stopped running

rddrgn2 · Mar 23, 2011

hey all
I'm at a loss with my bike! i was enjoying a great ride in great weather and the bike just stopped running like i ran out of fuel! i checked the fuel and had over a half tank with good flow and proper mix!

when i got home this is what I've tried so far, different cdi, mag coil, spark plug, carb, fuel and tank w/petcock, fuel filter, all off my other running bike! all parts work fine on my cruiser but no joy on my mountain bike!

non running engine is a 66 cc china girl no odd noises when it stopped!
checked the seals and both seemed intact and installed correctly.

any idea's are welcome

mike

rddrgn2 · Mar 23, 2011

yep pulled the plug and turned the engine over with a drill and i have good spark! put all parts on my other bike and they work just fine! compression is the only thing i haven't checked. put the plug in and turned over with a ratchet and it seems good :-||

rddrgn2 · Mar 23, 2011

thanks nougat for the reply's
kill switch was the first thing disconnected. fuel to oil is 32:1. roughly 300-400 miles on it. no sudden noises before it quit. just died like it ran out of fuel. will recheck both seals. may be time to tear into it and check out the piston and rings. i wanted to turn the jug and piston 180deg any ways this will give me a reason to tinker in that direction! :-||

2door · Mar 23, 2011

From what you've told us it appears you have covered all of the most common areas. Because you've replaced so many external parts with no success, confirmed fuel flow and ignition, I'm guessing a major loss of compression. With no basis of comparison from prior to the engine dying and now it would be hard for you to tell if this is the case.
Please keep us informed as to what you find. Me thinks you're going to discover a reason after you pull the head and cylinder and have a look inside that little beastie.
Tom

rddrgn2 · Mar 24, 2011

hey all
just update as to what I've done and found. used compression gauge from the auto parts store and low and behold no pressure! pulled the head and jug and some how i got some trash in there. it scored the piston but not the jug or rings(thank goodness)!

my plan is to get the rings freed up, bevel the edges of all four ports in the jug, and file the ring grove edge where it is scored on the piston.

time to order gaskets and get back to it laff

rddrgn2 · Mar 24, 2011

not sure what trash caused it. all the bearings look great, crank spins free.
i think the ports had some casting flash that finally broke loose, rinsed it out and found no metal shavings. i broke both rings trying to get them off! oops my bad

2door · Mar 24, 2011

I'm concened that you report piston but no cylinder wall scoring. Are you certain of this? Broken piston rings and the resulting loss of compression can account for your original problem but I'm not seeing a damaged piston without the associated cylinder wall damage that normally comes with it. The tolerences are too small to allow "trash" to score the piston and not get into the cylinder. take another close look and get back to us with the findings. Me thinks you will be in the market for a new top end; cylinder, piston and rings very soon.
Tom

rddrgn2 · Mar 25, 2011

hey tom
yea it was weird to me as well(being a retired mechanic) that just the piston skirt was scored from the top of the wrist pin to the top ring. one of the side ports on the jug have a nick in it, but i dont know if that was there from the factory or not as i cant make it line up with the piston scoring. the rings were not broke until i tried to remove them.

rddrgn2 · Mar 25, 2011

i just ordered new rings and a complete engine so if my experiments on this engine dont work out oh well! time to cross hatch the jug while waiting for parts

Search

stopped running

rddrgn2

New Member

rddrgn2

New Member

rddrgn2

New Member

2door

Moderator

rddrgn2

New Member

rddrgn2

New Member

2door

Moderator

rddrgn2

New Member

rddrgn2

New Member