• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

sounds like an air leak...

  • Thread starter Thread starter Jagir
  • Start date Start date
J

Jagir

Guest
Hey gang,

Hoping for some help in diagnosing the following problem with my 1980 GS400.
Starts no problem, is all fine until it warms up (5-10 minutes of idle) then the throttle gets stuck at 4000 rpm. All I can do is play with the clutch at the stoplight to keep it lower.
There is some damage to one of the boots between the airbox and the carbs, but I passed a propane torch (unlit) around there while it was running and found no change.
Any ideas where I should go from here? (Obviously I should replace the damaged boot, but without having a parts shop close by, are there any other tests I can try?)
thanks,

J
 
Last edited:
Jagir said:
Hey gang,

Hoping for some help in diagnosing the following problem with my 1980 GS400.
Starts no problem, is all fine until it warms up (5-10 minutes of idle) then the throttle gets stuck at 4000 rpm. All I can do is play with the clutch at the stoplight to keep it lower.
There is some damage to one of the boots between the airbox and the carbs, but I passed a propane torch (unlit) around there while it was running and found no change.
Any ideas where I should go from here? (Obviously I should replace the damaged boot, but without having a parts shop close by, are there any other tests I can try?)
thanks,

J
Click to expand...

Hmm.... haven't heard of the propane method for checking for intake leaks. Interesting. Sounds much less messy.
 
propane enrichment test, haven't heard of that in years it was used to check the a/f ratio of carbs at idle. but remember propane ignites...
 
I was hugely surprised by how much better my friend's bike idled and rode after I sealed up the leaks between his airbox and carbs. So, yes, I'd say that's the most likely culprit. If the plug that corresponds to that damaged boot is white, then that is almost certainly the culprit.
 
nabrams said:
I was hugely surprised by how much better my friend's bike idled and rode after I sealed up the leaks between his airbox and carbs. So, yes, I'd say that's the most likely culprit. If the plug that corresponds to that damaged boot is white, then that is almost certainly the culprit.
Click to expand...

sealed with what?
j
 
Ideally, you should seal it with a new, undamaged boot - but, for testing purposes only: Use silicone sealant (let it dry for 24 hours) on the suspected areas and re-test.
By the way: No venom intended here, but this has been discussed a million times on this forum - Have you used the search feature? It will save you tons of time and money.

Jagir said:
sealed with what?
j
Click to expand...
 
Last edited:
If the head on the 400 has o-rings between the engine side of the carb boots you should consider changing those.
 
You must log in or register to reply here.
Back
Top