Dark oily sludge in barrel,head & piston
Posted: Sun Jul 08, 2018 2:29 pmHi there.
A quick question on behalf of a friend who is rebuilding an engine on someone's else's behalf.
What you are looking at is two pictures of a head. It is covered in a greasy dark grey sludge/film.
The back story is:
* 125 Special, rebuild engine
* Standard 125cc barrel, which has been honed
* New piston. No oversize
* Fairly new fuel (no more than a few weeks old)
* Clean carb, fuel tank and filter on the tap. Standard jetting & exhaust.
The engine starts, just about, you can ride the scooter round the block, when you stop it it won't start again. The spark plug is dark and wet. When you take the top end off, this is what the head looks like. Both the piston and barrel (which are not shown in the pics as they have been cleaned off) look the same.
The same engine will start well and run well with another 125cc barrel and piston taken from another engine my mate has in his garage. Same carb, jetted the same way. When you take the other barrel and piston off, it doesn't have the same sludge on it. The two barrels look the same: same standard porting. They are both original Innocenti products, the only difference is that my mate's own barrel is on a second oversize.
Any ideas?
Cheers, Nic
A quick question on behalf of a friend who is rebuilding an engine on someone's else's behalf.
What you are looking at is two pictures of a head. It is covered in a greasy dark grey sludge/film.
The back story is:
* 125 Special, rebuild engine
* Standard 125cc barrel, which has been honed
* New piston. No oversize
* Fairly new fuel (no more than a few weeks old)
* Clean carb, fuel tank and filter on the tap. Standard jetting & exhaust.
The engine starts, just about, you can ride the scooter round the block, when you stop it it won't start again. The spark plug is dark and wet. When you take the top end off, this is what the head looks like. Both the piston and barrel (which are not shown in the pics as they have been cleaned off) look the same.
The same engine will start well and run well with another 125cc barrel and piston taken from another engine my mate has in his garage. Same carb, jetted the same way. When you take the other barrel and piston off, it doesn't have the same sludge on it. The two barrels look the same: same standard porting. They are both original Innocenti products, the only difference is that my mate's own barrel is on a second oversize.
Any ideas?
Cheers, Nic