[Guaire]

I'm considering raising the peak RPM on my 2011 Bullet B5. The stock setting is 5500 rpm. I have no doubt about raising it to 6000. I'm thinking that 6500 would be alright. Has anyone raised the rpm to 6500? How did it work?
It has stainless steel valves, 1mm oversize intake. ACE Performance cams. Beehive springs. Power Commander V. ACE Motors Ignition Kit = high output coil. Iridium ND plug. Silencer = HD XL 883/1200, drilled through baffles.

[axman88]

Isn't the rev. limiter built into the ignition side of the ECU?

Does the ACE ignition take over the spark pulse generation and ignition timing functions?

[Guaire]

Isn't the rev. limiter built into the ignition side of the ECU?

Does the ACE ignition take over the spark pulse generation and ignition timing functions?

Hi Axman - Controlling the ECU's ignition is the Dynatek Power Commander V unit. I also have their AutoTune device. The AT can be screwed in, or removed. It is a Bosch sensor that is much more sophisticated than the standard exhaust sensor. They run separately. With the AT on, you take a ride. Then, take the suggested adjustments into the PCV. When the adjustments are finished, the AT is removed and the bung is screwed back on.
  With an approval code by Dynatek, you can adjust the rev limiter.
https://www.dynaonline.com

The ACE Motors ignition kit is a combination of ignition components. First, is a Dynatek coil. Also, there's zero resistance cable, spark plug cap and a ND iridium spark plug.
https://www.acemotorsonline.com
Cheers,
Bill G.

[Beeza]

If you multiply the rpm by .583 (stroke x2 in feet) you get the piston speed in feet per minute, in this case 3500. Another 500 rpm gets you close to 3800. Howeverrrrrr…….the increase in force goes up by the square - that pesky exponential function that has forever plagued mankind - which is another 17% more straw on the camel’s back for 500 rpm.

Henshaw got to 7,000 without the piston coming off. Pretty spectacular for what I think is the stock piston. In theory, the forged pistons should be more durable and perhaps less likely to break, but they are also usually heavier.

The other good news is that the rod ratio is long so the rings aren’t getting as much of a yank when the rod flips over tdc. There’s an Audi V10 that has a 93mm stroke that turns 8500 rpm but that’s a long way from a 1955 pushrod trials motor.

2500 fpm is a good number for sustained longevity and that works out to 4000-4500 which is a pretty sweet spot. Not loafing but not straining either. 3500 is double the load.

[axman88]

Hi Axman - Controlling the ECU's ignition is the Dynatek Power Commander V unit.

That's interesting.  I see DynoJet talking about the feature here:  https://www.dynojet.com/blog/what-is-rev-x-tend-on-dynojets-power-commander-v/

I see that ACE and Gashousegorilla were talking about raising the rpm limits of EFI machines using the PCV back in this thread, but I don't see them specifically saying how high they went. https://forum.classicmotorworks.com/index.php?topic=19639.msg231416#msg231416

Also, I've seen most sources state that the rev limit on stock machines is 5250, but there are also reports of variance in the number.  This guy says he hit his machine's limit at 4840, but didn't measure directly:  https://forum.classicmotorworks.com/index.php?topic=22134.msg248826#msg248826
I wonder if there is indeed this much variance from ECU to ECU?  I read somewhere that one way to game an ECU into raising the rev. limit is to change the clock chip.  Changing the perceived time between rev pulses, makes the ECU think the engine is spinning slower or faster.  I recall looking at a clock chip manufacturer's published specs. at one point, and they did allow for a tolerance of +/- several percent, it surprised me how much.

Seems that if you have a measured rev limit now of 5500, you will be good up to 6000 by checking the "Rev X-tend" box, and up to 6500 if they provide the key code.  That's kind of nice that Dynojet will look over your list of mods and weigh in on whether they feel spinning faster is appropriate.

[Guaire]

"Seems that if you have a measured rev limit now of 5500, you will be good up to 6000 by checking the "Rev X-tend" box, and up to 6500 if they provide the key code."

Dynojet does have excellent support.
Unfortunately, the Bullet doesn't have a factory tach. I have used one of those wrap around the plug wire digital read out tachs. But, I'm not as confident in them as I would be with a factory version.

While doing test runs for the AutoTune, I would do some high rev accelerations to what I was hoping would be close enough to red line. That ECU cut out hits like brick. I hate that thing.

[gizzo]

"Seems that if you have a measured rev limit now of 5500, you will be good up to 6000 by checking the "Rev X-tend" box, and up to 6500 if they provide the key code."

Dynojet does have excellent support.
Unfortunately, the Bullet doesn't have a factory tach. I have used one of those wrap around the plug wire digital read out tachs. But, I'm not as confident in them as I would be with a factory version.

While doing test runs for the AutoTune, I would do some high rev accelerations to what I was hoping would be close enough to red line. That ECU cut out hits like brick. I hate that thing.

There's probably a fair bit of wriggle room in the factory tach, too. Can you tap a test tach into the coil wiring like you would if you were adding an accessory tach on your old car?? I don't think the wire wrapped around the plug lead is great, either. The RPM info seems to bounce around and lag a lot more than a properly wired tach IME.

