1,000ft

[Doc Harley]

Guys, I need a little help...Going to pick up an Apex primary tomorrow and honestly don't know exactly what I'm looking at/for?!?! What should I be looking for to ensure the clutch is solid (not all warn out) it is a set screw style primary.
Note: the guy is super cool and would never try to stick it to me, but he's kinda in the same place that I am.

 

[RobX-1]

Obviously, you'll want to inspect for cracks like this as well as check the sheave faces to ensure there are no worn grooves and cracks; especially around the center of the sheaves:

As for the replacement, unless it was recently used and not stored, it will have some oxidation. Here's the one I picked up from Travis. Will get it cleaned up but it is solid and the sheave faces are smooth and flat. The unknow is the inner bushings that can only be inspected via disassembling the two primary sheaves:

 

[Doc Harley]

Obviously, you'll want to inspect for cracks like this as well as check the sheave faces to ensure there are no worn grooves and cracks; especially around the center of the sheaves:
View attachment 179829

As for the replacement, unless it was recently used and not stored, it will have some oxidation. Here's the one I picked up from Travis. Will get it cleaned up but it is solid and the sheave faces are smooth and flat. The unknow is the inner bushings that can only be inspected via disassembling the two primary sheaves:
View attachment 179830

Good tips, Rob...I'll grab a straight edge for the sleeve faces!
I'm assuming the inner bushing you speak of is a wear item. What would be considered a low mileage primary for that bushing to not be a concern?

 

[1nc 2000]

Spider has been know to crack from spring pocket out towards roller if clutches were over heated from belt slippage.

 

[Doc Harley]

Spider has been know to crack from spring pocket out towards roller if clutches were over heated from belt slippage.

Are you saying to remove the cover, pull the spring to verify??

 

[KnappAttack]

Never heard of a spiders cracking, thats a new one to me and not sure how that could even happen, but certainly down low on the sheaves for cracks from heat. Also buttons being tight on the towers, but certainly groves being worn on the faces. Bushings are going to need clearance for movement, but if the clutch looks good on the faces it should be a decent enough low mileage clutch.

 

[Doc Harley]

Perhaps pic will help. Groove towards the center. Is that going to be a problem? I assume so?!?!
*just recieved pic

 

[Doc Harley]

 

[Doc Harley]

No need to respond as I'm looking at another one.
Ty....

 

[maim]

View attachment 179835

looks pretty good. i usually crack mine within an inch of the hole. that groove is normal on all my clutches.

 

[Doc Harley]

looks pretty good. i usually crack mine within an inch of the hole. that groove is normal on all my clutches.

Oh, no way!! Lol. I just read a post (Knapp) in regards to grooves and thought for sure, that groove would apply?!?!
Is it just too low in the sheave to matter? Idk...otherwise and without verifying sheave for any low spots, they look ready to go.

 

[KnappAttack]

Perhaps pic will help. Groove towards the center. Is that going to be a problem? I assume so?!?!
*just recieved pic
View attachment 179834

If they have many miles at all, they will always get a little engagement grove in them, that is normal, you are engaging on a belt that is not moving after all.

Other areas on the face are from spending too much time at certain speeds for too long.

 

[Doc Harley]

If they have many miles at all, they will always get a little engagement grove in them, that is normal, you are engaging on a belt that is not moving after all.

Other areas on the face are from spending too much time at certain speeds for too long.

Okie dokie. I guess I'll just run a straight edge on them. Are little gaps to be expected when checking sheaves?

 

[74Nitro]

Spider has been know to crack from spring pocket out towards roller if clutches were over heated from belt slippage.

Right, I've seen a few do this. Had this happen on the Nytro I used to own. It started over revving then the roller arm broke right off.

 

[sideshowBob]

If they have many miles at all, they will always get a little engagement grove in them, that is normal, you are engaging on a belt that is not moving after all.

Other areas on the face are from spending too much time at certain speeds for too long.

When running an 8DN belt[hard like steel] you will develop a groove down low on the primary. The higher the engagement the sled is set up for the more the groove develops...kind of normal on most yamaha primaries.