Suspension, Clutching and More.. Question of the ages.

Specs (07 Rev 151 800r)

Now maybe my logic is a little backwards so hopefully somebody can please give me a hand a clear things up, I made a number of changes to my sled and I'm noticing "perceived" positive, and negative impacts.

This summer, I did the following (in this order)

As a result of a backshifting, and inability to sustain RPM under load or get peak RPM issue I changed my secondary to a team tied

The result was a snappy respond and quicker shifts, quicker and smoother shifting and quicker shifts between forward and reverse, but It didn't fix the peak RPM.

I then went ahead and did the following things all at once (I meant to space them out, test, and then try another..but as a result of a lack of snow and bordem I did them all at once)

1) Replaced my R.A.V.Es with 09 Raves (my 07's were cracked)
2) Replaced my head with a used trygstad billet head for my altitude
3) Replaced my top gear in the chain case with a 19t (and replaced fluid adjusted chain tension)
4) Rebuilt my Primary with specs provided by team to match the above (Yellow & Almond Team spring, and & 13.8s weights currently going to order smaller weights)
5) Replaced my belt (166)
6) Let out the limiter strap.

Now this weekend finally got my first pow ride, and here is what I noticed.


Clutch engages around 4100-4200 rpm
Sled Seems "less snappy"
Sled is capable of pulling 8800 RPMs in the flat (I had to 3/4 throttle it or I was afraid it was going to hit 9k)
Sled is capable of pulling around 8400-8500 on a small climb (and so far seems to hold, I was unable to hit the hill I was testing before when it would drop and bog due to a lack of snow on that part of the mtn atm, but will do afte the next storm)
Sled doesn't seem to lift the ski's much anymore (maybe a couple inches (and no I didn't get weight.. quite the opposite.. I'm down 60lbs)
MPH is drastically reduced.

Currently my clickers are on 4, I'm thinking of dropping them to 3), I haven't rejetted the carb but it seems to be running good in terms of not leaning out, would the new head cause it to run rich?! I would assume I would need to add more fuel. If I was running lean it would be Snappy as all heck no?

Secondly I assumed by putting in a 19t gear, and letting out my strap it would turn into a wheelie monsters which leads me to believe I am for some reason now down on power, or is my logic totally backward, and could it be the weights are to heavy in my primary?


Outside of that I'm really happy with the sled. I just want to make sure I dial everything in. So with that said, does everything as I described seem spot on, or did I miss something? Thank you for your time!

-Brahm

winter brew said:

Call Trygstad and use his jetting recs. for that head.
Don't let it spin over 8400rpm.....more than that you are not loading the engine and the result is lack of acceleration and alot of belt heat.
Make sure that jetting is close first......and do a full throttle/kill engine plug check to verify plug burn pattern.
Then play with the clutching.
What is your bottom gear and track length?

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Thanks for your quick response!

You brought up a great point!

Sorry I didn't mention it before. Clutch temp was always really low and appeared similar on both the primary and the secondary which I believe you said was something to strive for. It's a 151 track, and the bottom gear is stock. I do have the jetting recommendation from trygstad. I just haven't purchased the jets yet. (and I've never torn apart that side of the motor) I figure if I do dip into jets. I will do reeds at the same time.

Thanks again for the responses, I've never changed the jets on my sleds before. Do you guys have any links to articles/tutorials, also where is the best place to purchase the jets online. I don't think my local dealer stocks aftermarket jets.

winter brew said:

Any dealer should have or can order the jets you need. I would NOT ride until you have the proper jetting....might get expensive!
Pull your secondary, airbox, loosen clamps from carbs to carb boots and pull the carb rack back....probably need to unplug DPM wire and whatever else to get the carbs out just enough to get a wrench on the float bowl plug on the bottom. Remove that plug and the main jet is right there....a 1/4" socket will fit the jet.....remove and replace with the correct size, not too tight.

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Thanks, I'll order the stuff up. What's odd is the guy I bought the head from said he ran it and never changed the jets, from what I'm reading you lean it out when you get an after market head so I should be ok..just a little down on power. I'm pretty familiar with the result of leaning out motors..so I know that isn't an issue, but either way thanks, I'm going to give dave a call and see if I also switch reeds what jets I should get, and for now put the clickers down to 3 or 2 so I don't over spin.

ok, so I spoke to Dave, he said I the main jet is fine stock, I should switch to a 20 pilot, and shim the need 15/20ths?

Don't most of those things only effect partial throttle. So what would kind make it feel like it isn't as "snappy" at full throttle, and with that said what about my other issues, or things to note? (ie less wheelie, ect)

Thanks
-B

gman086 said:

You aren't pulling the skis because your power falls of dramatically past peak RPM's. 20 pilots can also help prevent off-idle bog which can kill that too. Center shock spring tighter and rear torsions looser helps but not ideal for the steep and deep where you'd want the opposite. You can improve motor response by going to the lower clutch pin weight that Team recommended. You can also ditch the ring gear IF your crank run-out is good which also helps. Not recommended for most '07's tho (poor balancing).

Have FUN!

