REPETE'S XS650B Preservation Carburetor

You might want to do an external fuel level check using a clear tube. The fuel levels in your float bowls may be off, lower on the lean running side and/or higher on the rich side.

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5T -
I did buy that tube - just never followed through with it. :(
I'll put the bike back up on the lift and check the levels with it. Seems easy enough.
Makes sense before continuing with the minuscule turning of the mixture screws every time I test ride.
So, the thread isn't "officially" dead yet.
Good thought!

Pete
 
Good Morning All,
I am confident that this'll be my last post on the subject of my carburetors which evolved into more than I had anticipated. And ultimately, all for the good!
I never did get to ride last week due to a lingering weather system that brought rain every afternoon. I finally got out yesterday.
Take a look at the plugs.

Right cylinder...
View attachment 156120

Left cylinder...
View attachment 156121

The right cylinder appears to be right about where I'd want it.
The left is a bit rich and I'm thinking it's just a matter of some time and trial and error of mix screw adjustment to get it right.
Also, I am still on the B8 plugs.... but I do (finally) have the B7's that were recommended. I'm figuring on getting that left carb dialed in to match the right and then switch over to the B7's to be able to monitor any changes. Basically working on one adjustment at a time.

The bike is running fantastic! And I've got the collective guidance of everyone here that has taken the time to respond to my questions to thank. Also, I would especially like to thank (in no particular order) 5T, gggGary, Grizld1 and 2M. Two words come to my mind: Driving Force! Thank you guys so very much! I am making another donation to the site in the spirit of the patience and mentoring the four of you provided me.

After the Holiday's I will begin another thread with some general questions about this XS.... just conversational stuff b/c as of now it is mechanically and electrically sound!

Thanks again to All! :bow::bow:

Pete
You really need to know whereabouts the mixture imbalance is in the Rev range. I would suggest doing a plug chop after an uninterrupted steady mid throttle for say 3 to 4 miles. Kill the engine and check the plugs then. If you let it idle or go onto the pilot circuit it will spoil the plug colour. If it still looks unbalanced you may check the starter jet plungers to make sure they or it are sealing properly. Just a thought.
 
Try to have the bike level and check both sides without moving it. I have a small brass wedge I can use under one of the centerstand legs to level it up. I place a torpedo level across the front motor mount.
 
Try to have the bike level and check both sides without moving it. I have a small brass wedge I can use under one of the centerstand legs to level it up. I place a torpedo level across the front motor mount.

Also great advice!
I have plastic jamb wedges I can use to level off.

Rasputin the plug pics are after a long country ride followed by several miles of "city" light to light riding followed by idling at the gatehouse to my community. So the pilot circuit is in play with the coloration you're seeing. I'll do a "chop test" once I'm certain the floats are equally and properly set. They have been done and checked prior with a caliper (several times wheres the carbs were removed and torn down multiple times), but the liquid level will be the best indicator. The bike runs beautifully at 1/4 throttle and above.... smooth and responsive. It's the occasional "pop" and deceleration brabble I've been chasing and my concentration has been on the pilot circuit.

Pete
 
The measurements in the pic labels are the normal measurements you take when setting the float height with the bowls off, carbs turned upside down. The measurement is taken from the carb body float bowl gasket surface, not the raised lip surrounding it, like so .....

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Notice the ruler is sitting down inside the lip, not on it.
 
5T....
I'm completely with you on the method of measuring the float heights and doing it from the recessed gasket surface. That's exactly how I did mine. Carefully and cautiously.
But the pics you've provided determining the float height (your examples of 26mm, 28mm, etc.) have me confused.
When using this liquid level method, is the target a known desirable fuel level that to me appears to be the joint between the bowl and carb body?
I base this assumption on the last picture showing a properly set level. The liquid level is right at the joint. The only thing I've taken (and perhaps incorrectly) from the other two pics is that you're demonstrating the maladjusted float heights by showing the difference between the actual liquid level and the desirable liquid level... being the aforementioned joint since that is where it appears to me where you are measuring from.
Can you clarify for me?
Thank you.

Pete
 
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Yes, the "target" level is right around the seam the bowl makes with the lip on the main carb body. This puts the fuel level a couple MM below the top edge of the bowl since that top edge is actually up inside the lip a little bit. You don't want the fuel level at or above the top of the bowl or it will be constantly soaking into the gasket and may start leaking. It can also cause rich running if too high.

The two low level pics are from a local guy's bike I worked on. The bike ran OK but was very difficult to start, hot or cold. This turned out to be the reason why. I'm guessing it was starving for fuel during the start process. The pics are from my initial clear tube check. The numbers are what I found when I took them apart and measured the float settings. With the ruler in the pic, I was trying to determine the relationship between the tube reading and the actual setting. It seems to work out to about 2 to 1. Being about 1mm off on your setting seems to show as about a 2mm difference on the tube. The one found set at 28mm illustrates this pretty well. That setting is 4mm off and the fuel level in the tube is sitting about 8mm too low.
 
GREAT INFORMATION!
Zz
GREAT INFORMATION!

I have a direction....
I will attend to the Advance Shaft
I will clean & polish the nipple and adhere it into the carb body.
I will revisit and verify the butterfly condition
I will ensure that I'm getting a flow through those pilot holes and the mix screw hole hole.
I will get into see my local small engine dealer
And I will report back later in weekend when through.

Thank you gentlemen!

I'm close. So, very close! :)

Pete
Howd it go for ya?
I have a direction....
I will attend to the Advance Shaft
I will clean & polish the nipple and adhere it into the carb body.
I will revisit and verify the butterfly condition
I will ensure that I'm getting a flow through those pilot holes and the mix screw hole hole.
I will get into see my local small engine dealer
And I will report back later in weekend when through.

Thank you gentlemen!

I'm close. So, very close! :)

Pete
 
I guess I dropped the ball without a conclusion.
Little by little I went through all items on the list. Without going back through to reread it all (I am at work) I think the only item I failed to address was the use of the leveling tube. By the time I had gotten around to it I had the bike running well... no more popping or brabble... so I chose to simply enjoy it.
It's given me absolutely no reason to revisit any carb tuning at this point... a year and a half later.
Runs fantastic although I did develop a charging issue and if I can't sort it out I'll seek help.
These guys were/are fantastic!
engaging, knowledgeable and patient.
I could never thank them enough.
 
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