No Compression

[markd]

Hello fellas, i need a bit of advice please?

I am running a mugello 186 v3 kit on li casings, the kit was fitted at the turn of the new year, its was completed stripped and rebuilt, GP crank, 30ml delly, JL3 pipe, going to work the other day, just lost all power to the scoot, pulled over, and i have lost all compression?. Now i am numpty when it comes to anything engine wise, ive been told that i could of holed the piston.

the engine has done around 2.5k since the rebuild. Obviously i would like to find the cause of the holed piston ( if its that) and get the old girl back on the road, will this involve a big strip down again, or is a case of just making sure the barrel is ok and replacing the piston?

all advice greatly appreciated

thanks!

[oldbiker]

no compression sounds like a holed piston,

if not it could be an oil seal put in wrong and come back out again (unlikely)

or you may have ring damage (unlikely going on what you have said)

either way I think you will have to get the socket set out. If it is a holed piston you will need to find the cause of the problem, timing, carb, etc.

should be a simple enough job, count it as a learning experiance and try to enjoy the work

[soulsurfer]

A quick check of a holed piston is to see if you have any aluminium on the spark plug. If it is you'll need a complete top end strip down including taking the crank out as the bits of your piston gets in everywhere and needs to be thoroughly cleaned out.

[markd]

thanks for the replies

just had a quick check of the plug, and theres no visible signs of aluminum on there. is that good news?

[Jet200]

Might just be the cylinder head gasket blown (fingers crossed! ) It happened to me. Took cylinder cowling off and I could see and feel where it had gone. Good luck

[lammydave]

had the same as you... no compession on a muggy... but had only done 50 miles..

what's the colour of the plug?

if it's light grey, then suspect the worst..

mine was a holed piston caused by a bad fitting inlet manifold, creating an air leak...

good luck, hope it's not that!!
keep us informed.....

[markd]

yes dave it was light grey...odear this sounds expensive!..well gonna whip the barrel off and have a look and see the damage.