Idles .. running .. then revs drop and stalls, any ideas ?

[wullvfr]

is it a erratic idle,up and down etc........

usually this indicates a vacuum leak!!!!!

it sounds as if you have done not a bad job.

and if you have set the idle whilst warm then it doesn't leave much else.

what about valve clearance,have you ever checked this?

this is also a culprit for poor idle


william

[400_Rider]

Hi William :)

No it's not erratic idle, well it starts off ok, but as soon as I start to ride, literally 2 mins into the journey come to a junction and it'll just wanna stall all the time.

I do set the idle perfect when the engine is warm, well I say perfect I set it around 3,000rpm any lower and it'll just stall anyway but as soon as I ride it, revs wont stay at that

Can you explain more to me please what you mean by vacuum leak ? does that mean just the rubbers that the carbs go into on the engine ? or can a vacuum leak mean something else ?

I have not checked the valve clearances, kinda don't know how to do it and the thought of that scares me a little, although I would give it a bash if theres a how-to guide anywhere ?

Thanks again mate.

Matt :)

[wullvfr]

vacuum leak is where too much air is getting drawn into the cylinders,usually this is when the carbs are not seated correctly on the intake rubbers....

is all hoses connected correctly!!!!

3000rpm is too high,when you are starting the bike is it with or without the choke,make sure the choke is working correctly!!!
does the revs rise when you put it on and go back to normal when you put it off.

is the bike running on all 4 cylinders?next time you start the bike check the headers and see if they are all hot!!!

the main problem you are having is the bike stalling usually after running it,under load and stopping at junctions,does it do this everytime?


william

[400_Rider]

Howdy Will :)

Yeah I defo make sure the carbs are into the cylinder rubbers proper, the only other hoses is from one of the vacuum pipes which goes to the tank and the fuel feed, I can't see any other hoses.

I have to use choke to start the bike and then take the choke off and revs drop and I usually have to increase the idle to compensate so it will idle as it goes too low.

Yes it did stall all the time when stopping at junctions.

I have been out to the bike this morning and it wont start ! this is gettin unbelieveable now ...

I put choke on, no throttle and it didnt fire, so I left it a mo, tried again only this time with 50% throttle and it sounded like it wanted to start but didnt, and that was cranking it more than I would have like to have done, maybe 6 or 7 seconds of constant cranking, after that I left it and come away and been sat ere thinkin about it ever since.

I wonder if the problems are related ? the bike wont ever start off the button but will eventually if I jump start it or bump start it.

The bike has new iridium plugs in it and a coil upgrade from a gsf650, neither of these upgrades inproved matters nor made them any worse.

I am wondering now about if I am getting a good enough spark or not, could the fact that it wont start off the button on its own point to the CDI ?

I guess I should take the plugs out and see what kinda spark I am getting ? I tried this last time and there was a very feint blue spark that I only saw once or twice, so then I got the coils, havent tried this again since.

Sorry to be a pain lol any ideas what I should try next ?

Thanks in advance and Merry Christmas :)

[wullvfr]

the problem could be electrical,but i would not have expected this to cause the idle too be high!!!!!!

check all connections by the cdi,coils!!!!

next time you get the bike fired check to see if each exhaust is getting warm,this indicates if each cylinder is firing!!!!!

because the bike keeps cutting out at junctions you may have set the idle too high to compensate for this problem meaning the idle will actually be fine once set correctly.

do you have a multimeter?......

there could be a weak spark and possibly bumping or jumping the bike helps it start because of this but i would check the charge rate at the battery next time it is started,and check what voltage the battery has in it at the moment before starting the bike.



william

[400_Rider]

Thanks for that Will.

I'll get back to you on those points when I get it started again, had the bike in the house yesterday, stank of fuel, feel ill so am gonna have a day away from the fumes

Cheers :)

[gsxr400 racer]

adjust the fuel screws try in one half turn at a time then back to what you had then out 1/2 turn till it stops

[400_Rider]

Do you think it could just be that ?

I have stripped the bike down to next to nowt, ordered an auxilirary fuel delivery system so I can work on bike without tank and airbox on, I've also ordered a compression tester and my next purchase was gonna be a colortune to see what colour the spark was when combusting, supposed to be blue and if its red means too rich, sommat like that.

This bike will run, oh yes it will