A few questions on VM29 carbs

[KEITH KRAUSE]

Just another quick thought. Are the air jets removable in the 29's?
If so, does Jeff or anyone know, was there a standard air jet size? This jet feeds the air screw, so it obviously could factor in.

[Rock]

Yes, they are removable and are available in different sizes. I had them out and cannot find a number on them anywhere. They are very small. The air jet that was supposed to be standard for the gs1000 set up carb is the .9 jet. I may pull one again and lightly polish the outside with steel wool and look with a magnifying glass again to try and find some identification marks of some kind.

[KEITH KRAUSE]

OK. I was just wondering about the air jet size. Not trying to complicate things more.
I really think the set up I suggested will work. The only possible problem could be some popping at decel', but I'll keep my fingers crossed. Be sure to synch well, etc.
Trying to get a smooth transition from the pilot to cut away to needle is what we're after. I sure hope it works.
I'm going on vacation beginning this Saturday morning until the 21st. I know you said it will be a few days to try any more tests. I won't be around a computer (probably a good thing.) I hope when I get back you'll have good news. Good or bad, let us know.
If I can, I'll post again any thoughts or a "plan B" if I have time. Good luck.

[Rock]

I was able to see a number on one of the air screws. They are 0.9 You really need a strong magnifier to see the numbers. According to the information on Sudco these are the proper jets. Have a great vacation.

[KEITH KRAUSE]

I was able to see a number on one of the air screws. They are 0.9 You really need a strong magnifier to see the numbers. According to the information on Sudco these are the proper jets. Have a great vacation.

Yeah, I'm sure they're fine. Was just wondering about them.
Hope to read good news when I get back.

[Rock]

Here's the update. I took Keith's advice and replaced o-rings on intake. I also replaced plug wires, checked timing on Martek unit, o-rings on air screws. I did move the timing mark slightly as it was just off the mark a tiny bit, maybe 1/16 of a inch. I also re-oiled my K&N air filters. I has them oiled very lightly (barely) before and maybe not enough. I also installed a Pingel valve. I would think most of these would cure a lean problem, not a rich one. I also went back to all original jets to start over from the beginning. I now have #25 pilots, 115 mains, and needle on middle clip as it was when I got the bike.

It now runs PERFECT on the pilot circuit, a nice tan color at 35 mph chop test. I also ran a few at 40mph and it does show a little leaner but still a light tan to ash color. So I'm assuming the needle is getting ready to come into play at a bit more throttle and supply more fuel.

It is now lean on the needle at 1/3 throttle. I mean white clean plugs. I figure I need to now raise the needle a notch and try it. Hopefully it doesn't screw with the pilot circuit. I'm going to try this today or over the weekend. I hope my floats are not to low and causing this now. It runs like a bat out of hell at high speed though and really pulls with no hesitation.

Even after just riding around the plugs show no richness at all. I don't know what of the above changes fixed the rich pilot problem but I happy to have finally get some where with it. Every thing has turned around 180 degrees. The mix screws are now set at 1 1/4 to 1 1/2 on all carbs. I had spark with the old wires, do you think the new ones may provide a spark that much hotter to change this? And to look at the spark it is blue but I'm not real impressed with the strength of it. My lawnmower provides more snap than this.

[jeff.saunders]

Glad you are making progress. It sounds like you are very close - raising the needle may get you where you need to be..

The spark from stock coils and old wires is not very impressive. If you compare to aftermarket (Dyna, Accel, etc), you'd be amazed at the difference.

The wires do deteriorate with age, as do the coils. Often replacing wires and plug caps helps - but on many of these older bikes, the wires are molded into the coils making replacement tricky or near impossible. You can buy NGK cable splices - but considering the price of them (about $27), it's better to put that money into a new set of coils. $110 gets you a set of Dyna coils - another $16 gets you a set of wires.

A good set of coils will help give a cleaner burn - it allows you to run a touch richer with less fear the plugs will foul.

[Rock]

I do have Accel coils that came on the bike. I checked them for resistance and that was fine, about 3 1/2 ohms. They have a blue spark but you can't hear any snap like I have seen on other types of engines. It doesn't seem like a very big spark either but maybe that is normal? I don't know any other way to check them. They are I'm guessing well over ten years old. This bike was parked for ten years and I don't know how much use they saw before that but I can tell they have been around and probably used for several years. I will try and find out.

And anyone needing Mikuni parts, Jeff is the guy . I ordered some on Tuesday and had them in the bike Thursday. My order before this one from him was handled quickly as well. Great service Jeff!

[Rock]

Well I raised the needles up one notch and everything went black. Pilot circuit included. Not as responsive either and seemed a bit boggy on take off. One mistake I may have made was I replaced the mix screw o-rings after getting a good read on the plot circuit and did not check the needle circuit again before changing the needle height. The o-rings were about .012 bigger than the old ones and wonder if I was sucking air through the old ones giving me the lean burn. I think I will go back and retry the middle position on the needle before trying a spacer. I did not sync again yet but the all the plugs were so black I didn't want to spend the time to do it unless the plugs looked good.

edited to add,I also changed the plug gap to .035 as suggested for Accel coils rather than the stock specs that call for .030 gap.

[KEITH KRAUSE]

Just read the latest. Getting late and I gotta work this morning. So I'll be brief and maybe offer some help later.
I still think the needles in position 3 and 17.5 pilot jets with the air screws adjusted for highest idle followed by a good vacuum synch will fix you up ( even if you think it doesn't make sense) .
You also mentioned a possible float level problem?? I thought you had them set?

[Rock]

I did have the floats set. But I was always leary about the needle valves. I took them to a local shop and they said they were good. I was concerned about the weight of the float sagging the spring some what when I was setting the height. Well I put the new needle valves in this morning and it resulted in some of the floats being nearly a 1/16 too high when the new valves were installed. So the floats were actually keeping the fuel low in the bowls. They were wrong. The springs in the new valves were stronger in the new ones.

I have now replaced every o-ring and pretty much rebuilt the carbs totally to rule anything out. I did get 117 pilots but have not tried them yet. Could the low float setting cause a lean burn on the needle circuit?

[KEITH KRAUSE]

If you had weak float needle valve springs, that would allow a higher and richer fuel level, not a leaner level.
I can't say this problem would effect any circuit more than the others. It should effect all three the same. Fuel would be too easy to draw. Weak springs, leading to a high fuel level, usually result in some minor fuel spillage out the overflow lines or the filters and a raw fuel smell while sitting.
It would effect the pilot circuit and cause you to think the pilot jets are too large. It could explain why the air screws don't respond as normally as I think they should.
If the floats are reset now, I'd go test first. If your floats have a "range" of setting, I'd put them right at the mid-point. I always set all basic maintenance things correctly before playing with the jetting.

[Rock]

I always set all basic maintenance things correctly before playing with the jetting.

I agree with that. I didn't think it was right the springs had some sag in them from the wieght of the bowls when the carbs were inverted to set the hieghts even the the shop told me it was "alright". At this point all o-rings and gaskets have been replaced in the carbs except I haven't taken the jet blocks out and replaced the gasket there. Valves and timing and plug wires have been taken care of also. Thanks for the continued assistance and I'll let you know how it goes. Jim

[robinjo]

What is the correct float height for VM29's?

And do or don't they have a connection for the pet cock's vacuum hose?

I know have a pair of these babies!

[KEITH KRAUSE]

What is the correct float height for VM29's?

And do or don't they have a connection for the pet cock's vacuum hose?

I know have a pair of these babies!

23 mm on the floats...no vacuum port. Good reason to buy a Pingel valve.
Whaddaya mean "I know have a pair of these babies"?