Won't run after valve adjustment!

[MikeG]

I've done the valve adjustment on my 16V 1982 GS750E 4 times now with nary a hitch until tonight.

Today I did two things differently. I didn't use a new gasket as I didn't have one but was planning on riding a lot in the next month. I also used a torque wrench to torque the valve covers bolts to 7 ft lbs.

When I got it all back together it started right up with choke but as soon as I let the choke in it stalled. After a couple more of these starts each time getting harder to run it just wouldn't. I checked all the connections I had undone to confirm I didn't leave anything disconnected.

It feels like a fuel flow issue but the petcock is working.

The way I adjust is to use a .004 tappet gauge and tighten it just snug on that. I figure it is right in the sweet spot of .003-.005 so I should be ok, right?

I had to walk home 45 minutes tonight and will he headed to where I park my truck in Wilmette in the morning (just what I wanted to do on a day off!)

Any ideas on what to eliminate as possibilities?

 

[almarconi]

Will it run if left on prime?

You should probably sync the carbs after you adjust the valves. Not sure this would cause your problem but it should be done.

How about the battery or your charging system? When was last time battery was replaced. Is the charging system working?

 

[Steve]

Most likely ones that comes to my mind?

Did you get the plug wires on the correct plugs? :-k

Did you move the throttle cable to affect idle speed? :-k

.

 

[MikeG]

New agm battery two weeks ago. Luckily the spark plug wires are labelled but I'll check them in the am as well as picking up a new set which is overdue. I didn't mess with the throttle cable at all.

When I twisted the throttle it bogged and quit so the first thing I'm going to recheck in the morning when I have plenty of time is the fuel. I didn't try running it on prime, that'll be the first thing I do.

 

[Guest]

Make sure you have fuel in the tank - I've had times when I couldn't figure out why my bike wouldn't start or stay running, only to realize I was out of fuel. Don't trust the fuel gage.

Also verify the vacuum line to the petcock is attached...

 

[Steve]

You shouldn't have to "run it on prime", just set it to prime for no more than a minute to fill the carb bowls, then set it back to RUN.

And, it's normal for the carbs to bog if the "choke" is still on more than about 1/4. Our carbs do not have a normal, automotive-style choke, they use an enrichener system that opens a separate set of air and fuel ports when you activate your thumb lever. The high engine vacuum pulls the air and fuel through the enrichener passages, providing the rich mixture that is necessary. If you open the throttle, you destroy the high vacuum and the engine tries to run on the normal jetting, which just does not work too well when the engine is cold.

If things are properly adjusted, you should only need to use your "choke" for about 30 seconds (probably set to no more than half), then get on and ride. About the time you are in second gear, you sould be able to turn off the "choke".

.

.

 

[Guest]

Spark/Fuel/Compression
Not that many factors

 

[MikeG]

Yeah, it should be fairly simple to track down the problem. It just hit me at the worst time, last day of a stressful week, 45 minutes from home, no time to work on it, and I was planning on going for a ride tonight!

I knew what you meant about the choke, normally I set it about half, start her up and ease it off after 15 sec or so. This time, it just bogged and quit

Ah well, now I can get there early and have all morning to work on it.

 

[MikeG]

Success! I replaced the spark plugs while I had the tank off and figured out that somehow the vacuum line got pulled off from the petcock where I couldn't see it.

Off to ride, see y'all later!

 

[BassCliff]

Hi,

Great news! I'm glad you found it. Sometimes it's the simple things. If I don't triple-check my work I often miss stuff like that too. I guess I'm getting old.


Thank you for your indulgence,

BassCliff