Question for the cat guys...

[jimfsr]

Ok, Got the boy's custom built 1998 Jag 340 done and a few miles on her. The motor is all stock. Revs out to about 6500, but I need to get about 7000 out of it. What are the procedures for rpm changes on the cat clutch system. The doo's are easy, just turn the bolts in the primary, The comet type do not have this feature, so what to do?

 

[indy_500]

Is the secondary on this roller style or button style?

 

[jimfsr]

button style secondary.

 

[indy_500]

You could move the secondary spring into the different slots, there should be 5 of them. Couldn't tell you which way increases max rpm though. Also could try stiffer primary spring. Wouldn't lighter weights also make it max out at a higher rpm?

 

[arcticman]

Moving the spring will increase rpm.

 

[scott_l]

Ok, Got the boy's custom built 1998 Jag 340 done and a few miles on her. The motor is all stock. Revs out to about 6500, but I need to get about 7000 out of it. What are the procedures for rpm changes on the cat clutch system. The doo's are easy, just turn the bolts in the primary, The comet type do not have this feature, so what to do?

ok double education for me on this one! Why do you "need" 7000 rpms?

good luck

 

[snowfish]

Should have no problem tweaking an extra 500+rpm by changing the secondary's spring hole.

Use a Sharpy Pen to mark the sheaves so they go back on at the same "twist". Tighter secondary spring will raise you rpms. If the secondary has been apart, by someone other than you, it may be off by 1/4 -1/2 turn.

Setting for 7000-7200rpm's max will give the best power, through out the shifting range, for this particular engine.

 

[jimfsr]

Thats what I was thinking for rpm. I moved the spring one hole and it didn't make any rpm difference. I will try the next(last)hole available. If I cannot achieve the target rpm, I suppose a different spring? Odd that it should be anything other than the stock settings, but who knows. My son could care less, but I need it to be the best it can be. Thanks for the info. I posted some pix in another thread. JIm

 

[snowfish]

Are you pre-loading the spring before engaging the mounting holes? Manual says 120 degrees, so a little better that 1/4 turn pre-load.

RPM's should change with the different holes. I'd be willing to bet no change with out the spring pre-loaded.

A New spring never hurts. However I saw minimal shifting difference when I changed the original springs on my ZRT600. Nicer? Yes! Night & Day? No.

 

[jimfsr]

I did a little research... the clutch is engaging at about 2500 rpm, way too low. The book says about 3500-4000. So I checked the spring and weights, all are stock. I think the clutch is just loading the engine too soon, looks like its time to try a few heavier springs.

And yes, there is prewind on the spring at installation in the secondary.

 

[jprdave]

Lighter weights in the primary will have more effect on max RPM. Have fun, clutching can be sooo much fun!!