no idle!

[the-honk-bonk]

Hey people, had to replace my carbs after the old ones got thrashed in a crash. Now she won't idle on cold, and doesn't want to know about choke.Idles ok when warm. Had to replace the exhaust also..had to replace everything practically.
Carbs are balanced.
No air leaks.
New main jet size #102(came with new carbs)
Old jets #96
Race exhaust (straight through).
Upgraded air filter.
Plugs are light brown..

Dont know if this means anything but the temp gauge stays below the 'normal ' mark when on the road, it used to sit perfect on the line..(obviously it rises at the traffic lights and stuff)

I think my problem is over fueling possibly at idle since it wont take the choke.

Anyone any ideas????

[RedexRobB]

What colour are the plugs? That will give some indication of the fuelling.

[the-honk-bonk]

Light brown on the ceramic..

[RedexRobB]

I've just noticed u actually said that. Sorry.

How do you get it to run,hold the throttle open?

[the-honk-bonk]

yep, give it a few twists at first the revs shoot up, after 3 or 4 twists it doesnt do so well(it sounds exactly the way when I get fuel freeze in winter!!).
Generally she starts on the button, idles fine for a few seconds then its a downward spiral to 0 revs if you dont hold the throtle at about 2000rpm-even at that it doesnt sound perfect.. If she conks out, you have to wait awhile-put on the gloves helmet etc and try again, and keep warming it up. Once shes warm the revs stay put at about 1500 or so. No flat spots all the way to the red. I get my fuel from a variety of stations, filter is clean...

[RedexRobB]

Do u get a clean spark from the plugs?

[the-honk-bonk]

That I dont Know, I will check the 4 of them this evening, looking for bright blue sparks I suppose. They are about 1 1/2 year old. Will post up results this evening.
Many thanks.

[RedexRobB]

Should be a fairly blue spark yes. Also worth checking the earth points are nice n clean on the top of the gearbox n frame.

Also give the ht leads a look over, make sure they are well screwed into the plug caps n coils. Some times its worth cutting about 5mm off the ht lead n rescrewing the caps so there's a fresh contact, but see how u go with the plugs first.

Something I've done in the past when I had an idle problem, is clean the plugs and run it under 3k, then whip the plugs out n check, fingers crossed you'll be able to check which cylinders are playing up by the state of the plugs.

[the-honk-bonk]

Thats some good ideas. ok, bluey purple spark on all plugs. All earths are clean as far as I know. I did notice a light ticking noise around the coils-hard to destinguish with the engine running but its there and its not mechanical, im gonna replace the leads(have some fresh ones) to see if im loosing power from one of them..ill try the pulling out the plug technique too and see which one is acting the maggot..weekend job!

[RedexRobB]

That other ticking noise could well be your problem them. I had the same problem on an XJR400 i used to have, and made it a giraffe to run as the lead was breaking down and shorting on the frame. And exactly as you describe once it was warmed up it didnt seem to have a problem.