Slabby VM29 Flatslide Carbs

[yyt]

Slowly but Surely I got to the carbs.

I will not bore you with the ultrasonic cleaning and rebuilding, carbs are in good condition and I got most parts n seals that needs to be replaced after 30 years.

Got my own theory why these carbs rattle, at first a long time ago I thought the problem was from the gap between the body of the carb to the slider (throttle valve in the book).

Playing with the set-up I noticed there is a large free play between the Shaft and the carbs shaft bore.

Got a nice video clip, but pics. only here:

So I my opinion the rattling comes from the sliders (throttle valves moving up n down.

It also affects the Idle …

Measured things, thought a bit..

Used IGUS Plastic Bearing, had to cut in half.

Assembled the 4 carbs for proper smooth movement and glued the bearings with 3M Scotch-Weld Epoxy Adhesive DP460.  

 

[bluedog59]

Nice mod. A full run down on exactly what you did would be cool. 

[yyt]

OK. I'll get some more pictures of the stages n get back to you.

[nlovien]

appreciate also the detail - this issue is also there with RS carbs, or at least I've got measurable rod wobble on mine

[yyt]

I don't have any experience with other carbs shaft diameter, for the VM's  I chose the IGUS Bearing:

The important diameter is the shaft, the length can be relatively easily cut to what you like with a dremel bit or small saw and trimmed/ chamfered with scalpel/model knife.

I had to cut 2 bearings extra short for the Throttle/return spring bits on the shaft.

On the carbs where the shaft is, there is a felt ring (after 30 years is useless) held in by a brass cap.

The bearing goes in the cup, a bit of a tight fit.

The bearing is press in with a clamp, don't press too much, the bearing just has to be sited in the cup.

After inserted, you can move the bearing slightly for proper alignment for the 4 carbs (can use a 10mm drill to align).

I started with one of the center carbs, connected the upper and lower plates to the chosen carb.

Than 1 by 1 I aligned each carb, bolting to the plates and making sure the shaft turns freely.

After all 4 carbs are connected to the plates and the shaft moves freely, small notches are made with a dremel bit (3rd pic. of first topic).

Than the Epoxy Adhesive  is applied so it attaches to the bearing and the aluminum carb body.

That about it.. think writing is harder than doing it

[bluedog59]

Brilliant,thanks very much.

How much are the bits per bank of carbs ? I've got 3 sets and if I'm going to one I my as well do all three.

[yyt]

I bought 25 bearings as is was better priced, 3 bearings are enough, cut to 2 per set of carbs.

 

Later on i will be needing to synchronize the carbs.

I saw there's some options : the Chinese 4 analogue gauges, Carbtune or Motion-Pro.

Any recommendation?

[Swiss Toni]

That's an interesting mod! And it hasn't stiffened the throttle action up at all, or you don't know yet?

[yyt]

I wish I could have put here a video clip showing me turning the shaft with 2 fingers.

I don't have a new set to compare with, I recon there is a bit of friction but if the bearings are set right it's almost not noticeable.

[Swiss Toni]

Definitely a mod worth doing then. Thanks for sharing it!

[yyt]

Will appreciate recommended  carb. synchronizer?

There are:

4 analogue vacuum gauges, hoses adapters mounting plate.

Glycerine filled Vacuum Gauges.

Motion Pro SyncPRO carburator Tuner.

Carbtune - 4 column Sync manometer.

A Penny for your toughs..

 

 

 

[Blubber]

I've got the carb tune pro for about 5 years

Suits my needs. Only use it once a year for the yearly checkup.

Cheap way to ease your mind 

[E T]

Carbtune work fine for me

[yyt]

Next interesting mining on the VM29..

Does any one test the Accelerator pump?

I decided to check all the valves of the float chamber after while cleaning the carbs, what seemed like a spring came out of the bottom fuel brass adapters connecting the  float chambers together of the accelerator pump:

Than I started to test the 2 valves and the plunger for proper work on the 2 float chambers having the system.

Actually, before I realized I can't attach a video here I made a really good one showing how it works.

Luckily I have a spare set of VM29. I found 1 bad Outlet check valve and at another bad plunger filling valve.

To fix the plunger filling valve seemed easier ...

