• 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.

'81 GS850 Won't Start

  • Thread starter Thread starter Mattias44
  • Start date Start date
M

Mattias44

Guest
I know this thread title may wear thin on many members' patience, but I feel like I need some clarification/direction. First a little history:

The bike ran (sorta) when I bought it, but the PO had to use starting fluid to start it and keep the revs above about 1500 to keep it running. I limped it home and started cleaning the carbs. I soaked them in Berryman's for about 18 hours (all together, used 2 gallons, I have no patience). When assembling them, I realized I forgot to remove the pilot air jet, so I paid special attention to it and the passage in the carb body with the carb cleaner/compressed air.

I put everything back on the bike and set up an aux fuel supply to run the engine and it wont start. The PO had pods on but said it wasnt re-jetted (and partly why it ran like crap). I put the stock airbox, sealed with weather stripping, back on. It still refused to start until I sprayed a shot of carb cleaner directly into the upper section of the airbox (into the snorkel does nothing). Once it was running, cylinder 1 was not firing (cold exaust) and it died anytime I took the choke off. I replaced the plugs/caps and noticed they were all a little dirty with carbon deposits.

I am getting spark but now I cant get it to start no matter what i do. It turns over and it sounds like it tries to sputter every couple cranks or so. Feeling frustrated I tested the compression in cylinders 1 and 2 (battery was tired from trying to start it so I only did the LH side) and they were both around 60 PSI and about doubled when I added oil to the cylinders.

Now here are my questions:

1. Could the bad rings as suggested by the compression test keep the bike from starting?

2. If the filter that came with the (used) airbox was WAY over-oiled (as in dripping), would that keep it from starting?

3. When I re-installed the choke plungers, I used a bit of oil to lube them up. Could that oil have clogged something important?

4. I have read on numerous threads here that valve clearances being out of tolerance can cause hard starting, but I feel like it should at least TRY to sputter, even though I haven't (yet) adjusted them.

I'm about to pull the carb bodies off again and re-soak/clean them, but if that doesn't get it started, I'm pinning all my hopes to the valve clearances.
 
#4 wasn't really a question, sorry. Would the valve clearances being out of spec cause it to not start or run at all? BTW this bike has 17.5k miles.
 
1 y es
2 yes
3 yes
4 yes

You're on the right track, if it starts with cleaner it has ignition and air. It just needs fuel

Did you follow the carb cleaning tutorial?

The valve clearances are important, but that alone won't keep it from starting at all

THe low compression is probably a combination of stuck rings and tight valves

Put some penetrating oil into the cylinders to help free the rings
 
Last edited:
7981GS said:
Fully charged battery and new spark plugs?

Daniel
Click to expand...

I have been keeping it hooked up to a battery tender and messing with it once a day so the battery has a full charge. I just put new plugs and caps on it today, although the old ones looked darn near new, save for the carbon buildup.
 
Big T said:
Did you follow the carb cleaning tutorial?
Click to expand...

Yes, i used o-rings from MrRobertBarr and did everything according to the tutorial. The only thing i missed was the pilot air jet, but I removed/cleaned them upon reassembly. They jets themselves were pretty clean so I feel like the dip had ample opportunity to penetrate the passage.
 
Well I went out and tried again before going to bed and miraculously it fired right up with no choke. The only change I can definitively say is that i removed the in-line fuel-filter that (I'm guessing) the PO put in. Next step will be to check out the petcock to make sure the filter element is still good so I can throw away the in-line.

Its still only running on cylinders 2,3, and 4, but my guess is that has something to do with the low compression (hopefully just a stuck ring) in cylinder 1. Would a proper carb sync possibly cure the dormant cylinder?
 
Mattias44 said:
Well I went out and tried again before going to bed and miraculously it fired right up with no choke. The only change I can definitively say is that i removed the in-line fuel-filter that (I'm guessing) the PO put in. Next step will be to check out the petcock to make sure the filter element is still good so I can throw away the in-line.

Its still only running on cylinders 2,3, and 4, but my guess is that has something to do with the low compression (hopefully just a stuck ring) in cylinder 1. Would a proper carb sync possibly cure the dormant cylinder?
Click to expand...
Get #1 cyl firing before you start fiddling with carb sync. Make sure you check for correct petcock operation while you're inspecting it. It would be prudent to check valve clearances - no telling when it was last done.
 
The airbox-to-carb boot on #1 was only partly on and was probably leaking pretty bad. Its starting and running pretty well now, but the idle will hang around 3000 RPM if I'm cruising and pull in the clutch. I've got new boots on both sides of the carbs with new o-rings on intake boots. I've sealed the airbox with weatherstripping and put a new air filter in. I don't have the breather hose connected (PO had pods, so no hose) but I've read that that shouldn't matter and wouldn't cause a hanging idle. Would a proper carb sync possibly help the hanging idle?
 
Yes. You need to synch the carbs. However, the sync measures the vacuum on each of the carbs. The vacuum made by the cylinder is effected by the valve clearances. You need to set the valve clearances before syncing or your sync will be off.

So, valve clearances first and then sync. This should do wonders for the running condition.

Good job and good luck.

Chris
 
You must log in or register to reply here.
Back
Top