#1 carb still testing my sanity

Okay - put carb rack back on the bike after further inspection, cleaning, adjusting and scratching head. Losing count but I think 4 times now removed and replaced.

Still NOTHING. No doubt, it's not getting fuel from bowl to cylinder. I even ran with the enrichment circuit open with no luck.

*floats set properly
*plenty of fuel in float bowl.
*vacuum matches other carbs

What could possibly be the issue? driving me crazy.

 

Checked the spark plug on #1? Wet with fuel? Getting spark on #1?

 

Spark good and strong. No fuel on plug. Definately no fuel to cylinder.

 

Put a new plug in it, crank/run the engine for a moment, then remove that plug and sniff it.....if it truly isn't getting fuel, it won't stink of gas.

And if it really isn't getting fuel, then you either have a stuck (closed) float valve needle, completely clogged fuel valve passage hole (in the brass seat), clogged screen, plugged-up fuel supply tube, or the intake valve isn't opening.

Or a huge honking hole in the piston, and thus no vac being created in that cylinder.

 

* plug - no fuel odor
* New screen from your kit
* float needle - new from kit and seems free as other carbs
* completly colgged fuel valve passage ?? unsure of description
* clogged screen - new from kit - seems unlikely but will check on next removal
*clogged fuel supply tube -- need direction on specific location??
* intake valve not opening --- how does one diagnosis?
*hole in piston ---- vacuum with tool is same as other cylinders .. does not seem likely.

thanks Len ,,,, If you can clarify those areas where I'm mechanically changelled I'll look at the others as I pull the rack again.

 

Main jet & pilot fitted as per manual, which would be wrong.

 

Hold on.

We've discussed "wet-setting" the floats a number of times and the answer has always been "done it."

However; if you had WET-SET carb #1 you would have known right then that there is a fuel delivery issue.

Pull the rack, set it up level, and properly wet-set the floats. Any fuel delivery issues will immediately reveal themselves in the process and make it much easier to diagnose.

 

Yep, wet set fuel level on bench. I'll do it again as the rack will come off again. All 4 fuel bowls set the same and to spec last time. All seem to maintain proper fuel level when on bike.

I'm on two chat threads for same issue, this one and 'carb problems again ..... , and again'. so I keep an eye on each.

Took bike off center stand, cranked it up, and now my plug has fuel on it, but only fires intermitently. Piolot mixture screw set to 3 full turns out as a starting point.

I can only think of one reason it would fire intermitently .... too rich. This carb seems to go from too rich to absolute lean in a heartbeat .... can't imagine center stand angle would be enough to change anything.

 

When you set float levels, is that off the bike, or the bike on thecenter stand?

Just for giggles swap a needle/piston/diaphargm to another carb and see if you get the same issue. If you do that would be a lack of vacuum otherwise it will be a blocked passage.

 

I wet set the floats when rack removed from the bike and on a bench stand to make sure it was level.

I'll look at swaping needles .... thanks for the thought.

 

When I first got my bike the pilot screw for one carb was open about 5 1/2 turns, and if I closed it much I got no ignition at all on that cylinder. It ended up being a bad intake gasket the caused it to suck a lot of air. When I replace the gasket everything fell into place. Open the pilot screw more and see if it fires, and if so, I'd look for an air leak.

 

I did a propane test with no reaction ..... so pretty sure no air leak around intake gasket. thanks for the hint.

 

Just to double check and confirm .. .... ??
*main air jet hole is to the rear of carb (80)
*pilot air jet is placed toward the front of the carb (225)

just continuing to search for my mistakes.

 

Main jet ( bigger hole) goes on the bottom of the emulsion tube.

Dave

 

thx

 

Yes this is correct for the placement of these AIR jets.

 

oops......reading to quick, just saw 'jets'........my bad.

dave