had my engine spin balanced

970SnowSlayer · Feb 1, 2012

800PowerFanatic said:
I still don't know where I stand on this. Adding weight doesn't make much sense but then sometimes some way it can, if Perks have really done their research and testing very intensively is it possible at all? I mean when I had his product on the vibration was there till 2300 RPM then completely disappeared. Why does it disappear on all 800R's at 2-2300 RPM? And What about the MPH gain ?

theres not really a right or wrong in the addition of a 5th counterweight, it certainly can correct an unbalance. simply stated, its not standard procedure for balancing a performance 2 stroke sled crank, or any performance crank.

to be frank, my single biggest issue with the kit as a whole, is the addition of a counterweight without physically checking the balance of the rotating assembly, and determing at what exact degree the mass needs to be placed at, to correctly balance the crank.

the phrase "all 800r's", we most certainly do not know that all 800r's with perks kit installed will show the same results. as evidence, read back, not everyone has reported the same performance gains.

I too, am all for products that work. I want this guy to suceed just as bad as the next, not bashing him, or the product, im all for innovation. I just cant help but "question" it. Once again, I hope this all works out for both Perks, and his customers.

800PowerFanatic · Feb 1, 2012

So are you saying that there is a possibility that perks crank balancing is effective? Do you have any explanation to the MPH gain?

970SnowSlayer · Feb 1, 2012

backcountryblazin said:
theres not really a right or wrong in the addition of a 5th counterweight, it certainly can correct an unbalance. simply stated, its not standard procedure for balancing a performance 2 stroke sled crank, or any performance crank.
.

if the luck of the draw is that the pie weight places the mass where the unbalance is then the result would be a more balanced rotating assembly, there the possibility exists for a performance gain. to reiterate, my issue with the design of the kit is that there is too much of a "shot-in-the-dark" factor in regards the where the added mass ends up in relation to where the true unbalance on any given crank. not every single crank is going to have the unbalance at the exact same degree. I do not see EVERY single 800r crank being unbalanced at the exact same degree and by the exact same amount of weight. plain and simple. if thats the case, the Rotax has been f'ing up 800r motors for what..going on 6 years now? ...how logical does that sound?

I dont mean this in a rude way of any kind, but if a guy gets some books on performance engine balancing, engine design and theory, heck just do some googling, and after some self education, he can form his own opinion of the system and the theory behind it. If it makes sense to you, then great. I have my opinion, im sticking with it. When im ready to balance my motor, I will do it the same way thats its been done for a long time, tried and true. brp gave me enough to worry about when I took possesion of one of their products :face-icon-small-win I dont want to make the list longer with unproven mods.

to each their own opinion.

970SnowSlayer · Feb 1, 2012

eddy said:
1) The 800R shakes more than any Rotax I have owned. Fact!
2) Back in the day there was an option to add 1 or 2 pound crank weights to single cylinder two stroke dirt bike engines (typically 250cc and up). This resulted in better traction and a more controlled powerband that made the bike perform better in most every condition except perfect traction. I know of no additional crank failures resulting from this external weight. Even today: XC and Enduro bikes have the bigger flywheel even when the lighting coils are not required. MX bike are the only ones with the lightest (quick revving) crank/flywheel assemblies.
3) With all the drive train components of a snowmobile (generator, clutches, shafts, chains, gears and track) considered: It would seem that a little more crank weight would cause very little negative effect IMHO.

eddy, your totally right with the flywheel weights that were used in lots of cross crountry and enduro 2 stokes back in the day. (avid dirt biker, Ive done this mod myself). the weight is symetrical, due to 2 stoke bikes having absolutly NO bottom end, the weight helped tremendously when lugging the motor down through the tight techinical terrain when conditions did not permit running in the 8-9k rpm powerband, helped avoid stalling out at low rpms as well. Made big improvements with keeping the 2 stroke power much more rideable and trackable through the tight nasty single track. But, point in hand, this is a different application and is designed to simply add 360 degrees of mass to the rotating assebly, to help keep rpms more solid. it was not placing an added mass at a particular degree with the purpose of correcting an unbalance.

eddy · Feb 2, 2012

Perks

Here is my take away: If Perks gets the balance improved by 80% and the extra 1.25 pound (net of the weight loss on the primary) flywheel rotor does no harm: This looks like a good improvement. Time will tell!

