Chunky start in the morning...

[2wheelN00B]

Ok, but really. I'll give it a try, but isn't the petcock the ONLY reason it could be flooding? If fuel is getting to the carbs when it's off, the petcock is the only culprit, correct?

[BassCliff]

Ok, but really. I'll give it a try, but isn't the petcock the ONLY reason it could be flooding? If fuel is getting to the carbs when it's off, the petcock is the only culprit, correct?

Yes, that would be my diagnosis. But there may be more than one problem. The definitive words of wisdom on the subject have been collected on my website on the following page:

Carb Notes (sync, etc)

See the "Overflowing Carbs" article. My thanks to Mr. bwringer.


Thank you for your indulgence,

BassCliff

[2wheelN00B]

Ok

Finally turned the bike off to work on it, but not before...

I let it sit a week because it rained all week, now the only way it starts is with starter fluid, and I started it up this evening and revved it up some and around 4000 to 4500 RPM's it loses power & dies.

But, the petcock was replaced. I can't even test if it did what it was supposed to do now, due to this issue.

[Don-lo]

You probably fouled a plug. One of your needle valves is probably leaking very slowly, so that the fuel in the line (after the petcock) is draining off into one or more carbs. Overnight, it was enough to cause just a rough start, but after a week it was enough to foul a plug. Putting the bike on the centerstand can slow the drainoff.

[Steve]

STEVE:

IT does start better, much better after it's warmed up. Valves, as in, a carb rebuild? Why, for my own general knowledge, would that be letting the carbs flood? I guess I just don't know the function of the valves.

No, the valves are the devices on the top of the engine (under that hourglass-shaped cover) that allow the mixture from the carbs into the cylinders to be burned, then allows the burnt mixture out through the exhaust pipes. When these valves are mis-adjusted (usually too tight), they do not properly contain the mixture in the cylinders for combustion, making it hard to start the engine.

Look on BassCliff's site, he has factory service manuals for your bike, as well as personalized tutorials (with pictures) on how to adjust the valves. If you look at the bottom of my signature line (the section below every post I make), you will see that I offer an Excel spreadsheet that helps determine what shims you might need to adjust your valves. Read through the procedure several times. It's not hard, but does take attention to detail. Feel free to ask questions. We have all had to do this, many of us have done it MANY times.

.

[Larry D]

So, you say, the petcock was replaced.....by you ? Or did you find out the the previous owner replaced it ?

Regardless if the petcock is new, that's great !! Now, for the next step.

Dip and rebuild your carbs with new o-rings from cycleorings.com and using this guide.

http://www.thegsresources.com/gs_carbrebuild.htm

After that, get a new valve cover gasket and adjust your valves, using this guide.

http://members.dslextreme.com/users/bikecliff/images/16valve_adjustment.pdf

After these basic maintenence items are done, you'll have a great baseline to get the carbs tuned in and will be riding in style.

EDIT: You don't need shims. Steve gets his 8 and 16 valve engines confused sometimes.......Your (our) bikes have a tappet screw adjustment for the valves. Loosen a nut, adjust the screw until it's in spec and tighten the nut back down. I highly recommend getting tappet feeler gauges for this task, much easier to use than the standard straight feeler gauges.

[Steve]

EDIT: You don't need shims. Steve gets his 8 and 16 valve engines confused sometimes.......

So true, so true. I saw the "750L" and did not notice that it was an '81.

HOWEVER, the intent remains the same ... ADJUST THE VALVES.



(Thanks for the correction, Larry.)
.

[Larry D]

So true, so true. I saw the "750L" and did not notice that it was an '81.

HOWEVER, the intent remains the same ... ADJUST THE VALVES.



.

+1

Adjusting the valves is like giving candy to a kid.....they love it !!

[2wheelN00B]

Ok

I replaced the petcock.

Replace Plugs (?)
Rebuild Carbs
Adjust Valves ( where would I get a tappet feeler gauge? )

I should probably suck it up and do it now eh? I was waiting for winter, but it seems it can't wait that long.

[Larry D]

You probably should go ahead and do it now......depending on where you are, there's not much summer left anyway.

I forget where I got my tappet feeler gauge. Just google it. An auto supply place around you may have them, but, none around me did. I know I ordered them online somewhere. It's only one gauge, not a set of gauges. Make sure you get the one that falls within the spec of the needed valve adjustment.

Make sense ???

EDIT:: Here you go....

http://www.denniskirk.com/jsp/produc...afCatId=&mmyId=

[DanTheMan]

A good, large Sears store also has tappet feeler gauges in their tools section. Oh yeah, don't use starting fluid unless you'd like to fry a piston for lunch. The instant heat of ether combustion is very bad for your engine that the ether does.

[Larry D]

Oh.... I forgot. Because of the way the valves are, you can adjust two at the same time. Don't quote me...but, for example, you could adjust #1 intake valve at the same time do #3 exhaust valve. Not sure if that's the sequence, just using it as an example.

So, if you have a helper.....I'd get Dad.....do two at once. In which case, you're going to need two identical tappet feeler gauges.

It's not a requirement to do two at once but it makes the job go a little faster.

[2wheelN00B]

Larry,

I will look into this.

Dan,

Thx.

Will keep updated. Hopefully soon.

[fenderfreek]

My local AutoZone has the big thing of tappet gauges for like $6 or something. I paid $4 I think for the single tappet gauge I needed from Z1, so it's your call. You really only need the one, but for an extra couple bucks you might can get a whole set.

The whole thing might take you a good 2-3 hours the first time as you try to learn everything, but when I do it again, I know it will take no more than an hour. It's a very simple process once you get it down the first time. Also, get a valve adjuster tool - I did mine without one and that's probably what took most of my time. It'll be worth every penny next time around.

[Steve]

Actually, you will want to get two tappets gauges anyway. Since you have two valves that are actuated by one lobe on the cam, the rocker is forked to reach the two valves. I have heard that it is best to have feelers under both of them and adjust them both at the same time to make sure the rocker is not cocking sideways, affecting your measurements.

.