I drove my 2 month old rebuild engine 250 trailblazer the last couple of days full throttle and just dies and and five seconds later while still moving it will start to pick up speed again, WHAT COULD THIS BE?

 

I can tell you that with the setup that you have your main is wat to big. You will lose tons of top end with to big of a main. You should be between 150-160 main. If you burnt it up over the winter it may be because the needle and air screw were on the wrong setting for cold. 190 Is way big for you.

 

Well, for winter it was for that, but i did a spark test with it and it wastn' too dark, just a tad too lean, but i will try the 180, but did u also see my other mods I have on it?

 

I meant to say it was a tad too fat, but i'll see what it looks like tomorrow!

 

Well the only thing that I see in your mods that would make a jet change is the pipe and K&N filter. HSP uses a 150 main with that pipe and you would go up 1 size for the filter. That would be a 160. In the winter I usually jet up 1 size bigger then jet back down in spring. Or you can just put the stock airbox on for the winter so you dont have to rejet. Even with all the mods that I have when I had the 34mm mikuni carb I was running a 180 jet and it was a little rich. The boring is not going to need a rejet and it wont give you any better performance. Boring is just there to save money in the long run.