has anyone jetted a ttr 225?

I've rejetted my TTR-225 after putting a big gun exhaust system (header and muffler) on it.

Rejetting is pretty easy, but takes a little manuvering to get the carberator out. Once the carb is out undo the four screws on the bottom of the carb and take the float bowl cover off. The main jet is in the middle there.

As for what jet to run, I can't remember. I know I experimented with the stock jet and and both a plus or minus two sizes on the jet. I'll have to look sometime.

I wasn't able to get the bike to run right without back firing so I took it to my Yamaha dealer. I brought the jets I had and they did the jetting/pilot air screw/tuning work.

One thing they did do along with changing the jetting was to drill out the brass plug that covers the pilot air screw on the carb and adjust it.

I've done a couple small alterations to it also, but after all that the bike runs better. Though I'd like to find someone with a stock ttr-225 so I can compare the before and after. I did noticed though that 1st is all but useless unless I'm stuck on an up hill. The engine seems to pull better and sound wise it does sound deeper and louder but not like it's bigger siblings.

I was told that with the T-4 jetting was not required. I am running stock exhaust, but have pulled the snorkel and gone to a uni filter. That made quite a difference. Did you guys notice a major power increase with the new exhaust. Was it worth it?

I'm not really sure if the exhaust was worth it. When I first put it on, I did notice an increase in a little more low end torque, but that might've been either the jetting, exhaust, mental, or some combination of those. I wasn't expecting much of a change in performance though. I expected the bike to get louder with the idea that people would have a little more warning when I ride around on the trails, I was hoping for a slight weight reduction, and I must admit that I was also going for a cool factor in a slightly woffy exhaust sound. But I need to find someone with a stock 225 so a comparision can be made. That removed snorkel and Uni filter though, that I did notice. Also replacing the stock rubber for M12's was a good move for me.

dirttrails,
As i said my ttr225 is stock, if you are ever in Chico get a hold of me and we can drag race and ride them on some trails . See what kind of difference there is then we will both know.