OK I don't know shit about 2 strokes, after 30+ years of tuning... Do not belvie me do your own research like I did 30 years ago. Talk with Kenny Roberts, CalCruthers, Erv Kanamot, Scott Clough, John Ritter, MotoCarrera.
Denco engineering was local, I had a KH250 I wanted it to sound awesome, they knew of me a a shop rat for Honda and Yamaha, I got a part time gig. Porting and building pipes for Denco. I could ony get there 3 days a week,I had Vocational studies we were putting the 1st turbo on a Yamaha xs1100. I was the Hydro dyno guy. Did piston top rinds to reduce compression, remove 2nd ring on piston.
2 strokes
I loved 2 strokes a 100cc motor could make you scared.....
I got to drg race a few 250/350 from denco, had a good time. was quick
I got a Yamaha RD350 when my brother crashed my KH250, we traded.
I learned about porting and chambers [the sound wave] liked the power. Used to race up Highway 9 everyday. One week end raced up my road for fun found a lame duck on a Hond 900f with number plates. Kicked his ass until the last corner, it was Reg Pridgmore. He found me at the gap and told me [like in my face] you should get off the street and race. OK well he found me at Emery Honda and knew the parts manager and told him "Get him on the track"
OK #1 leak downs are Key to a well tuned 2 stroke.
If it can hold 3# for 10 minutes- find the leak, 3 minutes at 6# still look for leaks.
Most leaks are intake manifold, some base gaskets- bad surfaces, bad heads same thing surfaces.
2stroke no leak
timing- more advance = quicker. More retard= pipe hit, find the setting that makes power.
jetting
start FAT, reduce jetting x2 [saves time] better go 1 steep smaller
Worse- 3 steps up - better increase until not good.
Adjust timing- mix ratio, jetting to obtain max tune.
I Blew up many a fast motors, learned and made corrections, end of season 2 stroke competition= max tune - frag a motor you got 10 month to fix. Who made it to the end was key.
JT
offering tuning for a price
seehttps://yamahard-treacher.com (https://yamahard-treacher.com)
https://www.youtube.com/watch?v=9ws3O4IB1Jw (https://www.youtube.com/watch?v=9ws3O4IB1Jw)
https://www.youtube.com/watch?v=9jBjEE0CA4M (https://www.youtube.com/watch?v=9jBjEE0CA4M)