PSI Twin Pipes

[SRX500F82]

Hello. Have anyone of you tried Psi Pipes on your Vmax. That were made for the Exciter 570. I know there is a difference in the Stroke 68.00 Vs 64.00 mm they have their Peak at 8100 Rpm on that Motor. I have a set just put in to my -81SRX and they almost fit right in. But i figure how to get them to spin at 9000 Rpm and give the best H.p there. I have the dyno charts for the 91-93 Exciter SX stock 93.4 Hp Psi Twins 105.6 Hp They seems to really gain big H.p on the 569cc Motor. The pipes on the Vmax540 as AAEN and PSI made. Make less H.p than stock Exhaust did. As you can see in the article in this site. But You Could get 104 Hp at 8500Rpm with the Psi Pipes with Big mod on the Motor. But the Stock Exhaust also made 106H.p with Same mod this was tried out here in SWEDEN by a race shop in the late -80's i have the Dynocharts from them when they raced the sled. Thank You Michael.

[Nye Racing #13]

No stick with your stock pipes! Tim Bender told me to stick with stock pipes

[opsled]

Hi Michael, The NYE guy is probably right and I don't think I would be messing with Exciter pipes unless I could get them to fit without wrecking them. If you could get them on good enough to try them with say the right side panel left off it would be interesting to see what they would do. If you are looking at Exciter SX dyno specs you have to remember that the SX was a different animal than all the other 570's. Here in the states it was only offered in 93 and it was the strongest Exciter made. If setup right they would out perform the 600 Vmax without any trouble. It had racked slide carbs, different cylinders, timing, cdi and pipe. The cylinders had no bridges on the intake ports unlike all other 570's and the ports and port timing were also different. In stock form they were real strong and could give alot of 700's a preaty good run. We do have a 535 Vmax engine running twin 600 Vmax pipes in a friend of mines 78 SRX chassie and it runs super strong. It's clutched to run at around 8500 but will run to 9000+ without any problems. He ran down a kid in an F-7 last year on the river in a 2500 ft run which is not an easy thing to do. The engine has been nicely ported and the intakes raised. The head has also been cut, timing advanced and he is running 44mm center powerjet Mikuni's which are also not supposed to work on these engines. So I think that there are mods that can be done to get alot more out of these engines but if yours is stock internally you will probably get the best results with stock pipes and if you still have the 440 in your 81 you will be in a bigger guessing game.
Good luck, Phil (opsled)

[Nye Racing #13]

Wow I had a 78 440 Mod! I thought about putting the 540 Vmax motor in it? If my old SRX had a set of wings, I know it would FLY

[SRX500F82]

Hi Phil. The 87-90 Exciter have Stock 77HP at 7200Rpm and with the same Psi Pipes that the SX had. they make 92.7HP at 8000RPM. Not bad there either. So i will try them and se how they make power at 8000RPM on the -81 SRX440 and clutch them up slowly to 9000Rpm to see if they make any different from stock pipes. Im running 42mm carbs W/UFO's here's a pic. I think they gonna fit well after some small mods. And even fit in to stock hole.

[Vmax540]

"He ran down a kid in an F-7 last year on the river in a 2500 ft run which is not an easy thing to do" Wow........ That is one good running sled !