mikstr

Thanks

nath981

mine starts contesting around 10,000 rpms.

Acc to the info presented here, it appears that there was neglect and blame on both sides, but mik is willingly picking up the tap, and the tweeter gave him his blessing, so it looks like all is copacetic in this particular case.

If I were putting my bike on a dyno, I wouldn't feel the need for anything over 9500 unless I were going racing, would get that in writing, and would be there to make certain they took care of my baby.


.........I may be a little nuts. errr, Maybe i need to skip the "may be". haha

For example, when I had the frame stretched on my semi in order to accommodate a larger sleeper, I required that the garage allow me to work along side the mechanic(and it was only one guy who had the expertise) who was going to do the fabrication. At first they gave me the run-around about insurance and liability ho ho, then finally agreed when I threatened to go elsewhere.

I was there everyday, all day, for over a month till we got it done. They told me I was the only person to ever require such a thing, which i figured out well before and wasn't impressed with that info.

That said, i learned a lot and enjoyed every minute of it and would do the same again without reservation. The guy who did the job was a genius who understood everything he was doing and why, contrary to the "take off and replace" pretend mechanics you find in most facilities today. We had a great time and the days flew by quicker than I would have imagined. It was my privilege for sure.

Tweety

Redline is 9500, but revlimiter is 10300 RPM... And with a dyno, you will not be able to limit the RPM's to 9500 like that... There RPM rises much faster than you will see on the road... You are deliberately making the bike work against a lighter load than normal riding, to not strain things, but a known and controlled load, that makes the calculations meaningful compared to real world...

So if you put that requirement in writing, the reply you get from every dyno operator will be "NO! Go elsewhere!"... And it won't be for the reason with your ecxtended cab, but the simple fact that they cannot make that promise and expect to keep it, so anyone taking that order, walk away anyway...

You can roll off "around" redline, say anything from 9000 to just under 10000 but then you won't get consistent and comparable data, so the whole thing becomes pointless... So the normal procedure is to hit the revlimiter (but not bounce on it repeatedly...), which is completely harmless to any bike, the VTR included... The limiter is there for that specific reason, to limit RPM's to a safe point...

So, mikstr and the tech was going on the info they had, that the box had a revlimiter higher than normal, but a limiter... It didn't... So the RPM's reached unsafe levels before anyone could react and roll off... Ie, most certainly not the tech's fault... Not anybody's fault really... And the rules of dynoruns are simple... Your risk, your cost, but under controlled circumstances... Or go elsewhere...

nath981

I never saw anything here indicating that mik and the enginator were going on the info that there was a rev limiter higher than normal. Where did that come from? Inadvertantly to 11 grand doesn't sound like they had much of a plan. Not making certain that there was indeed a rev limiter seems to me a critical piece of information ignored, esp if as you say it is difficult to control rpms on a dyno.

Speaking of which, if the dyno operator could not guarantee in writing that he would not exceed a target RPM limit, then I would not let him touch my bike. No way. That's bullshit as far as I'm concerned, esp when your engine is at stake. If the engine fails at or under target rpms, then, no problemos, because something was wrong with the motor that caused the failure and it likely would have come unglued later anyway.

I don't agree that no one's at fault here, but it's really none of my business. I like to analyze ****-ups in order to lessen the possibility of re-dos, esp one as costly as this. I appreciate your efforts and respect your opinions, so thanks for your remarks.

GTS

Doing a fair amount of dyno tuning and running the dyno for a handful of dyno days at the shop I used to work for tweety is very correct on how fast the revs climb, and how hard it is to cut it off at a specific RPM. You can get it close but not perfect.

The more I read about this and think about it the more I'd say it's a faulty cam. I mean we've got short cams operating a single cylinder. So there isn't much tortional stress on them as compared to an inline engine. And the amount it reved over wasn't all that much in comparasin. That thing shoudn't have broken. Floated and bent valves, maybe, floated and busted a ring, possibly. Snapped a rod or had a crank failure, probably not at such a marginol amount over the stock redline but maybe. But a cam snap? No. I'd be giving the cam manufacturer a call and see what they'd do to warranty or at least do a regrind on one of his cor cams.

