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rharrison356
1st December 2006, 05:24
Has anyone changed valve springs in order to increase rev limit to 7000 rpm? How did you overcome the ECMs rev limiter? Any other modifications?

biknut
1st December 2006, 05:30
My ignition has adjustable rev limit, but I hate to rev my motor past 6500 and even that makes me cringe. It's the thought of the piston speed that worrys me. How often do you want to rebuild your motor?

CBAS5
1st December 2006, 05:30
I don't think you need to change the valve springs to rev the engine to 7K rpm. I think the stock valve train can safetly rev to 7K rpm. If you look at the SE catalog they have a chart where they put in SE E cams and increased the rev limit to 7K rpm without changing the valve springs.

lagerdrinker
1st December 2006, 05:42
my engine isnt making any significant power over 4000 rpms. i shift when needle hits around 5800rpms to keep it off the limiter

Swankster
1st December 2006, 06:17
my engine isnt making any significant power over 4000 rpms. i shift when needle hits around 5800rpms to keep it off the limiter

Damn! lager are you srerious? Mine is just seriously kickin in around that range:D . Serious!
Swankster

lagerdrinker
1st December 2006, 06:34
Damn! lager are you srerious? Mine is just seriously kickin in around that range:D . Serious!
Swankster

yeah, heres my dyno sheet. from around 4-6k rpms i gain 3 hp. still using 883 heads and 497 cams. need headwork done to get more

http://xlforum.net/photopost/data/500/medium/bike_pics_0271.jpg

roadster
1st December 2006, 07:35
7K is a bit silly with these motors. Maybe keep some spare cases on hand....


You'd be better off winding a stock Chevy 350 to 8K

cadiero
1st December 2006, 15:56
The XB's have a 7K rev limit stock. I would think the motor can handle it.

Jimbos883
1st December 2006, 16:20
The XB's have a 7K rev limit stock. I would think the motor can handle it.

Don't forget the XB's are a different animal. You guys can correct me if I'm wrong but I think the Buell's have a lighter flywheel asembly and the stock valve trains are different that a Sportster's. So going to 7k with one is easier.

I think that if H-D thought a stock Sportster could go to 7k they would of allowed it from the factory. Performance bike selling point, yes? I know that the SE ignition lets the motor rev but I'm sure they felt that the usage of that unit would be for modified motors not stockers.

Plus I have to agree with Lager why would you want to rev a stock motor to 7k it's not like it's going to make any more power. If you are racing you try and shift within the power band not outside of it.

seajay
1st December 2006, 16:23
My '04 stock ignition rev limiter was 6k.

ed_in_az
1st December 2006, 16:34
yeah, heres my dyno sheet. from around 4-6k rpms i gain 3 hp. still using 883 heads and 497 cams. need headwork done to get more

http://xlforum.net/photopost/data/500/medium/bike_pics_0271.jpg

Lager, you're going from 58hp to 65hp from 4,000rpm to 5,300rpm. Yes torque drops but it should be pullin' good up there anyway. My motor doesn't start dropping off until 5,500rpm. Between 4,000rpm and 5,500rpm is some fast acceleration. Well, fast for a 50yr old design.:rolleyes:

CBAS5
1st December 2006, 17:02
Don't forget the XB's are a different animal. You guys can correct me if I'm wrong but I think the Buell's have a lighter flywheel asembly and the stock valve trains are different that a Sportster's. So going to 7k with one is easier.

I think that if H-D thought a stock Sportster could go to 7k they would of allowed it from the factory. Performance bike selling point, yes? I know that the SE ignition lets the motor rev but I'm sure they felt that the usage of that unit would be for modified motors not stockers.

I have done some research on this trying to find the answer and I really think it's safe to rev these engines to 7K rpm. The reason you wouldn't want to do it to a stock bike is because you aren't making any more power past 6K rpm. Also, I'm not 100% sure, but I think the flywheel was lightened on the rubbermounts.

Look at a SE catalog at the beginning where they have dyno charts. They have a rubbermount with SE E cams revving to 7K rpm without any valve train changes. By it they have a solidmount with 536 cams revving past 6K rpm and they list changes to the valve train (at least springs from what I remember). If it wasn't safe, then why would Harley do it?

Jimbos883
1st December 2006, 17:12
I have done some research on this trying to find the answer and I really think it's safe to rev these engines to 7K rpm. The reason you wouldn't want to do it to a stock bike is because you aren't making any more power past 6K rpm. Also, I'm not 100% sure, but I think the flywheel was lightened on the rubbermounts.

