Tonite, I installed a new CVT belt and the stock 650i/750 secondary spring too. Here's a few things I noticed tonite...

The first thing to catch my eye about the stock 650i/750 secondary spring, which is a purple color by the way, was that it measures about 1" shorter than the stock P650 secondary spring! To me, a whole inch is a BIG difference, and I had my doubts that it would work properly on my clutch. I don't have any way to measure the 650i/750 sec spring's resistance, but I could easily tell by pressing on it with my hand that it provides MORE pressure than the my old stock P650 sec spring (which now has 500 miles on it) and my old EPI Black sec spring (which now has 1500 miles on it).

Secondly, I noticed is that my EPI Black seems to be wore out. When I first installed it on my 03 P650 about 2 years ago or more, I recall the EPI black being a tad bit longer and it had noticeably more pressure than the stock secondary P650 spring (again, I simply compared the pressure of the EPI black spring to the stock P650 sec spring by pressing on them with my hand). Tonite, I could tell that the EPI spring was very easy to press down...in fact, my EPI Black sec spring with 1500 miles seemed to me to have the SAME pressure as the stock P650 sec spring with 500 miles. Another reason I believe the EPI Black was wore out was b/c I recently switched out sec springs (EPI Black to stock P650 sec spring and back) and I didn't notice much difference in performance. When the EPI Black was brand new, it provided NOTICEABLY MORE BACKSHIFTING AFFECT whenever I let off the gas. LET THIS BE A REMINDER TO YOU FOLKS TO CHANGE OUT YOUR CLUTCH SPRINGS OCCASIONALLY B/C THEY DO WEAR OUT!!!

Thirdly, I mic'd my CVT belts and found that the new P700 belt is about .003" wider than my old P700 belt (with approx. 1,000 miles on it).

Lastly, I would have liked to give my first impressions of the stock 650i/750 sec spring, but I only had a chance to ride it up and down my street a few times. I really need to reserve my opinion of this secondary spring until after I go for a real good ride. I will say that the mid-range seemed to be a little more perky than before...but again, hard to say for sure in such a short ride. I'll report back in a week or two (after I go riding again) and let everyone know my first impressions of my current CVT springs combo (I now have both the stock 650i/750 secondary spring and stock 650i/750 primary spring installed).

Happy trails...[img]i/expressions/face-icon-small-smile.gif[/img]

 

i'm kind of surprised that the 650i doesn't have it's own springs. with it's smaller displacement, shorter stroke, and higher compression, i would have thought that the power delivery would be enough different to warrant it's own springs. i have some springs to try when i go in for maintenance, but i'd like to hook up a tachometer and do some timed runs to provide a baseline first.

monty

 

Yeah, I would've thought the 650i and 750 would have different clutch springs too. Kaw. claims on their website that the 650i has an improved clutch with better throttle response and quicker engine revs (something like that). So I initially thought they redesigned the clutches for the 650i...well, I was wrong b/c when I compared the p/ns, I discovered that the 650i has the same clutch weights and clutch sheaves (both sec and primary) as the 650SRA, P700 and BF750...the only diff. that I found was the 650i has different clutch springs than the 650SRA). Then I searched the 750 p/ns and found that the 650i and 750 share the same sec and primary springs.

If you think about it, it is also surprising that the 650i, 650SRA, P700, V-force & BF750 all share the same lift and duration specs on their cams (only difference is that the 650i, BF750 & V-force share the same cam timing...which is retarded 10 degrees as compared to the cams used on the 650SRA and P700). I would have expected the bigger v-twin motors (BF750) to have larger lift/duration than the smaller v-twins. I'm sure Kaw. designed it that way to save money (only have to make 2 cams for all these motors).

Happy trails...[img]i/expressions/face-icon-small-smile.gif[/img]

 

Good info,

 

Always an education to read your posts--KEEP IT UP---
I am also very interested in the workings of these clutches--I am presently experimenting with the Comet clutch---seeing that it is the lowly 360, I replaced the pink comet primary with the orange comet primary spring---lowered my engagement to near stock, but dont seem to have the rpm's at wot---I think I am going to drill holes in the weight arms (they seem awfully heavy for the 360, and are the ones recommended by comet for all prairies) to see if I can get my rpm's back.

Good point on the springs--my black secondary was put in over 3000 miles ago--probly worth replacin, and my belt is also the original--I am kinda thinkin that replacin these two will make quite a difference??

My question to you mikey---I still dont like what I am readin about the Dayco Belts---but the price is very appealing---do you use DAyco's???? If not, where do you purchase your belts?? ONLINE?? or do you have a connection.

 

DOA,
Thanx for the compliment and good to see you posting again...I haven't seen you post in a while.

Oleman,
I would strongly suggest you stay away from Dayco belts...I've read many bad reports of lugs breaking off or complete belt failures on the Dayco. I think the OEM belts are very reliable and worth the the extra money. I usually buy my OEM belts at ronayers.com I think I paid about $75 plus shipping for the new belt I just bought from them. You might shop around online to see if you can find a better deal...seems I've seen folks post prices as low as $65 for an OEM belt, but that was a year ago or so.

Yes, you should see at least a mile per hour more or so on the top-end if you replace the belt with a fresh one. At least, that was my experience the first time I replaced my OEM belt (that had 1,000 miles on it at the time)...I haven't checked my top-speed since putting on the this new OEM belt, so I can't confirm if I gained another 1mph with this new belt or not. Basically, a fresh (therefore wider) belt can be pushed to the outside edges of the primary clutch more, so that you have slightly taller gearing and get slightly more top-speed. And yes, definitely replace your sec spring while you are in there adjusting the shims for the new belt.

Happy trails...[img]i/expressions/face-icon-small-smile.gif[/img]