H1 Dies off choke

[lozza]

ust picked up a H1 that has been stood for 2 years.

It will start on the choke, and then idles at 4000+ RPM but dies if it is taken off - it does run if i use the throttle but quickly dies if left to idle.

I've had the carbs out, cleaned and checked them thoroughly and they are in good condition. i didn't check the float heights but it ran before it was stood so i can't imagine they have changed?

I've also drained the tank and filled it with new fuel and put a new fuel filter in and have run it for long enough to make sure all the old fuel is out of the system.

Things i have noticed -
-the fuel filter only fills up a third but i can see fuel flowing through it.
-there is a gap of about 1 mm between the two halves of the airbox at either side.
-the revs pick up SUBSTANTIALLY if i partially cover the airbox intake both on and off the choke.

ive tried screwing the idle adjuster all the way in and out but still no luck.

ive tried to give as much info as possible here, any ideas??

[lozza]

Had a look at the rubbers that sit against the carb mouth.

3 out of 4 of them have the ends a bit bent and folded over. could this cause the problem im experiencing?

Good one:

Bent one:

[banner001]

bike is running lean by the sounds of it - thats why it needs choke - for extra fuel, and explains why reducing the available air (by covering airbox) makes the bike pickup better.

you have 4 pilot adjuster screws located underneath each carb, you need to screw each in clockwise until it starts to get tight and you need to measure how many full turns this took (i.e. 2 and 1/2 turns clockwise, or 1 and 3/4 turns etc...) they should all be the same.

as you are lean you need to screw them in slightly, so if your current settings are all "2 turns out from fully in", try 1 and 3/4 turns out from fully in, or maybe just 1 and 1/2, turning them this way richens the mix, going the other way leans the mix.

[lozza]

Ok so that does make sense and im going to just go ahead and do that because im sick of not being able to ride when the weather is so ridiculously nice out...

but surely this is just covering up a problem somewhere else? I checked the pilot screws and they were all at 2 and 1/4 turns as per the manual, if its supposed to run like this but doesn't then I'm getting excess air in right?

[tomrowley20287]

My bike would stall above 4000rpm when I first got it too.

Re strip and clean your jets, blow them through with compressed air, rebuild them at re-set all the mixture screws and that should sort you out.

Your problem is the transition from one circuit to another...

Up to 4000k is the idle circuit (I think) and above that it the main circuit (I think)

So re-clean again extra thoroughly.

[lozza]

My bike would stall above 4000rpm when I first got it too.

Re strip and clean your jets, blow them through with compressed air, rebuild them at re-set all the mixture screws and that should sort you out.

Your problem is the transition from one circuit to another...

Up to 4000k is the idle circuit (I think) and above that it the main circuit (I think)

So re-clean again extra thoroughly.

Think you're right there mate just took it apart again and got the pilot jets out which i managed to miss last time.

2 out of 4 were completely blocked - hopefully I can get a set before this weather dies down.

[tomrowley20287]

Don't buy new ones, just clean the old ones! Get some brake cleaner and soak them then blow them through.

[lozza]

Don't buy new ones, just clean the old ones! Get some brake cleaner and soak them then blow them through.

been soaking them in carb cleaner, managed to make some progress on one but the others getting no where - is brake cleaner any better?

[banner001]

they need to be sonicated ideally, its the only way to remove the dirt.

[lozza]

Ok left them a while longer in the carb cleaner and cleared the blockage!! ticks over and runs without choke thanks all