Look at a SE catalog at the beginning where they have dyno charts. They have a rubbermount with SE E cams revving to 7K rpm without any valve train changes. By it they have a solidmount with 536 cams revving past 6K rpm and they list changes to the valve train (at least springs from what I remember). If it wasn't safe, then why would Harley do it?

Reread my post, I stated a modified motor not a stock motor. I'm not arguing the 7k rev limit on a modified motor just a stock motor. What's the sense of running a stocker up to 7k? Is it going to make anymore horsepower, will it keep pulling I really doubt that. So why rev it that high? It doesn't make any sense to me to rev a stock motor that high, but if you get your n??s off doing then go ahead and do it, it's your bike.

cadiero
1st December 2006, 17:13
XB's valve train is the same as the XL, heads are the same. XB flywheels are slightly different though, along with the pistons. Although the pistons are still the same construction. XB's come with the SE "E" cams stock. If the XB can handle the "E" cams and 7000K RPM's, so can any rubbermount.

Jimbos883
1st December 2006, 17:21
XB's valve train is the same as the XL, heads are the same. XB flywheels are slightly different though, along with the pistons. Although the pistons are still the same construction. XB's come with the SE "E" cams stock. If the XB can handle the "E" cams and 7000K RPM's, so can any rubbermount.

Sorry to say you are talking two different stock motors the 1200 Sportster does not come with the "E" cams, the flywheels are different between the two. It's not the same motor if it was why would H-D offer the "E" cam as an upgrade for the Sportster.

Again I'm not arguing that the modified Sportster motor can rev to 7k I'm stating that the stockers make no sense to rev to 7k rpm. Stock motors don't make any more horsepower or torque above 5500 RPM so what is the logical reason to rev that high?

Would someone please explain to me the reason to run a stock Sportster motor to 7000RPM.........please.

NRHS Sales
1st December 2006, 17:37
If you have stock cams in a sportser there is no good reason to rev it to 7,000 rpms. Jiumbo is correct. But with a simple cam swap to something like 497s then it is a benefit to take it to 7,000 rpms and your top end is perfectly fine with it.

Jimbos883
1st December 2006, 17:51
If you have stock cams in a sportser there is no good reason to rev it to 7,000 rpms. Jiumbo is correct. But with a simple cam swap to something like 497s then it is a benefit to take it to 7,000 rpms and your top end is perfectly fine with it.


Thanks Dan

CBAS5
1st December 2006, 17:59
Reread my post, I stated a modified motor not a stock motor. I'm not arguing the 7k rev limit on a modified motor just a stock motor. What's the sense of running a stocker up to 7k? Is it going to make anymore horsepower, will it keep pulling I really doubt that. So why rev it that high? It doesn't make any sense to me to rev a stock motor that high, but if you get your n??s off doing then go ahead and do it, it's your bike.

I agree with you that there's no reason to do it with stock cams. My only point was that it was SAFE to do so. That's an important point because the solidmounts didn't have that capability without making changes to the valve train (as far as I know).

biknut
1st December 2006, 18:08
I agree with you that there's no reason to do it with stock cams. My only point was that it was SAFE to do so. That's an important point because the solidmounts didn't have that capability without making changes to the valve train (as far as I know).

Even if you modify the valve train, doesn't the piston speed still become dangerously high?

Jimbos883
1st December 2006, 19:11
I agree with you that there's no reason to do it with stock cams. My only point was that it was SAFE to do so. That's an important point because the solidmounts didn't have that capability without making changes to the valve train (as far as I know).


It maybe safe to do but what is the point to doing it? CBAS5 tell me what are you going to gain in doing that? Why would you advocate anyone running their stock motor to 7k?

And again you are comparing oranges and apples, the new generation of motors is different than the older ones just like the older xlch motors are different than the "solidmounts" you speak of. I think it's called progress.

CBAS5
1st December 2006, 19:38
It maybe safe to do but what is the point to doing it? CBAS5 tell me what are you going to gain in doing that? Why would advocate anyone running their stock motor to 7k?

And again you are comparing oranges and apples, the new generation of motors is different than the older ones just like the older xlch motors are different than the "solidmounts" you speak of. I think it's called progress.

We are in complete agreement here. I am not advocating it. The point I am making is that in the rubbermounts it is SAFE to run to 7K rpms. That's it. The point you are making is that although it is SAFE to run to 7K rpms. you GAIN NOTHING with a STOCK engine (and I agree with that).

