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Discussion Starter · #1 ·
Is it the same Gear parts in 600ace and 900ace?

Can I use sprockets, chain etc. from a 600ace in a 900ace?

I want a lower gearing for better accelereation..

Thanks in advance
 

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Unfortunately that link has some errors, so be careful. For example Ski-Doo's fiche shows that my 2015 Renegade 900 ACE has a 19T top sprocket. According to my owner's manual it does not. It has a 24T top sprocket. Haven't cracked it open yet to look.

I don't know exactly what interchanges. For sure the bottom sprockets interchange. If your machine currently has a 49T, you can put in a 51T, part number 504152971. Pretty sure you'll need to get a link longer chain for it to fit also. Top gear I'm not sure. Realize the reverse gearcase drastically limits your options up top...none of the 2 stroke stuff will carry over. I'd like to think top gear from 600 ACE and 900 will interchange, but I'm not entirely convinced because the chaincases themselves have different part numbers and I don't know why. I believe the 600 comes with the 19T, and the 900's come with the 24T. These are probably your only two top gear options. That would be a massive change to drop to a 19...probably way too much for what you want to accomplish. So that means you'd likely need to go smaller on the bottom also, if you go all the way down to a 19T up top. So you'd be looking at buying both gears and again a shorter chain will be needed.

Valuable info here that might help you decide what to do, chain length recommendations and gear ratio comparisons at a glance:

https://www.ibackshift.com/article/gearing-150.asp#sprocket_gear_chart

Again I don't know if the top gears interchange. Someone else might know.
 

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Actually the 900 ACE shorty and Renegade come with a 24 tooth gear, the 600ACE shorty has a 24 tooth gear but the 600Ace Renegade comes with a 21 tooth gear and these are shown in the parts fiche. - Bill
 

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Aw crap, you're obviously right. Turns out I was looking at the wrong dang gear on the fiche and reading the diagram wrong...the reverse gears say 19T, not the top gears. Fiche is correct and I was wrong. Thank you for the correction.

Do you know if that 21T top from the 600 would interchange directly with the 24T top from the 900? I assume it would. If so that gives JoTT many other options and ratios to consider.

So presumably 21T and 24T are the only two available top options for this chaincase? Or do you know of others? I know someone in the aftermarket was making larger top gears as well mostly for the Turbo 1200 guys, but that won't help JoTT here.
 

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I did the switch on my Expedition Sport 900 Ace from 24 - 49 to 21 - 52. I used the Expedition 600 Ace part. Everything fit no problem. I didn't need to change the chain for this setup. For the top gear there is not much choice, 19, 21 or 24 tooth.

I switched gearing because I was going with a 2 inch Challenger track. I didn't try the setup so far but I will be pretty soon. It is snowing!!!
 

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Discussion Starter · #7 ·
I did the switch on my Expedition Sport 900 Ace from 24 - 49 to 21 - 52. I used the Expedition 600 Ace part. Everything fit no problem. I didn't need to change the chain for this setup. For the top gear there is not much choice, 19, 21 or 24 tooth.

I switched gearing because I was going with a 2 inch Challenger track. I didn't try the setup so far but I will be pretty soon. It is snowing!!!
Thanks for sharing! :)
 

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I did the switch on my Expedition Sport 900 Ace from 24 - 49 to 21 - 52. I used the Expedition 600 Ace part. Everything fit no problem. I didn't need to change the chain for this setup. For the top gear there is not much choice, 19, 21 or 24 tooth.

I switched gearing because I was going with a 2 inch Challenger track. I didn't try the setup so far but I will be pretty soon. It is snowing!!!
 

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Hi there!
thats also what i would like to do on my expy sport. The dealer however Said it was Hard To Change gears in the 4strokes. Please keep post on how it turned out.
 

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Well I did a first test drive Friday night, there was 6-8 inch of snow. I was only able to run the sled for short run. I didn't have a long snowy stretch to run full throttle for a long time. Here are the preliminary result. Keep in mind I did a couple of mod at the same time. I installed a Cudney clutch kit, a 2 inch challenger track and changed the gearing from 24-49 to 21-52. A stock Expedition Sport doesn't have lot of power to spin the 154 1.5 inch track. So I was scarred putting the 2 inch challenger would kill the ACE. I felt like I needed more. So I did! Definitively with the 21-52 and the clutch, the track turn way much more than before. I can't tell so far the effect on top speed, but getting there will be quick! I was running around 130 km/h, 80 mi/h top speed before the mod. I wonder how big of a drop I will get on the top speed? My girlfriend as the same sled, 2015 Expedition Sport 900 Ace. I will be able to have a fair comparison between both sled in snow. I may try the 21-49 gearing if I end up loosing too much.

The 2014 Expy sled was at the dealer for a track swap with the 2015 Expy we bought. So at the same time they did the gear change since the gear case was open. The bottom gear is simple to change, just like the two stroke. The upper gear is more complicated because of the mechanical reverse on a 4 stroke. The is a couple of gear that need to be taken off. Saying it is hard to change is a big word, it just take more time than a 2 stroke.

Waiting for more snow, now that the rain made the first one disappear!!!
 

