VM29 specs, manual, tuning tips for GS750/1000???

[Chuck78]

I am getting ready to swap some VM29 A7 smoothbores onto my bike. I ordered all new gaskets and o-rings & needle valves (not seats) yesterday, and was hoping to find a source for specs, rebuild/tuning manuals in particular, and some setup advice.

They have nylon 110 main jets now which I was told aren't made anymore because ethanol eats them up. Not sure on pilot size since they are the recessed vm22 style.

I read that the a7 was specifically for the gs750/1000, and should have a 1.5 slide cutaway. Sounds like they use the same jet needles as the vm26, and main jet style. Slides and slide linkages look far advanced over the OEM vm22/26/28. Like a keihin CR sort of, and brass floats, nice!

They came off an 860cc gs750 with stock cams and I assume yoshi 69.5mm pistons. 110 mains. Haven't torn them down anymore to see pilots or slide cutaways.
The sides and bowls were beat to heck unfortunately, with the rim of the outer edges of the outer carbs being bent in & cracked along the gasket surface of the bowls, but they will still run. I am on the fence about trying that aluminum brazing product to repair this, or if just to heat & bend it back & be gentle around it... Heating to 500 degrees to braze is going to be risky...

Any sources for manuals, tuning guides, float heights, etc???? Please recommend tuning specs for jets and needles if you can. 920cc 10:1 gs750 v&h k&n rc2222 dual oval open filters.
Was running gs750 vm26's 112.5 mains 15 pilots 0-4 needle jet was needed with 5dl36, so I swapped to gs1000 vm26's and with different main&pilot air jet sizes, those needed 117.5 mains, 15 pilots, & o-6 needle jets with 5dl36 in middle position or 1 position lower needle height, can't remember. 17.5 pilots on the 1000 spec vm26's

 

[chuck hahn]

Heres the exploded view and the float ht is in the box. parts with a blue part number on the parts list are still available.

http://www.sudco.com/Catalog37Digital/index.html#/172/

 

[chuck hahn]

Jetting link at the very bottom here..

http://www.sudco.com/Carburetor01.html

 

[Chuck78]

Thanks Chuck! Any links to VM29 rebuild manuals? The internal slide linkages look different completely from the vm26/22, so I wondered if there were any different helpful instructions specific to 29 smoothbores

 

[Chuck78]

Aha...
http://www.sudco.com/Catalog37Digital/files/mobile/tablet.html#172

That says the a7 was a Kawasaki version, and comes with the 1.5 slide cutaways, and the a12 was the gs750/1000 version with 2.0 cutaways. Everything else was the same. I had read the opposite on both elsewhere on a forum. I wonder how the 1.5 vs 2.0 slide will affect things down low???

Only other difference was the z1/kz1000 version was fitted with 120 mains, the gs750&1000 versions fitted with 115 mains.

I saw a shop selling extended pilot fuel screws for vm29's for $70, but these gave no pilot fuel screw on the bottoms! Were those not smoothbores then? Are the Suzuki versions different and have a fuel screw like the OEM Suzuki's VM carbs???

 

[chuck hahn]

Basic differences are they use a jet block and there isnt a pilot jet screw on the bottom. Dont dip them with the jet block gaskets in there..just a thin paper that will probably get ruined if you do. Jet blocks come out the slide towers when doing the disassembly.

 

[Agemax]

be very careful with those jet blocks, very easy to strip the threads in them rendering them useless. If you do remove them be sure to fit new gaskets or it will cause major idling problems

 

[Chuck78]

 

[chuck hahn]

just cosmetic. bowl gasket will still seal. sucks though

 

[Chuck78]

So I noticed a hundred or two dents in the intake side of the fuel bowls when I got these, looked like a frustrated mechanic took out some aggression. I did not notice these impact bent/cracked areas on the outsides of the #1 & #4 carbs until after I had opened them up after ordering parts for them...

This won't affect the running of the carbs as it is just the rim around the gasket area for the fuel bowl, but this kinda sucks!

I could heat lightly & bend back, but afraid I might crack them further.
I had thought about getting some of that aluminum brazing rod from aluminumrepair.com, but I am afraid the carb main body will act as too much of a heat sink to make that work, and also looking at the photos, I see a brass plug near there that probably has some permanent sealant on it. I suppose I could jbweld over the plug after the brazing, but this is a risky repair that I'm not sure I want to attempt.

$500 for the smoothies with k&n pods, carbs were good running but needed some cleaning upon inspection. Not a terrible deal but the damage was a major bummer.

What do you all think of these cracks? The lesser one, if you zoom in, has two more hairline cracks on either side if the obvious one.

 

[chuck hahn]

Stuck floats and too hard on tapping them at some point. I got some of that aluminum repair rods from Harbor freight thinking it would work to repair broke float posts.

The post just suddenly melted down way before the rod could get hot enough to melt also. Not that it made me mad at that point as the post was already snapped. Dont waste the money on the rods.

 

[Chuck78]

JB Weld & silver paint i guess...

The OEM carbs are an aluminium-zinc alloy, where as the smoothbores are more pure aluminum, so maybe the rods would work better on the smoothbores? I typically use an infrared thermometer to measure temp when heating aluminum parts to keep below the melting point, and would probably opt for the 2nd generation rods from aluminumrepair.com as opposed to the harbor freight rods. Still, quite a risky venture that I am hesitant on.

 

[Chuck78]

Also, why don't smoothbores have overflows???

And who makes a fuel level tube adapter for the float bowl drain/main jet plugs, to measure actual fuel level with a transparent u-tube??

 

[chuck hahn]

I myself wouldnt gamble on it!!!! Think youre bummed now!!!!

 

[chuck hahn]

I took an old drain plug and drilled a hole down the center. Got a piece of aquarium air hose and sarted to grind the perimeter of the drain plug down till I ogt it to fit snug inside the tubing. Screw it in the bowl and hold along side to see the fuel level.

 

[Chuck78]

Alrighty well I guess I'll look for a spare vm29 smoothbore float bowl or drain plug to drill & tap a tiny hose barb into unless I can find a fuel level adapter. I have replacement needle valves for good measure, but am going to stay with the stock seats for now.

 

[chuck hahn]

#30 on the parts list and shows its still available from Sudco You have to call them for prices and be aware they will ask if your a dealer. I tell them no and they inform you they charge an extra 5 bucks if your not a dealer. Well if you need it you need it..right???

http://www.sudco.com/Catalog37Digital/index.html#/173/zoomed

Wont need to add a barb for the tube. just measure the OD and drill the hole a few thousands under size. Poke the end of the tube thru with a small screw driver or something. Being a little under size should seal the tube to the plug

 

[Spyderman]

Also, why don't smoothbores have overflows???

And who makes a fuel level tube adapter for the float bowl drain/main jet plugs, to measure actual fuel level with a transparent u-tube??

check Z1 they have lots of parts for smoothies and i have seen that they have the fuel level adapter for the drain plug

 

[steve murdoch]

Website says currently out of stock, but a phone call might have different info.
http://www.z1enterprises.com/ItemDe...ool+for+VM29+smoothbore+carbs&item=ZSM-VM29FT

 

[Chuck78]

Any idea if the VM33 float bowl drain plug is the same thread/size as the VM29? I found a spare vm33 drain plug. Z1 is sold out of the fuel level adapters and waiting for more to be manufactured