Who knows about starter clutches?

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mgdavis · #1 Unread post by **mgdavis** » Sat Dec 09, 2006 11:59 am

Apparently my starter clutch just went tango uniform. I didn't even know my starter had a clutch. Does anybody know how pricey these things are, and how hard they are to replace? The bike is a CB750, '79 model year (see sig line).

BuzZz · #2 Unread post by **BuzZz** » Sat Dec 09, 2006 10:04 pm

'Clutch' is a word that most people associate with only one type of mechanisim, but actually applies to many types of system.

On your starter it is just a device to allow the engine to spin faster than the starter can once the motor fires and speeds up, preventing the teeth from being stripped off before the starter can dis-engage... most of the time. They can get sticky and then, as you know, it's game over for the starter clutch.

Here's one I found on e-bay, just to show what it looks like....

http://cgi.ebay.com/ebaymotors/1979-Hon ... dZViewItem

Google is your friend...

honda750 · #3 Unread post by **honda750** » Sun Dec 10, 2006 5:33 am

yep...a centrifugal clutch

centrifugal force causes the gear to slide to the end of the starter shaft and then it comes in contact with the flywheel. It should be easily replaced but if you get just the gear/assembly that'll slide onto the shaft, be REALLY careful when taking out the pin that holds the gear on. It's REALLY easy to bend the shaft slightly, and tehn you have no starter at all. Make sure you have the shaft supported on something to it can't be beant AT ALL. It should be pretty darn cheap even on this old of a bike. Also, make sure you find out all the models that use this clutch b/c there are probably hundreds, and some are probably cheaper than others.

Good Luck
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mgdavis · #4 Unread post by **mgdavis** » Sun Dec 10, 2006 8:39 am

After I posted I fired up Google and started looking around. The only question I was unable to answer is: How difficult is this to replace? Does it just sit behind the starter, or is it something that requires a lot of teardown to reach? I haven't had a chance to look through my shop manual again, but the first inspection didn't give me any information on how to R&R the part.

honda750 · #5 Unread post by **honda750** » Sun Dec 10, 2006 3:44 pm

Umm...I'm not specifically farmiliar w/ this bike, but it should be right on the end of the starter when it is taken out. Just take out the starter cover and the starter should come right out and it will be easy
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mgdavis · #6 Unread post by **mgdavis** » Sun Dec 10, 2006 7:27 pm

Awesome. I was worried it would be affixed to the crank or some other PITA location. Now, to find a clutch...

CORSCO · #7 Unread post by **CORSCO** » Mon Dec 11, 2006 4:54 am

The starter clutch is on the crank. The alternator/stator rides on the starter clutch. You will need a flywheel puller to replace it.

mgdavis · #8 Unread post by **mgdavis** » Thu Dec 14, 2006 7:11 am

When I looked at my manual it appeared that I need to remove a sidecover, and then everything comes out pretty easily. IIRC, you are a bike mechanic, CORSCO. Do you speak from experience with this engine, or just generalities?

CORSCO · #9 Unread post by **CORSCO** » Sun Dec 17, 2006 10:50 am

mgdavis wrote:When I looked at my manual it appeared that I need to remove a sidecover, and then everything comes out pretty easily. IIRC, you are a bike mechanic, CORSCO. Do you speak from experience with this engine, or just generalities?

I speak from generalities. My father has an emerald green '74 CB750 but I have yet to do anything to it. I will try and remember to look it up when I go back to work on Tuesday. But I am pretty confident that it is just like I mentioned above. But, I try not to work on the old stuff, harder to make a profit

! Just remember to order a gasket if you try to tackle it yourself.

mgdavis · #10 Unread post by **mgdavis** » Tue Dec 19, 2006 7:06 am

Thanks CORSCO. I appreciate the input from someone more experienced than myself. I forgot to check my manual so thanks for checking yours.