke quads at nationals. It started with Doug Gust, on a 250r/DRZ hybrid. The engine's downfall is weight, and weak crank cases. I've broken a few sets of cases on my biggest builds. This is what I have handy for pictures, so this is what I'll share for now. That is a head that is meant for a 490cc big bore stroker tuned to hit peak hp around 9500 rpm. It has +1 intake valves, +2 exhaust valves, and it flows way beyond what a stock head can flow, both in and out. It's easy to get caught up in the glory of big numbers, BUT, this head would be a dog on most DRZ's. This head may flow quite a bit, but air velocity is just as important as air flow. A 400 cc engine doesn't create as much demand as a 490cc engine, so this head on a 400 or 434 will have to reach a higher rpm before the air velocity is high enough to aid in cylinder filling. I believe you guys have already covered that topic in this thread. This next part is my take on things, and won't be the most proper explanation, as I'm not a physics guy. So with a 4 valve head, we have a lot of valve area per the cylinder bore compared to other designs. Because of that, we are blessed with the potential for a lot of airflow. To achieve that airflow, the throats and bowls need to be in a certain size relationship with the valves, which ends up with the port being pretty big for the engine size. Early 4 valve stuff always had way too big of a port. All common porting practices at the time kept them that way for quite a few years. The answer to this port velocity problem seems simple. Just make the rest of the port smaller right? Well, fluid dynamics complicate that a bit. First of all, the size that will have the ideal velocity is a little tricky to figure out, and that's what determines your minimum cross sectional area (MCSA) and If you expand out to the bowls too abruptly, you will get separation and lose flow. On the inlet side, you need to let air in from a carburetor, which has a little restriction built in, so we run a carb that's borderline too big, meaning that our inlet is too big too. The shape of the port needs to resemble a venturi. Well, venturis are complicated also. You have a converging angle coming in, and a diverging angle coming out and you need to find a balance between the two that doesn't accelerate the intake charge too rapidly to keep the fuel suspended, and you can't expand too fast after the MCSA or you will get separation and turbulence in the port. Finding that balance is where the fluid dynamics research comes in. I know I haven't explained it the best, but my head hurts, and I have to leave for now. I once found some great videos on fluid dynamics that relate to this. I'll try to find them.
  49. 8 points
    Lot's of babbling and misinformation above...Beta's aren't a boutique brand, parts are easy to get. They handle well, particularly the '20's. Great turning bikes that really work well off-road. They aren't down in power compared to the equivalent Ktm. My '20 in particular, has much better over-rev in comparison to the older bikes. My '15 300 didn't feel any slower than similar Ktm's either. The suspension is a matter of preference. There are some slower Youtube reviewers that claim that Kyb's are too stiff. In reality, they come on a bike called the 'race edition' and if you ride aggressively, they work really well. They are probably my favorite stock forks I've had.
  50. 8 points
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