sxviper32
New member
what's the difference between the mikuni tmx carbs and lectron carbs? what are the advantages and disadvantages? i know the mikunis are generally cheaper than lectrons but they seem very similar in functionality to me. thanks!!!
RJH
New member
answer soon
Good question - I'm out for the rest of the day - but I'll give a reply this evening.
Just a note - all carbs are good today right down to the Dellortto - if you have the stuff to tune - that carb with.
You'll notice the Lectron is more similiar to the TMS Mikuni rather than the TMX (American) or TMXx (Asian)
Good question - I'm out for the rest of the day - but I'll give a reply this evening.
Just a note - all carbs are good today right down to the Dellortto - if you have the stuff to tune - that carb with.
You'll notice the Lectron is more similiar to the TMS Mikuni rather than the TMX (American) or TMXx (Asian)
RJH
New member
Let me just say this first, to stop the dudes who read the first paragraph then jump in with complaints. The Lectron is a very popular carb for drag racing. Some who use the Mikuni often mimic the characteristics of the Lectron in setup. 
Please feel free to fall asleep at any time; I’ll try to be brief.
Mikuni has several current model carbs for different applications and end users and it’s not a straight progression but a series of side models. The most recent American model would be the TMS built very similar if not identical to the Lectron. You would be hard pressed to find a TMS as they proved not popular.
Like the Lectron it was jetted basically by a needle and the slide. You need to have some depth about running on just the needle as it takes some understanding a feel. You could use a TMX the same – take out the MJ and find a fat needle at the top and run that way – it would work very well with just the needle.
As a side note – I really like the Dell’orto for its huge adjustability. It was very easy to run without the MJ if the needle was too fat, however – that’s not a good idea performance wise. You see – you can change the emulsifying tube and the needle on the flat slide Dell’orto – just like the older VM Mikuni. You simply combine a fat needle with the skinny emulsifying tube and bingo it’s a Lectron.
Ok – the Lectron and TMS are great for drag racing as you don’t let off for a turn. I’ve talked to some winning dudes and they swear by Lectron. The key word here – winning dudes. They can go from one race to the next and not change jetting. I’ve seen lots try Lectrons in situations getting off / on the throttle and it’s not popular. For the simple reason you would need a pocket full of needles and some depth as to how they work.
The needle only jetting may simulate a MJ size of say 220. Well – that’s a pretty small jet and is probably good for 40 to 50 degree shift in temperature – so that makes it easy. Get up to the 450 size and you need to change halfway down the track – for optimum performance.
Moving down the Mikuni ladder you have the American TMX flat slide starting from scratch. You would probably be better off with this – only because you can get parts to test with. Lower than the TMX would be the TM – good as well as it’s more adjustable and finally the VM round slide – which is also good but doesn’t have the nice pillow of air under the slide and air speed of the flat slide.
Moving sideways – we have the Asian TMXx originally requested by Suzuki to meet the space limitations they had. The major improvenmnt here is the slide seal (another story). Each bike manufacturer has their own jet package for each bike. Yamaha bikes even have different needles for Europe and North America.
I did have problems (and fixed it) with the new TMXx high speed air correction jet hole, but I understand they fixed that problem in about 03 as well.
You have a Yamaha sled I presume – so I assume you still have the TMXx or D shaped heavy slide carb. That carb is the best you’re going to get. You will probably have mucho problems switching to the Lectron, even thou it is excellent for drag racing.
That Yamaha carb is restricted in so much as the needles each have the same specific taper %. Say… you raise the clip to the top – the next step is the next needle which is in affect is the same as adding 4 more grooves to your existing needle and so on in either direction. They did that as they match the fuel requirements to what they think the engine wants. I fooled them – I cut my own needles Ha!!!
Stick to the stock Mikuni, would be my suggestion.
Can't wait till we get the new Kehin on a 4 stroke
Look out
Any questions?
Please feel free to fall asleep at any time; I’ll try to be brief.
Mikuni has several current model carbs for different applications and end users and it’s not a straight progression but a series of side models. The most recent American model would be the TMS built very similar if not identical to the Lectron. You would be hard pressed to find a TMS as they proved not popular.
Like the Lectron it was jetted basically by a needle and the slide. You need to have some depth about running on just the needle as it takes some understanding a feel. You could use a TMX the same – take out the MJ and find a fat needle at the top and run that way – it would work very well with just the needle.
As a side note – I really like the Dell’orto for its huge adjustability. It was very easy to run without the MJ if the needle was too fat, however – that’s not a good idea performance wise. You see – you can change the emulsifying tube and the needle on the flat slide Dell’orto – just like the older VM Mikuni. You simply combine a fat needle with the skinny emulsifying tube and bingo it’s a Lectron.
Ok – the Lectron and TMS are great for drag racing as you don’t let off for a turn. I’ve talked to some winning dudes and they swear by Lectron. The key word here – winning dudes. They can go from one race to the next and not change jetting. I’ve seen lots try Lectrons in situations getting off / on the throttle and it’s not popular. For the simple reason you would need a pocket full of needles and some depth as to how they work.
The needle only jetting may simulate a MJ size of say 220. Well – that’s a pretty small jet and is probably good for 40 to 50 degree shift in temperature – so that makes it easy. Get up to the 450 size and you need to change halfway down the track – for optimum performance.
Moving down the Mikuni ladder you have the American TMX flat slide starting from scratch. You would probably be better off with this – only because you can get parts to test with. Lower than the TMX would be the TM – good as well as it’s more adjustable and finally the VM round slide – which is also good but doesn’t have the nice pillow of air under the slide and air speed of the flat slide.
Moving sideways – we have the Asian TMXx originally requested by Suzuki to meet the space limitations they had. The major improvenmnt here is the slide seal (another story). Each bike manufacturer has their own jet package for each bike. Yamaha bikes even have different needles for Europe and North America.
I did have problems (and fixed it) with the new TMXx high speed air correction jet hole, but I understand they fixed that problem in about 03 as well.
You have a Yamaha sled I presume – so I assume you still have the TMXx or D shaped heavy slide carb. That carb is the best you’re going to get. You will probably have mucho problems switching to the Lectron, even thou it is excellent for drag racing.
That Yamaha carb is restricted in so much as the needles each have the same specific taper %. Say… you raise the clip to the top – the next step is the next needle which is in affect is the same as adding 4 more grooves to your existing needle and so on in either direction. They did that as they match the fuel requirements to what they think the engine wants. I fooled them – I cut my own needles Ha!!!
Stick to the stock Mikuni, would be my suggestion.
Can't wait till we get the new Kehin on a 4 stroke
Look outAny questions?
RJH
New member
Meaning?????
What does Bling Bling mean?
What does Bling Bling mean?
sxviper32
New member
wow, thankas for the stellar info man!!! much appreciated man! i wasn't going to switch to lectrons, too costly and they don't seem popular so must not be for my use. i have the tmx 38's tho, which seem very popular and good on modified yamaha's. i was just always curious on the difference with the lectrons. whats so big on the keihin's? is it polaris that has keihin's on them, or am i mistaken? thanks again man for the clearification and info 
shortstop20
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My Pro-X 800 has TM40 carbs.