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Author Topic: mikuni jets swapping between TM32 and VM32  (Read 1755 times)

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strat71

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on: September 14, 2016, 08:26:35 pm
you know i got a TM32 on my bullet...
took a while to find the perfect spot, i.e.
  • pilot jet: 27.5
  • needle jet:P4
  • needle: 5FP17 (stock on my TM32)
  • needle position:2nd groove from the bottom
  • main jet:185
i've been given a VM32 and am considering giving it a try in place of the TM32.
why?? some considers the TM series superior to the VM series...  maybe to get access to the choke.. if the change doesn't change a thing on the ride, i could live with it...

anyway, i was about to just put the TM32 jets and needle on the VM32..
the pilot jet and main jet are the same, they could be swapped.

BUT the needle jet has not the same shape, i can put it in the VM32 but it's not fitting as it should, i don't know if it's important or not..

moreover, the stock needle is not the same: 5FP17 on the TM32 and 6DP17 on the VM32... the size don't seem the same, 2 groove distance seems to separate one from the other...

so my question is:
what jet combination would you try to get the same carburation??? pilot jet and main, no problem..

should i use the VM32 stock needle and change the needle jet, hotter needle jet since needle seems leaner??? a P6??.
or use the TM32 needle and find a VM32 P4 needle jet?

thanks for help...
Ben
ps pictures of VM32 (on top) and TM32 (on bottom) needle jet
and of VM32 (right) and TM32 (left) stock needle
« Last Edit: September 15, 2016, 12:07:55 am by strat71 »


Adrian II

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Reply #1 on: September 15, 2016, 06:41:30 pm
The only possible reasons I could think of for using a VM as opposed to a TM carb would be 1) space considerations caused by the taller carb 2) more classic appearance, if that were an issue.

Having said that, the VM32 is still a fine carb, I had one on a tuned 350 BSA B40 a few years back, big improvement over the Amal I had been using.

A.
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strat71

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Reply #2 on: September 15, 2016, 07:21:59 pm
the main reason i am considering this is because the choke is unuseable with a TM32 on a bullet... stucked under the tank, with the engine bracket just in front of it...
it's warm here, i can start my bullet with a little patience, but still...
Ben


Hondo

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Reply #3 on: September 15, 2016, 09:09:11 pm
Quote
the main reason i am considering this is because the choke is unuseable with a TM32 on a bullet... stucked under the tank, with the engine bracket just in front of it...
Mine is in the same spot. It will be a little stiff when new but now I can hook it with one finger in the dark and open and close it. They also make a cable to actuate it but my bars are slick and don't want the clutter.


tooseevee

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Reply #4 on: September 16, 2016, 06:05:43 am
you know i got a TM32 on my bullet...
took a while to find the perfect spot, i.e.
  • pilot jet: 27.5
  • needle jet:P4
  • needle: 5FP17 (stock on my TM32)
  • needle position:2nd groove from the bottom
  • main jet:185
i've been given a VM32 and am considering giving it a try in place of the TM32.
why?? some considers the TM series superior to the VM series...  maybe to get access to the choke.. if the change doesn't change a thing on the ride, i could live with it...

anyway, i was about to just put the TM32 jets and needle on the VM32..
the pilot jet and main jet are the same, they could be swapped.

BUT the needle jet has not the same shape, i can put it in the VM32 but it's not fitting as it should, i don't know if it's important or not..

moreover, the stock needle is not the same: 5FP17 on the TM32 and 6DP17 on the VM32... the size don't seem the same, 2 groove distance seems to separate one from the other...

so my question is:
what jet combination would you try to get the same carburation??? pilot jet and main, no problem..

should i use the VM32 stock needle and change the needle jet, hotter needle jet since needle seems leaner??? a P6??.
or use the TM32 needle and find a VM32 P4 needle jet?

thanks for help...
Ben
ps pictures of VM32 (on top) and TM32 (on bottom) needle jet
and of VM32 (right) and TM32 (left) stock needle

            Yes. The enrichener on the TM 32 is a bitch, but everything can't be easy, can it? It's a great carburetor. Even with my totally fucked up fingers and hands, I've figured it out, but, yes, it's not easy.

             2nd thing: Every jet and needle, etc., has a specific identifier type and number and specific jets and needles go in specific carbs according to their numbers. You can't just guess or switch around what goes in what carburetor.

               Go to http://jetsrus.com/ and read, read, read. There is all you need to know on that website. And there are many others also. Google is your friend.

                SUDCO is another good place to just go and look around at stuff and read.
2008 AVL Classic.Extensive head work by Ace.Ace canister/TM32/Ace manifold.Small open bottle/hot tube removed.Pertronix Coil.Bobber seat.Fed mandates removed.Battery in right side case.Decomp&all doodads removed.'30s Lucas taillight/7" headlight.


1 Thump

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Reply #5 on: September 16, 2016, 10:38:20 am
the main reason i am considering this is because the choke is unuseable with a TM32 on a bullet... stucked under the tank, with the engine bracket just in front of it...
it's warm here, i can start my bullet with a little patience, but still...
Ben

There are two solutions to the choke problem:

1.  Choke cable and lever from manufacturer.
2.  Home made choke lever. I know of a gent who devised one for himself. Picture posted in the Ace forum on yahoo.


strat71

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Reply #6 on: October 30, 2017, 12:42:15 am
long time since i started this thread... i finally took time to tweak the VM32... i thought it'd be interesting to compare the jetting on both TM32 and VM32 on the exact same bike.
long story short... here's the jetting comparison
carb              ---- TM32 ----- VM32
pilot jet          ---- 27.5 ---- 30
needle            ---- 5FP17 ---- 6DP17
needle jet       ---- 389P4 ----- 159Q6
needle position ---- 2.75 ----- 3,75
main jet           ---- 185 ----- 185

Ben
« Last Edit: December 28, 2017, 05:09:14 pm by strat71 »


rep_movsd

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Reply #7 on: November 02, 2017, 04:29:54 pm
There are two solutions to the choke problem:

1.  Choke cable and lever from manufacturer.
2.  Home made choke lever. I know of a gent who devised one for himself. Picture posted in the Ace forum on yahoo.

I believe I was that gent - here is the pics : https://photos.google.com/album/AF1QipMGs5XabQSywwi1ktlEENFGH9h8-Lb9_N4xqQbH

To be honest, the screw in the plastic knob didn't hold very long, so I am going to have to take the knob off and use some other method - perhaps a small brass cylinder with a grub screw to hold it onto the stem.


heloego

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Reply #8 on: November 08, 2017, 06:52:54 am
I fabbed a lever for the right side on my VM32. You'll have to scroll down a bit to find it, but since I didn't order one with a right-side lever this was a cheap alternative.

https://imgur.com/a/FE840
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sherman_desouza

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Reply #9 on: March 13, 2018, 01:35:14 pm


Adrian II

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Reply #10 on: March 14, 2018, 08:04:35 am
Does that fit the TM as well as the VM series?

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...