79 440 exciter clutching

I have a 79 440 ex and it is the worst clutched sled i have ever rode. I plan on getting a new comet 102c with the oil pump gear so i can tune the clutch. Is there a better secondary that fit this jack shaft? the spring isn't very adjustable and I don't think there are different helixes available for this sled.

If you aren't happy with it the stock clutches they are worn and/or have been changed from stock. Comets won't perform any better, last any longer or have more tunability than OEM. Your choice on what you run is nothing more than that, your choice. There were a few different helixes made by Yamaha for that style of secondary as it was used on many different models including the factory race SRX 340/440's. For more options guys are also useing the later style secondary helixes as used on SRV's, Phasers etc. Requires a little machining at the snap ring face to allow it to fit. Needs are obvious with a side by side comparison.

opsled

I heard you can't get parts for the primary clutches , thats why I wanted to go comet for the parts availability. The sled engages at 2500 rpm , starts to shift at 7300 and by 50mph it starts to to pull down to 6900-7000 where it was holding but I didn't have room to get over 65 mph

like OP said nothing wrong with the SRX/EX primary .....or secondary for that matter ....you are dealing with one of the most tuneable clutches even by today's standards just have to have the knowledge .............you heard parts are hard to come by ....walk into you dealer and order up what you need aside from weights and springs you can get it all yet ..............my overall guess is that your clutch has been neglected like so many i have seen and is in need of a full rebuild .....

OP knows that i run these clutch's yet on all my racers stock to full mod aside from a few with full polaris set up on them there is nothing better .......

now for the comet ....go ahead and put one on it will work but not last long unless taken care of .....me personally i have a few comets for testing purposes on the shelf but honestly they are better off in the garbage with how they are built

how did you get a polaris secondary on a yamaha ? I want a clutches that are tunable.

bought a jackshaft conversion for Micro Belmont $235 i think it was for the kit ......

like i said the stock clutch's are very tunable more so than polaris many springs and a few helix's ..........you do not tune with your seconday you tune with the primary and with all the adjustments on a yamaha primary ....anything is possible

I have rivets that go in my 01 SX700r clutch weights , do this use rivets to change weight too ?

yes rivets are the same ones used in the late model sleds .....more so your issue is that the stock exciter spring for 79 is just too weak for what i guess your are looking for springs from the srx/ex primaries and and 80's ypz clutchs all fit you can also make teh polaris and comet springs work by grinding the inside of the spring out to a bigger diameter

if its comet you want go ahead and get that primary but unless you really want to spend some money stick with the stock secondary, clean it good, grease the moveable sheave bushing and put a polaris secondary spring in it. nothing wrong with that clutch.