I know I am comparing oranges and apples. That's the point. Solidmount: 7K rpm NOT SAFE. Rubbermount: 7K rpm SAFE.

If you look at a lot of japanese sport bikes they spin the engine past the point where they make peak hp or tq sometimes by up to 3K rpm. I'm not saying that's a good thing, just that it happens.

NRHS Sales
1st December 2006, 19:44
If you run sustained rpms at 7,000 then it would be hard on the lower end but the occasional burst to 7,000 is perfectly fine on the lower end. Pre XB Buells used to have the same bottom end as other Sportsers and it was commonplace to put a 7,000 rpm rev limiter on them with no issues.

Turbota
2nd December 2006, 01:11
My 04 Sporty has seen bursts to 6,900 - 7,000 at least a hundred times ... Never had a problem.

But, like others have said ... If your engine stops making power at lets say 5,800 revs, there is absolutly no reason to spin it any higher.

rharrison356
2nd December 2006, 20:02
I don't think you need to change the valve springs to rev the engine to 7K rpm. I think the stock valve train can safetly rev to 7K rpm. If you look at the SE catalog they have a chart where they put in SE E cams and increased the rev limit to 7K rpm without changing the valve springs.
According to Harley, the valve springs are essential for changing the rev limit safely. BTW, my Race Fueler came in, so now it is time to install. I also agree with Swanster, as mine is still strong near the 6000 mark, so adding a few RPMs is not a bad idea. My bike is used for touring, but I like to know the power and rpm's are there if needed.

Gone
2nd December 2006, 20:21
I think that if H-D thought a stock Sportster could go to 7k they would of allowed it from the factory. .

Not so. Factory redlines are established based on two factors: Need - if it stops making power at 5,200 rpm, why encourage customers to wing it to 7.000 and drastically shortening the engine lifespan? Long term reliability - the engine needs to be able to achieve redline safely for thousands of miles, without undue wear or valvesprings that are tiring and ready for a major crash.

Yamaha ran into a marketing snafu by advertising a MUCH higher redline than actually acheived on the '06 R6 AND equipping it with a tachometer that was skewed to show those rpm. Big numbers are like too much food on your plate. You like all you see but might not like what all you get.

CBAS5
2nd December 2006, 20:55
Not so. Factory redlines are established based on two factors: Need - if it stops making power at 5,200 rpm, why encourage customers to wing it to 7.000 and drastically shortening the engine lifespan? Long term reliability - the engine needs to be able to achieve redline safely for thousands of miles, without undue wear or valvesprings that are tiring and ready for a major crash.


I think redlines also have an effect on passing emissions; so they may not set them at an optimal point based on that.

Yamaha ran into a marketing snafu by advertising a MUCH higher redline than actually acheived on the '06 R6 AND equipping it with a tachometer that was skewed to show those rpm. Big numbers are like too much food on your plate. You like all you see but might not like what all you get.
Reply With Quote

It's more than just yamaha. A lot of sport bikes (if not all) have inflated rev limits after they stopped making peak horse power for a long time. I've seen it inflated by 1-3K rpm. So some engines actually stop making power at 9K rpm, but the rev limit is 12K rpm. I think for some reason higher redlines sell more sportbikes.

It seems like the opposite with cruisers. They want to make as much torque as possible down low.

whittlebeast
21st April 2007, 14:38
What is the redline / rev limit on the 07 EFI motors?

AW

addertooth
22nd April 2007, 17:49
Redline, hmmm where do I start. Lets talk about gears first. First gear has more mechanical advantage than second. Second gear has better mechanical advantage than third... and so forth. You can accelerate faster (more G's, faster change in speed) in a lower gear with LESS horsepower and torque, than you can in a taller gear with a few more HP and foot pounds of torque. This is why a stock 600cc crotch rocket which produces smaller HP and torque number than a stock sportster consistantly beats it at the drag strip. You have shifted to second, and likely third gear while he is winding his weaker engine out to 14000 RPMs in FIRST gear. At 14k RPMs he is producing easilly half the torque you are, but his lower gear gives him a far superior mechanical advantage, thus he out-runs you.
If (and only IF) you are trying to get fast acceleration (read as DRAG racing, or Light to Light street drags), you will see a performance gain by staying in first and second gear longer due to a higher rev limit. This is a assuming you don't have highly restrictive heads, cams, intake, exhaust on your bike. The XB/2004 and up 1200 heads breath extremely well, far better than their predecessors.
Most sporty engines don't really start strutting until about 3000 rpms, (A good 2 in 1 exhaust will extract more power at a lower RPM point). With a 6000 RPM limit you effectively have 3000 RPMs to accelerate in. With a 7000 limite you now have 4000 rpms which you are staying in gear before shifting, a significant increase in time you are staying in first and producing the best acceleration your bike can produce, shift to second, and acceleration WILL decrease. Addertooth

