Ok finally got my short rod motor trx250r out since my hip replacement. Ran great putted around alot. Open it up get on the pipe and it would pull hard. Get where i can really go hit high end of 5th gear into 6th and it stutters like its off the pipe(aka power band) as though before it comes on the pipe rough and not smooth. 110 sunoco 30:1 belray MC1 oil, b8es ngk plug. Boysen reeds do have some age but rpm doesnt seem to be a factor since it doesnt do it in any other gear or free reving. Just annoying will run about 67mph in 6th stuttering. There should be alot more left.