Carb sync and valve adjust-still not too happy

[BassCliff]

If you think the bucket might be hanging up, I have scads of them. If you think you might need a couple, let me know, if you'll cover the shipping I'll just give you a few.

Hi Matt,

PM sent. Thank you!


Cliff

[SqDancerLynn1]

With choke out it runs. That says you still have carb problems or maybe lack of fuel. Have you checked the petcock, tried running on prime..

[ssanderson111]

With choke out it won't die.....but it also won't rev up past 4-5,000 rpm. That was with the petcock set to "on". I'll try it with the petcock set to "pri" later today.

[robertbarr]

At this point I'd suspect the petcock screen, especially following the tank liner work.

I had a similar problem that developed on an '82 850, and it drove me nearly batty (OK, short drive...) until I finally pulled the petcock for the umpteenth time and gutted the screen. That solved the problem.

I don't know WHY that solved the problem, because I had tried checking the flow rate (into a fuel can) and it flowed fine -- full tank or nearly empty, made no difference. On the bike, under operating conditions, it would starve the carbs so much that the bike would stumble a bit and die. The lower the fuel level in the tank, the more likely it was to happen.

I dubbed the operation a 'screen-ectomy'.

Just one more idea for ya.

RB

[ssanderson111]

Robert, are you suggesting that I remove the screen from the plastic skeleton completely, while leaving the skeleton attached to the petcock? Or should I completely remove the whole filter (for lack of a better word? it looks like a filter!)?

[Ranger]

If you remove the plastic piece that is the filter completely, keep in mind you're going to lose your reserve as well.

[1948man]

http://www.thegsresources.com/_forum/showthread.php?t=168187&highlight=breather+hole

Last post in the above thread would seem to doubt that the vent hole is a factor but I guess that has been ruled out anyway.

[robertbarr]

Robert, are you suggesting that I remove the screen from the plastic skeleton completely, while leaving the skeleton attached to the petcock?

That's what I did to mine, and it solved my problem. Of course, it leaves you pretty much unfiltered. There are usually tiny filters on top of the inlet seats, but I think those were intended to be a 'last resort' protection.

That opens the 'auxiliary filter' can of worms, but that's another topic.

[Steve]

That's what I did to mine, and it solved my problem. Of course, it leaves you pretty much unfiltered. There are usually tiny filters on top of the inlet seats, but I think those were intended to be a 'last resort' protection. ...

I don't think the VM carbs have those little filters, do they?

I have only done a couple sets of them, but don't remember seeing any.

.

[Suzuki_Don]

I don't think the VM carbs have those little filters, do they?

I have only done a couple sets of them, but don't remember seeing any.

.

Steve, he has CV carbs on the bike going by the pics in his first post, but we don't really know for sure as no-one has mentioned what bike it is that is being worked on.

The other issue I am a bit concerned about is the excess shim clearance on exhaust #2, up to .5mm. Others are talking about a stuck bucket, but if this was the case it could only be stuck up which would create less clearance to the cam lobe. The bucket can only go down as far as the valve stem will allow it, unless the valve springs are broken which has been mentioned before. Also it has been mentioned that there is a lot of white smoke out of the #2 exhaust pipe (is this a coincidence).

I think a compression test is in order. Remember the old rule, don't start adjusting carbs and looking for fuel problems until the engine is in mechanically A1 order first.

[tas850g]

When I dipped my vm's I don't recall any screens.....but maybe I missed them.

Waiting to see if by running the bike with the petcock on pri will make a difference.

[Tom R]

Also, make sure your fuel line isn't getting kinked when everything is put back together.

[kdo58]

I had a similar problem, it ending up being a small piece of rubber from the fuel hose, I would take the carbs off and check the fuel bowls and did not see any thing.
I finally took them completely apart, and the small piece of rubber would move back and forth between different carbs in the transfer tubes between the carbs. It was stuck behind the float needle seat.

[ssanderson111]

The bike is an '81 650 G. Carbs are CV

When we first check the #2 exhaust clearance, we got less than .04mm. We changed the shim accordingly. With the new shim in place, the reading was over .5mm! The bucket was visibly not returning at high as it should be. We left the appropriate shim in and started the bike up after adjusting all of the other clearances. The engine was noisy as heck at first, but as it warmed up and we gave it some revs the noise went away. Also, when using the tappet tool, the bucket applied resistance as it was depressed...

The fuel line isn't kinked at all. I doubt there is anything obstructing the fuel connections between carbs as I had them apart and cleaned a few weeks ago.

I'll be able to see how it runs with the petcock on "pri" tomorrow and will update you asap. Thanks again for your help! Keep the suggestions coming!

[kdo58]

The fuel line isn't kinked at all. I doubt there is anything obstructing the fuel connections between carbs as I had them apart and cleaned a few weeks ago.

I had just cleaned mine.