Evi|grin
23rd April 2007, 03:45
Redline, hmmm where do I start. Lets talk about gears first. First gear has more mechanical advantage than second. Second gear has better mechanical advantage than third... and so forth. You can accelerate faster (more G's, faster change in speed) in a lower gear with LESS horsepower and torque, than you can in a taller gear with a few more HP and foot pounds of torque. This is why a stock 600cc crotch rocket which produces smaller HP and torque number than a stock sportster consistantly beats it at the drag strip.

While i understand and agree with parts of your post i think you should look at this.

http://www.motorcyclistonline.com/performancedata/

I dont see any inline4 crotch rockets making less hp but they are making much less torque. Most or all of the small vtwin crotch rockets make less. SV650 might be one of the few exceptions.

The reason a 600cc inline4 like a R6 will smoke you is its 106+hp and only weighs 424lbs wet depending on the year. It doesnt need a huge amount of torque to take off hard just a lot of rpms and a good rider. Sure gearing has an effect but the hp difference is huge.

I went the other way on my bike i capitalized on the stock large lowend torque by getting exhaust with less peak hp and more lowend torque. Plus im now running 2.8 to1 on my final drive, stock was 3.1 to 1 roughly.

I now have worse mechanical advantage but more lowend torque. Do you want to guess which pulls faster to 90+mph? Im not saying its a good idea for strip use but on the street it was an improvement.

mtl-XLR
23rd April 2007, 04:00
My Stage 1 remap reset my rev limiter to 7000 rpm ... Harley obviously must feel that the engine can handle it .

roadster
23rd April 2007, 04:01
The Sportster showed 674HP pretty stout! Torque no make go fast. Horsepower cause big zoom.

Goshawk
23rd April 2007, 12:19
Will the stock rev limiter keep my bike from going over redline in all situations like during a missed shift at high rpms? Someone said they try to keep off the limiter. Is there a reason why?

HOGDADDY
24th April 2007, 06:30
7K is a bit silly with these motors. Maybe keep some spare cases on hand....


You'd be better off winding a stock Chevy 350 to 8K

Honestly I don't believe a stock chevy 350 will even rev that high maybe
5500 rpm tops with stock valvesprings and stock HEI is also limited to bout 5500.

the 302 z28 motor could rev that high

HOGDADDY
24th April 2007, 06:34
I think I was bouncing off the rev limiter today in my stock (rare):p 1200c while ripping thru town and was thinkn maybe if it was just litlle bit higher.

Gone
24th April 2007, 06:58
Don't forget the XB's are a different animal. You guys can correct me if I'm wrong but I think the Buell's have a lighter flywheel asembly and the stock valve trains are different that a Sportster's. So going to 7k with one is easier.
I think that if H-D thought a stock Sportster could go to 7k they would of allowed it from the factory. Performance bike selling point, yes? I know that the SE ignition lets the motor rev but I'm sure they felt that the usage of that unit would be for modified motors not stockers.
Plus I have to agree with Lager why would you want to rev a stock motor to 7k it's not like it's going to make any more power. If you are racing you try and shift within the power band not outside of it.

The Buell XB's and '04+ Sportsters are essentially the same internally with very minor differences. The Buells get a higher rev limit to take advantage of the .551" cams, etc. The stock cams in the Sportster sign-off at about 6,000 rpm.

Gone
24th April 2007, 07:04
Will the stock rev limiter keep my bike from going over redline in all situations like during a missed shift at high rpms? Someone said they try to keep off the limiter. Is there a reason why?

If you screw up and downshift at too high of an rpm, the igniton cut-out will not stop the bike from over-revving the engine.
Is there a reason why you should stay off the rev-limiter? The question should be restated: Why would I want to bang the rev-limiter? It surely isn't doing anything to help the engine by deliberately abusing the system.

aussteks
24th April 2007, 07:12
yeah, heres my dyno sheet. from around 4-6k rpms i gain 3 hp. still using 883 heads and 497 cams. need headwork done to get more

http://xlforum.net/photopost/data/500/medium/bike_pics_0271.jpg

This is why I hate dyno sheets...

