Ski-Doo Snowmobiles Forum banner
61 - 80 of 101 Posts
These are my results on my 03 800X BONE stock except gear and beavertail delete. With 2500 miles 1.25 track, 144 studs, 600 belt, and 440X handlebar kit.

26/43gear ratio = 98MPH (1000 ft.)
25/43gear ratio = 100MPH (1000ft.)

26/43gear ratio = 99MPH (1/4 mile)
25/43gear ratio = 101MPH (1/4mile)

I have never been clocked in a one mile stretch, however, I have raced a 2003 F7, 2003 ZR 900, 2001 ProX 800, and 2003 REV 800 (stock gear ratios) with both gear ratios in over a mile with these results:

26/43gear ratio = Beat only the 2003 REV 800 (because I had a better start)
25/43gear ratio = Beat all of them from stop to finish.
 
One thing you will find from gearing down a substantial amount to measure, and I don't mean one tooth, I mean two teeth or more will make a substantial difference that you can feel in the seat-o-pants...
...The effect gearing down has on flyweight; Gearing down gives flyweight the motive to act like a heavier mass than previous gear. The fact is the C of G of the flyweight is now at a farther relative position away from the clutch shaft centerline per mph/shift position on the shift curve.

For lack of better numbers lets use 90mph and pick the difference between 23 gear and 25 top gear.
*Where is the belt centerline on the primary at this steady mph?

At previous gearing [25] the belt centerline and the center of gravity position of the TRA arm is lower and closer to the clutch shaft or if you like..the engagement position. When depressing the fuel to accelerate, you'll find the engine will shift at whatever rpm and peak at the proper rpms.

With the newer lower gear [23] the belt centerline and the center of gravity position of the TRA arm is higher and farther away from the clutch shaft or if you like..the engagement position. When depressing the fuel to accelerate, you'll find the engine will shift at a lower rpm than the 25 gear and the peak rpm will be slightly less than proper rpms. You could lose 100 rpm or more because the weight is heavier and pushing harder at the 90mph speed.

Now there are a few advantages to this. From rest, as the sled speed increases, what inevitably follows is the flyweight does more work. The primary will capture slightly more the "meat" of the torque curve, especially on trail where you are on and off the gas somewhat. The weight is taking advantage of a cooler exh pipe which some know that a cooler pipe makes more torque at lower midrange rpms.
I always get nearly the same comments that tuners can get a higher mph cresting the top of a hill and holding the skis in the air longer up hills. More bang going over the hill and especially when letting off the fuel to go thru the bottom safely, they ascend back up another, the engine is right there with improvement to get to peak rpms.
And nearly always recording the same top speeds on hardpack light loaded road conditions.
 
These two I had to add about a gram of flyweight to push the secondary open to get my top end back.
[2.38] 18/43 = 81, 82 mph [geared for 76] got into overdrive
[2.44] 18/44 = 81, 82 mph [geared for 74] got into overdrive
You will notice here that I mentioned I had to add a gram of flyweight. I lost mph originally with this gearset. I also noticed that on prolonged running with this my secondary temperature was higher than normal. I would stop suddenly, pop the hood, measure as close to the center of the sheaves on the secondary. The temperature was higher than previous gears. If there is higher temps, then what is happening? Belt slip. At that shift ratio there is not much belt contacting the surface of the secondary sheaves. The arc angle of contact is low in overdrive, so the sheaves could not do their job of gripping the belt. I ended up increasing my pretension from 19 lbs to 23 lbs, ran and retest, recorded increased rpms because of pretension change. I added nearly a gram to push the engine back down and reveal an equivalent mph to the latter gear ratios.
Now with this addition of flyweight it does not make hardly a difference at all in the lower shift ratios because the TRA arm C of G is close to the clutch shaft center. However that little bit of 10ths makes a large difference at full shift. Remember the force is squared at the rpms.
 
