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General Discussion => Tech Tips => Topic started by: rajvijayarajan on June 27, 2013, 07:59:29 am

Title: Mikuni VM24 Vs VM26.... Which One?
Post by: rajvijayarajan on June 27, 2013, 07:59:29 am
I have to replace my stock Mikarb carburetor and one of the suggestion was Mikuni VM26. The original carb is a Mikarb 24". Can anyone give me a logic of going for a VM26 as against a VM24. Your comments would really help me take a decision immediately.

Ps. I have a 1996 Std 350
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: AVL Power! on June 27, 2013, 09:06:45 am
Hello Raj,

If I were you then I would have plonked a VM28 carb which is used in the CI500s. They are good and for the 350's it's really a good upgrade. I am assuming that you are from India and there a Mikarb VM28 will cost you 1500 bucks! Pretty cheap :)

-Sanket
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: ace.cafe on June 27, 2013, 11:49:05 am
Measure the diameter of your inlet port at the entry to the head. You have no need to use a bigger carburetor than that size.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: AVL Power! on June 27, 2013, 12:32:36 pm
But the 350s have 28mm inlet port, for that a 28mm carb would be the best fit right?

-Sanket
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: ace.cafe on June 27, 2013, 01:47:04 pm
But the 350s have 28mm inlet port, for that a 28mm carb would be the best fit right?

-Sanket
Yes, if the port entry is 28mm, then the 28mm carb would be suitable. However, it is likely that any  improvements would only be felt at higher rpms, compared to a 26mm carb. So, if you plan to use the bike at rpms around 5000rpm or even more, then the 28mm carb will help when the throttle is wide open.
There will be no difference at part-throttle conditions, compared to the smaller carb, because the throttle slide is presenting the restriction, not the carb size.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: D the D on June 27, 2013, 02:45:53 pm
You might want to try the VM28-418 Flatslide Mikuni for a little crisper/quicker throttle response.  Costs a bit more, but gives better performance than the roundslide.  I have one on my 500 in place of the Mikarb 28mm and it improved torquiness, if that's a word.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: AVL Power! on June 27, 2013, 03:34:43 pm
TM28 or the TM30 with slightly ported inlet would be great! But the TMs are 7 to 8 times the price when compared to a Mikarb's VM28 here in India :P
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: ace.cafe on June 27, 2013, 04:14:05 pm
TM28 or the TM30 with slightly ported inlet would be great! But the TMs are 7 to 8 times the price when compared to a Mikarb's VM28 here in India :P

Very doubtful that the 350 would ever need any more than the 28mm carb, unless racing.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: Arizoni on June 28, 2013, 12:04:38 am
rajvijayarajan:
As you've probably gathered by now, most of the riders outside (and some in) India want to get the maximum power out of their motorcycles.  That is the reason larger carburetors are often suggested.

Not knowing what you want to accomplish makes it difficult to make a recommendation but if you want to get the maximum power at the expense of  worse fuel economy do as the others are suggesting and try to get the larger carburetor.

If greater power is not what you are after and you are wanting the best fuel economy then try to obtain a carburetor that is the same size as your present one. :)
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: D the D on June 28, 2013, 02:43:26 am
There are 24mm and 26mm OKO PWK "D" slide carbs for less than Mikuni.  And Mikuni does make a TM24 Flatslide, but apparently skipped 26mm and 30mm in the TM series.  They even called the 28mm Flatslide a "VM28-418" to make it confusing.  Any would be better than the Mikarb, but that's my opinion after tuning hundreds of Mikunis and one Mikarb.  Someone in India may have the opposite view.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: rajvijayarajan on June 29, 2013, 08:34:44 am
Give you a small background,
The cylinder head of the bike 1996 Std 350 was replaced about a year back. Since the original wasnot available and was out of production, The factory supplied me with a cylinder head made specially for me. This was same as the OEM but my guess is that this was used for 350 models that use catalytic converter. The outlet port is blocked though (Will attach a photo to give better clarity.

This was the reason that i checked on the VM24 Vs VM26 as i am not sure which would be a better fit. I am not much of a mileage person but not keen on oversizing to a 28" (Guess this is a good fit of the 500 cc bike).
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: AVL Power! on June 29, 2013, 10:56:05 am
I feel that any carb that matches the inlet port should do good but I am no expert and to be honest I have learnt a lot of things from Tom and others who posted here. So the choice is yours :) but I did see an AVL 350 with 28mm dellorto which pretty much flies.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: D the D on June 29, 2013, 05:19:52 pm
Split the difference and use a 26.  That way you know you won't lose bottom end torque and KPL/MPG, and you won't be wondering "what if" about a bigger carb.  ;)  I'm sure the top end will be plenty with a 26mm vice 28mm.  I have a 28 flatslide on my stock head 500 and she still has some pull at 65mph, so a 26mm isn't going to restrict top end on a 350.
Title: Re: Mikuni VM24 Vs VM26.... Which One?
Post by: D the D on July 08, 2013, 04:27:45 pm
 rajvijayarajan,
What did you finally fit to your bike?