rev limit
Thread Starter
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3rd Gear
Joined: Sep 2007
Posts: 7
Likes: 0
From: Michigan
rev limit
I posted this on another forum but did not get a responce. Are harley cranks twisting because of over reving the engines. My bike has a rev limiter that will not allow the engine to operate above 5500 rpm. If the stock bikes are twisting because of over reving why does the motor company set the limit at 5500 and not 5000 rpm. I have hit the rev limiter several times while pulling out on the highway and trying to get underway before I got runover. Why would they set the rev limiter to 5500 rpm unless the engine is manufactured to be able to turn 5500 rpm. I do not mean sustained rpm but just be able to hit it. I do not abuse my bike, I do not drag race or burn out or down shift to too low a gear but I think that the engine sould be able to operate within the designed rpm (as set by harley) without comming apart. I know that limiters can be raised to a higher rpm but I am only talking about stock (or close, pipes intake and fuel managment) bike that have not had limit raised. Please anyone with comments?
Road Warrior
Joined: Nov 2007
Posts: 1,984
Likes: 7
Make sure you are real warmed up before hitting any rev limit. Hopefully you are warming up or you will do lots of damage.
HD cranks are put together with a press fit. The desigh calls for a 0.007 interference between the Crank Pin and the Wheels. During some period of time, for some reason, (I don't really know the exact period), these requirments were relaxed it seems. The desigh ought to be bullit proof if done as desighed.
Also as a side note I just recentely found the counter weight sprokets for the ,B, engine are also pressed on and can slip. Another thing for me to worry about.
HD cranks are put together with a press fit. The desigh calls for a 0.007 interference between the Crank Pin and the Wheels. During some period of time, for some reason, (I don't really know the exact period), these requirments were relaxed it seems. The desigh ought to be bullit proof if done as desighed.
Also as a side note I just recentely found the counter weight sprokets for the ,B, engine are also pressed on and can slip. Another thing for me to worry about.
Last edited by Old Gunny; Jul 21, 2009 at 07:51 AM.
Banned
Joined: Oct 2007
Posts: 11,436
Likes: 13
Dont WORRY so much, just GRAB A HANDFULL and ride. Enjoy yourself, if the FREAKING CRANK GOES. It GOES and theres not a FREAKING THING YOU CAN DO ABOUT IT. This CRANK issue has gotten out of control, FEAR MONGERING!
Thread Starter
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3rd Gear
Joined: Sep 2007
Posts: 7
Likes: 0
From: Michigan
Yes I ride em hard, always have. I just think that the way the cranks are put together they should hold up to rpms set by the motor company. I have had a lot of bikes over the years (mostly harleys) and have never had as many problems as most people seem to be having. I know all mechanical parts can have problems but not on the large scale that I see on the forums. I have mechanically hot rodded many bikes and cars and I know that the extra pressures and stress need reinforcement, but stock vehicals operating within manufactured given parameters should hold up if quality control, engineering, r&d is present. I have had problems with other bikes 77 flh that leaked more oil than opec has, but with current technology even the old tractor (harley) motor should be bullet proof by now. After all they have had almost 100 years to get it right. Dont get me wrong I love harley's and have had at least one in the garage since I was 17. I am just worried that they wont be around forever if they dont get there sh*t together. The motor company seems to be more worried about getting other brand owners to convert, than keeping the die hards comming back for a new bike every few years. I have four right now and I have not had a crank shift, so mabey it is just a few people that have beat the **** out of their bike and the rumor mill starts running overtime.
Road Warrior
Joined: Dec 2007
Posts: 1,270
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i think most of the problem ypou read about are over hyped and people trying to sell products.
heres a good rule of thumb...
if you are going to build the motor over lets say approx 120/120 hp/tq its a good solid investment to get the crank checked welded and balanced. plus the timkin bearing its stronger then stock.
then at least you know if you lets say take it down the track its safe.
other wise just a big bore eup grade i would not worry about it.
but you said you ride hard now how hard is hard.
me i ride hard i run at the upper rpm band a lot ..havent did it much this year as i am just enjoying the ride.
like i stated if you plan on going with more hp then as a piece of minf get it done if not just enjoy...
heres a good rule of thumb...
if you are going to build the motor over lets say approx 120/120 hp/tq its a good solid investment to get the crank checked welded and balanced. plus the timkin bearing its stronger then stock.
then at least you know if you lets say take it down the track its safe.
other wise just a big bore eup grade i would not worry about it.
but you said you ride hard now how hard is hard.
me i ride hard i run at the upper rpm band a lot ..havent did it much this year as i am just enjoying the ride.
like i stated if you plan on going with more hp then as a piece of minf get it done if not just enjoy...
