Possible clutch problems?

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Sep 24, 2017
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Hi. The other night I was riding home and I got to a fairly steep hill. I was doing around 100km/h and around 3000RPM. With no one else around I wanted to see what the power of the bike was like, so I quickly accelerated. The RPM quickly went up to 7000 but there was only a slow gradual increase in speed. I was going uphill at the time, so I was just wondering whether this was a built-in clutch safety feature to prevent clutch damage with a heavy bike. My big fear is that the clutch needs replacing, however the bike has only done just over 22,000kms. Any ideas?
 
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I would try bleeding the clutch. My 07 will soon roll 99000km and had clutch problem 20000km ago. I did a clutch bleed and the problem went away

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dduelin

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The OP described a slipping clutch. The plates should not be worn out at the mileage but the problem is there. Perhaps an oil was used that contained friction modifiers that ruined the clutch plates. I'd try an oil change to an oil that displays JASO MA certification without a doubt.
 

mlheck

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The OP described a slipping clutch. The plates should not be worn out at the mileage but the problem is there. Perhaps an oil was used that contained friction modifiers that ruined the clutch plates. I'd try an oil change to an oil that displays JASO MA certification without a doubt.
+1 on changing to a correct oil first.

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STumped

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+3 on the friction modifiers in non-motorcycle oil. Most 10w40 or higher weights do not have friction modifiers and will not cause problems with wet clutches. However, most oils of 10w30 or lighter weights do contain them and will cause slippage of a wet clutch. FWI, it doesn't even have to be heavy powerful bikes. I have personally ridden little 250's and even 125's that had 10w30 oil with friction modifiers and their clutches slipped a lot! Even with only 5-10 horsepower on tap! LOL

hat20271, definitely NOT normal behavior. If the bike is new to you, there is no way of knowing what the previous owner used for oil. Change the oil (and filter) and see if it gets better. If not, worst case would be that you have to change out the clutch plates. :/

Let us know how it goes.
 
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Note that it can take a while for the clutch plates to return to normal after a dousing in the friction modifiers in modern oils. It might take an oil change or two to get the slip out of the clutch.
 

jfheath

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Sorry to hear about your clutch slip.

The incorrect oil is a definite probable cause, and if the previous owner didn't know that there is a difference between the typical car dry clutch and the typical motorcycle wet clutch - the wrong oil could easily have been put into the engine.

However, there is another possibility which is easy to check. The clutch lever acts on a short push rod which pushes on the piston of the clutch master cylinder. At the lever, the rod pushes against the obvious cylindrical brass bush which sits partly under the handlebar bracket. What isn't obvious is that the brass bush has a blind hole in it - which is drilled part way through the bush. It is shown in the diagram, but is facing the wrong way. The end of the push rod MUST sit inside this hole when the clutch lever is replaced. If it doesn't, then the clutch will always be partially depressed. As the engine heats up, the clutch fluid expands and presses the clutch in a little further, causing the clutch to slip.

How long does it take to do this ? Well I know for certain that on a brand new bike, with zero miles on it, the clutch will start to slip after 7 miles and leave you stranded with no drive at all after 10 miles.
If the experts that assembled my bike can make a mistake like this, anyone can !

On an older bike there is more wear in the clutch plates and a probably a little air in the fluid. The onset of the slip might not be as rapid as this.

Remove the nut under the clutch lever, unscrew the bolt, and ease the lever out of the bracket, checking how the pushrod is seated, and where the hole is.
You could mark the circular end of the brass bush to indicate where the hole is before reassembling.
 

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OP
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OK gentlemen, an update.

Today I rode from Nowra to Wollongong (in Australia, about 70-80kms). As soon as I reached the first attempt to overtake some cars, clutch slipped. This continued to happen on every hill, so I had to nurse it gently up hills. I took it to a bike shop and the tech got on, started it up, put it in gear, held the front brake and proceeded to rev the throttle and let the clutch out.

The back wheel didn't move. At all. And the engine sounded like it should be.

So with that, there were two options:

1) change the oil and hope that was the problem, or
2) replace the clutch (for an estimated price of just below $2000 due to having to remove the whole engine to do it).

I chose the former. Changed the oil and took it for a ride. A marginal improvement, but overall the slippage is still there. I expected that it may not be a quick fix, so I'm going to keep riding it (but around flat streets rather than hills). I'll keep an eye on it for the next few weeks and at the sign that it starts getting worse I'll have no option than to change the clutch.

It sucks, but that's the story so far. :/
 

Blrfl

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Give the new oil some time. As mentioned earlier, it takes time and a change or two to get all of the slippery stuff out of the clutch pack.

And don't go anywhere near that shop again. Despite what the service manual says, replacing the clutch doesn't require removing the engine.

--Mark
 

dduelin

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Yes, the engine does not have to be removed to replace the clutch. One of the members here posted a detailed thread on a clutch replacement.
 
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+1 on giving the oil time to work and then change again fairly soon. The first change obviously made a difference.
Good luck.
Upt'North.
 
