Carbs - Flat slide Mikuni's TM34/36

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PhilGT750
Posts: 11
Joined: Thu Apr 11, 2019 1:43 pm

Carbs - Flat slide Mikuni's TM34/36

Post by PhilGT750 »

PXL_20220319_060314505.MP.jpg
Hi Guys,
After trying a multitude of GT750 CV carbs without success, I'm looking to pull the trigger on some flat slide Mikuni's. The dealer asked if I know what jetting I want installed, he pointed out I could quite easily spend another couple of hundred bucks on jets. So suggested I ask if anybody already has a well running bike as a starting point and he could have those jets installed on the carbs I purchase.

So anybody have a GT750 with Flat slide Mikunis installed they would like to share jetting information, if you don't want it published the info, please email me phil-1089@bigpond.com

One of the problems with the standard carbs is, having to fit K&N type filters, I cannot stop the slide flutter, and the bike will not rev properly. I do have some new diaphragms coming, but am pretty certain they will not cure the problem.

Many thanks

PhilImage
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750ynot
Posts: 110
Joined: Mon Mar 21, 2022 8:37 pm
Location: South Wales

Re: Carbs - Flat slide Mikuni's TM34/36

Post by 750ynot »

Is that a 3 into 1 and back into 2 expansion chamber, wondering if that is the route cause of your problem, belly doesn't look very large, and the tuned length looks short favouring high revving, but the thin belly is a worry IMO.

The earlier carbs were VM32 sc, if your problem is low down fitting bigger carbs with what looks like a 3 into 1 back into 2 pipe fitted will only increase low end power loss.

The BS40 carbs flow around the same amount as the VM32, may be better looking for some earlier VM32SC carbs, everything has an effect on everything else, and if I am right about the exhaust your in unknown territory, unless someone has the same set up including exhausts, and even then it would only be a ball park figure, just cause it works on 1 doesn't mean it will work on another.

Hope that is of some help to you.
Tony
Kettletimes3
Posts: 1620
Joined: Thu May 03, 2012 12:58 am
Location: Sunny Wales

Re: Carbs - Flat slide Mikuni's TM34/36

Post by Kettletimes3 »

750ynot wrote: Mon Apr 04, 2022 5:24 pm Is that a 3 into 1 and back into 2 expansion chamber, wondering if that is the route cause of your problem, belly doesn't look very large, and the tuned length looks short favouring high revving, but the thin belly is a worry IMO.

The earlier carbs were VM32 sc, if your problem is low down fitting bigger carbs with what looks like a 3 into 1 back into 2 pipe fitted will only increase low end power loss.

The BS40 carbs flow around the same amount as the VM32, may be better looking for some earlier VM32SC carbs, everything has an effect on everything else, and if I am right about the exhaust your in unknown territory, unless someone has the same set up including exhausts, and even then it would only be a ball park figure, just cause it works on 1 doesn't mean it will work on another.

Hope that is of some help to you.
Plus one on this.
PhilGT750
Posts: 11
Joined: Thu Apr 11, 2019 1:43 pm

Re: Carbs - Flat slide Mikuni's TM34/36

Post by PhilGT750 »

Hi Tony, to answer a couple of questions:-
---Is that a 3 into 1 and back into 2 expansion chamber, wondering if that is the route cause of your problem, belly doesn't look very large, and the tuned length looks short favouring high revving, but the thin belly is a worry IMO.

The expansion chamber has been lengthened since that picture was taken and the exhaust is based on the very sucsseful Bromlech 3-1. The pipe now measurements as a Bromlech 3-1 and the two silencers has been changed to a larger bore single silencer, size wise identical to the Bromlech


The earlier carbs were VM32 sc, if your problem is low down fitting bigger carbs with what looks like a 3 into 1 back into 2 pipe fitted will only increase low end power loss.

As above

The BS40 carbs flow around the same amount as the VM32, may be better looking for some earlier VM32SC carbs, everything has an effect on everything else, and if I am right about the exhaust your in unknown territory, unless someone has the same set up including exhausts, and even then it would only be a ball park figure, just cause it works on 1 doesn't mean it will work on another.

Quite correct, but a ball park figure on jetting is better than nothing
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750ynot
Posts: 110
Joined: Mon Mar 21, 2022 8:37 pm
Location: South Wales

Re: Carbs - Flat slide Mikuni's TM34/36

Post by 750ynot »

Sorry, not trying to teach you how to suck eggs so to speak, wish I could help more, but I don't have TM's fitted, hopefully someone else will chime in with more help on your set up.

Seems you know about the importance of the pipe and the effect on carburation, good luck with it.
Tony
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Carbs - Flat slide Mikuni's TM34/36

Post by madforitkev »

Phil

On my project bike I bought some new TM36's as a stop gap before I changed to fuel injection.

I did a couple of dyno runs and got them in the ball park but they still needed some work for optimum performance, some of which would have been timing related.

So longstory short is I have a set, nearly new with a selection of jets. If you are interested?
Honest baby....this is probably the cheapest bike I have ever bought!!
PhilGT750
Posts: 11
Joined: Thu Apr 11, 2019 1:43 pm

Re: Carbs - Flat slide Mikuni's TM34/36

Post by PhilGT750 »

Would be nice, and thank you for the offer, but i'm 12000 miles away downunder.
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madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Carbs - Flat slide Mikuni's TM34/36

Post by madforitkev »

Ha...I was due to go to Sydney this month!!

Delayed until October now. If you still need then then, let me know.
Honest baby....this is probably the cheapest bike I have ever bought!!
PhilGT750
Posts: 11
Joined: Thu Apr 11, 2019 1:43 pm

Re: Carbs - Flat slide Mikuni's TM34/36

Post by PhilGT750 »

Okey dokey
[img]file:///C:/Users/Samm/Desktop/PXL_20220319_060304440.jpg[/img]
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