Mikuni vm26 jetting

[Jayman77]

I have a TT250 at sea level what jetting should I use and can anyone post a link to a set of pilots and mains for the carburetor

I am now using stock muffler and air box

But I have the eBay muffler and am considering air box delete

But for now just want to set up for stock

[Megadan]

Originally Posted by Jayman77

I have a TT250 at sea level what jetting should I use and can anyone post a link to a set of pilots and mains for the carburetor

I am now using stock muffler and air box

But I have the eBay muffler and am considering air box delete

But for now just want to set up for stock

Main Jets. Part Number N100.604.
https://www.jetsrus.com/a_jets_by_ca...arge_round.htm

Pilot Jets. Part Number VM28/486
https://www.jetsrus.com/a_jets_by_ca...-486_pilot.htm

There is no end all-be all jetting combination, BUT I can get you close.
To start, I highly recommend buying the genuine jets. Myself, and others, have had mixed results with the cheap jet kits on Amazon and ebay. Genuine jets will guarantee that you get consistent and correct sizing and threads.

For a completely stock bike at sea level I would say order a 105, 107.5 and 110 main jets, and Pilot, a 27.5 and 30.

I suggest starting with the 110 main and 30 pilot. This combination was a bit rich on my Hawk, but I am also at 1000ft altitude. Others at sea level have found those to work better for them. If you can't get a steady idle with the 30 pilot jet without having the idle mixture screw less than 1 turn out then step down to the 27.5.

The 110 main may also be on the rich side, as others have run a 105 at lower altitudes with success. The reason I suggested the 107.5 is to have an option if the 105 is a tad too lean and the 110 is a tad too rich. "Between" sizes are handy. However, you don't have to order it right away, and could order it later if you find yourself in that situation.

For the exhaust and pod filter, which is what I currently have, I am running a 117.5 main jet and 27.5 pilot with the needle in the middle clip position.

A good rule of thumb with these bikes with the intake and exhaust mods, if you don't do them at the same time, is to step up a full jet size for each one. Thus, if you have a 105 main and you put the exhaust on, then you will want to step up to a 110. Then when you add the intake, you would step up again from a 110 to a 115.

For a modified bike, it would be safe to say order a 115, 117.5 and MAYBE a 120. Some people run a 120 and seem to have luck with it, but I have found it to be a little too large at my altitude when combined with a properly sized pilot jet and needle settings.

At minimum, a 105, 110, 115, and 120 main and the 27.5 and 30 pilots should cover most of your needs, and then you can order a between sized jet like a 117.5 if you find the need to.

This is obviously just a basic guideline, and I always highly suggest spending the time to dial in all of the jet sizes and settings. The mixture screw is honestly the most tedious part to dial in, because it's in a pretty terrible location. I have found a small ratcheting bit driver like this one to be the most cost effective solution without having to remove the carb. http://www.sears.com/craftsman-5-pc-...p-00941715000P It's very tedious using one of these because you have to fiddle with it to find the slot in the screw, and you only get a small turn out of it, then fiddle some more to find it so you can turn it again, and over and over and over....

If you are feeling a little more spendy, then something like this will make things a lot easier. http://www.ebay.com/itm/Motion-Pro-M...tWcGwH&vxp=mtr

And, if you are feeling REALLY spendy, then there is this option. By far the best, but hard to justify spending as much on a tool to adjust one screw as you did on the carb and all of the jets lol. http://www.ebay.com/itm/Motorcycle-T...UQksbA&vxp=mtr

These will allow you to use the idle drop method to really dial it in. Once you find the sweet spot, shut the bike off, let it cool down, remove the carb, mark the screw and housing for a point of reference, and then turn the mixture screw back in until it lightly seats, and count the turns half a turn at a time. Write that number down somewhere for future reference. Then just set the mixture back that number of turns and line up your reference marks.

Properly jetted you should have all the power you need without sacrificing much, if any, fuel economy. I still manage to get between 65 and 72mpg on my bike, and I like to use the throttle rather spiritedly.

[Sochin]

I followed Dan's recommendation for my elevation and my bike runs pretty darn good now, I'm still playing with the needle position a bit.

[Jayman77]

I ordered the 110 main and the 27.5 pilot to start with
I am going to keep the exhaust and intake stock for now
I have the aftermarket exhaust and cone for later down the road if I become board with the bike.