RPM's with RKT drop-ins

[summitpeaking]

I have an 05 X 800 that I put Kelsey's drop-in piston kit in last fall. The installation went very well, but I can't seem to get any RPM's out of it. Kelsey's specs say to shoot for 83-8400 with that setup, but I'm lucky to get 8000 on hardpack and rarely hit 75-7600 in the powder or on the hill. I installed a DJ clutch kit (I told DJ that I had the drop ins when orderring) to try and alleviate the problem, but didn't notice much of a difference.

Does anybody have a few other items that I should check here this offseason? I plan on checking a few things when I get a chance, but maybe I'm overlooking something obvious. Any help is appreciated.

Thanks fellas.

 

[jacmmaxwell]

What is your pin weight and did you have RKT reflash your MPEM? Also what was your installed compression?

 

[xpspenziv]

If it pulled rpms before it should pull them easier now. Throttle cable installed to get full throttle? Pin weight? More power needs more weight . What clicker you on after clutch set up?? Does it sound like the motor is straining? Something else seizing up or binding up.

 

[summitpeaking]

If it pulled rpms before it should pull them easier now. Throttle cable installed to get full throttle? Pin weight? More power needs more weight . What clicker you on after clutch set up?? Does it sound like the motor is straining? Something else seizing up or binding up.

The motor ran well before I put the kit in, but had almost 3000 miles on it, so I figured it needed a little freshening up.

Throttle cable: Never checked, but it wasn't an issue when it was stock. I will check that when I get a chance.

Pin weight: Not sure on that off the top of my head, but I will check. Didn't change it from the way I had it set up with the stock motor (not stock pins though, i don know that). I could go all the way up to clicker 6 and still not get the rpm's I need.

It doesn't really seem like the motor is straining necessarily or that anything else is binding up, it just seems to lack the snap that I was hoping for. Living in Nebraska, it's kind of difficult to do a lot of test and tuning, so I just rode it like it was. For this upcoming season, I'd like it to reach it's full potential.

Compression was 145-150 psi after installation. I will check it again to see if it's fallen off some. I did have the MPEM re-curved as well last year.

 

[jacmmaxwell]

I would verify the pin weight is what DJ's kit called for, his spring may require less weight than what you had in there.

I would verify that you're getting full throttle pull, did you rejet to run with the RKT head? If I recall his head runs a leaner than stock setting. Also make sure your RAVES are opening/working correctly and are clean.

Here is a link to DJ's kit manuel http://www.mxzx-revzone.com/upload/documents/he3_rev_800-summit_button.pdf

 

[xpspenziv]

x2.

piston drop in shouldnt require no re jetting. pull primary to inspect arms move freely and weights,check ramps for wear. is it noisy?

 

[RKT]

The drop in kit requires a main jet change or it will not work properly.. If yours is a Powertek, drop to a 380-390 main.. if a non-power-tek drop to a 370 main.

If it is a power tek, then you are looking for 8200-8300 rpms if non-powertek 8400-8500 rpms..


Also, if it is a non power tek and does NOT have my MPEM reprogramming, then 8300rpms max is the best you will do until you get the programming.

If you are running Amsoil or any other synthetic oil, the engine will never perform until you get it out and re-scuff the cylinder walls and ring faces. Hopefully, this is not the case.

If you are running MANY of the aftermarket silencers, the kit may not work right .

Bottom line.. this kit is over 10 years old... so, there are really no mysteries left.. If the instructions are followed, the kit puts down some serious power, if you diverge from over 10 years of development work.. well.... you may not get the performance that is there to be had..


More power almost NEVER means more pin weight.. this is a real bad misconception.. But that is another subject altogether..


Feel free to call anytime if you have questions

Kelsey

 

[doofun]

I have a rk tech drop in with the dj clutch kit. listen to kelsey this isn't his first rodeo. mine runs great around 83-8400 and holds when climbing in powder. get it set up and you will be very happy. listen to kelsey and joey you got two of the best in the industry to work with.

 

[Dynamo^Joe]

1 If it pulled rpms before it should pull them easier now.
2 Throttle cable installed to get full throttle?
3 Pin weight?
4 More power needs more weight .
5 What clicker you on after clutch set up??
6 Does it sound like the motor is straining?
7 Something else seizing up or binding up.

When power increase is by maintaining standard bore and rpm increase then Point #4 is misinformation and false.

If the hp gain is by virtue of rpm increase then must reduce pinweight.
Example if an engine is a 7950 engine that uses 17g pinweight and now a hp gain by virtue of rpms to go to 8300.

summitpeaking writes)I'm lucky to get 8000 on hardpack
Joe writes) A quick calibration search would be to try to get that 8000 rpms to change with the current flyweight used while on the road.

