Hi guys!! Carbs questions.

[Guest]

Hi All,
new to the forum, and what a wealth of Knowledge!! has helped me so far in getting the GS650L that i have acquired running, albeit badly!
So a few questions to see if anyone can help.

Its a gs650l 1983. Have cleaned, rebuilt and bench synced the carbs. Only seems to be running on 3 cylinders. No 4, is not doing much. have checked leads, all sparking nicely, floats all working and set. fuel is getting in. New Orings on inlets, and rubbers are good.

On my bank of carbs, I have the vacuum port between 1&2 carb which is connected to the petcock, and but I also have another vacuum port between 1&2 carb, identical to the left hand one, which is has nothing attached to it, but is sucking in air. Does his need to be blocked? or am i missing something?

Have not done the valve clearances yet, so wondering of this could be stopping no 4 cylinder firing up.


Thanks in advance guys.

Alex

[Steve]

Welcome and all that, but I am a bit confused. You have a vacuum port between 1&2 and you have another one between 1&2?

The port that is on the "T" between 1&2 and 3&4 is not a vacuum port, it is a vent. The hose on that will get draped over the airbox and not connect to anything.

The vacuum port that is supposed to go to the petcock is actually on the top of the engine side of #2 carb. Note that they are numbered from left to right, as you are sitting on the bike.

Valves should be adjusted, and they should be done before doing a vacuum sync on the carbs.

.

[tom203]

Get to the valve clearances (they get smaller and smaller).. As to hoses...

http://members.dslextreme.com/users/storagecliff/images/hose_locations.html

[Alex Brady]

Welcome and all that, but I am a bit confused. You have a vacuum port between 1&2 and you have another one between 1&2?

The port that is on the "T" between 1&2 and 3&4 is not a vacuum port, it is a vent. The hose on that will get draped over the airbox and not connect to anything.

The vacuum port that is supposed to go to the petcock is actually on the top of the engine side of #2 carb. Note that they are numbered from left to right, as you are sitting on the bike.

Valves should be adjusted, and they should be done before doing a vacuum sync on the carbs.

.

Cheers for the response. Yes the vents are on the Ts between the carbs, which are both on and draped over the airbox, the vacuum line is attached to carb no 2, as it should be, on the side of the carb facing the engine, but there is an identical port on the number 4 carb which is just attached to nothing. It sucks air in the same as the number 2 carb does for the vacuum line. Only just picked up the bike. But have had a GS1000 before and remember only one vac line so, not sure if someone has rebuilt the carb stack at some point.

[Alex Brady]

Get to the valve clearances (they get smaller and smaller).. As to hoses...

http://members.dslextreme.com/users/...locations.html

Thanks Tom. Yes had a look at those pics to check before, and the vacuum port on carb 2 is same, but I have exactly the same port on carb 4 as well? Odd.

[steveb922]

Pretty sure that's not right. Sounds like your carbs may have been messed with. Can you post a pic?

[Alex Brady]

Pretty sure that's not right. Sounds like your carbs may have been messed with. Can you post a pic?

Yes definitely think something is wrong! Will post a pic this evening whn I'm back from work.

[Steve]

Sounds like somebody broke a #4 body and substituted a #2 body.

If you can post a picture of the right side of the carbs, it would help a bit.

The 'fix' could be as simple as capping off the vacuum port.

.

[Alex Brady]

Sounds like somebody broke a #4 body and substituted a #2 body.

If you can post a picture of the right side of the carbs, it would help a bit.

The 'fix' could be as simple as capping off the vacuum port.

.

Hi Steve, yeah that's what I think carb internals had slightly different parts in them. I have a spare no 5 carb which I can swap. But will take a photo when I get in from work.

[Alex Brady]

Right, so a pic of what i was talking about...carbpic.jpg

[Steve]

Wow. Somebody spent a LOT of time with that carb.

That is, indeed, a #2 body, but someone has fitted a #4 throttle shaft in it. Except for the vacuum port, it actually looks OK.

Cap the port, but put a clamp on it (can be as simple as a zip-tie) so it doesn't blow off, just in case the bike hiccups.

.

[Alex Brady]

Wow. Somebody spent a LOT of time with that carb.

That is, indeed, a #2 body, but someone has fitted a #4 throttle shaft in it. Except for the vacuum port, it actually looks OK.

Cap the port, but put a clamp on it (can be as simple as a zip-tie) so it doesn't blow off, just in case the bike hiccups.

.

Cheers mate. Will try that. See if it works. If not will prob just change out the carb for a no 4. Will be doing the valves this weekend.

[Alex Brady]

Replaced the carb with a NOS no 4 carb, and runs much better, still have to do the valve clearances, but all cylinders firing well now.