For those with a gade.....
Image

I Asked my dealer and without hesitation said drop the top gear 2 teeth,
without even knowing what the gears were.
Opened it up, 23/43 stock, went to 21/43.
Then we noticed I hadn't been using all my clutch, had 18 hours at that point,
getting my check up.
Took it for a rip, wow, I was already impressed to that point,
but this just blew me away?!
Couldn't get my head around it for a bit but as explained here earlier,
the smaller gear can do more - faster.
It gave me more "yank" and decent top end, 105 radar on ice.
I'll let the triples fight it out on the lake.
It's the trails where it really shines.
Image
 
Gadex
You mentioned you went to a 21 top gear I went to a 22 on my gade same top end but was wondering if you could use the same chain as with the 23 tooth.It looked like I was getting close to the end of the adjustment.
 
Yea joe I am using your kit and it is working great especially on the trails always right there and a lot of fun.I am still waiting for more weight from thunder so I can set it up on clicker # 3 as I am using #2 right now.I figure 25 to 26 on # 3 should be just right for 8000 rpms(hitting about 8250 now on #3). With the weight and on #3 do you think it will pull harder? As for the 7 cat he hit a ditch last trip out chain case gone AGAIN $300.00 to fix it this time.I don't think he is going to keep it together long enough to try himLOL.
 
This is a great topic guys....so I sighned up for the Dootalk forum!!
I am also currently running the 25/45 in my 800HO w/1" track, it seems to pull harder but I am going to go all the way down to 23/45.
My top speed on the LCD speedo didn't change going from the 26 to 25 on the top gear on hard pack so well see this weekend how the 23 pulls.

Anyone else try a 23/45 on a 04' 800 ??
 
Discussion starter · #76 ·
Dynamo^Joe said:
[2.38] 18/43 = 81, 82 mph [geared for 76] got into overdrive
[2.44] 18/44 = 81, 82 mph [geared for 74] got into overdrive
Some guys think you ar egoing backwards gearing down but like Joe said look at the quote he is geared lower and yet he went faster then what he is geared for!

I talked to Duane the fella that makes the Paragon clutch and he explaind it to me like this if you want to go 118 MPH gear it to 118 mph or lower it will go faster. He also explained that with the big gears IE the 26/45 thats deared for what 140 MPH somewhere in there that the sled will never pull it and it generates tons of head slipping the belt trying to pull that gear up top. Just something to think about.

Im going to run 22/43 and 22/45 this weekend on the paragon as to Duane's recommendations.
 
Discussion starter · #78 ·
Man that's what makes it testing! You maybe able to extract more MPH from the shorter gear but you may have to make some clutch changes to accommodate the smaller gear too. I would hold off after I get some solid testing on it I'll post back to you my findings.
 
Well my results are in I put 23/45 gearing in we race on a river and the race is not done untill the sleds are wound out. In the morning a freind has the same sled 800ho he would take me out of the hole 2 sled lengths and stay that way untill top end and I would start to creep on him but did not get by unless we would race about a half mile basically dead even. In am it was -5c later in the day +3c sled hooked up really good and I could stay in front all the way. Sled is over reving a bit clicker 3 8100 rpm, and raced clicker2 rpm 7750 and my buds sled was better.Sleds are stock except for my gear change. I am not sure what I will do may try the 25 tooth gear because I dont have a 24 tooth. We were seeing 115 to 116 mph on speedo NO GUN Just sled for sled.
 
Is it that hard to put a gear in and go test vs asking "will it work for me"??

Sometimes I wonder how "some guys" get out of bed in the morning- buy some gears go to the lake mark off a 1/4 mile and test- god forbide ya might learn something.

Getting info on the forum is nice BUT for exact answers for your sled,your riding weight,your track,your state of tune,your elevation,your clutch kit.............. DO IT YOURSELF- BJ

BTW- Olav Aaens clutch tuning and carb tuning manuals are still the best manuals (along with a DOO race manual) you can read.
 
61 - 80 of 101 Posts