I have a problem with a mates 02 125 Sherco and before I tear it apart I thought I ask...

when hot it runs like it's lean, if you flip the choke on it runs much better, the carb has been apart resently and apparantly was clean.

The exhaust note is very crackley and it's running out of puff on full throttle, if it cuts out it's a cow to start unless you use the choke or leave it for a while.

I'm thinking it's a jeting problems but is there anything else I need to look for? Timming?

Thanks for any help.

Nick

If it was running OK before the strip then it can't be jetting. Favourite would be a float level problem, possibly something bent by rough handling when apart?

It sounds like fuel starvation, either from the "rough handling" or the fuel pipe being pinched, but I would suspect that it's the pilot jet that is blocked. Try blowing the pilot jet through again and then try it.

Tony

and if neither of the above.............................. exhaust needs cleaning out, you know how to do it?

Also try the carb inlet filter, make sure it's not clogged - where the pipe goes from the tank to the carb, take the 10mm bolt off the carb and clean the gauze filter inside.

and if neither of the above.............................. exhaust needs cleaning out, you know how to do it?

No I'm afraid I don't, I did have a quick look and there seems to be no way of splitting this one, can the packing still be changed?

no, inless you know a really good welder, best way is........... fill with thinners, slosh around for ages, then plug one end, let stand for couple of hours, remve plug empty thinners, then stand inlet (big diameter) side down in a bowl over night, watch the tar come oozing out

sounds more like an electrical problem?

if its feeling like its running lean when its hot,might be a stator failure?

sounds more like an electrical problem?

if its feeling like its running lean when its hot,might be a stator failure?

ie when the stator coils get hot,the spark is getting poor

ie when the stator coils get hot,the spark is getting poor

no, that is a myth

Spray wp40 around the intake manifold when it is hot. My bet is it has a leak there.

Alan

No I'm afraid I don't, I did have a quick look and there seems to be no way of splitting this one, can the packing still be changed?

I've posted this before but here's what i did:

Soaked the silencer in fuel, for an hour or two. Put the silencer in the middle of a large patio area, carefully at arms reach, applied a blow torch to the end of it. Burns like wild fire for 20 or 30 seconds, then dies down to a small flame.

At this point I blast it with a compressor to provide the oxygen, swapping ends now and then. It turns in to a blue flame and sounds like a jet engine. Kept this up as long as i could keep it burning for.

I repeated the whole process MAKING SURE IT WAS ALL COOL BEFORE APPLYING MORE FUEL. (next day in my case).

It's been clean as a whistle since.

I know I said I've done this twice so it sounds like it's really temporary, but one of them was a second hand one off a 125 which was full of oil when i bought it (after I bent mine beyond easy repair).

Errrrr.....needless to say - safety warning here, creating a jet engine is probably not entirely safe - use a good sturdy pair of sandles

I stripped down the offending item last night and found the pilot jet was clogged up and the choke was rusty, I cleaned and blew out every orifice I could find.

The only damage I could find was up inside the main tube where the needle is, from the float bowl end it looks as if some of the brass has been snapped out.

So I went looking for pic's this morning to see what it should look like and found a description of how to strip and clean on the sherco website, it doesn't have an image to show the innards

but it shows a pic of the main jet in the float bowl bolt !!!!

Now I'm either blind but this carb didn't have one - I've just pulled the plug out the bottom to check and nothing NO MAIN JET? how the hell did it run, my mates boy did a trial on it last weekend?

So anyone know what size main jet should go in in 02 125cc Sherco, this should at leat go some way to sorting the problem of bad running....

Regards

Nick.

PS. definatley going to have a go at burning the patio furniture while cleaning the exhaust.... never liked it anyway

Edited January 23, 200818 yr by Finn

Try a 118-120, should be ok.

I've posted this before but here's what i did:

Soaked the silencer in fuel, for an hour or two. Put the silencer in the middle of a large patio area, carefully at arms reach, applied a blow torch to the end of it. Burns like wild fire for 20 or 30 seconds, then dies down to a small flame.

At this point I blast it with a compressor to provide the oxygen, swapping ends now and then. It turns in to a blue flame and sounds like a jet engine. Kept this up as long as i could keep it burning for.

I repeated the whole process MAKING SURE IT WAS ALL COOL BEFORE APPLYING MORE FUEL. (next day in my case).

It's been clean as a whistle since.

I know I said I've done this twice so it sounds like it's really temporary, but one of them was a second hand one off a 125 which was full of oil when i bought it (after I bent mine beyond easy repair).

Errrrr.....needless to say - safety warning here, creating a jet engine is probably not entirely safe - use a good sturdy pair of sandles

Bikespace, your method will work if you are careful! You can also use a commercial high output electric heat gun to set it off! Once the flame starts, switch to air only to feed the flame!

If it has too much fuel and deposits in there, it will overheat and melt down! Some ice on the oulet and body may help!