2 Stroke engine problem, need help please
- Thread starter millard
- Start date
millard
Registered user
Stripped the carb and poked every orifice through with a piece of copper wire then blew through with 100psi. All clear but no difference.
Let it warm up then blipped the throttle and let it run at that for a while. There's no tacho so difficult to say what it revs at when they don't die down but it's nowhere near screaming, just a very high tickover.
Cut it and here's the plug
Took it for a run and going up hill on 1/2 to 3/4 throttle in third, cut it coasted in and here's the plug
It goes real well out on the road, no fuss , no drama, just goes like stink. I'm almost tempted to ignore the tickover problem, if it wasn't for the cost of the possible consequences
whatdya reckon?
Let it warm up then blipped the throttle and let it run at that for a while. There's no tacho so difficult to say what it revs at when they don't die down but it's nowhere near screaming, just a very high tickover.
Cut it and here's the plug
Took it for a run and going up hill on 1/2 to 3/4 throttle in third, cut it coasted in and here's the plug
It goes real well out on the road, no fuss , no drama, just goes like stink. I'm almost tempted to ignore the tickover problem, if it wasn't for the cost of the possible consequences
whatdya reckon?
vilguy
Registered user
First plug chop looks absolutely spot on to me. Nice brown colour.
Second one looks a bit sooty but its not that bad. Id maybe do a couple more just for some comparisons but to be honest.... doesnt look too bad.
Not worth stripping the engine for it.
Second one looks a bit sooty but its not that bad. Id maybe do a couple more just for some comparisons but to be honest.... doesnt look too bad.
Not worth stripping the engine for it.
alimey4u2
Registered user
They also do this Mill...
http://www.bestultrasonic.com/index.php?cat=CARBURETTOR_CLEANING_SERVICES&ActinicSID=2ead1f4e5e9a4be0ade24b4b1e7aa693
Ps Are you sure your reeds/seats are not damaged & shutting off tight..
millard
Registered user
Well I finally today got around to trying the next size up in pilot jet, No 48,,
Guess what ????
No difference.
So in went pilot jet No 50.
While I was waiting for the engine to warm up again I thought I'd turn the tickover speed down a wee bit and bingo, problem dissapeared. Not what you're thinking, it's not as simple as having the throttle stop screw wound in too much, here's what happens:- when the throttle stop is wound back to a fairly low tickover speed the revs die down nicely when blipped, but turn it up just a touch, and I mean much less thean 1/8th of a turn (literaly a few degrees) and the revs increase very slightly as you'd expect but when you blip the throttle the revs stay on the high side, just as before. I can still force them back down to a nice low tickover by slipping the clutch, in gear, brake on. Into neutral clutch out and it stays stable, as it always had during this process.
So I went back to the standard pilot jet, size 45 and same thing happens.
So what do you think's happening here? Any clue as to why a few degrees on the throttle stop should induce a problem but back off a few degrees and it's cured? Just like an on off/switch - "Problem/No Problem"
Answers on a postcard please !!!!!
Anyway, fuggit, I'm off green lanning up by Alton/Basingstoke this evening wi Mike (Dolly Rocket) and a few others so I'll let you know if it survives, or not.
Millard
Guess what ????
No difference.
So in went pilot jet No 50.
While I was waiting for the engine to warm up again I thought I'd turn the tickover speed down a wee bit and bingo, problem dissapeared. Not what you're thinking, it's not as simple as having the throttle stop screw wound in too much, here's what happens:- when the throttle stop is wound back to a fairly low tickover speed the revs die down nicely when blipped, but turn it up just a touch, and I mean much less thean 1/8th of a turn (literaly a few degrees) and the revs increase very slightly as you'd expect but when you blip the throttle the revs stay on the high side, just as before. I can still force them back down to a nice low tickover by slipping the clutch, in gear, brake on. Into neutral clutch out and it stays stable, as it always had during this process.
So I went back to the standard pilot jet, size 45 and same thing happens.
So what do you think's happening here? Any clue as to why a few degrees on the throttle stop should induce a problem but back off a few degrees and it's cured? Just like an on off/switch - "Problem/No Problem"
Answers on a postcard please !!!!!
Anyway, fuggit, I'm off green lanning up by Alton/Basingstoke this evening wi Mike (Dolly Rocket) and a few others so I'll let you know if it survives, or not.
Millard
Shep
Shep of the Dessert
Damaged throttle stop screw? or if it hits the end of the slide a damaged slide?
D6
Registered user
probably a step/indentation worn on the angled bit of the slide where the stop hits
vilguy
Registered user
bugger it, just ride it till it dies.
millard
Registered user
Yep yer right Digg.
tried to rectify it but didn't make a lot of difference. Think I'll try a new slide.
Took it out to a horsey event wi the TRF on Sunday. Great day out on trails we wouldn't normaly be allowed on wi bikes. Did about 78-80 miles and it behaved itself well, so fairly pleased wi it. Just a wee bit o fettling and it'll be there.
millard
Registered user
vilguy
Registered user
Crms for ever! rraaahhh Anyone want a wr400? i sold my crm to buy it thinking it would be a beast compared to the crm. Ive since decided all 4 stroke offroad bikes are for puffs.
Pint of premix for me landlord.
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