Mikuni VM vs TM

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geo46er said:
Greetings,
Just a little info to pass on. The single hole stock looking front airbox plate is available from Norvil part# 06976755. The question then becomes will the stock rubber air tubes fit whatever type of carb that you are trying to mount?
The one-into-two manifolds are available from Sudco, SM23 for 32-34mm carbs part# 005-037 or SM-23A for 36-38mm carbs part# 005-038 price each is $150usd. The bolt on rubber flange mounts 32-34mm or 36-38mm sell for $23usd each.
The whole Mikuni kit typically with VM series carb can be had for a little over $300usd which of course includes manifold, gaskets,rubber flange, carb, cables, and airfilter. For slightly more (approx. $50usd) the supplier can substitue the TM series carb.
If you already have the VM set up TM carbs can be had used or new off Ebay some what cheaply, jets and needles are cheap, needle jets are $15usd each.
One more note, if you pick up a used manifold check to see if it is made to mount a single Amal carb (IE bolt spread center to center = 50.8mm) as this will make it very difficult to install a flange for a Mikuni carb (ask me how I know).

GB
Click to expand...

Hi GB,

Wow, thats a ton of info., many thanks.


Kevin
 
I did that modification to use the an altered aircleaner for a single Mikuni carb. I know the TM is shorter than the VM, but the VM wasn't even close, so one way or another you need to make some room. Cutting down ther perforated surround is easy and it's really just for looks. The K&N filter is very stout and is where the seal is anyway. The carb mouth lines up with the single hole front plate on the filter, at least using the manifold from Sudco. The only tricky part is that you need to machine the bellmouth on the carb to accept the accordion bellows hose thing. It takes a lathe, but it's a 10 minute job. K&N makes elements in many shapes and dimensions. The hot tip is to use an oval and give up a small amount of surface area in the top corners. It's a snap to pull the carb and you do buy some room for that *#*%ing boot.
http://store.knfilters.com/search/univ2.aspx?ID=S0002
Mikuni VM vs TM
 

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cmessenk said:
Kevin,

I had the Mikuni TM carb installed on my Combat after months of frustration with my brand new Amal carbs. I had some very reputable folks try and get the Amals to run correctly ("bill" on this site and Mike Carter in Altoona, FL) but it continued to stall at red lights and cough & spit when crusing at slow speeds. I had the TM installed and it was like night and day. My bike is now a 1-kick starter even after a week in the shed....idles perfectly at 1000 rpm and will out-pull all my other buddies on their Commandos. My setup is:

Main Jet: 240
Pilot Jet: 35
Needle Jet: Type 389, Size P-0
Needle: 6DH3
Airjet: 2
Slide: 4
Click to expand...

Soooo... you've got a set of useless Amals... Whatcha going to do with them? 8)
 
cmessenk said:
Kevin,

I had the Mikuni TM carb installed on my Combat after months of frustration with my brand new Amal carbs. I had some very reputable folks try and get the Amals to run correctly ("bill" on this site and Mike Carter in Altoona, FL) but it continued to stall at red lights and cough & spit when crusing at slow speeds. I had the TM installed and it was like night and day. My bike is now a 1-kick starter even after a week in the shed....idles perfectly at 1000 rpm and will out-pull all my other buddies on their Commandos. My setup is:

Main Jet: 240
Pilot Jet: 35
Needle Jet: Type 389, Size P-0
Needle: 6DH3
Airjet: 2
Slide: 4

Mikuni VM vs TM
Click to expand...
 
Tried to post a question last night, but see my text didn't load.

I just installed a single Mikuni VM34 on my combat engined roadster.
Settings as received are:
main jet 220
pilot jet 25
needle 6DH4 in middle groove
slide 2.5
Runs great from 1/4 throttle, but has uneven acceleration below that as well as a lumpy idle. Have openned the air screw more which helps.
Any 750 combat owners out there that have this set up perfectly dialed - let me know what you are using. 850 settings won't help.

Thanks,
 
bpatton said:
I did that modification to use the an altered aircleaner for a single Mikuni carb. I know the TM is shorter than the VM, but the VM wasn't even close, so one way or another you need to make some room. Cutting down ther perforated surround is easy and it's really just for looks. The K&N filter is very stout and is where the seal is anyway. The carb mouth lines up with the single hole front plate on the filter, at least using the manifold from Sudco. The only tricky part is that you need to machine the bellmouth on the carb to accept the accordion bellows hose thing. It takes a lathe, but it's a 10 minute job. K&N makes elements in many shapes and dimensions. The hot tip is to use an oval and give up a small amount of surface area in the top corners. It's a snap to pull the carb and you do buy some room for that *#*%ing boot.
http://store.knfilters.com/search/univ2.aspx?ID=S0002
Mikuni VM vs TM
Click to expand...


Hi bpatton,

Many thanks for the pic & info. so it was your post I came across about adapting the original air filter.

It's good to know it can be done :D

I had the Norton out yesterday to do some plug chops to see how the carbs are doing and in fact it was running quite well on the twin Amals, the tickover was quite steady if not a little high 1400rpm. I think classic bikes do this to you just when your thinkng of changing something it starts working OK :)

The only problem yesterday was I ran out of petrol on the motorway :oops: I was so busy thinking about my plug chop & where to cut the engine & pull in to check the plugs I totally forgot to check how much petrol I had :cry: Thankfully the weather was fine & the breakdown guy arrived in about 30mins. I still have to figure out the petrol taps both left & right have "off" & "reserve" on them, so basically on or off.

