Mythbusters: OE Rev limiter and overrev dangers

[acammer]

So, I am new to the Vmax, but not at all new to street bikes, and wringing their guts out. As I am sure most of you have experienced its real easy to miss that 1-2 shift when you're leaning into a wheelie and struggling to watch the tach out of the bottom of your eye. I've read the service manual and it does state there is a rev limiter in the factory ignition. Now, I can't be sure, but I will bet I kissed at least 10,500-11,000 briefly, no hint of a cutting out in any way. So, its either even higher than that, or it just doesn't exist. What can you guys confirm, or deny, regarding the supposed stock limiter.

Secondly, what are the realistic dangers of a brief over rev with this particular motor. From what I've read 10,500 is about the limit that you want to consider at the strip. How much over rev tolerance does this motor allow for.

I can tell I need a shift light for sure with this bike, I am trying to decide if I can be ok with just that, and still be at risk for an occasional missed shift, or if I should take a chance on a Dyna 3000 (which has a pretty poor reputation from what I have read), for the limiter function. I don't intend to race the hell out of this thing, but I didn't buy a Max to putt around with either, and some high performance riding will be taking place on a regular basis. I have searched the forum extensively and found mixed info, so I figured we could start a new, lively discussion and see if we can clarify some of the facts around a potential stock limiter, and what amount of over rev the Max will really tolerate.

 

[mattness]

my 03 to my knowledge didnt have a rev limiter. a shift light helped a shit load. mine was from raptor performance and worked great and oit was bright as hell even in the day. the stock 09 shift light sucks ive been pondering buying one to throw on the gen 2! lol.

i always shifted before 9k

 

[m-cman]

There is no rev limiter on any Gen 1 Vmax and it is really easy to over rev in the lower gears when on V-Boost. The only way I know to get a true rev limiter is with the Dyna 3000. Only bad thing I have heard about the Dyna is they crater if you go the COP's mod without adding resistors or using the special wire harness developed by a member here. (Search COPs for more info). So far I don't know of a true waterproof shift light so if you ride in rain much that could be a problem. I need a waterproof unit so I am leaning toward the Dyna 3000 if I can ever find a low price.

 

[KJShover]

Yup, no rev limiter via stock ignition.
I've had my Dyna 3k ever since I got my bike. I've had no problems with it at all.
I also am using a shift light, I've had a raptor and I'm now using a harlan. The harlan is a little cheaper. Nothing wrong with the raptor light. I just went with a different setup, then went back to a small shift light.

 

[allisontech]

I had the same problem you have, I swore I saw 10 grand or so on my factory tach. I purchased an SST light which also has a digital tach read out on the side,and a max RPM recall. I found I need to set the light for about 8500 to make a 9500 RPM shift happen, "So when Vboost kicks in these engines spool up pretty quick!" I have a video of it here on the site. Search SST shift light.
Bill

 

[SpecOps13]

I saw 10,500-11,000 several times with my 94. I had done the Kawasaki O-Ring Mod and the COO Fix so I know that didn't pop the dreaded O-Ring after it was done. I bought a Dyna 3000 in a group buy here. The bike runs great with it. I set the rev limit to 9,000 as there isn't any HP to be made above that anyway. HP actually falls off right there...

My 89 has the stock ignition as there is no longer a Dyna 3000 available. It has the Kawasaki O-Ring fix in place. I will eventually find a rev limit solution for it though. Stock Ignitions have No Rev Limiter.. High revs can be a bad thing with these engines. Also floats the valves with stock springs...

 

[acammer]

Yamaha really didn't think this through very well, this bike will easily pull well last the rev limit in gear, let alone on a missed shift. I hate to spend the money on a 3000, but it may save bigger problems down the road.

Who has actually broken from an over rev? How did it happen, and what were the results?

 

[one2dmax]

As noted already there is no "rev limiter". The ignition doesn't really know what to do about 11,2000 but it will still rev past that even. I've looked down many times and see the needle coming down off the stop.

The dyna is the only real available limiter out there and some don't like it as they say it doesn't work well in an unloaded rev (IE missed shift). I've not had that same problem with them (though we have had a few problems).

The factory lowered the Redline from 9500 to 9000 the last few years of production. They probably found out that over revving tended to cause rod failures. The small end fails from that as well as being steel on steel. Our reworked rods have bronze bushings installed to help prevent that galling/wear.

I try to suggest not going over 10K but most should maybe not go over 9500. These bikes make peak power around 8500-9000 anyway though those first gears use the gear amplification which makes them pull hard even well over that rpm level.

See pics on our facebook site in the broken parts photo section to get an idea what happens.

Sean

 

[85vmax]

My '85 will pull strong all the way to about 10800, you hit the wall a bit over 11k,(flouting valves) like Sean said...many a times I've seen it at 12k. I try to shift by feel but no can do on the Max...it'll keep pulling till you break something:bang head:
I now have the Dyna 3000 with no regrets....limiter set at 10500 (not recommended to go over 10k with stock springs) bar mounted 4 inch tach/shift light set at 9700....I pretty consistently shift at 10200 at the track (shift recall)....works best for my ride......too much catching up to do shifting at lower rpm for me.

Oh yea...just get a good shift light, I never hit the limiter.

 

[acammer]

I try to shift by feel but no can do on the Max...it'll keep pulling till you break something:bang head:

Yea, I am finding that is a significant issue for me as well, everything I have had before started to fall off and you'd know when to shift, Mr. Max just keeps pulling, in gear, way beyond where it should. I am considering adding a Dyna to my current order with Sean, maybe I will see how I feel after a shift light.

