Clutch engaging late

Discussion in 'Mechanics Garage' started by saszta, Jul 24, 2010.

  1. saszta

    saszta New Member

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    '91 VFR 40,000kms

    Hi guys. It seems that a common problem is the clutch engaging late in the lever travel. I've read a sh*t load of posts about the topic and sticking pushrod, worn plates/disks, leaky slave cylinder all seem to be possible culprits.

    If I understand the clutch engagement/disengagement mechanics correctly, air in the system would cause the opposite effect - clutch engaging early or very close to the bars, or not even completely disengaging.

    I've flushed the lines, cleaned and lubed the pushrod, cleaned out the MC (polished the bore) did the same with the slave, bled the system (banjo bolts etc), changed the judder spring, metal plates, friction plates and pressure plate springs (all oem except for kevlar disks).

    Symptoms still persist. Now I've ordered the seals and the spring for the slave cylinder in hopes that this may be the problem but I would think that if the seals are leaking on the slave then the clutch would have trouble disengaging rather than late engagement at the lever.

    By the way, I've adjusted the lever as close to the bar as possible, helps a little. The clutch slip zone is very small too - on or off. Once engaged the clutch does not slip at all.

    Any thoughts besides the slave being the culprit?


    Thanks.
     
    Last edited: Jul 24, 2010
  2. nbogert

    nbogert New Member

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    I too have a 91 VFR, a 750. I too have read quite a bit about this problem. I personally haven't experienced it..yet..god I hope not lol. I can offer some knowledge that may be a stretch, but could help with trouble shooting. How old are the clutch friction plates? Is the clutch slipping? Here is the stretch...what is the manufacturer of the friction plates installed recently? Do you use full synthetic oil? I ask these questions because I know for sure that EBC says they don't recommend their kevlar plates for use in full synthetic oil. They say it slips and doesn't work properly. Why? I don't know, but a service man pointed it out to me when I was purchasing a new set for my bike. He too has no clue why, but I read it too. I know this to be a fact because a friend had installed them in his older CBR and had the exact same symptoms you are describing. Could be a stretch...or could be the culprit. Hope this helps.
     
  3. saszta

    saszta New Member

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    Nope, not using synthetic oil. Not a slipping problem at all. In fact it's the opposite. The clutch doesn't slip enough. What I mean by this is that the clutch is supposed to have a zone of slippage while it is engaging/disengaging. This zone is very small in this case and when letting out the lever the clutch abruptly engages only at the end of lever travel.

    Using regular GN4 10W40 honda oil. Oil level is correct and so is clutch fluid level. We;ll see what happens when I rebuild the slave cylinder next week. I'll post results.

    Any further guesses are welcome...
     
  4. donald branscom

    donald branscom New Member

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    NOT a guess.
    Synthetic oil does not cause a wet clutch to slip.
    Oil with "ENERGY SAVING" friction modifier additives WILL cause your clutch to slip.
    (Cars have dry clutches.)
    You did not tell us how many miles are on the bike.
    You cannot adjust a clutch . You can only adjust when it engages.
    First check your fluid level.
    second make sure the slave cylinder has been bled, and is not leaking.
    Many times a clutch that engages at the end of the travel of the lever ( if all else is good),
    can mean the clutch plates are getting thinner and in need of replacement.
    We would need to know how many miles on the motorcycle, and the model.
    One more thing....weak clutch springs can cause this symptom.
    But again, we do not know how many miles are on the bike.
     
  5. saszta

    saszta New Member

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    It's at the top of my original post: '91VFR 40,000kms (that's about 25,000miles)

    Please read my responses - it's not a slippage problem.
     
  6. donald branscom

    donald branscom New Member

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    Yes I under stood that.
    I was just responding to the oil statement.
    I wanted to cover all the bases.

    Mileage???
     
  7. saszta

    saszta New Member

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    Can you clarify what you mean by mileage? Clutch disks and friction plates have all just been changed if that's what you're referring to.
     
  8. tris1948

    tris1948 New Member

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  9. tris1948

    tris1948 New Member

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  10. donald branscom

    donald branscom New Member

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    I mean how many miles on the motorcycle???
     
  11. donald branscom

    donald branscom New Member

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    Now we are getting somewhere.
    You have just changed the friction discs in the clutch.
    Is that when the problem started????

    Also I can assure you that the push rod would not be affected by that small amount of corrosion that was mentioned. The pushrod has hundreds of pounds of pressure on it.
    The push rod goes through 3 different pieces of the engine case.

    BTW were those stock clutch friction discs, or high performance disks??
     
