Carb Trouble

theres to sets of two jets two under the top lid under rubber diaphram ... and two under the bottom fuel bowl ....i would check the rubber diaphrams for holes and that there seated properly also check the slides to see if anyone has drilled holes to modify them if you found one set of jets the wrong way around check the others oposite end

 

kmoe also posted this .....
By air jets, he means the ones under the top hat, below the slide diaphragm. All of the service manuals have their positions labeled incorrectly.
This is the corrected image:

 

RickCoMatic posted it; I just borrowed the image.

 

I linked that picture. Everything is put together correctly. Its just a matter of making sure everything is clean, sealed, working, and the carbs are connected to the bike properly.

 

i dont know much about head gaskets on air cooled bikes but for some reason im thinking head gasket or warped head for someone just to dump it on its side like rubbish for so long and you having suposedly saying it got good spark turning over and carbs all good and clean

 

I apologize for missing this earlier.

Without a way for pressure to equalize in the bottle, fuel will stop flowing as soon as enough gasoline flows out to cause a low-pressure area in the bottle. Vent it.

 

I would not jump to that conclusion.
Head gasket failures do occur, but even then a bike will usually run.

 

Ruined the rubber on the valve for the float and the plastic for the choke to slide with carb cleaner so I got to replace those. As soon as I put the carb back together (healthy) I'm going to try and vent the water bottle. It makes sense that the vacuum won't work against the pressure in the bottle; I suspect that to be the problem.

 

not exact same carby but gives you the gist

 

Check your valve clearances and compression test too.

 

If you're sure you're getting gas into the bowls, but it's not getting to the cyl, then either your floats are not set right,or you have other clogs there

 

Finally got the carb put back together and I borrowed a dirt bike tank and it starts up! Lesson learned; vent necessary. Thanks everyone for the help (even if you gave bad advice -- we're all here to learn). I'm having difficulties trying to get it to idle now. I started another thread asking for help with the idle problem; I'd appreciate any further input helping me get my bike running.

 

I noticed the thread, but didn't catch that this was the same bike. Please keep one thread per machine so we can look at everything that was done previously.

 

From the other thread.

 

K-moe: "
Start by telling us how you cleaned the carbs. Did you do a full dissasembly, dip, and replace the throttle shaft seals?
Did you perform a bench synch?
Are the intake boots cracked?
Did you replace the vacuum caps and vacuum line for the petcock? "

Full dis assembly.
Soaked the smaller pieces and used q-tips + carb cleaner on the rest.
Replace the throttle shaft seals with a homemade fiberglass ring (I think we're talking about the same thing.)
No bench sync.
One is cracked but its before the fastener, not between the carb and engine.
The current petcock doesn't have a vacuum line. I should probably get a new gas tank asap.

 

Really I'm not expecting anyone to say "do this" and it work. I'm more of expecting a list of things to look at.

 

Problem one. Fiberglass rings do not a seal make. I hope that you are talking about the plastic washers that go on the throttle shafts, and not the seals that are rubber and have to be dug out from the throttle shaft bore.

Throttle shaft seal (not actual size)


This is a different carb, but it shows the seal (green in this case) in the throttle shaft bore.



Leaky throttle shaft seals will create a lean feedback loop that will cause the engine to race.

Bench synch is an important step and should not be skipped: http://www.xjbikes.com/forums/posts/51960/

The crack on the intake boot may, or may not, be an issue due to the location. We'll tackle that by spraying carb cleaner on the crack to see if the idle changes, but I would like to know more about the throttle shaft seals before we go there.

 

First things first I'll get a good throttle shaft seal. I through that that was more of a bearing to keep the Al grinding is there any solution to this seal without going out and buying the designed part. Maybe rubber grommets from Lowes or auto zone? The choke plate shaft's have grooves notched into them that could hold o rings.
I was under the impression that to bench sync you must have the bike idling first. How would I go about the bench sync without an idle?
I can't seem to find any seals made for my 650 online for sale a link would be great.

 

In my opinion there is no good substitute for the proper throttle shaft seal, however........
@Polock has an alternative that involves doubling up viton o-rings. Perhaps he'll chime in with the details.

A nench synch is done with the carbs on your workbench, and is done in order to help ensure that your engine will idle upon the first startup. http://www.xjbikes.com/forums/posts/51960/
After you get a good idle, then you do a running synch using a monometer, or vaccuum gauge (home-made is fine).

Start a conversation with Chacal. He has the throttle shaft seals in stock, and will never sell you the wrong part (unlike most of the online retailers).

 

Thanks! I'll get on that asap. Work is picking up as well as I got a second job at Harley Davidson so it may be a little while but I'll post as soon as I complete my checklist.