Law - Weight determines rpms
If need more rpms, then reduce flyweight

8300-7950 = 350 rpm
Law - 1g flyweight = 200 rpms change.
If have X grams then reduce 1.5g and go retest to see if the 8000 changes.
If it does not change in clicker 4, then go to clicker 5.
If that 8000 does not change again, then you can determine there is something outside of the scope of clutch calibration.

Analysis; you have considered a method of 2 calibration changes that should have increased the rpms by about 400~500; nothing happened.

Summary; There are engine management issues that need to be checked. (fuel delivery/other, muffler, etc...)

 

[xpspenziv]

When power increase is by maintaining standard bore and rpm increase then Point #4 is misinformation and false.

If the hp gain is by virtue of rpm increase then must reduce pinweight.
Example if an engine is a 7950 engine that uses 17g pinweight and now a hp gain by virtue of rpms to go to 8300.

summitpeaking writes)I'm lucky to get 8000 on hardpack
Joe writes) A quick calibration search would be to try to get that 8000 rpms to change with the current flyweight used while on the road.

Law - Weight determines rpms
If need more rpms, then reduce flyweight

8300-7950 = 350 rpm
Law - 1g flyweight = 200 rpms change.
If have X grams then reduce 1.5g and go retest to see if the 8000 changes.
If it does not change in clicker 4, then go to clicker 5.
If that 8000 does not change again, then you can determine there is something outside of the scope of clutch calibration.

Analysis; you have considered a method of 2 calibration changes that should have increased the rpms by about 400~500; nothing happened.

Summary; There are engine management issues that need to be checked. (fuel delivery/other, muffler, etc...)

hes not getting an rpm increase, hes losing rpm with a power increase. looks like he needs to take out wt to get rpms with a power increase. doesnt sound right.
i understand pulling pin weight out to get rpm. Thought with a power increase it would pull the same weight using less power. may be another issue as you 2 suggest. I guess im wrong. learn something everyday.

 

[summitpeaking]

The drop in kit requires a main jet change or it will not work properly.. If yours is a Powertek, drop to a 380-390 main.. if a non-power-tek drop to a 370 main.

If it is a power tek, then you are looking for 8200-8300 rpms if non-powertek 8400-8500 rpms..


Also, if it is a non power tek and does NOT have my MPEM reprogramming, then 8300rpms max is the best you will do until you get the programming.

If you are running Amsoil or any other synthetic oil, the engine will never perform until you get it out and re-scuff the cylinder walls and ring faces. Hopefully, this is not the case.

If you are running MANY of the aftermarket silencers, the kit may not work right .

Bottom line.. this kit is over 10 years old... so, there are really no mysteries left.. If the instructions are followed, the kit puts down some serious power, if you diverge from over 10 years of development work.. well.... you may not get the performance that is there to be had..


More power almost NEVER means more pin weight.. this is a real bad misconception.. But that is another subject altogether..


Feel free to call anytime if you have questions

Kelsey

It is a non-Powertek motor. It does have the MPEM re-flash, as performed by the BRP Race Dept in Wisconsin. Main jet started as a 370, but am down to 360 now. I run Injex full mineral oil. Never used synthetic or semi-synthetic at any time with this sled. Stock pipe and muffler.

I will double check everything you mentioned to make sure my memory is correct.

Since we are in the dead of summer (and the 100 degree temps outside confirm that), obviously I can't do much testing for another couple months. I just wanted to get a jump on things this season. Usually I wait until about a week before our first trip before I check things over.

Thanks for the help everyone, and keep the ideas coming if you have anything else.

 

[Dynamo^Joe]

hes not getting an rpm increase, hes losing rpm with a power increase. looks like he needs to take out wt to get rpms with a power increase. doesnt sound right.
i understand pulling pin weight out to get rpm. Thought with a power increase it would pull the same weight using less power. may be another issue as you 2 suggest. I guess im wrong. learn something everyday.

Hey, howzit goin...

Stock 800 "cc" ptek rated rpms @ 7950.
RKTPDI 800 "cc" engine displacement has not changed. Known RKTPDI modification rated rpms @ 8300
For the greatest component of the hp increase is by virtue of rpm increase.

This portion neglects "engine management issue" for the mentioned 8000 rpms. (discuss flyweight)
xpspenziv) hes not getting an rpm increase,
Joe) then its because there is too much flyweight for the "rpm increase" needed.

xpspenziv)hes losing rpm with a power increase
Joe) The first test he reported was 8000 full throttle on a road. He's not losing rpm because there never was 8300 in the first place. The flyweight is too much for the engine to achieve the rated rpms of 8300.

