The following questions have been lingering in my head eversince I got my 125 which I have yet to race. I have been looking for some kind of FAQ for 125cc gp racing on the web, but there really isn't a good FAQ around. I think someone should put one together. Anyhows, here goes the questions I have: 1. What are A-kit/B-kits? Are they for engine/bodywork/both? 2. Howcome everyone else has ram-air and I don't? (maybe this is related to question 1?) 3. What upgrades are most effective assuming that I have a limited budget? 4. As far as riding 2-strokes go, how is it different from 4-strokes? From what I saw on TV, the WGP guys feather their clutch until they start accelerating where as superbike guys don't use the clutch once they're done downshifting. Perhaps this is due to way 2-stokes deliver the power? Thanks!
1. A/B kits correpsond to the factory race kits and affect both engine and bodywork as the kits have ram air setups requiring special bodywork with air intakes. 2. While just starting out stay way from RAM air. It adds complexity you don't need. Keep your bike stock and.or a knwn quantity. 3. Suspension if you're heavier than the Japanese rider who had your bike before you. A decent maintenance plan, replace everything at the recommended intervals or you will wind up on your head(my crankshaft bearings were about to fail. VHM heads are a worthwhile expediture though. Do you have decent crash spares? Do you have all the jets you need. Decent tires? These bikes are competitve right out of the crate, don't waste your money until you are wringing a good amount of performance and are getting beat by faster 125s in the hands of equal riders. 4. 2 strokes have no engine breaking so there is no need to downshift through the gears but rather downshift to the gear you need next. Most 2 strokes have electronic shifters eliminating the need for clutching while shifting. I don't use one(I have one) yet. Starting involves massive clutch slippage, once oyur going the clutch becomes irrelevant. 125 power delivery is pretty steep but still weak(40HP at best) Riding style, aero-dynamics(stay tucked), good braking techniques and a wide open throttle will help you the most. When 4 strokes are braking you can pass them wide open. learn how to draft. Feel free to contact me with other questions, this is my 2nd year on a 125. check out www.two-stroke.com search for a topic you are curious on and you will find info. [email protected]
Hey Fresh, I'm in the exact same boat you are! I have found lots of good info at www.fatbaq.com. But, its only good if you have a Honda. Good luck!
Thanks for the info. I have more questions now if you don't mind. What's the difference between a-kit/b-kit? Which is better? Also, you said that you click into the gear to need next. What if you clicked in and ur engines speed exceeds 14k? I can't imagine that being good. In a similar note, i noticed that there's no redline on my 125. Is there a rev limiter like the 4 strokes that'll stop the engine rpm @ 14k or like one of my friends suggested, is my engine going to "blow up?"
Fresh, A-Kit is so complicated I could write a book and it looks like I am. A-Kit parts are a package that work as a package. You need to have the entire kit to get the gains the kit was designed for. Pipe, silencer, cylinder, cases, reed cage, programable CDI, power valve shut off harnesses and tons more. It also takes a piston with a differant ring opening location so that they can change the ports to a more aggressive location. It usually requires the cylinder to come off a few times a day and the rings/piston to be dressed due to ring stick.It is VERY hard to tune except for a few with alot of experiance. Maint. is also extream. Price of a full on A-Kit is in the $5-6,000 range just for the parts. It is not a Honda kit. They are only for a few that have direct factory support that get the true kits from Honda. Honda does release information to a few companies like JHA and Harc Pro and they make knock off kits. They are never as aggressive and trick as the Honda kits so that there boys always have the edge. As performance increases at the factory they trickle changes to the knockoffs slowly. A full on Honda spec 125 will make in the 47-48 HP range when running and tuned correctly. A B-kit is available from JHA and Harc Pro etc. It is a more aggressive set of parts to push the stock set up more. Anyone can buy one however they do only make al limited supply. Again it also can be hard to tune. You need to be able to really be able to tune it also. It uses the standard piston and when tuned correctly it will not want to seize but it has to be running and jetted correctly. I would estimate a good B-Kit engine to run in the 43-45 range. Cost about $3500. Bottom line is that you should not look at these kits until you have alot of experiance and have riden past the capabilities of the stock unit that is very good. If you get a cylinder or a pipe that is fine but you need to also get to a dyno or really be in touch with how the bike feels to get it to run right. Sometimes you can put on a part and tune it as you would stock and loose power. My opinion is that unless you have the experiance, you cannot tune these kits to have nice linear power and end up being a handfull to ride with a hard hot getting onto the power band. Stock runs so smooth and lets you really learn how to ride these razor sharp machines. Mine is stock 100% and I put gas in it and just have fun with no problems. Stockers usually have about 39-40HP and another 2 isnt going to have me dramatic drop in lap times. I only use my clutch for one thing.. starts. People have differant theories on this. Most upshift and downshift without and clutch. It has no engine braking and you want to shift fast and late when braking or it will load up with fuel and be rich when you get on the gas again. There is no reason to rev your bike to 14,000 and that is very high unless you know you have a perfectly ballanced crank. A stock bike peaks at around 12,600 rpm. After that is falls off so that is where you want it to be. I like to run to about 13,500 at the end of the longest straight so I can still have a good gear for the rest of the track. It is a comprimise. Yes if it is jetted lean enough to rev far enough it will break a crank end I would think. There is no rev limiter in the electronics. These are just my opinions and observations from my experiances. I encourage anyone to correct any of my issues so that I also can learn. Thanks for hanging around. I am board. Bill Cole #27
