Belt Deflection: HELP!!

4180 Views 14 Replies 5 Participants Last post by GregB, 3 mo ago

mcatzr700

Discussion Starter · 3 mo ago (Edited)

Please bear with me, this is my first snowmobile, new to me. I am at a complete loss, I have a 99 zr700, removed the secondary, pulled out all the shims between the sheaves, belt is riding so high on the secondary and deflection is still over an inch and a half. Brand new Dayco belt. What the hell am I missing? I have crossed referenced the Arctic Cat OEM part with the Dayco part numerous times (AC 0627-020 - Dayco HPX5017)

I do have an alignment bar coming in a few days but I can't imagine alignment is going to affect belt deflection this severely.

Is it possible the sheaves on primary are to far apart (if that's a thing)? And the belt simply rides to low on the primary? I can't find anything in the service manual that defines distance between sheaves on the primary.

I guess parallelism could be WAY off but again, I with deflection of over 1 1/2 inches I can't imagine parallelism will fix that.

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660catman

· #2 · 3 mo ago

This is the second time in a week that someone has posted an issue with a Dayco belt with the same part number.

Belt change, high rpm low speed

https://r.tapatalk.com/shareLink/to...ce=app[/URL]"]Belt change, high rpm low speed

tcat446

· #3 · 3 mo ago

" Is it possible the sheaves on primary are to far apart (if that's a thing)? And the belt simply rides to low on the primary? "

Not possible and is not the problem. Likely the belt length. Measure around the belt with a tape, or mark the belt and work bench with a marker so both marks line up. Then roll the belt till the mark on the belt touches the table and mark the table at the belt mark. Measure the distance between the two marks. Should be 47 3/4" Plus or minus 3/16" per spec.

mcatzr700

Discussion Starter · #4 · 3 mo ago

tcat446 said:
" Is it possible the sheaves on primary are to far apart (if that's a thing)? And the belt simply rides to low on the primary? "

Not possible and is not the problem. Likely the belt length. Measure around the belt with a tape, or mark the belt and work bench with a marker so both marks line up. Then roll the belt till the mark on the belt touches the table and mark the table at the belt mark. Measure the distance between the two marks. Should be 47 3/4" Plus or minus 3/16" per spec.

TY! I will measure the belt and I'm confident its the belt length. I went back to the stock arctic cat belt (which I thought was in bad shape) and the deflection is MUCH better. Alignment tool was delivered today so I'll sure everything up and check deflection one last time. The belt was slipping BAD which made me believe the AC belt was bad. I think it was a combination of poor alignment and the secondary needing some shims removed. REALLY appreciate the help. I'll put everything back in spec and report a final post. An observation about the Dayco belt, it feels MUCH lighter in construction than the AC OEM belt. Its WAY more flexible, the cogs (overall height of the belt) are much shorter than the stock belt and I believe its longer.

ejowrench

· #5 · 3 mo ago

mcatzr700 said:
Please bear with me, this is my first snowmobile, new to me. I am at a complete loss, I have a 99 zr700, removed the secondary, pulled out all the shims between the sheaves, belt is riding so high on the secondary and deflection is still over an inch and a half. Brand new Dayco belt. What the hell am I missing? I have crossed referenced the Arctic Cat OEM part with the Dayco part numerous times (AC 0627-020 - Dayco HPX5017)

I do have an alignment bar coming in a few days but I can't imagine alignment is going to affect belt deflection this severely.

Is it possible the sheaves on primary are to far apart (if that's a thing)? And the belt simply rides to low on the primary? I can't find anything in the service manual that defines distance between sheaves on the primary.

I guess parallelism could be WAY off but again, I with deflection of over 1 1/2 inches I can't imagine parallelism will fix that.

View attachment 373659

I use a 0627-035 belt in place of the -020 belt. Expensive belt, but it gives me no grief.

mcatzr700

Discussion Starter · #6 · 3 mo ago

ejowrench said:
I use a 0627-035 belt in place of the -020 belt. Expensive belt, but it gives me no grief.

Is the 0627-035 the same dimensions as the -020? And by the part # I'm assuming that's a AC OEM part.

ejowrench

· #7 · 3 mo ago

mcatzr700 said:
Is the 0627-035 the same dimensions as the -020? And by the part # I'm assuming that's a AC OEM part.

Pretty darn close, and yes, OE Arctic Cat belt.

tcat446

· #8 · 3 mo ago

It never hurts to clean the clutch faces with Brakleen in the red can. This will take off the rubber build up and allow it to grip better. Then rough up the gripping surface with maroon colored scotch brite.

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mcatzr700

Discussion Starter · #9 · 3 mo ago

Thanks for everyone's help, I did clean both the primary and secondary using brake cleaner (as well as clean the belt with some standard Dawn dish soap). Check out the difference in belt thickness, Dayco on the left with the OEM belt on the right. The OEM belt definitely fits better and has less belt deflection, after cleaning and removing all of the shims in the secondary I'm going to try it again. I still want to pull the primary and check Center to Center between the two clutches.

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660catman

· #10 · 3 mo ago

Right or wrong, this is why I use Cat belts. Those belts just look way off, never mind the measurements.
Hope it works out for you and let us know.

ejowrench

· #11 · 3 mo ago

mcatzr700 said:
Thanks for everyone's help, I did clean both the primary and secondary using brake cleaner (as well as clean the belt with some standard Dawn dish soap). Check out the difference in belt thickness, Dayco on the left with the OEM belt on the right. The OEM belt definitely fits better and has less belt deflection, after cleaning and removing all of the shims in the secondary I'm going to try it again. I still want to pull the primary and check Center to Center between the two clutches. View attachment 373680

Any way you slice it, that Dayco is the wrong belt. Time to use new references for belt selection.

tcat446

· #12 · 3 mo ago

I am thinking that Dayco is meant for a 440 or something smaller not requiring alot of power to be applied to the belt. If you go to their web site it should list belt HP ratings.

GregB

· #13 · 3 mo ago

On a 99 roller you add shims to open the sheaves to make the belt sit lower

mcatzr700

Discussion Starter · #14 · 3 mo ago

2

Again, thanks for all the help. Here is my final update, removed all shims from the secondary, ordered an Arctic Cat OEM alignment tool, aligned the clutches, also checked parallelism, put everything back in spec. Went back to the stock OEM belt (which probably should be replaced before the start of next season). Cleaned the primary and the secondary with some Scotch-Brite and some brake clean. The attached images show current deflection and where the belt is riding on the secondary. All looks in order but I really won't know until I attempt to run the sled under load. Here in Pennsylvania we've had a lousy winter and I have no snow at this point so unfortunately she may sit and wait until the start of next season. Hoisted the ass end up in the air and ran it pretty hard, primary and secondary are moving as they should. Some posts suggest if the ass end is up in the air the belt should move under no load, I don't know if that's true, mine does not do that. My primary does not engage until I apply some throttle. I agree, the Dayco and the stock OEM belt look completely different.

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GregB

· #15 · 3 mo ago

That will be fine. Once you are moving the belt deflection won’t matter anymore

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