Engine RPMs... what are the limits?

I own an 03 Max, that is stock except for the K&N filter, and I love it.
Purrs like an angry Bengal tiger down low, screams like a hungry T-Rex up top.

Yeah, the part about the screaming T-Rex. I don't do that often, and I do have a concern here. Specifically, since the bike has no rev limiter, for all I know, I could be, on the rare occasion, severely over-revving the motor. On those occasions when I do open it up, 10K is likely. I think the max I have hit is 10.5k.

Now, I have read here that the engine does not like to be over-revved.
This does concern me.

What is the max I would want to let the RPM's hit. Where are the weaknesses within the engine that make the high RPM's so bad? (Valve float? Con rod bolts letting go? Sheering the piston pin?)

Maybe I need to invest in an aftermarket ignition. Something with a programmable rev limiter. Would be nice to have anyways. Better ignition is always a good thing. ^_^

Well Dingy on here sells an an after market TCI called Ignitech, as well as being programmable with a laptop (if you wish that option) it also comes with a rev limiter.

http://www.vmaxforum.net/showthread.php?t=23506&highlight=ignitech

Biker Dash said:

I own an 03 Max, that is stock except for the K&N filter, and I love it.
Purrs like an angry Bengal tiger down low, screams like a hungry T-Rex up top.

Yeah, the part about the screaming T-Rex. I don't do that often, and I do have a concern here. Specifically, since the bike has no rev limiter, for all I know, I could be, on the rare occasion, severely over-revving the motor. On those occasions when I do open it up, 10K is likely. I think the max I have hit is 10.5k.

Now, I have read here that the engine does not like to be over-revved.
This does concern me.

What is the max I would want to let the RPM's hit. Where are the weaknesses within the engine that make the high RPM's so bad? (Valve float? Con rod bolts letting go? Sheering the piston pin?)

Maybe I need to invest in an aftermarket ignition. Something with a programmable rev limiter. Would be nice to have anyways. Better ignition is always a good thing. ^_^

Click to expand...

First things first, the stock tach's are pretty far off up at the higher rpm's so your probably not revving as high as you think... If you want a rev limiter then I suggest getting a dyna ignition, Sean Morley of Morley's muscle can hook you up with a good deal on one and it has multiple advance curves and you can set the rev limiter pretty much where you want too.. I used to run curve 4 because it felt like it had more punch down low but then I started racing and figured out et's were identical but on curve 1 (stock curve) I gained 1-1.5mph so I just leave it at curve 1 now. I think the rev limiter is set in 500rpm increments, I've got mine at 10,000rpm because I needed the extra rpm for 4'th gear on nitrous but in your case the 9500rpm setting would be fine. I believe the valve springs float and break after 10,000rpm and that's when bad things start happening lol hope this helps bud...

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Well sell both the Dyna and Ignitech. Both are good units. The Igni unit is much more advanced and a "tuners" dream. Plenty of support and the units bought direct from Dingy have the map preloaded. I leave mine blank so it can be programmed easily to either year chassis. The igni unit can also run the vboost as well as be set up to run COP's without resistors (so you can ether get cheaper adapter harness's or make your own).

I've revved mine over WAYYYY more times then anyone should ever admit. Typically you'll spin a bearing if done too many times and wobble out the small end of the rods (wrist pins). I wouldn't sweat it much though. As long as you let it warm up properly and get the oil thin enough to go where it needs to you should be ok.

Mine survived hard pulls up past 10k a handful of times without issue. That said, I wouldn't make a habit out of it.

On later models Yamaha actually changed the redline on the tach from 9500 to 9000, I guess to discourage over-revving.

Many people install a shift light on the speedo to help prevent accidental over-revving. Mine was set for 9300 to account for reaction time though after a while I could pretty accurately anticipate when it would light from the engine tone.

And yes, the stock tach isn't super accurate....mine over-read by around 5% compared to the Autometer I had on the side of the speedo. Not like you're looking down at the stock one when you're running to 10k anyway.

Yeah, I guess I may wanna invest in new valve springs at some point, as well as an Ignitech ignition. I like the idea of fully tunable curves. Big thing as far as ignition goes is initial advance. I was thinking maybe 4 degrees of initial advance more. The rest of the curve... well, lets see how she runs with different maps.

Do they make beehive springs for the Max? Combine that with titanium retainers, and I imagine valve float will no longer be a concern.

anyone notice like 97 bikes redlne is 9500 and I've seen now a 2000 and 2007 both red lines 9000 on stock tach

The engine runs out of power when stock over 9,000. Not much point to over reving.
Both of mine have the Kawi O-Ring upgrade and have seen indicated 10,500 once
or twice. The 94 now has a Dyna set to 9,000. The Vmax engine is a strong engine
but small things like valve springs could be the weak link. SkullDuggery is way faster
than my 94 but actually easier to keep out of red line when shifting.:confused2::ummm:

Someday, I'll get a shift light and the balls to run CaptainKyle at Desoto Speedway.
:rofl_200:Like I have a chance????

SpecOps13 said:

The engine runs out of power when stock over 9,000. Not much point to over reving.
Both of mine have the Kawi O-Ring upgrade and have seen indicated 10,500 once
or twice. The 94 now has a Dyna set to 9,000. The Vmax engine is a strong engine
but small things like valve springs could be the weak link. SkullDuggery is way faster
than my 94 but actually easier to keep out of red line whan shifting.:confused2::ummm:

Someday, I'll get a shift light and the balls to run CaptainKyle at Desoto Speedway.
:rofl_200:Like I have a chance????

Click to expand...

i ... EXACTLY , IF IT STARTS NOSING OVER YOU MIDAS-WELL SHIFT ! :confused2:

I have to admit mine has been over 10K quite a few times not on purpose though. I have tried all kinds of shift points at the track & 9200 seems to be my happy spot.

Mine runs 10,200 at the track so that when the rpm's drop into the next gear, I am at a higher torque range.

I ve run 11,000 on my track by accident on broken driveshafts, but that was factory tach so I am sure its not that accurate.

The point of no power past a certain point is understandable, but the drop in gear ratio pulls you past a point of power pull, so that if you rev slightly past that point, you pull yourself up higher for the subsequent gear change.

Just like launching out of the hole, I run 4200-4500 rpm. Any higher and it bogs out for me. Running at 4200 it pulls crisp out of the hole for me. Best 60 ft 1.686 so far, so obviously it works. But I guess my point is people get hung up on numbers ( I am a number person ). If you don't feel comfortable than shift lower. On the street my bike rarely sees 9000 rpm. No point in it. I am not trying to run a .10 tenth faster, I can't measure that performance without clocks, so why do it. At the track though I can, so I do.

Todd

I over-revved mine a few times in the past (usually during a bad shift when I used to fall between gears) after one particularly heavy fisted blast the small end developed a loud knock - I ended up replacing the conrods

My shiftlight is at 9300 just for the reasons Todd stated... I launch pretty high, about 7000rpm or so but I'm a heavy guy so I pretty much have to or it bogs bad.. I also agree with Todd about being on the street, your not gonna notice an extra tenth or two on the street so why beat the hell out of it? Rev limiters are a good idea for a missed shift or broken driveshaft though..

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As I always used to say, when the motor blows, you found its limit.....

I had mine to 10,500-11,000 many many times and never broke anything due to over rev

I think a lot of us have been at or over 10k R's, I know I have more than once! I purchased a shift light for this very reason (set at 9200 R's) and this year installed a Dyna 3000 (9500 R's rev limiter) so I should be set. I do have heavier valve springs too.