125CC 156fmi engine problem.

[wazza]

hi guys. i have an early model cr honda lookalike, the name is Scrambler, it has a 125cc engine, the number being 156fmi,the problem with this bike, is that it blows heaps of smoke , the engine is very quiet, and there are no rattles or anything like that, could anyone help me with this problem please. cheers wazza

 

[mrbrnz]

needs new rings or valve stem seals

 

[thump*140]

if it isnt making too much noise, but blowing smoke, there's a chance it's done a valve stem seal, or simply has worn oil ring...
is the smoke black, or blue? black is unburnt fuel, blue is usually oil burning... being a four stroke, it shouldnt be burning oil.

 

[wazza]

yes the smoke its blowing is blue, and it also fouls the plug after awhile,how much drama in doing valve seals, and oil rings, ive done 2 strokes, but never had a go at 4 strokes?

 

[thump*140]

its not overly difficult, but it really does depend on your mechanical ability, and whether or not you can bothered doing it... if money isnt too much of an issue, these engines are pretty much throwaway jobs... a new 125 motor could be sourced from ebay for a couple of hundred dollars.

 

[headsmess]

timing it again is about the only issue...

and is no issue if you LOOK AT IT before pulling it apart....

remove head, remove cylinder, get new piston, get cylinder honed, replace.

you might only have to remove the head and replace the head gasket.... even easier.

 

[Th3D3v1Ly]

I would say buy a nice new engine. Sell the old one for spares.

 

[wazza]

hi guys ,regarding the problem i had with this engine,i am happy to say that i have resolved it , i decided to strip it down,and have a look, the rings were gone, the end gap was huge, the bore was really good, i sourced a set of rings (56.5MM) and a couple of valve stem seals,a lower gasket, put it all back together(a snack), hooked it back to the bike, 4 kicks later, and away it went, no dramas at all, so thank yous all , for replying to my post. that project is now out of the way, i am going to start rebuilding a xr200. it will be a bit harder, being a ohc engine, where as the one i just done is a pushrod engine, total cost for that engine rebuild was $60,thanks again cheers WAZZA