Looks like lots of fun was had by all. Q: Why is the curve so lumpy? Is that a function of the sensors and or RF noise, or is it really missing like an SOB all the way up? Just throwing thoughts out there late at night when I should be tucked up in bed dreaming.............
Did you run CHT and EGT on the dyno? Please try that next time to see what's going on.
Is the stinger large enough to run on your bike? Too small is fine for raising pipe temps and getting the bike to run past the red line at the strip, but not so good on a dyno.
Pipe is designed for revs that you may want to avoid. 9500 is on the high side if you want the big end to last. Don't forget that force on the big end is a square effect. Double engine speed = 4 times the load on the big end. You need small rollers, singles in a light cage - preferably silver coated.
360 cc of hot gas into a 250cc pipe is probably not a huge issue but a drag bike doesn't heat soak the way your bike will on a dyno. BTW, we put an RD350 on the dyno last week. Stock supposedly 28-32 at the rear wheel. We got 52 when it was cool and 48 heat soaked on stock carbs (not stock jets) and not so stock everything else. Using that as a crude comparison, a 360 Bultaco could theoretically make 50-ish HP.
That reed set up is interesting but looks all wrong to my tired eyes. Think in terms of changes to cross sectional area. You want smooth transitions as much as possible. With old style reeds in the barrel, it's harder to get gas into the bottom end and then up into the transfer ducts. There will always be some horrible transitions, but think of the gas flow. Model it with smoke and a vacuum source if necessary. And the reed petals are a long way from the piston and will tend to react slower than they might need to. Also consider fiberglass reeds with lower Young's modulus. You can model that in MOTA as well.
Is there a simpler reedbox that would work with say V Force 3 or 4 reeds for say a Polaris 700 twin or say an Arctic Cat 900cc triple with a a larger carb? Bolt on reed boxes for an H2 are a touch spendy but might be adaptable. Just thinking about possibilities.
If you are stuck with that sort of reed box, consider larger one piece reeds and remove the dividers between the finger petals. For example we used YZ85 reed cages in place of RD or even RZ/TZ cages because they are two large petals in place of two pairs of finger petals. Check around to see what is available that might work.
You may also want to look at transfer port outlet angles in both planes. Think colliding streams. Think higher CR and ways to keep the motor cool with rich mixture. retard the timing and keep the cylinder cool but that adds heat to the pipe which eventually comes back to bite you too.
If you ran race gas on the dyno, then it has too much compression already or timing is too advanced or the pipe is all wrong. Try to model that pipe in MOTA and check exhaust temps and pressures. Also check blowdown timing and see if there's enough time are to stop hot gas from filling the bottom end as soon as the transfers open.
You could also looks at MSV in that shiny new head as well as faster burning fuel with less advance.
I am pretty sure that BB knows all this stuff - and a whole lot more. It's fun to work out what works and what doesn't. Keep having fun.
Did you run CHT and EGT on the dyno? Please try that next time to see what's going on.
Is the stinger large enough to run on your bike? Too small is fine for raising pipe temps and getting the bike to run past the red line at the strip, but not so good on a dyno.
Pipe is designed for revs that you may want to avoid. 9500 is on the high side if you want the big end to last. Don't forget that force on the big end is a square effect. Double engine speed = 4 times the load on the big end. You need small rollers, singles in a light cage - preferably silver coated.
360 cc of hot gas into a 250cc pipe is probably not a huge issue but a drag bike doesn't heat soak the way your bike will on a dyno. BTW, we put an RD350 on the dyno last week. Stock supposedly 28-32 at the rear wheel. We got 52 when it was cool and 48 heat soaked on stock carbs (not stock jets) and not so stock everything else. Using that as a crude comparison, a 360 Bultaco could theoretically make 50-ish HP.
That reed set up is interesting but looks all wrong to my tired eyes. Think in terms of changes to cross sectional area. You want smooth transitions as much as possible. With old style reeds in the barrel, it's harder to get gas into the bottom end and then up into the transfer ducts. There will always be some horrible transitions, but think of the gas flow. Model it with smoke and a vacuum source if necessary. And the reed petals are a long way from the piston and will tend to react slower than they might need to. Also consider fiberglass reeds with lower Young's modulus. You can model that in MOTA as well.
Is there a simpler reedbox that would work with say V Force 3 or 4 reeds for say a Polaris 700 twin or say an Arctic Cat 900cc triple with a a larger carb? Bolt on reed boxes for an H2 are a touch spendy but might be adaptable. Just thinking about possibilities.
If you are stuck with that sort of reed box, consider larger one piece reeds and remove the dividers between the finger petals. For example we used YZ85 reed cages in place of RD or even RZ/TZ cages because they are two large petals in place of two pairs of finger petals. Check around to see what is available that might work.
You may also want to look at transfer port outlet angles in both planes. Think colliding streams. Think higher CR and ways to keep the motor cool with rich mixture. retard the timing and keep the cylinder cool but that adds heat to the pipe which eventually comes back to bite you too.
If you ran race gas on the dyno, then it has too much compression already or timing is too advanced or the pipe is all wrong. Try to model that pipe in MOTA and check exhaust temps and pressures. Also check blowdown timing and see if there's enough time are to stop hot gas from filling the bottom end as soon as the transfers open.
You could also looks at MSV in that shiny new head as well as faster burning fuel with less advance.
I am pretty sure that BB knows all this stuff - and a whole lot more. It's fun to work out what works and what doesn't. Keep having fun.
