1200 bandit idles ok but rough running 3000 - 4500 rpm

[12002003]

Hi
Due to ill health my 1200 bandit was off the road for three years being started and warmed up every month.I paid a local shop to clean the carbs out and balance them but it has gone from a bike that needed very little choke to start and a smoothe ride to a bike thats a pain in the butt to start on choke that then idles smooth but feels like it running out of petrol between 3000 - 4500 revs.The shop said it was the header gasket leaking a bit but i want to confirm as it seems unlikely to me.Any constructive comments / advice welcome

[mudcow007]

Does yours have rubber inlets?

Might be worth seeing if they have cracked causing air leaks? with it idling spray something that is flammable around the carbs, if revs increase you got a leak

fuel filter? if so you might have crap swirling around in your tank?

[jaffa90]

[12002003]

HI
Thanks for the replies i will try to spray the inlet rubbers.Do you think running some redex through the system bearing in mind i do a tank every three days would help.
I did note when i got the bike back from the shop he said he had reset the pilot screws to factory recommendations because they were well out when he dismantled the carbs. Would buying a pilot screw adjuster tool be worth while?.
Would adjusting the pilot screw change the idling as well as that seems ok or is it a case of main jets still blocked, if so can anyone recommend were to buy new main jets so i know they will work when fitted.
Cheers for any advice

[12002003]

HI
Something else i thought i'd ask you guys is could it be the petrol tap needs a rebuild as this was suggested by a mate.

[Matt B]

[mudcow007]

my 600 bandit is a vac operated fuel tap, i rebuilt mine as everything else was mulled so thought why not. would have thought the 12 was the same?

if your carbs are similar to a 600 you just need a small bladed screw driver bent on a 90 degree as the adjusters are right by the fuel bowls fiddly but do-able

there is a basic filter on the inlet to the fuel tap, maybe this is clgged?

Id go with inlets. have the carbs been balanced since being stripped?

[12002003]

the carbs were stripped and balanced by the shop and the idle is spot on at 1200 revs no fluctuation.
I just tried sprayer GT30 i think it's called a penetrating fluid like wd40 that is highly flammable around the inlet rubbers but there was no difference.
Should have said earlier the shop guy said the exhaust header gasket on no1 cylinder was leaking a little and blamed that on the bad running? any comments on that.

[Snowdonia Rider]

Sounds like similar symptoms that I had with my GSXF 600 (so same style Suzuki air/oil cooled) that was cured with a new fuel filter after having the carbs stripped and cleaned.
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[jaffa90]

A bike that needs little or no choke to start it in the U.K. is running rich on the pilot feed side. You need to find out why this is the case.
12002003, the choke has its own starter jets giving more fuel at cold start ups providing you don`t touch the throttle after when it coughs in to life, it should run up to 3,000rpm when you start to reduce the choke lever. You can set off with part choke and reduce it more when running or coming to a stop. The choke is bypassed when using / twisting the throttle.
I cannot under stand why the tickover is set at 1200 rpm when 1000rpm will do,
If the carb is set to the e.e.c. regulations then you will not be able to blip the throttle to 5,000 rpm without hesitation.

[Matt B]

[jaffa90]

[12002003]

Hi guys
Thanks for the replies most helpful. Luckily I found the mobile number for the previous owners son who was a Suzuki dealerships mechanic who advised me as has been suggested by some of you the mixture was adjusted to make it run smoother and he is going to adjust it later this week to hopefully sort it out.
Moral of this story is don't throw away phone numbers as this one is ten years old.

[connormcc58]

Hi did you ever find a solution to this ? I seem to be encountering the exact same issue .

Thanks
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