But what Mik wants to do to fight it or just pay for it is his call.

7moore7

IMO those could be two different things... a mistake and someone being at fault that is...

My guess is that the shop has never broken a cam this way before. And Mik had every reason to believe that the HRC unit had a rev limiter. And it's not like the guy doesn't do his research (have you seen his threads on experimenting with oil mixtures and reasons for doing so?)

Also, if one were to go about the most financially stable motorcycle, one wouldn't test the limits of the bike or up the performance to the crafted machine that Mikstr has... Sometimes **** happens when you're playing in less traveled territory. My bike won't brake a cam, but mine has a normal black box and at best 110 hp.

I agree to maybe pursue the snapping of the cam... maybe there's something in that?

nath981

yeah i have gathered that revs can climb fast and that it would be difficult to target, say 9750 rpms, and specify that you wanted data at exactly that rpm without exceeding that number. Revs might go to 10+ before it settles at 9750. I understand this and that's why it's critical to do a pre-nup to anticipate this when you have so much to lose. Without first-hand dyno knowledge, I also think that machine quality as well as the expertise of the operator are factors which could minimize over-run time and amt.

I don't really think that mik has any grounds for a fight dyno-wise, even if he wanted to, because it seems that he didn't do his homework in terms of the rev limiter and a pre-nup stating rpm limits including overrun. Not his fault maybe but he loses anyway......kinda like crashing, no matter who's right when you pit your body against a steel beam, the result is not good.

In terms of the operator, it seems that, as the expert, he would feel compelled to alert customers of the need to verify rev limiter functionality and rpm limit numbers and maybe he was negligent in that regard.

Probably when mik gets it back together and dynos again at the same place, there will be no problems. Maybe there are some lessons to be learned here, maybe not. In the end, it may be good the engine failed on the dyno instead of while trying to pass his buddy's F4I at a buck forty.

nath981

I understand what your saying, mistake vs intention, dumbass vs criminal...semantics to me. The point is to identify what went wrong and why, in order that it may be avoided by me and possibly interested others when it's our turn. From my experience, this usually requires openness and calling it like you see it in an effort to be clear on the facts so that we can all maybe learn something.

I'm not the most politically correct in terms of politeness, read: rude and crude haha, and do not mean to personally diminish anyone. Speaking of which, if you want to discuss your oil mixing references, you're welcome to PM me. I stand by what i say, i try to live it through my actions, at least until I find out differently, at which point i'm willing to try your or whoever's way if it makes sense, in an effort to evolve and learn.

I've always lived this way, and more importantly now, in what i perceive to be an era of rationalization.........one where there seems to be the need for an increasing number of people to use their intelligence primarily to justify their own particular desired result, regardless of and separate from reasonable facts to the contrary, for the sole purpose of bolstering their weak self-concepts. Or........maybe it could be i'm looking in the mirror too much these days? "hey ! that's me"....Not!

Anyway, I ain't your local christian who goes to church on sundays to save his own ***, and then screws over people all week long. A little more proof to me that there is some serious rationalization goin on here today.

JamieDaugherty

Sorry to join in a little late...


I'm just thinking about the brand new set of Yosh cams sitting, still in the box, on my shelf and what role they might play in this discussion. I've been meaning to put them in my bike for about... wow, has it been that many years? A person can always be swayed.....

RCVTR

I believe that Yoshimura used the stock Honda cam castings. There were problems with the RC51 cam castings, and several brittle failures were reported with stage 1 and stage 2 cams from the stock castings. I'm not sure if it is a related failure, but it sounds very similar. I don't think you'll get anywhere trying for compensation for a 10 year old broken cam in a race engine that was overreved.

There are a lot of race engines with no rev limiter. The HRC ECU does not have one. The dyno operator needs to know this and cut the throttle. the cams would have been past peak torque and signing off. There is no need to tune it above about 10k RPM in a stage 1 engine.