varad

Hello. I have been out of pocket bikes for a long time. I finally figured out why my bike would not start but i still have new problems. The problem was my compression. I was reading like 20-25 psi. I also checked a chainsaw and leaf blower and they were at 130 psi and 115 psi. Just to make sure that was the problem, i bought a new piston and ring (stupid not to replace the cylinder) and it started but it runs REALLY bad.

when i give full throttle, the bike will not transition into full throttle. this is hard to explain but the throttle will alternate between going up and down until i let go of the throttle. I thought it was the carb so I got a dell orto 19 mm carb. Still the exact same problem with no improvement whatsoever. Is it my jetting?

Also, when I had the head off the engine, just eyeballing it, the piston does NOT look centered in the piston. The piston is tighter against the exhaust side of the cylinder and there are bad vertical scratches on the new piston/ring and the cylinder on that exhaust side. I think the 4 rods coming out of the block to secure the cylinder and head are bent and therefore setting the cylinder incorrectly. Just looking at it, they look bent so I will replace them. Or could it be a bad crank pushing the piston to one side of the cylinder wall?

Good spark, fuel is getting to the carb, squish at .05 mm, new base and head gaskets.

Now, I am ordering a new piston and ring, cylinder, and those 4 rods holding the cylinder and head to the block. Should i check anything else.
Sorry for not answering these posts I was really busy with other stuff. Thanks for all your continued help.

Admin

How is your exhaust? Remember that a two stroke uses the exhaust in the intake cycle (as well as exhaust). Check and replace your exhaust gasket and make sure your pipe isn't cracked.

Also a gouged head will lose some compression.

Chinese motors aren't known for great quality control. What you're looking at could very well be how it came from the factory.

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huckster

if you have bad scoring on the exhaust side you likely overheated it and willl continue to wreck the next motor if u dont find the problem. check your cooloing system and then look at your plug for signs of it running lean.
Temperature - It must be noted , that slight enrichment from 'ideal' may be necessary to assist in cooling the engine on extremely hot days, or in the case where excessive heat may be generated, such as for heavier riders or on circuits where the engine experiences sustained high loads.

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varad

I will replace the exhaust gasket along with the piston and cylinder. The exhaust is not cracked. On another forum, people are saying that my squish is too low causing too much compression and overheating. With the stock base gasket, squish with the ADA 17:1 head comes to .05. People are saying to either use the stock head or up the squish with the ADA to around .68. How does this sound? I will check my plug and cooling system also.

pb x-treme

my banshee's squish is @ .48 and i've had no overheating probs, except when i break the belt. go over your colling system and makr sure everything is floein smoothly. other than that u mite wanna step up your jet

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vampyre

you need new piston rings to go with that.

Admin

Nuttin wrong with a squish at .5

But you said .05, was that a typo?

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