cylinder barrel or oil pump? - 2 plug fouls today!

[fishtail]

was prompted into action on this today - when todays ride was cancelled due to the bike fouling a brand new plug in 3 mins... it then fouled another plug pretty soon.,

refused to start... had a look thru - and saw mention of worn rings... ( also a few people here suggested I take a look down my cylinder anyways! _

( this week had a major electrical failure - resulting in me juddering 30 miles with no powervalve! )

here's down my barrel







so how is it? - I uploaded some vids so you can see a few cycles - if the stills arent clear enough ( http://youtu.be/RkN0rjjJXzw )


wondering if I have lined up the right mark on the oil pump? ( seems to be 2 marks? ) one is a bit "A" like - the 2nd further round is more of an "I" and goes across....

it was more or less om the "I" when I got the bike - ( assume was right )

[knackeredMk1]

In reverse order -

The 'I' is a line and it should line up with the pointer at full throttle. Yours seems to do that.

The black on the cylinder head is not an issue but it would be a good idea to wipe/rub the carbon deposits off. Looks like you have bee running a bit rich which is much better than running lean.

You barrel badly needs a rebore but that's not why your fouling plugs, unless you haven't got enough compression for the engine to run anyway.

Other option is intermittent electric fault.

You really do need to strip the engine down and recondition it.

[fishtail]

cheers for the reply Steve..

those oil streaks on the barrel are the indicator the rings arent a tight fit right?

intermittent electrical fault? hate those! either break or dont! - always works when u testing it.. then doesnt when u testing summat else!

every time I took the plug out I could see it sparking.. and replacing the plug after a good wiping - seemed to start but then cut out..

I'm gonna take the barrel off tomorrow.. hope can get it done in a week,.. I might have a look at dropping the rest of the engine.. ( rear swingarm has side ways movement. )

I saw a thread covering taking gear box out / split crankcase etc.. so beyond swopping bearings what else should I do?

cheers

[njhardy]

I didn't think your cylinder looked too bad- I can't see any scores or burn marks on it, but its not easy to see if its oil or scratches in there... Yes its running very oily and there is a some carbon to clean off- this is easy to do using a Dremmel and polishing stone- also may want to take out the power valve itself and polish that up, as less rough for oil and carbon to stick to. Oil pump setting looks ok- if the 'I' and the pointer line up when on full throttle. I think you are running far too rich still and too much oil- this affects the mixture. How is the compression? If you can just about turn the cylinder over with your hand, then its too low. Now I have mine redone with the lovely TRX piston, I can literally stand up on the kick-starter before it turns over (mind you, I'm only tiny and I have increased the compression a little). If so, you need a rebore and new piston & rings. This can definately improve its running.

[fishtail]

its definitely oil...

I can wipe it away... could it be the rings are shot?

rebore here costs HK$600 = about 50 quid

+ piston + rings and small end bearing...

[fishtail]

is it advisable to "turn down" the oil a little bit? ie back it off so its not pumping so much oil in ( but away from full flow by how much???)

or is it that I put a bunch of cheap crap 2stroke in? ( havoline green power? )

( i ran out - and got this from the local gas station as opposed to bike shop.. probably an entire thread alone on which is best brand 2t oil? )

[knackeredMk1]

I stick to my guns re rebore & piston.

If the rings are worn that much then the bore must be worn even without there being significant marks.

[Active Rascal]

Without meaning to offend you.... You haven't accidentally left the choke on?

[knackeredMk1]

AR - Good point .

[fishtail]

not offended..

but nope not choke left on, tend to turn off after a few secs

crankcase seals?

[fallenmikethebike]

^^^^^^ possibly on the gearbox side, but the oil level would be dropping if that were the case, is this happening?
How clean do keep the filter?
Mike

[fishtail]

air filter - havent looked in about 2-3 months,,, but its only been out 6 or 7 times in that period?

oil level is fine ( ie weeps out the peep hole when I test.. might have over filled a tad when I changed it last.. - but in need of a change anyways... )

I just got one of those miner's lamps that straps on your head.. yes my neighbours think I am bonkers... I might go out and take a look after dinner... want to get it running again ASAP..

would prefer to do full recon starting in about may next year.. I'm going with steve's rebore idea - cos we half wa there - only takes a few days and thats done then?

[twistednuts]

Is there anythin on this bike you havent had to do?

[fishtail]

hmm gotta think about that..

( still a big list of stuff TO DO* )

air filter is about as clean as I got it when I cleaned it last- and still oiled up.. ( did I over oil I wonder? first time an all ..haha ) ( its a bit "damp" with oil at the present )


( * list of stuff to do - change crankcase cos its cracked... change bearings where ever possible, new seals... change drive shaft becus some numnut welded the frekin front sprocket on... take a look at the clutch since neutral is imposible to find and its draggin in when in gear,,, - swingarm bushes and bearing s - cos it moves left right... - chain guide block to drop for 48teeth sprock. weld bracket for chain guard.. )

but the brakes are nice now


I think I gonna take the barrel off - I reckon my theory is that the powervalve is full of gunk and its escaping up the side of the rings?

or like KnkMk1 said - intermittant electrical...

[Active Rascal]

Your air filter shouldn't really be 'wet' with oil... More so tacky. This will reduce the air flow, causing the bike to run rich and therefore foul your plug. Try cleaning the filter properly and allowing to to dry. Pop in a new plug and see how she goes as this is a quick try. Sounds like you have a lot of work to do anyway.