  12. saszta

    saszta New Member

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    Ya, good point about the pushrod - my thoughts as well.
    I just bought the bike and the clutch was like this from the start. It was a little worse though. So I figured the plates were worn, although it never slipped. I ordered the kevlar friction disks and Honda oem springs and metal plates. The old friction disks were a little worn but still within service limit and the metal plates were slightly worn with some glazing and two of them were very lightly warped. In any case, as I mentioned above, I changed it all out, disassembled/cleaned the master and slave, bled the system and it is better but engagement still seems too far out from the bar at the end of lever release.
    I may just not be used to these bikes, but I did ride a 2008 recently and the clutch started to engage after letting out the lever 1/4 length of its travel. To me that makes more sense.
     
  13. donald branscom

    donald branscom New Member

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    If you had ANY warpage of the metal disks, they have to be replaced, or it will not work correctly. Lay them on a glass plate and if you can put a .001 thickness gage or larger under the edge -change them.
    You have a mixture of Honda OEM parts and high performance parts. This can cause tolerance stack up. That means if each plate is .001-.002 difference and you add all of those thickness differences up then it could make a .005 something difference and then the pushrod will have to push further or not as far.
    So if all the metal plates are good and all the friction disks are new, and the system is bled it is what it is.
    To bleed it fully sometimes it is best to bleed it at the master cylinder instead of at the clutch slave cylinder.
    You can do that by just loosening the clutch hydraulic line at the clutch master cylinder on the handlebar.
    The reason is that bubbles like going up hill, NOT downwards and out the bleed screw at the clutch slave cylinder.

    One more thing....
    Since you have the kevlar friction plates and not the standard ones, it is common to get a different feel at the handlebar. and most high performance clutches DO HAVE a feeling of "its in gear or out" and not as progressive like stock plates.
    As long as the clutch works it is ok. It will not feel like it did when it was stock plates if you have high performance clutch friction discs.
     
  14. donald branscom

    donald branscom New Member

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    About clutch disengagement....

    If you pull in the clutch lever while it is in gear, and the bike does not want to creep forward then it is fully disengaged. There is not a problem.
     
  15. saszta

    saszta New Member

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    Thanks for your thoughts.
    Ya, there's no creep, clutch is engaging and disengaging and not slipping so it is doing its job. Just a little strange that the point of engagement is so far out from the bar. Could be the kevlar disks as you say, but I have my doubts. The thickness is the same as per service manual (~0.0119)
     
  16. ridervfr

    ridervfr Member

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    I have a 91 that I replaced the clutch friction plates, steal plates and springs with stock honda replacements after 70,000 miles. I had two issues in the 15 years I have owned my bike. Once the return in the clutch master was clogged, kinda like a hard lever. I stripped a wire and used the thin copper to clear it. It worked and the fluid shot up like a jet. Have water near by as it neutralizes brake fluid. Second issue I had recently, I did a full bleed at the banjo on the clutch master added fluid then bled off the slave. When I did this some goopy looking fluid came out and I suddenly got a nice lever again. Prior to doing the banjo deal I wasnt getting a nice lever. This bike dirtys clutch fluid fast. Change it often when it gets dark. I like the cable clutches over the ones we got but what can you do. Cheers, ride fast and take chances...
     
  17. donald branscom

    donald branscom New Member

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    That would have to be .119 or else it is eleven thousandths. -.119 is a little less than 1/8 inch.

    About clutches operated by cable rather than hydraulics.... I agree. much simpler.
    For the young guys operating sport bikes a cable operated clutch should not be a problem.
     
  18. saszta

    saszta New Member

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    Well turns out that rebuilding the slave cylinder had no noticeable effect. I hadn't noticed any leaks at the slave so it's not surprising. Not a bad thing to do anyway since the bike is a '91.
    So, I went to get an 'expert opinion' at Honda yesterday and what do you know but it turns out my clutch lever is bent. I thought it was a little curved but wasn't sure if that just how it was designed. Tech said no way, that lever should be much straighter and bike must have been dropped by prev owner. He suggested to pull the clutch in with two first fingers instead of whole hand - guess what? It feels fine when using it like that. So I can change the lever for a new one or just use two fingers and in fact I think I like using only two fingers on it. The engagement is in the right place for that and since the lever is bent outwards it doesn't squeeze into my last two fingers that are still wrapped around the bar. So, there you have it - problem solved. I guess the combination of the multiple factors of worn clutch plates, discs, springs old fluid and a bent lever combined to make for a bad clutch feel. Although the parts were not worn beyond service limit it was enough with the bent lever to have it feel bad.
     
  19. donald branscom

    donald branscom New Member

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    Glad you got a solution.
    Well I guess that is why photos are important. We might have seen that.
    Many owners of the same bike may have noticed.
    I have always pulled the clutch lever in with two fingers.
     
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