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About mavbike

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    anything that has two wheels and or goes fast
  1. mavbike

    Best aftermarket throttle for 150f

    I got one of the billet aluminum ones off e-bay, made for pit bikes. It looks cool, and only cost $40. Used standard cr125 throttle cable and it works great with my 28mm Mikuni. You can also get a standard CR twist throttle from Dennis Kirk or Rocky Mountain for less than $20.
  2. On the 150f pull the flywheel and look at the design. You can take a huge amount of weight off, easily. Wish I would have done a before and after weight on a scale.
  3. mavbike

    175 BBR kit

    I have a bike with the BBR175 kit. Choose a good machinest for the cylinder because there is no room for a mistake with the stock sleeve. It was a huge improvement over stock and I have almost two years on it now. I also put together a 150F for a friend, using Mike Coe's kit. The best way I could describe the difference is; stock bike is a mild kids bike, BBR kit is a sports car, Mike Coe's combo is a full on race bike that is still very reliable. With either kit, you can surprise some people on full size race bikes and the 150 is actualy more fun to ride in the woods than my KX250.
  4. You will also use the 230 cylinder. In the stock frame, I just re-drilled the original 250 upper (rear of head) mounts. Mike's kit is awsome by the way. I don't check the forum very often, but I do check e-mail every few days. Any more questions, shoot me an e-mail mavbike@yahoo.com
  5. mavbike

    Boring costs

    Depends on what it's on. (Most modern bikes are plated cylinders and would have to be sleeved or re-plated.) You also want to use a shop that works with bike motors. A lot of shops (dealing with 4 inch bore car motors) would consider accuracy withing .001 or so to be good. You want more accurate work than that for your bike. Car blocks generaly run $30 a hole. For more precise work, I would expect to pay $40-$60 depending on what it's for and where you are at. If the machinist is doing his job, he will need to charge more for a 2-stroke cylinder because the port edges have to be rounded or beveled, so the rings don't snag. Installing a sleeve on a 2-stroke would cost more because the cylinder has to be bored for the sleeve, sleeve pressed in, bored and/or honed, and then the ports still have to be matched and chamfered.
  6. mavbike

    adding some punch to an 03 150

    A friend and I are both running pre-05 Honda 150F flattrackers. Using Dunlop K180 front and Bridgestone dual-sport rears, on stock rims, stock suspension. I only weigh about 145, so I'm happy with stock fork. If I drive it into the corner, it squats and loads the front good. If I weighed more, I would consider something else though. Haven't had any problems with rebound on the rear, both of us have added pre-load. We're running mostly short tracks, often dry-slick, and/or rough. Some guys are running 17's with soft compound Maxxis and they are a little of an advantage on blue-groove. The 150F is heavier than a lot of other bikes in the class, but the full size frame makes it handle better. There is a LOT of potential in the motor too, depending on the rules. For motor options, shoot coeshow a PM. I don't get on the forum very often, if you need any info though, shoot me a PM.
  7. mavbike

    Taming a KX 65

    Changing the pipe helped for us. I went with the FMF (torque, not the rev) pipe, and it smoothed the hit. Later, I learned that the PC pipe smooths it even more. Before daughter out-grew it, I also tried Eric Gore's porting specs, with stock bore and stroke. That turned out to be the best way to go. I had not wanted to make any engine mods until she learned to control the stock motor better. Turned out that with the Eric Gore porting specs, the bike was both faster and much easier to ride.
  8. How much are you looking to get for the 17" wheel set. (I do have stock wheels, would like 17"s for flattrack.)
  9. mavbike

    where is loganbuilt Racing today?

    Another vote for Mike Coe. Just finished a bike with his parts. We have tried other combinations, but Mike has them all beat, hands down. He does have several options available, just let him know what you want the bike to do, or what the rules are (engine size limits) for the class you ride in:thumbsup:
  10. mavbike

    Yz250 Exhaust Problems

    Anywhere that has hydrolic fittings and lines should have silicone hose and stainless clamps.
  11. mavbike

    83 xl200r mods

    Contact Poweroll
  12. mavbike

    CRF230 to KDX220

    If you are easy trail riding, KDX220 is a good choice. If you are an aggressive rider, I would go for the KDX200. Look for them used in fair shape around $1,000-$1,200. Keep in mind that after about a year, you may be ready to move up again:thumbsup:
  13. mavbike

    Is hone job needed for piston replacement?

    Go to your local book store and get any book (on How to Hot Rod X-brand engine) Go to the cam section that explains cam dynamics and theory. Read the section about over-lap twice. A brief summary is that cams designed for high RPM use sacrifice some low RPM power. The reason is cam overlap. Over lap is when both intake and exhaust valve are open at the same time. The purpose of over-lap is so that the out-going exhaust flow can actualy suck more fresh fuel/air into the engine. The problem with this is that at lower RPM, the parts are moving slower and the air stream is moving slower. At low RPM there is actualy some reversion (where incoming fuel is pushed back into the intake). There can also be some loss in compression due to overlap. I'm not very good at explaining it. But we are not talking about the cam in the family grocery getter here. This is why in high performance engines (yes 4-strokes) there is a noticable power band. To test this, just start your bike and take off slowy in second gear. Roll gently on the throttle, to no more than 1/4 throttle. Now notice as the RPM climb slowly, you will reach a certain RPM where it's like someone flipped a switch and now the motor is making power. What has happened is that you reached the RPM range where the intake length, intake air speed, exhaust speed and flow, along with cam timing, have all started to work together. And yes, Peak cylinder pressure will be higher at this RPM and above, than at a lower RPM. At higher RPM, the out going exhaust has a certain amount of momentum. The ingoing fuel/air is also moving at a higher speed. On these engines, the cam is designed to take advantage of that. This is also why these engines produce more power for their size than an engine in a trail bike (Yamaha TT, Honda XR...ect.) This is why cam manufacturers recomend a given cam be used with a certain compression ratio. Why drag racers need stall converters. Why race engines genereal don't idle in traffic but the family car does. Now after a whole page article,,,,My $.02 is that you Don't over-rev any engine that you want to last. but you should run it "in the power band" to help seat the rings. I don't think I've seen anyone on this sight recomend to "over-rev" the engine. They just said go ahead and break it in the way you plan to ride it.
  14. mavbike

    Cornering - how to?

    Most of us learned on smaller (read less power) bikes. It sounds to me like you may be getting on the gas too hard. Try holding a steady throttle (not reved out, but in the power) and gradualy feed the clutch out. Use the clutch to control the power. I prefer to go into the turn a gear high. By the time I come off the corner (sometimes before I'm all the way out of the corner) I've picked up enough speed to use the higher gear and I can just launch out of the corner. If the rear is coming all the way around, you are getting on the gas too hard. Try rolling on the throttle slower. With practice, you will learn to feal the balance point. It may also help to find an open area where you can just ride in a circle (flat track style) and get a feel for a controled slide. Then you can learn to use the throttle to step the rear out and/or how much to let up in order to bring it back in.
  15. mavbike

    Ready to Buy - What should I pay??

    Paid $989+tax (no shipping or set up) in La for CRF50. Daughter started riding at 5. By 6 she could start the bike herself (when warm). For it's size, it is already a heavy bike, I don't know what the Yamaha weighs, but I wouldn't want anything heavier than the Honda already is. After bending the front forks and having to replace them (twice) I also got a set of the Chrome Molly lowers. Other than that it has been a great bike and we plan to keep it for the next two to grow into also.