B600 possible carb issue

[mikesaa309]

Hi all,

In my seemingly never ending quest to figure out why my 1997 blandit 600 won't reach it's top speed anymore I decided to check carb diaphragms for tears. Had them out all seem fine put em back in and starts and revs as it should. Took it for a test run just round town and it doesn't like sitting at a constant speed. For example if I get to say 30 mph hold the throttle so I keep to 30 it will make a grumbling/inline 3 kinda noise as if I'm going onto reserve. Never did this before I took diaphragms out. However when I open the throttle it seems to pull pretty well seems even better than it was though can't be 100% sure so doubt it but defo no worse than before no hesitation either. Just seem to be when I hold throttle steady.

Haven't had chance to test speeds like 60-70 odd so could be something to do with the low rpm/speed jets on the carbs. Only thing I can think of thats happened is one of the diaphragms being pinched by the top cover of the carbs but I had the air filter off today lifted the throttle slides and they all fall down at the same rate and aren't dropping instantly so there is a vacuum there.

I currently have the carbs off as I'm wanting to replace my throttle cables especially the open (pull) one as it's frayed at the handle bar end. While I've got the carbs off is there anything to check? I ride it often so doubt jets are clogged was going to check float level height but was reading online that it's a hassle in that if you don't get it right it can make it worse and difficult to get it back to how it was so I might just leave it plus would need new O rings for the carb float cover as well. Anyone got any ideas what that problem could be if it is to do with the carbs or if it's likely to be something else. As for top speed issue I'll probably just put up with it though it seems like acceleration is down a bit from what it used to be but could just be me being used to it plus I'd rather save up for a GSX1400 than spend money getting bandit back to normal running.

[jaffa90]

You say 30mph but what revs are you talking?
Pilot jets work mostly up to 2/3,000rpm, it could a weak mixture at that point or varying fuel levels in the carbs.
Have you an inline filter fitted just in case the fuel tap seals break up?

[mikesaa309]

Probably around 3-4k rpm like I say haven't checked higher speeds yet so might happen through out tho seemed to be okay at first when I took it round the block well a few blocks actually so seems at lower speeds talking like 15-20 mph it's okay and when idling it revs fine wouldn't think there is an issue.

And nope no inline fuel filter.

[jaffa90]

((((((( it's okay and when idling))))))))))))))
What is your idling / tick over rpm?

[mikesaa309]

1500 rpm did notice today tho I was able to start it without choke and it seemed to idle without cutting out like you'd expect with no choke from a cold start was also an off smell as if it was running rich/lean whatever it is though can't think what I've disturbed just by taking out the diaphragms/throttle sliders.

[Hong Kong Phooey]

Have you done the basics, new plugs (gapped correctly), carbs balanced?

Make sure no leaks, hoses in good condition/ routed correctly and clean the carbs out (remove jets, use carb cleaner with cotton buds etc). Keep the jets with the respective carb bodies, don't mix them up.

If you messed up the mixtures you might have guidance settings in the manual (e.g. 3 turns out)

If it has a fuel pump make sure that's working, along with the fuel tap.

[jaffa90]

1500rpm!!!!!!!
It should be 1,000rpm,
also you should be able to twist the throttle from 1,000rpm upwards without any hesitation.
Your carbs need sorting.

[mudcow007]

On my B6 i found the carb sliders to be gunged up, dunno where that had come from

As previously mentioned tick over is around 1k, remember to let it get warm before you piss about with settings though

does it start without choke all the time?

the float height, do a search on here for Pete carb cleaning (awesome post) he made a float guide from card to set the height - easy peasy - 18mm i think?

[mikesaa309]

Yep done all the basic stuff turns out tho there's petrol leaking from the fuel tap but it seems leaking from the metal pipe bit where the fuel hose goes dunno if there is a seal behind there that's gone maybe? Probably could be the reason why it was messing around when I test rode it.

Bandit seems to be too lumpy at 1k rpm well not lumpy just like lights start flickering and just seems too slow of an RPM plus it did 1200-1500 rpm when I first had it so have just assumed that to be the norm lol.

[mudcow007]

tap rebuild kit is about £20 from ebay.

chances are the diaphragm in the tap is gunged up or torn...

20min job

[jaffa90]

https://www.ebay.co.uk/sch/i.html?_odkw=suzuki+bandit+600+carb+kit&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xsuzuki+bandit+600+fuel+tap+kit.TRS0&_nkw=suzuki+bandit+600+fuel+tap+kit&_sacat=0