Who has checked alignment on their upper and lower gears?

[rockymking]

2007 Rev XRS 159(162" Challenger now...) Threw a straight edge on my gears to check alignment, while I had the chaincase open and there is a serious mis-alignment going on? Lower gear could stand to come out, towards the cover about 0.02-0.05" to align to the upper gear, using straight edge method. Lower 45T is definitely on correct and the upper 19T has the recessed side with part#, tooth count, etc facing out(towards cover), which is the only way I can see that gear being installed correctly; the other way and the pins on the chain are dangerously close to the inner chaincase? Funny thing is that the gears ARE aligned if the recessed part of the upper gear is facing inward? Am I missing something here or.....? Any help would be greatly appreciated...that'll teach me to not take a few quick pics before disassembly!

 

[akx]

How wide is your top gear ?

How wide is your chain?

How wide is your bottom gear ?

If your answers are.

15

15

13

thats how they come an there is no problem just remeber to run the chain tight.

 

[rockymking]

How wide is your top gear ?

How wide is your chain?

How wide is your bottom gear ?

If your answers are.

15

15

13

thats how they come an there is no problem just remeber to run the chain tight.

So lemme get this straight....BRP puts together a drive system with 15W top gear and chain and a 13W bottom gear? It seems that's what you're telling me and I gotta say that the possibility of that scenario never even crossed my mind. So really, I gotta measure the width of the 2 gears and I'll have my answer....chain width at this point is irrelevant. So my next question is.....why the f#*K would they do that? I can only imagine to resolve a clearance issue, but come on? Thanks for the info akx...I'll check on it as soon as I get home.

 

[akx]

ski doo has been doing this for years on there race sleds, it allows them to run a lighter bottom gear so there is less rotating mass.

 

[2walla]

less money!

It also allows them to not be too concerned with the tolerances on the chaincase and jackshaft machining. I wonder if the same engineer designed the crankshaft?

 

[rockymking]

Thank you much for the helpful info akx...

ski doo has been doing this for years on there race sleds, it allows them to run a lighter bottom gear so there is less rotating mass.

I sure appreciate your help regarding the gear alignment....and you were absolutely right about the description of gear/chain. I guess "if it ain't broke, don't fix it" applies here since the 13W/15W combo seems to work fine. Just wanted to give you props for steering me in the right direction regarding my question....Snowest/Snowtalk comes through once again in a crunch.