Released the brass ball with Dremel, got the spring from the float chamber with the outlet check valve problem and sealed it with the Scotch-Weld Epoxy.

Hope I helped some-one here.

Any Questions?

[yyt]

Need some help with the nozzle's bottom O-ring and the upper rubber part numbers.

They don't show on the parts list of the VM29.

[yyt]

He guys, I really need your help here..

For some reason when looking for Mikuni parts I can't find VM29.

The VM28 or VM30 are different types.

The closest is the TM33-8012 carb ( Suzuki DR350 ). The parts : (35)- N124.63 , (37)-TM29/14

 

[Guest YoshiJohnny]

2 hours ago, yyt said:

He guys, I really need your help here..

For some reason when looking for Mikuni parts I can't find VM29.

The VM28 or VM30 are different types.

The closest is the TM33-8012 carb ( Suzuki DR350 ). The parts : (35)- N124.63 , (37)-TM29/14

 

look for the 85 model GSXR750 on www.cmsnl.com

[Guest YoshiJohnny]

https://www.cmsnl.com/suzuki-gsxr750-1985-f-e01-2-4-6-15-16-17-18-21-22-24-25-34-39-53_model13570/partslist/FIG-12.html#.WxPXOUxFxPY

 

Edited June 3, 2018 by YoshiJohnny

[yyt]

That's the point.. it does not show the accelerator nozzle, bottom o-ring and top rubber :-(

[Swiss Toni]

If you email your picture to Robinsons, they'll do it for you!

[yyt]

I'll finalize my work on the carbs, hopefully soon the next post  on carbs will be after the first ride.

As for the accelerator nozzle, bottom o-ring and top rubber, you can't find them in the Suzuki carbs parts catalogue.

Even at " Robinsons ", they were very polite but couldn't help beyond the parts list which is missing these parts.

I found the top rubbers in Mikuni (TM33 carbs) : TM29/14 Rubber plug, Pump Nozzle.

The bottom o-rings I just got form e-bay : Viton - wire diameter:1mm/OD:4mm.

Wire D

On the Accelerator pump, I'll write my findings at :

Is my rod too long? Slabby Accelerator pump question

 

 

 

[nlovien]

On 4/30/2018 at 2:33 PM, yyt said:

I don't have any experience with other carbs shaft diameter, for the VM's  I chose the IGUS Bearing:

The important diameter is the shaft, the length can be relatively easily cut to what you like with a dremel bit or small saw and trimmed/ chamfered with scalpel/model knife.

I had to cut 2 bearings extra short for the Throttle/return spring bits on the shaft.

On the carbs where the shaft is, there is a felt ring (after 30 years is useless) held in by a brass cap.

The bearing goes in the cup, a bit of a tight fit.

The bearing is press in with a clamp, don't press too much, the bearing just has to be sited in the cup.

After inserted, you can move the bearing slightly for proper alignment for the 4 carbs (can use a 10mm drill to align).

I started with one of the center carbs, connected the upper and lower plates to the chosen carb.

Than 1 by 1 I aligned each carb, bolting to the plates and making sure the shaft turns freely.

After all 4 carbs are connected to the plates and the shaft moves freely, small notches are made with a dremel bit (3rd pic. of first topic).

Than the Epoxy Adhesive  is applied so it attaches to the bearing and the aluminum carb body.

That about it.. think writing is harder than doing it

recently did this to a set of RS38's which had a fair bit of wiggle on the slide lift shaft - had a random tendency to hang when closing - these have x 2 needle bearings and x 6 felt washers - pop out the felt washers and replace with 14mm x 10mm self lub plastic bush's = no more wiggle and "garage" testing - they now settle to idle quickly - no sign of the random hanging - a bit slower to self close - probably a bit more friction on the shaft as its now got a tighter clearance across all four - ok so increase return spring pre load

do I think this neat cheap tweak works - yip  for me

[tqmidget]

On 6/3/2018 at 9:38 PM, yyt said:

He guys, I really need your help here..

For some reason when looking for Mikuni parts I can't find VM29.

The VM28 or VM30 are different types.

The closest is the TM33-8012 carb ( Suzuki DR350 ). The parts : (35)- N124.63 , (37)-TM29/14

 

 

[Swiss Toni]

Glad this was ‘bumped’! Still a very interesting read. Was it ‘stickied’ at some point?