WHat RPM to prop Yamaha

[ucf_motorcycle]

I am running a 21P Tempest Plus on a 225 EFI Yamaha. I am pretty happy with the performance but a little concerned as the WOT RPMs trimmed up are 5800RPM.
Yamaha recommends WOT RPM to be 4500-5500 on this engine. Now I am not going to run it alot at WOT and this high RPM but I will for a few seconds here and there.

So should I up the pitch to a 23P or just leave it as is?

[whipper]

Pitch to get as close to max rpm as you can. You should be able to run max rpm for longer than 1 sec and not hurt anything. I would think for a mile or even more. The limitter should stop you from over reving. :thumbsup:

[Ted Stryker]

If You going to be doing alot of long stretch running and not alot of holeshotting from spot to spot then a 23-25 will work well depending on Your set-up... 5800 won't hurt the engine at all if it's in a good state of condition and tune, but 5400-5500 will probably yield a few more HP and be slightly easier on internals and fuel consumption... In marathon races there were V6's of all types that got run WOT for hundreds of miles, hour after hour and never hiccupped... Yamaha was one of the best also, and are still fine engines... When Mercury Marine was developing the 250XB (I think) a few years ago they ran some of those engines at WOT under full load of resistance for 6 months in test tanks... Those engines did have an advantage in regard to them never having to make a bunch of heat cycles or have to operate cold or sit up unused to the elements like our engines do, but still that is over 4,300 hours of hard running... These engines are tough, remember there aren't any valvesprings to soften or valves to float, and everything is roller bearinged so build up some heat and stand on it for as long as You wan't to if You've got the wallet to support the fuel...

[rangerguy]

If you would check the rpms on your motor has been updated by Yamaha to 6100 rpms.

[Ted Stryker]

If you would check the rpms on your motor has been updated by Yamaha to 6100 rpms.

If that's the case, then He's perfect... :thumbsup:

[ucf_motorcycle]

If you would check the rpms on your motor has been updated by Yamaha to 6100 rpms.


Really where did you find this? I have always heard 4500-5500 on the OX66 series engines. Which is why I was a little concerned about doing 5800. Send me a link to that update if you can find it.

[VectorPat]

Yes the 0x66 motors were always 4500-5500 but they could safely turn 5800, I wouldnt be doing it for a 20 mile run but the occasional run for a few minutes wont hurt. The 3.3ltr VMax HPDI engines were rated up to 6000rpm somewhere around 2008. Both engines have rev limiters at 6200rpm