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how do you unstick a stuck throttle valve?

Posted: Sun Jun 22, 2008 2:43 pm
Author: 02GF74
basically the cylinder that holds the main jets and moves up and down (well usually!) inside Mikuni carbs is stuck.

pulling on the throttle results in the hand grip twisting on the bars :o and I've removed the tops and can feel cylinder 2 carb throttle is stuck. :(

trying to avoid removing the carbs; so far have sprayed lots of release fluid and carb cleaner and still no joy. tempted to put a screwdriver or simular to attempt to lift the slider but that does not seem a good idea (or not got that deperate!)

Posted: Sun Jun 22, 2008 3:03 pm
Author: DogsbolloxofZ1B
I suggest you remove the carbs and have a good look at this, its very unusual for this to happen. Are you sure there isn't something external to the slide that's causing this?

Posted: Sun Jun 22, 2008 3:15 pm
Author: 02GF74
well the bike ran ok but has been left standing a few years with nothing done to it.

I remove the carb lid and can see the top part of the mech moving but using a finger stuck into the opening do not feel the throttle body slider move at all.

I cann imaging that anything has let go or come undone just by standing so am assuming the lack of lubrication or some moisture has cuased it to seize.

it may well come to takingn the carbs off .,..,. :(

Posted: Sun Jun 22, 2008 3:33 pm
Author: london calling
The only way to check and clean the carbs properly is to remove them and have them ultra-sonically cleaned.
With the carbs stripped you can check everything thoroughly and see if any new parts are required.

Posted: Sun Jun 22, 2008 5:05 pm
Author: Steve R
This happened on mine throttle was very very stiff when I bought it, it really had not been used for a while, tried as you have, sorting it without taking the carbs apart with no success.
In the end took the carbs apart and one throttle slide was very very tight to move up and down; I had not come across this before at all, I cleaned it with carb cleaner and solvol but no difference; in the end I sanded it down with 1000 grit wet and dry, cleaned it up and kept checking until it would slide OK then put it all back together, no problems since! and that was 3 years ago, but as I said I cant understand how it could happen?

Posted: Sun Jun 22, 2008 9:37 pm
Author: 02GF74
in the end I went for broke - held on to the throttle handle and pulled it open - bit more carb cleaner and it is freeed up. cracking the throttle is smooth and they shut off with a nice reassuring clunk. the spirit of project T103 must have been with me as usually go for broke ends up in tears.

Posted: Sun Jun 22, 2008 10:03 pm
Author: Iain marshall
Good to hear you got it sorted.T103, that was a long time ago :wink:

Posted: Mon Jun 23, 2008 6:59 pm
Author: Davy Doherty
Yea nearly 40 yrs...