Need a bit of help, my bike sounds like a harley

[Spike16]

well the bike wasnt run over winter cos I was at uni and couldnt find anywhere to park it where I wasnt worried it would get messed up or pushed over by a drunk student...blah blah blah, stupidly I didnt start it when I came home til recently,

first problem easy to fix, dead battery

went on after a few mins running it cleared up and revs free now but when I took it for a ride when under load at about 5k it gets a bad missfire, sound like it goes to 2 cylinders and turn into a harley, seriously its horendous.

well I thought it was gummed up carbs so I rebuilt them cleaned them all out reset floats, when I took the float bowls off I found one of the main jets had unscrewed and fallen into the bowls, problem solved I thought, and while I was at it fitted 120 and 118 jets 1mm throttle slide spacers and 0.5mm slide holes as it was running rich before.

Well iv just got it going again and gone on a ride and looks like the problems not sorted, still sounds like harley and massive flat spot, although I can ride through it now and then the bike runs ok just down on power and slight missfire in background, also lots of backfiring.


What should I try next? Im stumpt could the tap and couple of inches of pipe be blocked up? or plugs dead? anyone got any Ideas?

[Smev]

Could possibly be a bad earth mate.

Worth checking all electrical connections - may be some moisture in them after all the snow and crap weather over winter.

[eamer1989]

yea or charging system down and under load it starts breaking down m8, mine use to do it could rev past 6k as wasent charging enough

[LUCAS]

If the main jet had come out would it not have been running extremely rich at that point and oiled the plugs by chance?

The whole coming under load i have had in the past and it was the stator coil. A whole lot of spluttering and wouldn't pull but was ok at lower revs.

Hope you sort it mate now with the decent weather coming

[Spike16]

some good idea's their, im putting new plugs in the race bike so il swap the old ones out to the road bike as I know they wok fine

to make things worse iv woken up to find a largish puddle of fuel under the bike... have had time to look where its coming from but I did fill it to the brim so theirs a chance it could be just the overflow, cant think what else it could be.

this is not fun, I wana get out on bike , defo need to get it sorted by next weekend for BSB Thruxton

[Neosophist]

some good idea's their, im putting new plugs in the race bike so il swap the old ones out to the road bike as I know they wok fine

to make things worse iv woken up to find a largish puddle of fuel under the bike... have had time to look where its coming from but I did fill it to the brim so theirs a chance it could be just the overflow, cant think what else it could be.

this is not fun, I wana get out on bike , defo need to get it sorted by next weekend for BSB Thruxton

if it's leaking and you've been messing with the carbs it's usually..

* Leaking float bowl... remove / clean / apply silicone or new gasket
* Float height incorrect.. petrol over-flowing.
* Float not sealing correctly... petrol over-flowing
* Drain screw partially undone.. fuel leaking.

All of them are fairly straightforward to fix.. if a float isn't sealing there might be some crap stopping the float moving properly or the float needle might be dirty.

[Spike16]

Yeh check last night and I think its one of the float bowls not sealing so il wip them off and have a look tonight.

really fucked off now, took the bottom fairing off and where the fuel leaked and ran down the bottom of the fairing the pait has bubble up and is peeling off!!!!! its not that noticible when on bike but not happy and the two lugs at the front of thw fairing that attach the 2 parts of the belly pan have both broken, dont know where when or how this happened and not happy about it.

Guess thats what u get for putting ur bike up over winter to protect it from salt and not comuting on it as it wants u to :)

[Neosophist]

Yeh check last night and I think its one of the float bowls not sealing so il wip them off and have a look tonight.

really fucked off now, took the bottom fairing off and where the fuel leaked and ran down the bottom of the fairing the pait has bubble up and is peeling off!!!!! its not that noticible when on bike but not happy and the two lugs at the front of thw fairing that attach the 2 parts of the belly pan have both broken, dont know where when or how this happened and not happy about it.

Guess thats what u get for putting ur bike up over winter to protect it from salt and not comuting on it as it wants u to :)

Did you store it properly? There shouldn't have been any petrol in the carbs to go manky if you did...

[Spike16]

no I didnt, I didnt mean to store it over winter, I went to uni with the intention of coming home about 2 weeks later when I had found somewhere to park it but couldnt find any where that it wasnt gona get knicked or pushed over by drunk studnets.

When I came back at christmas the battery was dead so replaced that and it started up like it does now, it took a few minutes running to clear its throat a bit then was running well as soon as its under load tho it gets this aweful missfire

Im gona swap the plugs to the ones out of my race bike tonight take the carbs off and hopefully fix the leak so fingers crossed thats it and I can ride the bike to thruxton for BSB on the weekend :)

[Drunkn Munky]

Can only be plugs or gummed up carbs if it was running fine before storing it, might see ya at thruxton, i should be riding down if the weather holds up.