Hi everyone,

I was doing a bit of greenlaning earlier and on the way back on a main road, i hear a Bang, loud enough to hear over by DEP exhaust and my helmet. Then it sputtered out to nothing and lost all power so i had to walk it back.

It has compression and it does run for about 2 seconds before cutting out again.

I have read up about it and have an idea on what it might be, but what do you guys think.

Thanks

G

Hi everyone,

I was doing a bit of greenlaning earlier and on the way back on a main road, i hear a Bang, loud enough to hear over by DEP exhaust and my helmet. Then it sputtered out to nothing and lost all power so i had to walk it back.

It has compression and it does run for about 2 seconds before cutting out again.

I have read up about it and have an idea on what it might be, but what do you guys think.

Thanks

G

Its possible that the woodruff key that holds the stator onto the crankshaft may have broken/come out, messing up the timing, the bang you heard could be a backfire due to this, only guessing mind

I suppose the only way to find out is to crack it open :/

Could this be the piston or rings ?

Hi everyone,

I was doing a bit of greenlaning earlier and on the way back on a main road, i hear a Bang, loud enough to hear over by DEP exhaust and my helmet. Then it sputtered out to nothing and lost all power so i had to walk it back.

It has compression and it does run for about 2 seconds before cutting out again.

Very much doubt it's rings or piston, you say you've read up what the possible cause would be?

This sounds like timing gone kaput, if it were CDI gone, you'd get nowt, my lads scooter did same as your bike a while back, loud bang then nothing, turned out it was the woodruff key broke and slipped out

BTW does it still pop loudly when you try and start it?

No it dosent pop when I try and start it

Just sounds normal, but dosent actually run

G

hope it wast due to the 10w40 car oil i put in the transmission?

Very much doubt it's rings or piston, you say you've read up what the possible cause would be?

This sounds like timing gone kaput, if it were CDI gone, you'd get nowt, my lads scooter did same as your bike a while back, loud bang then nothing, turned out it was the woodruff key broke and slipped out

BTW does it still pop loudly when you try and start it?

Ok i have been ripping it apart today, out what the cylinder case in parts, as far as i can see the piston, rings case crank are all absolutely fine.

I havnt dug further behind the cylinder yet, so i am guessing its a problem somewhere near the gearbox, which if i am right, there is a woodruff key there?

G

So ill try fixing the timing first .

Fingers crossed

Ok i have been ripping it apart today, out what the cylinder case in parts, as far as i can see the piston, rings case crank are all absolutely fine.

I havnt dug further behind the cylinder yet, so i am guessing its a problem somewhere near the gearbox, which if i am right, there is a woodruff key there?

G

If you take off the left side crankcase cover, the one that covers over the front sprocket, you'll see the magneto , you'll need ratchet gun, or some sort of holder, to get the nut off the crankshaft, and also a puller tool to get the magneto bell housing off, this will then leave underneath, your stator, the stator is located and fixed onto the crankshaft by a half moon 8mm x 3mm ish woodruff key, if theres just a groove in the crankshaft, then the key has come out, and you'll need to try and find it, the magneto bell house is magnetic, so theres a chance it may be on there. Good luck.

Ok I could not find out what was wrong after debuillding it , so I put everything back together, and it is now running

Not a clue what happened : p

Well, two things have come out of this, one you have your bike working again, result!! and secondly you now know more about what goes where, and what does what, on your bike than you did a couple of weeks ago, it's a win, win situation, that's the thing about bikes Gaz, you'll never stop learning new stuff about them, I'm also presuming that you cleaned, then re-greased anything that needed it, along the way?

My thoughts exactly , learned alot actually! And yer did my best on the cleaning and greasing n gaskets ,

Thanks for the help