Topic: 750 Clutch Strength?

[Loudpipe]

The clutch on my 750F doesn't slip during normal riding or acceleration, but when I get on the throttle hard, mainly from relatively low RPMs in the first couple gears, it slips pretty badly. The revs will shoot up until I release the throttle some, and then they'll come back in line with the speed.  Is this normal, or do I have a worn clutch on my hands? How hard is it to replace the clutch?

[ofreen]

It ain't normal.  Does the clutch lever have the correct (or any) freeplay?  If it does, then it is likely your clutch needs servicing.

[Bob Wessner]

At the risk of starting another thread that mentions 'oil'  what kind are you using? Some additives in auto oil can cause problems in these clutches.

[eldar]

Yeah normally the 750 clutch is very tough, especially the later years. I concur with ofreen though. Adjust the clutch first.
Oh wait, did you change oil in the bike? If you did, what oil did you use? If you didnt, ask the guy you bought it from, what he last used.
Many oils today have moly or say energy conserving. These oils will in almost all cases, make the clutch slip.
Most 10-30 oils are like this. Get at least a 10-40, I have not seen any of these with moly. Many of us you rotella T which is made for diesel engines and it works very well. It is 15-40 or 20-40. cant remember which for sure.

Darn it bob!!

[Bob Wessner]

Darn it bob!! 

Sorry, I'll go now. 

[eldar]

I was typing it as you posted it!!

[Loudpipe]

I have no idea what kind of oil is in it, I just know it's probably about 3 years old, but with only a few thousand miles on it. the whole bike only has 15,700 miles on it, so it couldnt be super worn...right?

ofreen (or anyone else), describe "freeplay." Forgive me...I'm new to this two wheeled thing.

[eldar]

Freeplay is the distance you can move the lever before the clutch(or whatever part) starts to move. If you do not have freeplay, your clutch may not be completely dis-engaging.

Your oil MUST be changed. 3 years causes oil to oxidize and it will not protect right.
replace the filter too. I do recommend trying the rotella, however get whatever oil you can just make sure it is 10-40 minimum and does NOT say energy conserving on the back of the container, or have friction reducing additives such as LOTS of moly.

Dont waste your cash on motorcycle specific oil though.

[Big Jay]

We have a clutch kit for the 750 that has two more friction plates than stock. It is a direct bolt in. You will not slip this clutch.

http://cbrzone.com/clutches.html

Jay

[Sam Green Racing]

Hows your new shop doing Jay ?

Sam.

[MRieck]

We have a clutch kit for the 750 that has two more friction plates than stock. It is a direct bolt in. You will not slip this clutch.

http://cbrzone.com/clutches.html

Jay

The big problem I've found with the extra plates is it's tough to find nuetral because of the extra stack height. I've always used Barnett springs with the OEM plates

[eurban]

I'm using the APE extra plate clutch package in my 78K with an 836 big bore kit.  Just as MReick mentions I cannot for the life of me find neutral with the engine running (idle speed @ 1000rpms, clutch adjusted.)  Not really a big deal for the most part.  The other issue I had with this kit is that it did not directly fit my stock 78 clutch package which has the extra thick center plate that Honda installed on the late bikes to help eliminate the clutch racket at idle/nuetral.  I had to dump the thick plate and source an extra regular thickness plate to make it work. It ratttles quite loudly now.  No slipping now though.

[MRieck]

I'm using the APE extra plate clutch package in my 78K with an 836 big bore kit.  Just as MReick mentions I cannot for the life of me find neutral with the engine running (idle speed @ 1000rpms, clutch adjusted.)  Not really a big deal for the most part.  The other issue I had with this kit is that it did not directly fit my stock 78 clutch package which has the extra thick center plate that Honda installed on the late bikes to help eliminate the clutch racket at idle/nuetral.  I had to dump the thick plate and source an extra regular thickness plate to make it work. It ratttles quite loudly now.  No slipping now though.

I know the early F's, and later F's and K's if I remember correctly, have the last fiber plate with the larger width metal tabs. Another monkey in the wrench.

[Loudpipe]

Could the old oil be causing the clutch to slip? I think it's adjusted correctly. The clutch handle with move in just a bit before it starts to disengage, and must be let out a bit before it starts to engage.  I've got an oil filter on order from Autozone, which will be here in 2 days, so I'll change the oil then. I'll be out of town until it comes in anyway, so I won't be riding on old oil.

[eldar]

It could. The oil could not be penetrating the plates correctly and sludge could have built up. I have to ask though, why did you order an oil filter? Honda still stocks them and if nothing else, you can get the cartridge filter, the standard style, from walmart too. They have worked good for me.

[Loudpipe]

Oh...I just figured I'd have to order it.  A few years of owning an old British car and I've gotten used to having to order everything!

[nuke]

I've posted this in another thread on "has anybody used car oil for bike.." with no response so I try here.

Well I put Castrol GTX in my last oil change and the clutch is now slipping....lots. Didn't before. I read some threads on the subject, and a common response to these inquiries was not to use Molybdenum or energy conserving. AFTER the oil change, I read the container on the GTX and it did have the energy conserving logo. Could this be the problem?  If so how come so many of you are using the GTX with no problems? Are my clutch plates ruined by this or can I recover them by switching back. All these oil threads confuse me more than anything.      

nuke

p.s. I live in the Toronto area and its getting a little cold-er. to what effect does this effect clutch

[joeson]

My 78 750 started slipping due to cruddy cable,it did not let the spring return fully,pull the cover and check for proper operation, lube or replace the cable if adjustments at either end arn't satisfactory.I use castrol gtx 10w40 all goodthru all rpms

[Loudpipe]

That's a good call Joeson. I'll check that when I get home this afternoon. I hadn't considered the possibility of a sticking cable.

[eldar]

A sticking calbe is usually associated with very hard pull.

When checking to see if oil says energy conserving, look on the back. There is a label there that will say it. I think it is present in all 10-30 weight oils now.
You should use 10-40 anyways as a minimum. I dont think any 10-40 oils are energy conserving.

[nuke]

so if the energy conserving oil DID cause the slippage, will using 10-40 bring it back to normal or are the plates now saturated or to far gone to use again.

nuke

[Loudpipe]

Ok, I changed my oil and went on a short ride tonight (4 miles). At first it was still slipping like before, but it gradually got a little better. When I came home it was still slipping in 2nd and 3rd gears if I gave 3/4+ throttle from around 3000 rpms. Shortly after giving it throttle, the torque would overwhelm the clutch and rev up to 5000+ rpms and hold as the bike accelerated and came back into synch. Do you all suspect they're just not totally clean, or that after that distance the new oil should have done it's work?

Other than that, I'm pleased with the Rotella T. I ended up getting 15W-40. It quited up the clutch chatter and valvetrain, and the bike quit smoking...although I think that could have been because I added too much oil last time.

[eldar]

Well the old oil and sludge does need to be cleaned out Ride for 10 miles to get things nice and hot and that should help quite a bit.

In most cases, using the right oil will bring things back but depending on how long the wrong oil was used or how long it sat, it may require pulling the clutch apart to clean by hand. But if you just put in the wrong stuff, a thorough drain and refill will good stuff should take care of things prett quick.