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When you say Cudney kit...do you mean the PB80 ?

It will be interesting to know what your top speed is...with that gearing I would suspect you will get full shift...although that is a big track.

Thanks.
 

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What engine RPM did you use?

I am sure it will shift out all the way in cold hard trails.
 
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OK Thanks!

this sounds very interesting, He said something about the sprockets being pressed on to the shaft. That doesnt seem to be the case though reading what you write. Will get in touch whit them again, maybe i misunderstood them. I am coming from a Summit so i really miss the bite of the challanger track. I think the summit had 19/49 so i figure 21/49 might suffice.

I have only heard about the cudney clutch on this forum, i live in Sweden dont think we can get them here. anyway a new track is enough money as it is. I tried to get a stiffer spring to the primery clutch, thinking it would not shift up so quick, and maybe shift down easier. but skidoo does not seem to offer one yet.

There are`t that many expy sports around here, so it was nice to find this forum. hope my English grammar is good enough to make sens :)
 

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Dalton industries have a couple of springs for the Edrive2, you can buy them from, Speed Technology in Sweden

I installed one of them lasts week but it was to little snow to get a reel test. But it feels like i got some rpm back.
 

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I assumed 8,000 rpm in the gearing calculator. It will be slower if the target rpm is Doo's 7,250.

Johan, your english is better than most people writing on Dootalk! No need to apologize!

The gears are not pressed on the shaft. The only thing that makes it a little more challenging to change gears on these 4 stroke sleds is the reverse chaincase, plus all the electronics that are now bolted to the outside of the chaincase that need to be removed. It's just more parts in the way so it takes a little longer, but gear changes are very simple once you get in there...same as any old machine.

When people are referring to the Cudney clutch they are actually talking about his kit, which uses the CVTech-AAB manufactured Powerbloc 80 clutch. Cudney does not make the clutch, but he is one retailer of them, and he has developed a clutch kit to use that clutch on these machines. But there are many other places to buy the PB80 if you and/or he don't want to mess with shipping to Sweden, or if you want to tune your own. It's very very easy to dial in any custom RPM you desire on a PB80, and the clutches are maintenance free pretty much forever. Catalog of their products: http://www.cvtech-aab.com/contenu/catalogue_ang.cfm Contact them and they probably have PB80 distributors and dealers in your part of the world.

Agreed also Dalton Industries sells heavier springs for the Ski-Doo E-drive clutch if that's the clutch you're using. Good quality stuff. http://daltonindustries.com/ The two Edrive springs they sell are probably worth trying, much stiffer than the factory 900 spring, and will likely get you good RPM's. If memory serves we gained 500 to 600 rpms on my brother's 1200 using the stiffest Dalton spring on his E-drive, and the factory 1200 spring started stronger than a 900 spring is. So I'll completely guess/speculate that the stiffest Dalton spring might gain 700 rpms on a 900? Only testing can confirm and I might be way off. Even the 1200 factory spring should be an improvement over the factory 900 spring, if you want to keep with Ski-Doo parts. But I honestly don't think the 1200 spring is strong enough to get you to 8,000 rpm alone (I'm assuming this RPM is close to your target?), and they have a history of short lifespan. But if someone by you has a 1200 spring laying around to try for free...try it. If not I'd go straight to the Dalton springs...I think they will likely get you pretty close to where you want to be, and most who tried them on 1200's report better quality/longer life than Ski-Doo springs.

And certainly grinding material off of your Edrive weights to make them lighter is another method that is guaranteed to work to raise RPM. Use a gram scale and a grinder....lighten them up and keep them balanced until you get the RPMS you seek. Grind too much and you ruined your expensive weights! Since Edrive is a 6 arm clutch you can also just lighten 3 of them if you are always certain to keep them alternated to make sure the clutch is balanced....leave the other three stock weight. This minimizes risk or ruining all six if you haven't done this before. But this is an older school process that has been done for snowmobile clutch tuning, from back when aftermarket clutch parts were not available for purchase.

As always, tune at your own risk! These are just ideas I would be willing to try and have done in the past on other clutches, if you don't want to spend a whole lot of money on clutch tuning/replacement, or parts are not easy for you to find.
 

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Great info guys, thanks.

Dont think i will grind any weights just yet ;) I have a vague memory of my brother doing something like that to our SRV when we were kids. ;)).

I Have heard about speedtec, need to check out them Dalton springs.

Now i just need to get a new track and some gears before the snow starts to fall :)
 

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Discussion Starter · #19 ·
Great info guys, thanks.

Dont think i will grind any weights just yet ;) I have a wage memory of my brother doing something like that to our SRV when we were kids. ;)).

I Have heard about speedtec, need to check out them Dalton springs.

Now i just need to get a new track and some gears before the snow starts to fall :)
Yes great info! :righton

I would really appreciate if you shared your upcoming mods.
Top speed, acceleration improvements, performance in the snow. Even parts and prices if possible..

Ps. Have you seen my post about the reverse issue? Any thoughts? .ds

Thanks
 

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Yes i will gladly share my mods, if i ever get them done ;)

I am new at this, so i have not really learned how to navigate. Whats the name of the topic on the reverse issue?
 
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