2 Much Compression By ringinding1 (Read 1,063 times)

[ringinding1]

I have a 50mm bbk.The problem is i think i have to much compression.the scoot wont start with the electric start and i keep breaking the kicker half gear in the side case.has anyone else had this problem?Any input would be greatly appreciated.Uguys are great on this forum im new to the scooter tuning and learnin alot just from these forums. thanks again

[jofos]

I am thinking my problem also may be compression related, as in too much of it, as I get kick back from the kickstarter... I am also interested in finding out about this issue.

PEEPS?

[ringinding1]

I also get that kick back

[ringinding1]

I was told i can put 2 base gaskets in it to lower the compression

[redrocker1]

April13th. 2011 @ 11:30 P.M.C.D.T.

I had this problem on a 90 cc Honda.

Both intake and exhaust valve adjusting screws and lock nuts

were out of the rocker arms and laying in the rocker box!

I adjusted the valves per the Honda repair manual AND presto!

after 3 kicks it started and ran perfect.

With both valves closed YOU will break the kick starrter shaft!

redrocker1

[royldoc]

Are you using a stock head or did you replace it? I just did a 50mm bbk and don't have any problem. I would suspect camshaft timing or valve lash.



Roy

[ringinding1]

ok i did a compression test it reads 210.And yes i did replace the head with a scrappy dog big valve head.If i put a charger with a boost on it it will start and runs fine.and if i kick it it will start that is before i broke the half gear in the side case.I tried a new starter does the same thing.Any help would be great thanks

[royldoc]

I also put a big valve head on. I had to take the valves out and mill it down because when I got it it had a big gouge on the gasket surface all the way across. I milled about .010" off the head. Did you check to make sure the valves don't hit the piston? I put some modeling clay on top of piston about 1/8" thick. I assembled every thing but the valve cover. I did not use gaskets and didn't torque it down just snugged it up good This is just a test fit. You can do this with the gaskets just don't tighten the bolts and compress the gaskets. I don't use the gaskets because when I reassemble it gains that much more clearance. I set the valves to .004" intake .005" exhaust. then turn crank 2 full turns back to top dead center. I then disassembled it. If the valves hit the piston it will be easy to see. I very carefully peeled the clay off the piston. I sliced through the clay where the valves made an impression and measured the thickness. I cleaned every thing up real good and reassembled with gaskets.


Roy

[ringinding1]

thanks for the input royldoc