VM29SS subtle difference(s)?

[CockneyRick]

So i bought what i thought was a complete set & got a load of spares off here (sorry can't remember who)

The issue is, the spares appear to be exactly the same as the GSXR750F  fische.

However, the comp set are slightly different. Firstly the bowls don't have a draw up tube in them (others do)

Also on the side of carbs 1&3 there's a plastic arm that appears to rotate with throttle arm & does nothing but sit above a casting boss, the spares have a moving rod that passes from this arm down into the chamber, same as the fische again, Red circle.

 

So what are the complete carbs in pics that are virtually same & sold to me as VM29SS even though they are 29?

 

Edited March 17, 2020 by CockneyRick

[CockneyRick]

Having studied them further, the ones above  have the side tube/rod blanked off which explains why the float bowls don't have the plunger & spring, which the VM29ss do?

[Jaydee]

Hi Rick. The 2 white plastic arms you see on outside between carbs are hammers for the accelerator rods. Flatside don't like being snapped open really fast. They take a big gulp of air as a result which would cause the bike the stumble. To counter act the gulp of air, extra fuel is needed.

If you snap the throttle fast, the arms hit the accelerator rods downwards which in turn hit the 2 pistons down in the float bowls. The 2 pistons getting pushed down put pressure on the accelerator circuit (which is full of fuel) The only openings on this circuit is the tiny hole on the top of each of the 4 accelerator pump nozzles which squirt out a spray of fuel as a result.

If you take off the 4 bowls but keep them connected by the tubes that run between the bowls, you should see 2 bowls have pistons and 2 that don't.  Put 2 fingers over the empty holes. Now quickly press down one of the pistons,the other piston should pop out and vice-versa. This shows its a pressurized system when the two holes are blanked off. 

[CockneyRick]

Yep it all makes sense & logical.

Issue i have now then is, it looks like the set in pics have at some point had the rods/seals/plunger/springs removed & looks like an M4 bolt has been stuck in where the plastic arm would normally push the rod down.

Why would someone do this? 

And also, the 4x bowls on the pic'd set are the 2nd pic, the disassembled set (with the rods etc still intact) are 1st pic, which shows a brass  overflow tube sticking out?

Any reason they would be different @Jaydee  My thought is it shouldn't make much difference whichever i use?

Edited March 18, 2020 by CockneyRick

[Jaydee]

12 minutes ago, CockneyRick said:

it looks like the set in pics have at some point had the rods/seals/plunger/springs 

 

Edited March 18, 2020 by Jaydee

[CockneyRick]

Or he's deliberately done it so they don't hit the M4 bolt blocking the rod path perhaps? 

Any thoughts on the bowls though?

[CockneyRick]

Ignore that, just checked & when you turn the throttle cable housing, the arms do make an attempt to press the (non existent) rod.

So looking from other side they do work & are identical to the individual set  

[Jaydee]

Don't know about the brass on overflow. Probably it is what it is, an overflow. Just another circuit,  maybe nothing to do with accelerator circuit.

[Jaydee]

Should be handy enough to put the arms back to work. If you can get out the m4 screws and put in new rods (old coat hanger wire), you should be back in action.