Ultimate HDF Member
Joined: Feb 2007
Posts: 7,663
Likes: 7
From: Northeast Ohio
You have to realize that on these forums you are only seeing a snapshot of the entire HD population, and quite a few people only join forums to express their dismay at having problems with the product. Yes, there have been crank failures but it is not something to worry about, especially on a stock bike. As SeDeluxe put it, for piece of mind with a highly modified engine, it pays to have some crank work done. But for a stocker, or even a 103/107, I would not pay the extra money up front for the crank work, If it grenades, then by all means do it then.
Just ride it and enjoy, and quit worrying. All things mechanical break from time to time, but it is not worth the aggravation of worrying everytime you go out for a ride.
Just ride it and enjoy, and quit worrying. All things mechanical break from time to time, but it is not worth the aggravation of worrying everytime you go out for a ride.
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Club Member
Joined: Nov 2008
Posts: 5,481
Likes: 4
From: Georgia
You have to realize that on these forums you are only seeing a snapshot of the entire HD population, and quite a few people only join forums to express their dismay at having problems with the product. Yes, there have been crank failures but it is not something to worry about, especially on a stock bike. As SeDeluxe put it, for piece of mind with a highly modified engine, it pays to have some crank work done. But for a stocker, or even a 103/107, I would not pay the extra money up front for the crank work, If it grenades, then by all means do it then.
Just ride it and enjoy, and quit worrying. All things mechanical break from time to time, but it is not worth the aggravation of worrying everytime you go out for a ride.
Just ride it and enjoy, and quit worrying. All things mechanical break from time to time, but it is not worth the aggravation of worrying everytime you go out for a ride.
I just ride the hell out of mine and it has always worked for me. YMMV
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Outstanding HDF Member
Joined: May 2008
Posts: 2,543
Likes: 19
From: Ashland Ohio
I am one of the folks with a slipped crank. I agree 100% that this problem is very blown outta proportion of the percentage of engines that it IS an issue. I bet it is less than a percent of a percent, if even that. I MAY have done the crank in by being a poor rider. I can remember having NOT paid attention and getting into a spot where I HAD to slam the brakes. Mighta hit brakes while pulling clutch.... stopped engine dead in its tracks.
An internet message board has the effect of blowing crap out of proportion. People do NOT post that their (fill in blank) is doing fine. So, a person ONLY sees the people reporting problems.
I am mentally using my own crank issue to justify a BB kit with a SUPER DUPER bottom end. I feel that a simple true, plug, and weld would have sufficed, but me??? HAHA, I am getting the crankshaft from Hell... It will be a piece that stays with me if they ever repo the bike! HAH!!!
If I were a normal Harley owner that does less than 10k miles a year... Heck! I wouldn't worry about it at all and get a nice top end kit from Scott, Randy, or Steve (Hillside, Hyperformance, GMR).
An internet message board has the effect of blowing crap out of proportion. People do NOT post that their (fill in blank) is doing fine. So, a person ONLY sees the people reporting problems.
I am mentally using my own crank issue to justify a BB kit with a SUPER DUPER bottom end. I feel that a simple true, plug, and weld would have sufficed, but me??? HAHA, I am getting the crankshaft from Hell... It will be a piece that stays with me if they ever repo the bike! HAH!!!
If I were a normal Harley owner that does less than 10k miles a year... Heck! I wouldn't worry about it at all and get a nice top end kit from Scott, Randy, or Steve (Hillside, Hyperformance, GMR).
Last edited by wurk_truk; Jul 29, 2009 at 10:50 AM.