Bad Clutch Shudder

Message

RZResurection · #1 Post by **RZResurection** » Sat Aug 22, 2015 11:24 am

I have some rude clutch shudder when I launch hard.

I rebuilt the clutch and basket last winter. Brand new FZ600/1000 fibers and new dampers (urethane pucks)

I have a 180 back tire with a 39T sprocket. My feeling is that I need some more torque to move that big back tire. Maybe a bigger rear sprocket with a few more teeth on it might do the trick.

Note: The clutch does not slip

TIA

MK · #2 Post by MK » Sat Aug 22, 2015 2:25 pm

Did you check the clutch main bearing ?
I recently had two engines where that big roller bearing behind the clutch had excessive play.
Both had clutch operation issues as one of the symptoms.
And funnily both had pretty new baskets with straight cut primaries.

T.RexRacing · #3 Post by **T.RexRacing** » Sat Aug 22, 2015 2:33 pm

Why a 180? I run a 180 on my 1000CC Aprilia Tuono.

RZResurection · #4 Post by **RZResurection** » Sat Aug 22, 2015 3:22 pm

T.RexRacing wrote:Why a 180? I run a 180 on my 1000CC Aprilia Tuono.

It was an exercise to prove to myself I could.

I realize there is no real benefit to it.

RZResurection · #5 Post by **RZResurection** » Sat Aug 22, 2015 3:25 pm

MK wrote:Did you check the clutch main bearing ?
I recently had two engines where that big roller bearing behind the clutch had excessive play.
Both had clutch operation issues as one of the symptoms.
And funnily both had pretty new baskets with straight cut primaries.

I didn't change that bearing out, but it didn't seem that bad either when i had the transmission apart. I'll check it next time I have it apart.

silverstrom · #6 Post by **silverstrom** » Sat Aug 22, 2015 9:25 pm

Excessive chain slack will come across just like a wonky clutch. Worth looking at the chain, sprockets, and alignment. Also worth verifying the cush drive has no play.

16/40 or 16/41 gearing would be my choice. I run a 45 rear on my RZ500, so I'm just a little odd anyway

RZResurection · #7 Post by **RZResurection** » Sat Aug 22, 2015 9:28 pm

silverstrom wrote:Excessive chain slack will come across just like a wonky clutch. Worth looking at the chain, sprockets, and alignment. Also worth verifying the cush drive has no play.

16/40 or 16/41 gearing would be my choice. I run a 45 rear on my RZ500, so I'm just a little odd anyway

Yeah, I do believe I have to go up a few teeth on the rear. I think ill go the 41 tooth route.

Cush rubbers looked to be in good condition

Odd is ok as long it works for you. Lol

RZResurection · #8 Post by **RZResurection** » Mon Aug 24, 2015 1:52 am

silverstrom wrote:Excessive chain slack will come across just like a wonky clutch. Worth looking at the chain, sprockets, and alignment. Also worth verifying the cush drive has no play.

16/40 or 16/41 gearing would be my choice. I run a 45 rear on my RZ500, so I'm just a little odd anyway

What happened to your last post? Didn't get a chance to reply.

Your a lot less odd in person lol

silverstrom · #9 Post by **silverstrom** » Mon Aug 24, 2015 4:16 am

RZResurection wrote:
silverstrom wrote:Excessive chain slack will come across just like a wonky clutch. Worth looking at the chain, sprockets, and alignment. Also worth verifying the cush drive has no play.

16/40 or 16/41 gearing would be my choice. I run a 45 rear on my RZ500, so I'm just a little odd anyway
What happened to your last post? Didn't get a chance to reply.

Your a lot less odd in person lol

Lol...I went back and read it and it didn't seem as funny the 2nd time so I deleted it.

RZResurection · #10 Post by **RZResurection** » Mon Aug 24, 2015 11:31 am

I thought about this more. I have a 17T front sprocket. What I remember from the gear calculators: 1 up on the front equals approx 3 on the rear.

I'm guessing that I should go up to the 45.

T.RexRacing · #11 Post by **T.RexRacing** » Mon Aug 24, 2015 12:52 pm

The only time my RZ clutch "shuddered" it had 3 broken fiber plates.

RZResurection · #12 Post by **RZResurection** » Mon Aug 24, 2015 1:25 pm

There are no broken fiber plates. All (virtually) brand new FZ plates.

I just had the clutch apart the other day - all good.

RZResurection · #13 Post by **RZResurection** » Mon Aug 24, 2015 1:56 pm

Just for comparison:

17/39 = 2.29 (current)
16/41= 2.56 (suggested)
17/43= 2.53
17/44= 2.59 (more or less equivalent)
17/45= 2.65

MK · #14 Post by MK » Mon Aug 24, 2015 2:15 pm

Usually when using 17 inch wheels you have to gear up quite a lot due to the different tire radius.
A 160/60-17 is much smaller than a 110/80 or 120/80-18.

In my 17 inch RGV conversions something like 19 / 43 is pretty equal to the stock 17 / 39 with 18 inch. With a larger 180 tire it'll be slightly different maybe 19 / 45 or so.

A good calibration point is 120 kmh in 6'th gear. Stock bikes have 6000 rpm at that point.
If you have less, then your gearing is taller. If you have more, then its shorter.

T.RexRacing · #15 Post by **T.RexRacing** » Mon Aug 24, 2015 2:53 pm

180/55-17 Circumference-1903MM Pirelli Diablo II
120/80-18 Circumference-1960MM Pirelli Sport Demon

Gearing Commander is a good way to determine the effects of changing wheel/tire size on gearing.

RZ/RD 350 & Misc. 2-Stroke Tech BBS