• 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.

1979 GS1000L Spark but not firing on Cylinders 3 and 4

dubwicht

dubwicht

Forum Apprentice
I am trying to trouble shoot this problem. The first day I started the bike it fired on cylinders 1-3 and now it fires only on 1 and 2. I didn't do a complete tear down of the carb the first time but am doing that now. Just wondering if folks can recommend other troubleshooting to rule out something else. I adjusted the valves nd timing over the winter and installed new points.
 
Last edited:
dubwicht said:
I am trying to trouble shoot this problem. The first day I started the bike it fired on cylinders 1-3 and now it fires only on 1 and 2. I didn't do a complete tear down of the carb the first time but am doing that now. Just wondering if folks can recommend other troubleshooting to rule out something else. I adjusted the valves nd timing over the winter and installed new points.
Click to expand...

You're learning the hard way.

Read the Newbie Mistakes thread linked in my signature. If you can't see my signature, go into your profile and turn on the feature to view signatures.

What you will learn is to do maintenance first, before hitting the starter button. Old motorcycles need love. They don't do their own maintenance. I don't even bother to try to start the bike until all the standard maintenance is up to date. And YES, that includes valve adjustment.
 
I have completed a good number of the recommended newbie stuff including brakes, new rectifier/regulator, tank cleaning, petcock rebuild, new intake boots and o-ring, Rotella oil etc. I have the other type of Mikuni carbs and not the CV type. I installed new coils as well. I didn't do the full dismantle because they were very clean.

The cylinder 3 and 4 plugs were wet with fuel. I have read that it could be a carb sync issue in that the two cylinders were so far out that they were not getting fuel. It didn't look that way when I dismantled them. Partially plugged fuel passages? Not the issue. Idle jets for 3&4 seemed to be partially blocked but no material came out during cleaning. It may have been my imagination.

I was experiencing fuel overflow from carb 1 - the float was slightly higher.

Ultrasonic cleaning is next. I will check compression as well.
 
Last edited:
You must log in or register to reply here.

Similar threads

peteGSX
1982 GS450 - No Spark
Replies
11
Views
121
peteGSX
peteGSX
dandypop
GS850G Won't Start, Electrical Issue, No Spark
2 3
Replies
54
Views
473
dandypop
dandypop
K
Sparks, Zats, Ignition Coils, and Gas Mileage
Replies
4
Views
109
kemp
K
crazyramen
Low Compression in 3 Cylinders 100 Miles After Rebuild
Replies
16
Views
165
rphillips
R
D
No Spark on 2 and 3! Frustrating as can be.
Replies
7
Views
142
pdqford
P
Back
Top