I think in another thread Indy Dan stated the Polaris 900 benefited from adding mass to the crank. Am I tracking with his idea here? Maybe this is OK for the 800R. I am not expecting the engine to be perfect, really! I spent $350. Trygstad wants $900 + rebuild to do just the crank balance job, I am trying to keep this in perspective. The reliability factor is noted as well - this is very important.

Given what I have heard for 800R lifespan there is room for improvment! If this kit helps a little and folks can get the recoil issue corrected:behindsofa: I think this will turn out OK. I feel for the folks with issues and hope you are able to work it out with Joe to an acceptable conclusion.

Remember: My opinion and $4.00 will still get you a cup of coffee at Starbucks!

madmini660 · Feb 2, 2012

800PowerFanatic said:
So are you saying that there is a possibility that perks crank balancing is effective? Do you have any explanation to the MPH gain?

I had the kit made to my sled with the bigbore and never gained any rpm's after the kit was on it or any track speed so I dont know what your smoking but it must be good stuff if it was adding horse power :face-icon-small-con
asked a friend that had it done on his 880 if his gained any rpm or track speed and he just laughted and told me the only thing that changed is he got really good a starting his sled off the clutch with a rope that's all that changed for me to and there's no way perks could have that much time on this kit because his sled only had like 350miles on it when I looked at it and thats what he was useing for testing and the mph he is telling about is topend not climbing or boondocking or real riding trackspeed

TT670 · Feb 2, 2012

Theres a profound difference between simply adding mass to control harmonics and adding weight at a specific location for the purpose of balance. If someone is balancing every crank assuming theyre all the same based on a small cross section of samples, its nothing more than a hip shot hoping he hits the target. Someones gotta be the guinea pig I guess and i feel bad for those who've had trouble but somehow I cant help but envision the cartoon where the word sucker is painted on the forehead of an unsuspecting victim.

Matte Murder · Feb 2, 2012

Where is Perks? Why doesn't he respond? He read the thread...

Randog · Feb 2, 2012

I had Perks do my clutch on my XP he wanted to do the engine, I thought about it but decided not to. The clutch was out 32 grams and I feel that is was money well spent I do not like the large cut in the side that he had to make to balance the clutch. Over all I think it is a good thing, I am worried about the clutch cracking where he ground it, he did radius the cuts. It did make the engine run a lot smoother. I think balancing the clutch is a good thing.

Demo250 · Feb 2, 2012

backcountryblazin said:
eddy, your totally right with the flywheel weights that were used in lots of cross crountry and enduro 2 stokes back in the day. (avid dirt biker, Ive done this mod myself). the weight is symetrical, due to 2 stoke bikes having absolutly NO bottom end, the weight helped tremendously when lugging the motor down through the tight techinical terrain when conditions did not permit running in the 8-9k rpm powerband, helped avoid stalling out at low rpms as well. Made big improvements with keeping the 2 stroke power much more rideable and trackable through the tight nasty single track. But, point in hand, this is a different application and is designed to simply add 360 degrees of mass to the rotating assebly, to help keep rpms more solid. it was not placing an added mass at a particular degree with the purpose of correcting an unbalance.

I've been following your posts very close and I follow your train of thought perfectly. You were able to put into words what I was thinking this whole time. I have a question though.

"this is a different application and is designed to simply add 360 degrees of mass to the rotating assebly, to help keep rpms more solid. it was not placing an added mass at a particular degree with the purpose of correcting an unbalance"

Has anyone actually examined this piece to see if it is adding weight at a certain degree? My thinking this entire time was that it would simply add 360 degrees of mass. ie - it is a perfectly balanced piece. This added mass would change the harmonics of the motor and absorb some of the low RPM vibrations. This would make sense, as it would make the motor FEEL smoother.

