Bike not run for a while, stalling.

Hello all,

Bike (01 curvy) has been left for best part of a year after a crash, only forks, wheel and fairing damage. Been putting it back together and it runs now...kinda. So i would like your advice. Only changes to the running have been a new (different) scorpion exhaust as the old one was scratched and has had restrictors put in now.

It starts pretty easily with the choke on, will idle with the choke and rev, even if you rev and drop the throttle it doesn't stall. When it is idling with the choke it misfires/backfires every now and then about once every 1-2 seconds. When off the choke it idles so low that it only idles if you lower the choke slowly and if you rev it and let it drop to idle it stalls. If you sustain some revs it will run without the choke but still mis/back fires.

Has a smell whilst running too. Hard to describe, almost like a burning smell.

So what do you think it is? seems like a bad mixture but i will admit im not that knowledgeable.

Carbs could be a bit gummed maybe. Burning smells are often just oil/carp on the pipes somewhere, but just check all the tubes hanging down the back of the engine. Can you ride it? If you can try some fuel system cleaner in the petrol and give it a gentle blast. Or take the carbs to bits and clean them. Is it a misfire or a backfire?

I cant ride it MOT ran out! Its more a backfire, Ill see if i can get the carbs off at some stage. Possibly take the restrictors out too

Put fresh fuel in, try and get rid of old stuff as unleaded fuel over time goes sticky and loses some of its properties.
Give your carbs a clean and maybe blast of air etc, fresh fuel, should run like a champ.

Your carbs are gummed up for sure. Get them off and clean them with some carb cleaner and compressed air (if you have access to it). also check you re-seated the air box and all carb rubber correctly, as air leaking in can also lead to misfires. If you haven't put fresh fuel in now, drain the system fully and refill with fresh stuff. would also be worth a new set of plugs too, or at least clean and inspect the old ones.

The "burning" smell could be just dust and oil burning off the engine and 'zaust if it aint been run for ages.

Phil

the carbs might be dirty, yes, but i think your problems might come from the exhaust. 1st, new exhaust can always has a smell to it when 'burning-in', so no worries there. 2nd, are your cabrs stock? if you put a 'racing' pipe on it, you need jetting! it is running quite lean, hence slow running of the choke. choke gives it extra fuel, so it runs a lot better with choke on. if you have a open pipe and stock carb, you need to get a larger main jet and move the clip washer on the jet needle... i just (well, 2 months ago, but parked for winter since...) installed racing Yosh on wife's SV, had very simmilar symptoms to yours with stock carb setup...

Originally Posted by smoky

the carbs might be dirty, yes, but i think your problems might come from the exhaust. 1st, new exhaust can always has a smell to it when 'burning-in', so no worries there. 2nd, are your cabrs stock? if you put a 'racing' pipe on it, you need jetting! it is running quite lean, hence slow running of the choke. choke gives it extra fuel, so it runs a lot better with choke on. if you have a open pipe and stock carb, you need to get a larger main jet and move the clip washer on the jet needle... i just (well, 2 months ago, but parked for winter since...) installed racing Yosh on wife's SV, had very simmilar symptoms to yours with stock carb setup...

Shouldn't really be that extreme though. I ran a full micron race system on mine with no re-jetting - usually only needed if you also put in a a free flow filter (K&N etc). He just swapped the can too, which won't make much difference. I'd still investigate cleaning the carbs first before thinking about re-jetting personally. Loads of folk on here run a race can without touching the carb set up.

weird, maybe euro fuel is differnt? mine (ok, wife's...) would hardly run, idle very low and stall off choke, all stock but the slip-on yosh... run perfectly 2 hours earlier, and again perfect 2 days later, after jetting. pretty much the same with my KTM SD, only worse... . would not even idle till i put new FI map on (also all stock, slip-on only...)

Originally Posted by smoky

the carbs might be dirty, yes, but i think your problems might come from the exhaust. 1st, new exhaust can always has a smell to it when 'burning-in', so no worries there. 2nd, are your cabrs stock? if you put a 'racing' pipe on it, you need jetting! it is running quite lean, hence slow running of the choke. choke gives it extra fuel, so it runs a lot better with choke on. if you have a open pipe and stock carb, you need to get a larger main jet and move the clip washer on the jet needle... i just (well, 2 months ago, but parked for winter since...) installed racing Yosh on wife's SV, had very simmilar symptoms to yours with stock carb setup...

Hate to be an anal 'arry, but the choke restricts the air to richen the mixture, rather than increasing fuel.

yeah...what i ment to say is it makes the mixture richer...
running ok on choke, and idling low and stalling when off choke usually points to lean mixture. dirty carbs are one possibility (running lean, but because carb is not flowing enough fuel due to dirt, not because of too-small jet).
for me, it was clear that it was the pipe, i went for a ride before and after installing Yosh...

if you have baffles for your can, put them in and see if it runs better...

Seriously, you guys really can run an unrestricted exhaust with stock carb??? which exhaust?? i just spoke to afriend with SV and TL, for him, just like for me, bike would run like crap and kept stalling with a stock main jet. Same on TL (full system) and on SV (slipon)...