loose compression

gian · #1 (**permalink**) 10-20-2009, 01:58 AM

hi guys i've been using my bike for almost 2months 80cc, my normal speed at flat ground 55kmh, my oil mixture at my first 4 liters is 16:1, and after that i used 20:1 and now im doing 25:1mixture ,i kept my bike in my garage about 3days coz its raining ,and when i use it i notice that something wrong with my engine, when i start it it has scratching sound inside and i run it at a distance of 8kms my normal speed went down to 40kmh, i check the cylinder head 1 of the 4bolt was loose i remove all the bolt and remove the cylinder head i see some slight scratches at the cylinder bore hairline scratches can be felt by my fingernails ,and when i put it back on i put red loctite and thighten the 4bolts about 10ft lbs and now it backs to normal works the same as before 55kmh, Now the question is does it affect the engine perfomance when i run my loose compression engine about 8kms at a speed of 40kmh, im confused about what gonna be the problem of my engine in the future, coz i run it loose compression

**BarelyAWake** · #2 (**permalink**) 10-20-2009, 06:21 AM

If you've the same performance as before you had a problem - then the compression loss (if any) is marginal.

I wouldn't worry about it, you did the right thing

Problem is - where did the lil thing that caused the scratch come from? I bet the shoddy air "filter" that came with the kit failed you and let a chunk of road grit in - replace it with a real one, like a K&N or similar.

I would like to mention I think yer runnin' a bit heavy with the oil, 32:1 is fine even with regular 2stroke oil, I'm runnin' 36:1 with synthetic - there's people runnin anywhere from 50:1 - 100:1 synthetics... but they're braver than I lol

**Bikeguy Joe** · #3 (**permalink**) 10-20-2009, 09:36 AM

I just hope you didn't use red loctite on the head nuts.

**Norman** · #4 (**permalink**) 10-20-2009, 11:04 AM

When you take off the head remove the gasket if the gasket isn't in bad shape give it a coat of cheap aluminum spray paint both sides install it wet or dry then torque the head bolts on. Ride it until its good and warmed up. Let it cool off completely recheck the head nuts again for proper torque. you might need to do this a couple of times. There is no need to loctite the nuts on the head. To help remove loctited head nuts warn them up with a propane torch this will weaken the locking compound and you should be able to remove the nuts.
You can see in my 2-stroke repair posts on how to do engine tear down etc.
Norman