If it is in fact adding extra weight at a certain degree though, with the intention of correcting an unbalance, it would seem completely careless to add the weight at any given area without actually testing in person to see at what degree it is unbalanced. What if the added weight was added to the same area that was already unbalanced? Now it is suddenly even further out of balance.

Am I in the ball park with these theories? Or am I out to lunch? lol

eddy · Feb 2, 2012

Perks Kit

Added flywheel is weighted at a certain degree.

brocknriley · Feb 5, 2012

...after our second recoil on our 08 800 broke yesterday, I figured I would jump on here and see what I could see...appears I am just another statistic of the Perks kit.

He has contacted everyone about the recall??? ...ya, no.

When you put his aluminum rotor on, you take the OEM steel spacer off...simple enough, no algorithm needed...

..some people got a spacer ring for the platic housing, and some didn't(like me), but it does not appear to make a difference...as it looks like failures have happened either way...

eddy · Feb 5, 2012

Perks

Please post if you were contacted by Joe Perkins unpromted: In other words you learned of the steel rotor by his call before you learned of it elsewhere.

winter brew · Feb 5, 2012

Is the MAG stub deaigned or tested to take a unbalanced mass? This piece is how far from the end bearing? About 3 inches? And at 8000+ rpm at approx 5 cm from centerline will exert approx. 3,700 "G's". So whatever the amount of weight being added to offset vibration times 3,700 and a few inches of leverage on the end bearing. Is it designed to have anything but a balanced flywheel on there? What would happen if you took a arm out of your clutch and ran at 8000 rpm?
Or am i misunderstanding the construction of the piece in question?

TreeThrasher · Feb 6, 2012

What I am much more interested in is what is actually causing the recoils too fail? We have two of these kits on two identicle motors. All parts in the motor were weighed and matched. Two identicle balance kits were produced for them. Both sleds have about 400 miles on them with the balance kits installed. One has never had a recoil problem. The other (mine) eats them as fast as I stick them on. I have actually given up on keeping a recoil on it. I have just clutch started it the last couple rides.

What part of your recoil is failing? The spring or??

nospinbalance1 · Feb 6, 2012

Perks balanced my motor in the snowmobile you decide

Joe ( perks spin balance ) had my snowmobile around 19 days ( Joe told me he would have it for 3 days ) I went to get it once but would not except it because he had it vibrating so bad , He told me he would get it right and call me when it was done.. This is perks work you decide !!! http://www.youtube.com/watch?v=QjWceKKUixQ

800PowerFanatic · Feb 6, 2012

I just don't understand the inconsistency. He is not going to have a good name with this reputation already. I mean he has some right mine rocks so does eddy's whats the deal?

revrider · Feb 6, 2012

nospinbalance1 said:
Joe ( perks spin balance ) had my snowmobile around 19 days ( Joe told me he would have it for 3 days ) I went to get it once but would not except it because he had it vibrating so bad , He told me he would get it right and call me when it was done.. This is perks work you decide !!! http://www.youtube.com/watch?v=QjWceKKUixQ

Thanks for shareing. The way your motor was vibrating in the video I thought it was going to come apart. I cant belive I was ready to have his ballance job done to mine. After reading everything on this thread thats not going to happen unless he replys to this thread and makes it right to everyone.

Matte Murder · Feb 12, 2012

Just wanted to get this thread back to the top so people could see it. There is finally a response from Perks about the video posted about the Polaris but nothing here. Perks, what "fix" do you have for the rope pull problems these guys are having? Also, since Perks appears to have put up a fake post on that thread is there anything fishy about the posts on this thread too?

brocknriley · Feb 16, 2012

Rode yesterday with the clutch rebalanced w/o the starter ring gear and the kit removed...left the flywheel weight off and ran a deeper starter recoil basket...spent the time and indexed the clutch to the crank to obtain the least amount off combined runout...all I can say is, wow, what a difference...and no more broken recoil springs.

had my engine spin balanced

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