This portion is for the advantage of more pinweight used on an engine that recieved more Hp near or at the original rated rpms.
xpspenziv)Thought with a power increase it would pull the same weight using less power
Joe) Example engine. 08/800R rated rpms @ 8150 rpms with 147hp on dyno(15.3g in clicker 4). Same engine after BB to 850cc+ and the mods contained therin, 169hp @ 8300 rpms with 18.3g for the new rated rpms.
The rated rpm of the new engine is still low enough to give authority to obtain more flyweight than the previous engine calibration.

This portion is to discuss changing pinweight and not observing an rpm change.
If there has been a flyweight change to the equivalent of approximate 200 rpms then the weight has been lightened enough a near equivalent of 5~6 hp. If the clicker was raised after the weight reduction, that clicker number too offers about 150~200 rpms change, add another 5 hp ability into the engine.
You have 1) lightened the pinweight to allow the primary to push less hard on the belt, and 2)raised the clicker to stall the rpms to force the engine to build rpms; the engine rpms are still restrained at the test of full throttle 8000, then there is another issue to look at regarding the engine system and its management.

One of the first details I check is the jetting(piston wash) to see if the engine is getting hot enough and/or two, the muffler - I will borrow and change out to see if there will be an rpm gain.

I had an engine that would not pump more than 7000 with an aaen muffler. I put the stock brp can back on and whammo, 8100. Put an hps can on and again 8000~8100. Put the aaen can back on and 7000. I kept bending the tang on the aaen muffler outlet and as i continued to choke off the muffler slightly, there was a 200 rpm increase....
...till finally I went too far and *pop* goes the piston

 

[xpspenziv]

Thanks for the schooling Joe. Much appreciated. Saved it.

 

[Idaho Slim]

10 year kit ............. and STILL the same story when it doesnt work..............


Good luck to you summitpeaking .......... yer gonna need it.

 

[BluDu]

hmmm. alot of disclaimers in there

 

[xpspenziv]

lean it out,advance timing and up the rev limiter.

 

[gus bohne]

WOW..

I find rkt's answer very offensive to anyone who rides and tunes as well as EVERY clutch tuner alive..

you make more power at the same rpm with a turbo,, WHY did we ever add weight, we should just let her fly ??

bottom line you have an engine issue, you are not making even stock power. tear it down and post pics so we can help you..

btw,, even the doo race shop suggests syntetic after breakin,, in 20 yrs wth doo Ive never used anything but synthetic and the results show the truth.. MORE power , no wear.. skirts dont even have the big W from Wiseco even scratched..Like new from the box at crazy boost levels.fullseason of racing.


we will help

Gus

 

[Dynamo^Joe]

you make more power at the same rpm with a turbo, WHY did we ever add weight, we should just let her fly ??

Gus

Heyyyyy Gustanggggggg....
I was helping a gent from HRCPerf calibrate one of his turbo sleds. If I remember right he went from 15.3g in clicker 4 stock; after the turbo application, up to 20.5g - maintaining original rated rpms.

 

[gus bohne]

Joe,, Started using a JBR billet tra last season on the rev turbo..

vs the tra3 same for same, 660 drags, 26 psi boost.

12 mph difference wth the JBR tra vs tra 3..
belt wear is NON existent,, shift is sooooooo smooth and firm...the sheeves are thicker than my skull and just beautiful.

I just love the clutch..best Ive used to date,, including the STM, micros and hrps'.

using crankshop 60 gram arms,24 grm pins std diameter rollers, my version 280 ramp,,clicker 2, 8700 rpm last 200 feet climbs from a solid 8400..wht wht spring..

Wth std lever 35 gram we were using 31 gram pins..I should have just tried stock eh'??

131 mph @ 660ft I LOVE THAT CLUTCH>

Now we just need 10,000 grand to tool up a 4 lever version..

Gus


sorry for the hijack man,clutch storys make me alll giddy

 

[byeatts]

WOW..

I find rkt's answer very offensive to anyone who rides and tunes as well as EVERY clutch tuner alive..

you make more power at the same rpm with a turbo,, WHY did we ever add weight, we should just let her fly ??

bottom line you have an engine issue, you are not making even stock power. tear it down and post pics so we can help you..

btw,, even the doo race shop suggests syntetic after breakin,, in 20 yrs wth doo Ive never used anything but synthetic and the results show the truth.. MORE power , no wear.. skirts dont even have the big W from Wiseco even scratched..Like new from the box at crazy boost levels.fullseason of racing.


we will help

Gus

After building/pulling down and checking many BB,s my conclusion is break in motor on mineral ,at least 2 full tanks then use full Syn. Very little engine wear.And more power pulls more pin weight/higher track speed, If your not adding weight and running same RPM,s then your performance part/parts is not working for you,The aftermarket Mod parts must all work in Harmony.Also Raising compression too far loses HP on long pulls as it get on the edge of minor det and most wont even know it.Very high compression heads will have an explosive hit off the flipper but proved to be the last sled to the top, and impossible to clutch.