2010 M8 Broken primary spring

[05765scott]

busted spring..

noticed that i could smell belt comming down the trail at allen creek last night checked belt was good checked out clutch when on trailer and busted spring on my 2010 hcr... Packed a spare d and d red spring ... what can i expect with it? its 170 330 stock is 143 290 i think any help is good!!

 

[Coldfinger]

broken primary springs on big twins has been a problem for many years....i totally solved this problem many years ago....the problem, is that as the spring cup starts to wear, 1 or 2 rides, the spring gouges the cup (face plate of the clutch), the more it does this, the more it coil binds, because it can't rotate anymore.....the solution.....put a delrin washer, or stainless steel or nylon, in the cup such that the spring seats on the washer....now the spring has something to rotate on instead of gouging the metal cup....i haven't had a broken primary spring in about 8 years...knock on wood..

How about this idea. Sounds reasonable. Has anyone else done this?
What size for the washers? Pics? Does the clutch have to be pulled to install the washers?

 

[newtrout]

How about this idea. Sounds reasonable. Has anyone else done this?
What size for the washers? Pics? Does the clutch have to be pulled to install the washers?

I'm convinced this makes a difference. You can get the glide washers from Thunder Products, and no, you don't have to pull the clutch.

I just took a little material (with a small carbide tip die grinder) out of the spring cup on both the cover and the spider to gain some clearance, then I added glide washers. After my first ride with a brand new spring, there is almost no visible wear on the spring. Previously, there was major wear on the outside of the coils on top and bottom after one or two rides on a new spring.

 

[Sunridge Sledhead]

Here's mine, 162" 2010 with 700 miles

Bingo! Mine too....same mileage! Couldn't hold R's over 7400 on a climb, so started checking and found it. The glide washer idea makes a ton of sense.

 

[Shift_Fast]

Another spring you can go to is the AC yellow/white. It has a slightly lower engagement and almost the same top end.

How much lower engagement? I have the stocker in on my 10 M8 right now and have a yellow/white sitting on the workbench. Right now it seems like it engages at about 4500rpm and when it does its very hard. Would like to find something that engages around 3800 or 4000 and not so hard.

Also, what tools are needed to change out the primary spring? Do I need a clutch compression tool?

 

[Coldfinger]

Just replaced a broken spring in my 2010 M8 w/550 miles. It broke sometime between 400-550mi.

Easy replacement.

Turn off key and kill switch. (safety measures)

Just remove (slowly & evenly) the driven clutch cover bolts.

Blow out clutch w/air compressor to clean out dust.

I installed the Yellow/white spring as recommended by Cat. Warranty item.
Before installation, I ground down the end of each spring just a tad to give it a little angle (took off the edge) ramp like the stocker.

If you torque the bolts, I was told 10 ft/lb (120 inch/lb) with a dab of blue loctite on each bolt.

Engagement seems to be 4300-4500 and it feels smother. I haven't been to the mtns yet to see how it holds top end but the specs indicate top end shouldn't change.

 

[Shift_Fast]

Just replaced a broken spring in my 2010 M8 w/550 miles. It broke sometime between 400-550mi.

Easy replacement.

Turn off key and kill switch. (safety measures)

Just remove (slowly & evenly) the driven clutch cover bolts.

Blow out clutch w/air compressor to clean out dust.

I installed the Yellow/white spring as recommended by Cat. Warranty item.
Before installation, I ground down the end of each spring just a tad to give it a little angle (took off the edge) ramp like the stocker.

If you torque the bolts, I was told 10 ft/lb (120 inch/lb) with a dab of blue loctite on each bolt.

Engagement seems to be 4300-4500 and it feels smother. I haven't been to the mtns yet to see how it holds top end but the specs indicate top end shouldn't change.

So you did not need a spring tool to get the cover back on?
Did you need heat up the bolts before removing them?

I am gonna try to do this myself, but dont want to get boned somewhere in the middle of the install? Also, do I have to grind down the yellow/white spring?

 

[Shift_Fast]

Thanks for the instructions. Just got it changed over to the yellow/white spring and installed the Thunder Products Glide washers also. Engagement didnt seem to change, but at least I wont have a broken spring in the future.