B-A-YamahaRider
New member
Does anyone have PSI, RPC, AAEN porting specs for 570 Exciters? I have PSI twin pipes on a racemod exciter engine that I have in my ice racing sled and I would like to do some more port work. I would like to see the specs for what any of these companies did when these sleds/engines were being PORTED by them. I just really need to get an idea of how far to go with porting and then the guys helping me out with porting can figure out the rest.
Any help is appreciated.
Any help is appreciated.
toydoc
Member
What year 570 do you have? What carbs are on it? What are the jet numbers in the carbs, needle, needle jet, main jet
YAMMIEGOD3:16
Active member
My Guess You Would Use The Exciter Sx Port Timing Spec. 3:16 (yammie Tony)
toydoc
Member
That would be best. SX spec and cut 1/8 off the intake skirt of the piston. Then depending on year of motor, you may need to liquid cool the case around the exhaust port, add weight to the flywheel, update jets
B-A-YamahaRider
New member
I am fairly sure the engine is a 90 or 91. We have 38mm carbs off of a Mercury Trail Twister, that are bored to 39.5mm.(Non liquid cooled carbs) We are currently at 340s for mains.
Everything from PSI that I have dug up has said that they ran 360 and 370s for mains, but they were also running 44mm Mikunis.
I would just really like to have the PSI, AAEN, RPC, or Bender porting specs for a baseline. If anyone has these I would greatly appreciate it if you could post them on here.
I have already done some porting but I left it fairly conservative on the exhaust ports, which I have found now that I am not reving enough to get to peak Hp.
Again guys, I have a freak show application, engine is in a 1980 SRX440 chassis, YPZ clutch, PSI twin pipes for 570 exciter, shaved cylinders and head, and many other mods. I really just need the specs from the above mentioned companies to get an idea of their baseline for their race only engines as this sled is only intended for radars and drags. I can take care of the rest with the guys I am tuning this thing with and we'll do our own version of the porting based on the specs I am requesting.
Thanks for any and all help. I appreciate it.
BA
Everything from PSI that I have dug up has said that they ran 360 and 370s for mains, but they were also running 44mm Mikunis.
I would just really like to have the PSI, AAEN, RPC, or Bender porting specs for a baseline. If anyone has these I would greatly appreciate it if you could post them on here.
I have already done some porting but I left it fairly conservative on the exhaust ports, which I have found now that I am not reving enough to get to peak Hp.
Again guys, I have a freak show application, engine is in a 1980 SRX440 chassis, YPZ clutch, PSI twin pipes for 570 exciter, shaved cylinders and head, and many other mods. I really just need the specs from the above mentioned companies to get an idea of their baseline for their race only engines as this sled is only intended for radars and drags. I can take care of the rest with the guys I am tuning this thing with and we'll do our own version of the porting based on the specs I am requesting.
Thanks for any and all help. I appreciate it.
BA
Yamaha Nutz
New member
here is a quick way to tell the year on the motor cast cylinders 87-90 chrome cylinders 91-93 sx had there own cylinders and flatslides i put a 97 sx 700 suspension in a friends sx last fall made the ride way better i will see if i have the Aaen specs still from when i had my motor
nutz
nutz