Let's talk clutch springs

[scott s]

Last year, when I got my '75/'78 combo bike running (1978 engine/carbs with '75 sheet metal), the clutch slipped badly.

I measured the discs and friction plates and, while showing some wear, were within spec.
I had several sets of springs, including some unknown springs with a dab of blue paint and some new, unopened Barnett Racing springs, plus some stock springs.

I measured a stack of discs and picked the best ones and installed new friction plates, too.
I forget the measurements on the springs, but I went with three "blue" springs (thinking they were stock) and three Barnett springs. Well...It turns out the "blue" springs weren't stock and I ended up the three heavy duty springs and three "HOLY SH!T, that's heavy duty!" springs.
It is nearly impossible to slip the clutch now, even when I need to.

I was circling the cul-de-sac in my neighborhood, first gear, riding the rear brake and trying to slip the clutch to make a tight turn. The clutch finally engaged and the bike lurched. I damn near took out a mail box!

I KNOW the adjustment is correct, so don't even go there. It's definitely the springs. I'd like to just go back to stock, but I'm leery of the used springs I took out. I can measure the height, but that doesn't tell me much about the spring pressure.

Are Mikes stock springs any good? I know he's had some quality issues lately. Where's a good source for good, stock clutch spring?

 

[5twins]

I wouldn't recommend any stock springs or the MikesXS HD ones either. I have a set from Mike's and while they're still working OK, I measured them a few thousand miles after install and they had already sagged a couple MMs. I feel it's only a matter of time before they're no good anymore. They're nothing special, I think they were that Parts Plus brand, sort of a generic replacement parts line. Call 3M at 650Central. He carries several different sets in varying degrees of stiffness. They're all well known brand names and will serve you much better than the crap ones from Mike's.

In the mean time, You might try 3 stockers and 3 HD ones. That will make it stiff enough so it won't slip but won't take King Kong to pull the lever, lol.

 

[oldbiker]

hi guys ,,,i,ve got my clutch in bits ,,,,, and i measured the clutch springs ,,,in the manual it states 34.6mm..... length,,,, mine are 41mm ,,,and they have been there about 11yrears since i purchased the xs650 ..... is the measurement correct ... i am going to get new friction plates as they are about3.1-3.2mm thick .... open to suggestions regards oldbiker

 

[5twins]

41mm means they're probably aftermarket springs. Your plates are in spec or better (spec is 3mm new, 2.7mm wear limit) for the later models.

 

[XSLeo]

I might try all the blue springs. One thing you can do is take them to a machine shop and have them measure the strength of the springs at a the installed height. I had measured it once and if I recall right it was about 1.125 inches.
I replaced my springs with a set of Kibble White 70 lb springs. No slip and still pulls easy. I think the stock springs are about 50 lbs.

 

[5twins]

Where did you get the Kibble White springs? I don't think I ever heard of those before.

 

[XSLeo]

I got them on Ebay. Around $20 for the set. I'll try to find my reciept. I have it in a folder some where. I think it's in one at my yahoo mail.
I think they were built by the same folks who build the valve guides. Not sure on that. The package my still be around some where. It was a plastic bag with a paper folded over the top that had Kibble White printed on it with XS650 and 70 lbs stamped on it. Maybe TX/XS 650.
I found the reciept for the Forodo clutch plates, I got the springs about the same time. 11/4/10 was the date on the clutch plates.

 

[XSLeo]

Looked all over the place. Can't find the reciept.
Just had a thought, I went on Ebay and searched Kibble White clutch springs. Came up with one set. They are for a 68-E84 Harley Shovelhead. Item #360355809072 They are red just like the ones I got. Set of 10 $35.95
The ad says made by Kibble White Precision Machining.
I just put Kibble White valve guides in the search. It came up with lots of guides. The ones they show are packaged like the springs I got. They are made by the same maker. Kibble White Precision Machining.

 

[XSLeo]

I searched Kibble White Precision Machining, they just make valve train parts now.

 

[5twins]

I Googled them as well. Seems they do mostly Harley stuff now. Sounds like you got lucky finding that set on eBay. They probably haven't made 650 stuff for several years now.

 

[grepper]

Well, after upgrading to a 750 kit and vm36 carbs I found that the clutch on my bobber couldn't keep up when I went full throttle at ~5K rpms. Theoretically the bike should take off because that's where the serious power is. The clutch just slipped (unless I went easy on the throttle).
My plates were still to spec, so I upgraded to FERODO clutch springs from 650Central. Last night I went for a test ride.. Zooming down a country road at 50mph, hit it hard and nearly slid off my seat, looked down and I was going 85 Yup, fixed my slippage problem

 

[scabber]

After I got my shell camed 750 running with mikes springs old clutches I had all kinds of clutch slipping called M M at 650 central he recommened the ferodo springs an new clutch discs. He said 30 year old clutch discs dont get it, mine were to factory specs. I bought the ferodo clutches and springs. No more clutch problems

 

[XSLeo]

When I first saw the Springs and the seller said they were Kibble White springs I thought that they would be good quality springs. They sure work good. With them and the Forodo plates it's great.
Thanks to Scabber on that. He's the one to reccomend them and gave me the place to get them at a good price. As I recall about $45 + $12 for shipping.
When I first got the 750 kit in and running I did clean up the steel and friction plates. It worked for awhile before it started slipping. I could just clean upthr fiber platres every couple hundred miles but the new plates was a lot less work.

 

[scabber]

Glad to help Leo. I was wondering how that old clutch was holding that 750 power. Are you still running that 30 and toping out at 130 ? 650 central sells heaver springs witch I was going to buy.I told MM what I was running and went with his advice on the ferodos. He Knows what works. Try the 32 the 118 mutch safer Qucker off the corners.

 

[XSLeo]

I'm still running the 17/30 set. I'm going to go back to the drum brake spoked wheel. I'll swap the sprockets then. The 32 on with the 18 inch rear tire should put it about what the 16 tire and a 31 tooth would be.
It don't run quite as stgrong as yours. The stock cam keeps it down just a bit. The on/off throttle isn't guite as noticable with the stock cam.