 

[one2dmax]

You'll be surprised and almost disappointing the first few rides after the dyna is put on. You'll hit it far sooner then you'd think but it will save you buying an engine later from me too.

Sean

 

[85vmax]

You'll be surprised and almost disappointing the first few rides after the dyna is put on. You'll hit it far sooner then you'd think but it will save you buying an engine later from me too.

Seans right...it's all trial and error...I was hitting the limiter every time it was set at 9500, 9700, & 10k my max pulls pretty good for a stocker.... thats also how I found my shift lag was about 500rpm at the track, but as the night gets longer the DD wears you down hence the 10500 limit.

I know on paper power starts dropping off at around 9k, but my bike is still pulling then, and the et times got better shifting high.

 

[acammer]

Well, I sold my backrest on eBay and made out pretty good, so I am adding a Dyna3000 to my current order with Sean, its cheap insurance.

 

[Rusty McNeil]

Some where in the factory service manual, I think under the subject of TCI, it mentiions vaguely something about a rev limiter function. I never could find it when I had the factory TCI in place. It would easily rev to well past 11,000-12,000

I'd call it a myth for sure, maybe the factory TCI retards timming past a certain RPM to slow over rev down but I wouldn't call that a rev-limiter, you never feel any "wall" with it, or even a noticeable power decrease.

With the Dyna I have it set at 10,500 and run a shift light set at 9,800, shift lag being what it is.

I'm very pleased with my Dyna, although I wish like hell the second Gen Dynas for the 90 and up (I think?) models had the external wire to trigger retard, would make big shots of nitrous a lot more feasible. The last gen of Dynas can only be retarded via dip switch settings as far as I know.

 

[acammer]

Some where in the factory service manual, I think under the subject of TCI, it mentiions vaguely something about a rev limiter function. I never could find it when I had the factory TCI in place. It would easily rev to well past 11,000-12,000

I'd call it a myth for sure, maybe the factory TCI retards timming past a certain RPM to slow over rev down but I wouldn't call that a rev-limiter, you never feel any "wall" with it, or even a noticeable power decrease.

That's what I was wondering about as I saw that reference in the service manual as well. But, like you said, it has been my experience that it'll pull, in gear, well past the red line, past 11k rpm, never mind what it would do on a missed shift to neutral WOT over-rev.

It does sound like a lot of us have made a few "opps" over-rev's without doing serious damage. That's encouraging that there is a little tolerance for it, because its just SO easy to do.

 

[Rusty McNeil]

That's what I was wondering about as I saw that reference in the service manual as well. But, like you said, it has been my experience that it'll pull, in gear, well past the red line, past 11k rpm, never mind what it would do on a missed shift to neutral WOT over-rev.

It does sound like a lot of us have made a few "opps" over-rev's without doing serious damage. That's encouraging that there is a little tolerance for it, because its just SO easy to do.

I've got 45,000 miles, never a valve adjustment, over 200 passes at the strip and a handful of missed shifts and no problems yet..Knock on wood...

I haven't ever missed shift since I stopped using the clutch on anything but the 1-2 shift, I firmly load the shift lever and blip/fan the clutch on that one, and firmly load the lever and blip the throttle on all the rest.

 

[Thevmaxrider]

Dyna also makes an inline rev limiter that works with the Vmax, though I do believe you need two of them. Would have to look up the part number, but it would allow you to keep the stock TCI box and still have a rev limiter. Don't run one personally as I have my EFI setup set to cut the fuel off at 11k rpm so I don't over rev. Though I don't miss shifts either with the air shifter setup.

 

[[email protected]]

Dyna also makes an inline rev limiter that works with the Vmax, though I do believe you need two of them. Would have to look up the part number, but it would allow you to keep the stock TCI box and still have a rev limiter. Don't run one personally as I have my EFI setup set to cut the fuel off at 11k rpm so I don't over rev. Though I don't miss shifts either with the air shifter setup.

http://www.vmaxforum.net/showthread.php?t=1734&page=181

see post #1805

mnmax said he got a drl300 to work on his bike. I've heard a couple other guys say that they tried but could never figure it out

 

[acammer]

http://www.vmaxforum.net/showthread.php?t=1734&page=181

see post #1805

mnmax said he got a drl300 to work on his bike. I've heard a couple other guys say that they tried but could never figure it out

Well, the Dyna3000 has been ordered, I think for the limiting alone it will be a good value, but it can't hurt to daily in a little extra advance either. Hopefully it doesn't prove to be a disaster.

 

[RaWarrior]

I run a Raptor shift light, set at 9200....a little bit early to account for reaction time. I have kind of the same view...I don't really race my Max, but I do make full use of it's power on the road. My shift light is on the side of the speedo, it's bright red and impossible to miss. The instant I see it, I always shift. There's just really no point (on a stock motor) to wring it out any farther....yes, it'll pull past that, but why stress the motor? Put it in the next gear.

Even in 4th gear, my motor will still want to "run away" with the RPMs. The shift light comes on at 135(Venture diff) and it's still climbing. Finally in 5th it levels out at about 88-8900@145 or so.

I learned from my Magna to always clutch the 1-2 shift. My Magna would either miss, or quickly pop out of 2nd maybe 25% of the time when hauling it through neutral into 2nd without the clutch and just rolling off the gas for a sec. With even a slight feather of the clutch, it happens maybe 1% of the time. It didn't have a rev limiter either....redline was at 11,500 and I'm sure I sent it to 13-14k a few times. I'm a lot more careful now with over-revving stuff....

It's habit now....I always clutch 1-2, even if I'm not romping on it. I'd like to think that will help prevent 2nd gear issues from cropping up down the road.