[axman88]

You guys might want to read through this old thread regarding adding electronic tachos  https://forum.classicmotorworks.com/index.php?topic=20421.0

And, I see in response #21, that a member reported getting up to 6940 rpms on his modified IB Bullet.

[Guaire]

 gizzo - the lag is really obtuse on the wrap around wire type. It's like have 2 tachs. One is the number read out and two is the engine that is clearly not in millisecond sync with the read out.

[Guaire]

You guys might want to read through this old thread regarding adding electronic tachos  https://forum.classicmotorworks.com/index.php?topic=20421.0

And, I see in response #21, that a member reported getting up to 6940 rpms on his modified IB Bullet.

Most of the iron barrels needed a crank balancing/bottom end rebuild. Specs were quite jazzy on the assembly line then.
Looks like the Koso is doable, but right now I'm into plug & play without the creative installation.
Funny, how RE will sell you a genuine factory contracted accessory jacket, but not a tachometer.

At this point, I'm leaning toward a 500 rpm rev rise. Then I'll get it on the local dyno and let them worry about the peak revs. One reason is, my usual everyday type UCE Bullet ride. Especially with this motor, I just don't need to bounce the peak rpm off the limiter. The bike just runs. I can always get back to it, and raise the revs up another 500 rpm if I want to.
  At Cycles of Silver Spring [Maryland], Rush Branson took  my bike out for a quick test ride. His summary was, 'lots of mid-range'. That about tells the story of this build. From idle to rev limiter, it's one giant mid-range. I believe the ACE Performance cam profile has a lot to do with that. This cam doesn't have a low rpm flat spot followed by a big hit at high rpm. It has strong pull across the rev range. And that fits my real world driving of this bike. That's the original design set up by ACE's concept.
I may still get a tach on there though. I believe I've got the laggy slow response thing down pat. I'm going to have to spend more than 20 dollars on a tach from Amazon.

[9fingers]

Gashouse did work on my bike.......super nice guy and, as I call him, the number 2 RE 500 engine guru in the country. Number, Scooter Bob,  1 trained him and number 1 was the USA Service Manager for the previous importer. Anyway, besides his custom cams, PC and AT he also changed the airbox to an open filter and I changed the header and pipe. He was comfortable raising my RPM to 5,750 but he thought going much beyond that was asking for long term issues. Guaire, with your valves and if you changed to a lighter piston, you could probably go a little higher, but I am no guru. We didn't dyno mine but Gashouse has done enough similar mods and has good maps for the PCV and with some fiddling we got it set up very well. Mileage went down a few MPG.....I care not.....and he estimates approx 32 or 33hp at the crank. I have a bit over 10k miles on mine and all is good.
Good luck with yours!
Scott

[Guaire]

Hi 9 fingers - Now that's a good looking Bullet! I'm probably not going to change the piston. I want this Bullet to be sort of an 'everyman' set up, without going all out. Just your basic improvements here and there with its own Power Commander V/AutoTune map. That's why I think that 500 + is the max for me. In regular riding, I don't bounce off the rev limiter. The power band is not peaky, so the power is more of a constant, steady type. After a test ride, Rush Branson suggested a dyno tuning. I believe that's what I'll do with this one eventually. Then we'll have a good idea how the mods spec out.
Bill G.

[Bert Remington]

9fingers -- I too have a GG/SB engine but it's still in the box.  And I haven't opened the box yet.

Did you stay with hydraulic lifters or did you change the hydraulics to "solid" per GG's instructions?  If you did change, I'd appreciate any information on the adjustable rods that are supposed to be used.  They might be in the box but if they aren't then I'll need to buy custom ones.  Thanks.

The reason I chose solid lifters is to reach the higher RPM needed for the Ton.

[Bert Remington]

I stumbled across the HMC 4-valve cylinder head product.  Looking at the dyno chart, the 612cc long-stroke engine was run to 6400rpm and the 535 to 6100rpm.  So what are the significant parts contributing to high RPM:

-- lighter valves with matching springs
-- probably lighter piston and maybe wrist pin
-- reground cams with perhaps appropriate ramp to avoid valve float

Apparently the stock hydraulic lifters are used but perhaps converted to "solid" per GG instructions.

I looked for the 4 valve cylinder head topic Guaire suggested but didn't find it.

[9fingers]

9fingers -- I too have a GG/SB engine but it's still in the box.  And I haven't opened the box yet.

Did you stay with hydraulic lifters or did you change the hydraulics to "solid" per GG's instructions?  If you did change, I'd appreciate any information on the adjustable rods that are supposed to be used.  They might be in the box but if they aren't then I'll need to buy custom ones.  Thanks.

The reason I chose solid lifters is to reach the higher RPM needed for the Ton.

Hi BR, no changes to the valves. I was not interested in anything near the ton after riding mine at upper 70's mph with car and truck buffeting causing the bike to shake its head and the whole bike begin the wiggles......scared the crap out of me. I just wanted to be able to maintain 55 up the long hills in NY state, and that we achieved.