I think I'll go for the single TM and see what happens. I'll decided, once I get the kit, what air filter setup I'm going to use. I'd say this will all be a winter project as the weather over this side on the pond, dispite volcano's erupting :roll: , is really nice & sunny.

Can anybody recommend a supplier for a TM34 kit? I know I can get the 'bits' from different companies but to keep the shiping costs down it would be better to deal with one company.

All the best

Kevin
 
Mikuni TM34 750 kit.

click said:
bpatton said:
Can anybody recommend a supplier for a TM34 kit? I know I can get the 'bits' from different companies but to keep the shipping costs down it would be better to deal with one company.
Click to expand...
Click to expand...

This is an old thread that came up in a search last week.
I couldn't find a TM kit online and a reply from one of the bigger shops said it was not available.
Sudco replied this morning that it is in stock at $445.60 which I guess is RRP. (fwiw)

Since this thread might there be other venders doing this kit ?

The PWK kits from JS Motorsport Products looking interesting also.
What of the fuel injection ?
 
Re: Mikuni TM34 750 kit.

for $445 you really should give serious thought for Jims PWK twin carb kit -

the thing about VM vs TM for a single carb on a standard bike is there will be little to no real world detectable difference between the 2 (they both will work very good once setup correctly) - i've ran both and and have to admit the bird in the hand is probably better than chasing the one in the bush for a single VM vs TM - even if on the bench a TM is a better flowing carb (as noted by others) the limiting factor with this type of setup is the intake efficiency of the 2:1 manifold -

with 2 PWKs (or 2 VM or 2 TM's) you'll have a better breathing bike at higher RPMs - you need to decide what type of riding are you going to do

Time Warp said:
click said:
bpatton said:
Can anybody recommend a supplier for a TM34 kit? I know I can get the 'bits' from different companies but to keep the shipping costs down it would be better to deal with one company.
Click to expand...
Click to expand...

This is an old thread that came up in a search last week.
I couldn't find a TM kit online and a reply from one of the bigger shops said it was not available.
Sudco replied this morning that it is in stock at $445.60 which I guess is RRP. (fwiw)

Since this thread might there be other venders doing this kit ?

The PWK kits from JS Motorsport Products looking interesting also.
What of the fuel injection ?
Click to expand...
 
Thanks for the replies.
The JS Motorsport twin PWK kit would be good but being a small port 750 it would need the manifold reducers added so that might be closer to $600 by the time it was in the mail.

The aim for this bike (The 71 Fastback) is to make it usable (reliable) at a moments notice and on a any time,any distance basis.
More so a overall package than performance.
Of course those light JSM pistons would be good,with the rods ........ and the cam .............
The aim is not to go down the slippery slope if possible.
 
click said:
bpatton said:
I did that modification to use the an altered aircleaner for a single Mikuni carb. I know the TM is shorter than the VM, but the VM wasn't even close, so one way or another you need to make some room. Cutting down ther perforated surround is easy and it's really just for looks. The K&N filter is very stout and is where the seal is anyway. The carb mouth lines up with the single hole front plate on the filter, at least using the manifold from Sudco. The only tricky part is that you need to machine the bellmouth on the carb to accept the accordion bellows hose thing. It takes a lathe, but it's a 10 minute job. K&N makes elements in many shapes and dimensions. The hot tip is to use an oval and give up a small amount of surface area in the top corners. It's a snap to pull the carb and you do buy some room for that *#*%ing boot.
http://store.knfilters.com/search/univ2.aspx?ID=S0002
Mikuni VM vs TM
Click to expand...


Hi bpatton,

Many thanks for the pic & info. so it was your post I came across about adapting the original air filter.

It's good to know it can be done :D

I had the Norton out yesterday to do some plug chops to see how the carbs are doing and in fact it was running quite well on the twin Amals, the tickover was quite steady if not a little high 1400rpm. I think classic bikes do this to you just when your thinkng of changing something it starts working OK :)

The only problem yesterday was I ran out of petrol on the motorway :oops: I was so busy thinking about my plug chop & where to cut the engine & pull in to check the plugs I totally forgot to check how much petrol I had :cry: Thankfully the weather was fine & the breakdown guy arrived in about 30mins. I still have to figure out the petrol taps both left & right have "off" & "reserve" on them, so basically on or off.

I think I'll go for the single TM and see what happens. I'll decided, once I get the kit, what air filter setup I'm going to use. I'd say this will all be a winter project as the weather over this side on the pond, dispite volcano's erupting :roll: , is really nice & sunny.

Can anybody recommend a supplier for a TM34 kit? I know I can get the 'bits' from different companies but to keep the shiping costs down it would be better to deal with one company.

All the best

Kevin
Click to expand...

Kevin,
Have you tried http://www.motocarb.co.uk in Liverpool for the TM carb kit ?
sam
 
Just as a little sobering benchmark, everyone is aware/remembers the TM was a LOW COST (to PRODUCE, and to sell in volume to the OEM's) replacement for the venerable VM, right?. The VM is a fine choice for the old Norton. Any benefit claimed by running a TM versus a VM on this engine is purely placebo. Just my worthless opinion :mrgreen:
 
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