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Look in the articles section, there is a nice write up with pictures on how to replace the clutch.
This job can be done in your garage with very few hand tools, and a flat metal ruler. You'll probably want to replace both the friction plates as well as the metal plates just to be safe, and also the springs.
The job only takes about an hour, however, it may take several hours to scrape the old gasket off the engine and cover.
Igofar
 
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You didn't state what kind of oil you used for the oil change. Pick up a couple gallons of HDEO (Diesel Oil) in 15w-40 weight, these oils have alot of detergent and acid neutralizers and cleaning agents that will help clean your engine faster than normal automotive or motorcycle oil, and they are quite a bit cheaper also. If you can get your hands on some Mobil Delvac 1300, Valvoline Premium Blue, or Chevron Delo 400, any of those will work.
 
OP
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OK people, another update for you!

Firstly, thank you to everyone for your invaluable advice! It's good to have a wealth of information all in the one place to reference when needed. :)

So here's what I did; I drained out all the oil and replaced it with Honda GN4 10w-30, which is the recommended oil in the manual. Took it for a ride and although it felt a little better but the slipping was still there. SO I left it overnight for the oil to settle.

Today I rode back from Wollongong to Nowra (70-80kms). It became apparent that the slipping was not only still there, it was getting worse. Riding along at 80km/h and reaching the 100km/h section, it took at least two minutes for the bike to slowly creep up to 100 through very delicate throttle movements. I ended up going through some smaller towns in order to avoid large hills, but I always seemed to end up being stuck behind someone who didn't quite understand what the accelerator pedal was for!

So after a horrific ride home, it now seemed that it was definitely the clutch gone. I wouldn't have made that deduction if there had been even a marginal improvement in the clutch, but as it got worse I sadly realised that it was indeed the clutch plates. I rode it to a mechanic in Nowra and told them the quote the other shop had said. They were stunned (as I believe a lot of you were, as was I), and they looked it up on their computer and told me the engine didn't need to come out and it was only estimated at around 4 1/2 hours. So with that and the parts, it's still well under $1000, so now it's there awaiting repair. Still expensive, sure, but it really does feel like the clutch is well and truly going. By the end, it was bordering on unrideable, and I don't think a number of oil changes would ultimately have returned it back to a fully functioning clutch. I'm sure the "test" the other technician did on it didn't help the clutch situation any, in fact, I think it made it worse. Definitely won't be going back to them. That bridge is burnt.

So now I wait for the final bill, but sometimes these things happen, and new shop guys were really nice. They were almost apologetic over the new price, but I was fine with that.

I just want to get back to riding again. :/
 

dduelin

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Once the friction plates in the clutch are glazed from the overheating caused by the friction of slipping they are usually ruined but it was worth a try to save them. At least you can trust the second mechanic.
 
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I'd make sure they replace the springs (cheap) as long as they are in there. Probably no need but as long as they are in there, torquing the primary drive gear bolt wouldn't hurt.

The biggest PITA is scraping the old gasket off after pulling the housing. The only trick is sliding a flat blade ruler in there to keep the idler sprocket from coming off. No special tools required to change the plates and springs. You can do this at home for the price of friction plates, springs and coolant.
 
OP
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The bike shop guys are going to show me the plates when they're removed. I'll post pics when I have them.

As for the post about the clutch change, that's one of the first things I saw that showed that you don't have to pull the whole engine out to change it. Unfortunately, I'd prefer to get it done by someone who knows what they're doing and not myself. And yes, the springs are being replaced at well. :)
 
OP
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An update!

Firstly, it has taken 5 1/2 months, but here's why:

I put it in on a thursday (Sept 28). They said the mechanic had a week off the following week, but I was ok with that. The bike was unrideable anyway so it was easy just to leave it there.
After he got back, he didn't look at the bike until friday (Oct 13).
Then they had to order parts from Honda, who had to get them from Japan, so that took a further 2 weeks.
The parts came in (Oct 27), but they didn't start working on the bike until this past monday(Nov 6).
They finished it tuesday(Nov 7), but the owner of the shop tests the bikes once fixed, and he wasn't in the shop until this morning (Nov 8).
I picked it up once it was tested, and all good.

It's an unusual feeling, not riding for over 5 weeks then jumping back on. A lot about how it used to feel was forgotten. What I can say is this: it almost feels like I can feel every gear tooth as they revolve. It's hard to describe, but it's like a fine vibration unlike the cylinders working. I don't mind it at all, and I'm sure it cold also be because the clutch is new and might need a little time to wear in. They didn't say that, I might have just made that up.

The downside of this little exercise is that it cost just over $1290. There were a few other things I had done to the bike too (a coolant seal near the thermostat needed replacing because it was leaking). Labour was only $500, which fits in with bike shops over here who charge $100 per hour labour (there's a lack of good mechanics around too, according to the shop owner). Parts were over $600.

Ther one thing I forgot to do was get a shot of the plates, however I did ask to see them. Very glazed. Some were passable but most of them looked cooked. The shop agreed that the cause was probably the wrong oil put in sometime in the past. That won't be happening again. ;)

Thank you to everone for the invalable advice. Now back to the open road. :)
 
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