In answer to the original question, I's gonna try 7200...just to hit the overshots in 1st and 2nd.

CustomBlue
24th April 2007, 07:28
If you screw up and downshift at too high of an rpm, the igniton cut-out will not stop the bike from over-revving the engine.
Is there a reason why you should stay off the rev-limiter? The question should be restated: Why would I want to bang the rev-limiter? It surely isn't doing anything to help the engine by deliberately abusing the system.

hitting the rev limiter shuts OFF the bike!

also..I've said it on another thread....the SE ICM module raises your rev limiter to 7K and also changes the curves.You are producing torque and HP well into 6K,the motor will handle it.I'm living proof,but,for how long is th question....it's a trade off,ya want power/speed,ya give up lifetime!

CBAS5
24th April 2007, 07:40
In answer to the original question, I's gonna try 7200...just to hit the overshots in 1st and 2nd.

I think due to piston speed the limit of these engines is 7K rpm. I think you are running a big risk of blowing up your engine at 7200 rpm.

Goshawk
24th April 2007, 09:08
If you screw up and downshift at too high of an rpm, the igniton cut-out will not stop the bike from over-revving the engine.
Is there a reason why you should stay off the rev-limiter? The question should be restated: Why would I want to bang the rev-limiter? It surely isn't doing anything to help the engine by deliberately abusing the system.

My question does not say anything about wanting to bang the rev-limiter or deliberately abusing the the system. The question clearly asks what the result of hitting the rev limiter would be, nothing more.

Gone
24th April 2007, 09:12
hitting the rev limiter shuts OFF the bike!

also..I've said it on another thread....the SE ICM module raises your rev limiter to 7K and also changes the curves.You are producing torque and HP well into 6K,the motor will handle it.I'm living proof,but,for how long is th question....it's a trade off,ya want power/speed,ya give up lifetime!

It can shut off all it wants - if you downshift at excessive rpm, the bike enertia will physically force the engine to momentarily overspeed.

Gone
24th April 2007, 09:29
My question does not say anything about wanting to bang the rev-limiter or deliberately abusing the the system. The question clearly asks what the result of hitting the rev limiter would be, nothing more.

It shouldn't affect too much 99% of the time (some fuel will continue to feed into the cylinders on carbed engines - the light with a nice pop when the ignition comes on) . But, having the engine abruptly shut down at max rpm and then abruptly restart near max rpm, is not "friendly" to the engine or drivetrain either. High performance engines (sportbikes and high output cars) usually have "soft-touch" rev limiters that cut out only sufficiently to prevent over-revs, to minimize any possibility of damage. I did not mean to infer that you personally wanted to bang the rev-limiter - though I see lots of ricer-car guys run up and down the streets in first gear doing just that, because they think it sounds cool.

whittlebeast
24th April 2007, 13:47
Always remember that a foot full of first gear by accident when at redline in second will zing the motor to 8450 RPM all it takes it moving your foot the wrong direction once. At this point both the ignition and fuel will most likely by shut off but the pistons will still get there assuming the tire is still spinning. Max load on the rods is top dead center between intake and exhaust stroke. Rods streatch .001" per thousand RPM so the pistons just went .0025" higher than they have ever been and just bounced off the carbon rings in the cylinders off the compression rings. This is all bad. This is all fairly common in the shifter cart world with redlined in the 13000 rpm range and we shift about 35 shifts per min. Sometimes we screw up and see 16000 rpm or so on the data loggers.

Note: all shifts (up and down) wile on the clock are made without using the clutch

see http://www.youtube.com/watch?v=EAO_cW619-c

AW

rob@robertsystems.com
24th April 2007, 20:46
Dan dyno'd my 883 / 1250 last weekend. The HP "curve" is a straight line. It starts at a couple of HP just off idle and goes up to end at 83HP at 6k. He told me to take it to the dealer to get the rev limiter reset to 6800 and expect 90 + hp.

07 883R, NRHS Stage 2 heads, Axtel 1250, N6 cams, zero gap rings, flat top pistons, D&D 2 into 1 pipe.

CBAS5
24th April 2007, 23:48
Dan dyno'd my 883 / 1250 last weekend. The HP "curve" is a straight line. It starts at a couple of HP just off idle and goes up to end at 83HP at 6k. He told me to take it to the dealer to get the rev limiter reset to 6800 and expect 90 + hp.

Sounds good. After you have the rev limit raised are you going to re-dyno the bike to see how much more hp you made? If so, can you post the dyno sheet?