G MAN

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Thanks for the reasponse, It doesn't appear to be bogging. It just doesn't seem to rip up the RPM range as quickly, as far as going past the peak RPM. I'm going to change my clickers before the next time out (down 2, and go from there).

I don't necessarily "want" to pull the skis, it's more how I gauge whether or not my sled is running correctly (how torquey it feels). I do have 20 pilots, and lower pin weights, and shims for the needle on the way. I don't think I'm going to ditch the gear though, not worth risking anything that might mess ith crank balancing.

snowyo said:

It may be a moot point and you seem like you got the right wrenching going on,but not to sound like a rookie but also make sure your belt is sitting a touch higher than a credit card thickness in your secondary.......just putting it out there.....but i'm sure your fine.

A simple compression check helps ease the mind 2....

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My belt deflection is good, but it's a new belt. I'll double check and make sure it didn't stretch. As far as compression, I don't think that's an issue unless I didn't seal an o-ring correctly when I replaced the head, but I believe I would notice the issue in other areas.

evandaigneault said:

you might not have to change your main jets. I have the SLP kit with an aftermarket pipe and i jetted up like SLP recommended. I have an EGT gauge and by watching that I have slowly ended up jetting back down to the stock 470 mains from what SLP recommended which was 500 mains. I'm also running at low elevation mostly too (3000ft) here in AK, so if anything it should have run leaner.

So you might be fine with your stock mains. Just watch your plug color. I would shim the needles though, just to be safe, imo.

Evan

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Thanks Evan, I'm running around 9k+ (at least thats where I was testing) the lowest I get is around 8k

gman086 said:

Ramp angle also plays a role. Higher clickers = poorer shiftout but quicker RPM build. Honestly going down to clicker 3 or even 2 could have improved your situation dramatically. Strongly recommend quick-clickers!

Cheers,

G

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Thanks G, I haven't changed the Ramps I had 415s which is what team recommended. Hmm. I'll let you know after I change the clickers and take it for another ride, hopefully that helps. I put my order in today if I'm lucky I'll have the parts from SLP on friday to install friday for a Saturday test ride. I really want to get everything as close to where it needs to be by sunday.. we might have a big storm coming in starting on monday.. I can't miss out on it! The only thing though, is if I recall team said I would have my clickers set @ 4 with this setup, so maybe once I put the lower pin weights in I'll have to go back up to 4?

98psi700rmk said:

Your problem is you have way to light of weights in your primary. Your over reving the sled to outside its power band. (your probably down to 100 HP or so here well outside the power curve) 8800 is WAY WAY to much RPM and 8400 Max would be one thing but personally I wouldnt want more than 8250-8300 RPM's. Some guys like to clutch a hair over peak rpm so when they get into a long climb and back shift they are in the rpm range that makes the most power. If it were me doing this I wouldnt want to go above 8400 rpm's. Throw some more weight in your primary weights (however you do this on a skidoo) so your not going to pull any more than 8400 rpm's and then see what you think. Your making this much harder than it has to be the rest of your stuff seems fine.

I might not be a skidoo guy but clutching is clutching regardless of the make or model.

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Thanks for the response, just to clarify. I'm not romping around @ 8800 rpm, that's just where I noticed it flash up to when testing (before I back off..and quickly) It seemed to flash up to around 8500 during a climb. So more weight will reduce RPM, but doesn't it require more effort to spin more weight? Should I not adjust the clickers to curb the RPM?

98psi700rmk said:

Think about it like this if you can pull 8500 rpm's when the sled is under load. From what I know of on the 800R motor your power drops off on the stock curve significantly around 8400 RPM's. So lets say you had around 150-155 Peak HP at something like 8300 RPM's. By pulling that 8500 rpm's in your climb your sled is outside of the powerband and now making less HP, in the flats you saw even higher around 8800 RPM's you have even less HP than you had at 8500 rpm's.

Two stroke twin motors are peaky. They make the most HP in a certain rpm range, lower than that range and higher than that range the power drops of substantially.

What your trying to gain through your clutching is making the motor spin in the desired RPM range that makes the most power all the time. For your particular application you wouldnt want this to be anymore than 8300-8400 rpms to have the sled use the maximum power its making. Honestly I would clutch the sled so it pulled no more than 8200-8250.

It really doesn't Take "more power" per say to pull more weight it just makes the motor use the most power that it makes available. That being said you can put in too much weight making the sled pull too LOW of rpm's as well. Its kind of a touch and go thing, try adding it in small increments and then go test until you get to your desired peak rpm range.. no more than 8400 no less that 8200 in that range your sled makes the most HP. But like I said I would shoot for a nice mid range rpm of 8250.

All of this is if your secondary is where you want it to be as well. A good test to see if your team tied is where it should be would be to put your stock secondary back on and see what rpm's your pulling then.

I hope this helps.

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Thanks again, it does help with the peak rpm issue, but it still gets me wondering why does the sled not feel like it's got as much "umph" in the 4000+ rpm range ie.. sure it can get to 8500, but it doesn't get to 8500 as quickly as it used to get to 7800. That's where my major concern is.