I have a 1995 Honda RS125 that I started racing this season. I went to a Track Day at Texas World Speedway on Monday and sometime in the last afternoon session something went wrong with the bike. It had been making good power and seemed to be jetted right, infact I took 5 seconds off my previous best lap times. However on the last session it would not rev over 8,000rpm and if I kept the throttle open it would keep reving at 8,000 then suddenly jump to 13,000 and produce no useable power. So I brought it into the pits and took off the body work and looked at the bike from underneath. As I looked up at it to the left of the manifold I saw oil dripping. I am no 2-stoke mechanic so I need some help with this. Does anyone know what this could be? I am hoping it is just a topend, and I have the parts on hand to replace that. Does anyone know someone in the Dallas/Ft Worth area I could bring it to? thanks David
there is a whlole host of things you want to check... first is that all your jets are okay and not mucked up, second is your plugs, third is your reeds (are they intact?), then pull the tank and check the filter on the petcock... if it's plugged up you won't get enough flow at higher rpms and that'll muck up the motor's ability to rev. also check the seal on the exhaust maifold to the pipe and make sure it's good and tight, that you haven't lost a spring, reed cage is fastened down well, etc. read the manual. the manual is REALLY good on these bikes and if you go through it step by step you're likley to find your problem pretty easily. jf
When I first got my 125 I got a lot of oil spray comming from the front exhaust port between the cylinder and exhaust flange. I replaced the gasket and sealed with high temp silicone and the problem went away.. As for the loss of power, check the cylinder base gasket as well as what JF has said..you might be sucking in air somewhere....
the other thing is that Ian Emberton sells a nice replacement exhaust manifold that makes life better as well. [email protected]
thanks thanks everyone I will start tearing into it tomorrow. I am not the best mechanic, am I getting in over my head?
READ THE MANUAL - READ THE MANUAL - READ THE MANUAL - then you won't be in over your head and you'll have more confidence. This is the wrong sport to be in if you don't want to take the time to absorb the information that's free to you. READ THE MANUAL... it's actually quite good. jf
'Not being the best mechanic' is probably an advantage actually. The manual is step-by-step enough for anyone to follow, and if you dont have the pre-concieved idea you know better, you'll follow it to the letter and do it all right. Top end stuff is very easy, as is clutch stuff. Strip it down whenever you can, and it'll become second nature. If your uncertain of somthing and it's not in the manual, ask on this noticeboard, thats what it's for, and we've all been through the stage your at right now
I always had loads of oil where you describe it till I fitted one of the manifolds mentioned earlier, I got it from GP City. Was the plug cap fitted ok? should go on with a real good click.
Trying it Wednesday I get back from traveling on Wednesday so I am digging into it Wednesday night, wish me luck, I have the manuel in time. David
Thanks to all Well I dug into the top end with a friend that owns a NSR 250. With his guidance and the manual I managed to change the top end. I heat cycled it 3 times and ran it 8,000 rpm for a mile, 9,000 rpm for a mile and 10,000 rpm for a mile. Now my neighbors hate me but the engine is running great! Of course I took that great engine down to Texas World Speedway this weekend, discovered my clutch was burned out. After changing the clutch I did my best laptime ever at TWS, until I highsided coming out of Turn 6. Anyone want to sell me an upper? thanks for all the advise David
I have a complete Mail box style upper and lower, I have a stock 97 upper lower and Tail..... Does that help?
