Clutch is slipping

In Honda's manual for my '94 VFR750F, the spec on the clutch steels is
in chapter 1: "General Information" in the tables of specifications
(before torque values and lubrication points).

fwiw, for my '94 VFR:
clutch spring free length standard: 44.4mm service limit: 41.2mm
clutch disc thickness A standard: 2.92-3.08mm service limit: 2.5mm
clutch disc thickness B (judder spring side) standard: 2.92-3.08 service
limit: 2.5
clutch disc thickness C standard: --- service limit:---

clutch plate warpage standard:--- service limit:---

HTH

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

Ah, those pages are missing from my computer version of the manual.

Cross-referencing from the heathens on the CBR web forum answered today,
they said:

Spring free length is 48.9mm
service limit is 47.5

Looks like the springs aren't the same free length.

Okay these match up exactly with what the heathens said.

I don't know what the C type clutch disc is. I'm guessing that for the
clutch plates, it's 2.5mm? I know they're very slightly warped, as I can
feel it as I'm engaging, but the clutch doesn't have any problem fully
disengaging so I bet it's not a problem.

Ya sure damn did! Thanks a bunch... I'll be opening it up at 12PM sharp
tomorrow, taking pictures and letting you all know how it goes.

Phil, Squid-in-Training

 

May I then suggest searching for a complete (paper even?) version of the
manual? The CBR600 was really popular, so there's probably some floating
around used if paying the new price (Helminc.com, Honda's authorized
distributor for the US lists it new at $45) is too much.

We've been over the OEM vs aftermarket manual issue here before, so I
won't give the full speil. I recommend OEM from an official source (if
new), and try to avoid obviously faked/pirated versions (e.g. those on
CD).

That done, good luck with the job.

As for the type "C" clutch plate, the clutch diagram and parts list
don't show any such thing. Perhaps that's why no service limit or other
spec is given.

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

No, not all auto intended oils have that. You just need to do a little
homework up front. The difference in cost is significant.

 

That done, good luck with the job.

Inline pictures with my story:
Okeydoke. So I try the leaning it on its side deal... works like a charm.
Actually just on the sidestand while parked on a slope. No draining of oil
needed.

http://plaza.ufl.edu/phillee/cbr/1.jpg

So I was able to yank off the clutch cover, damaging the gasket, and placed
it aside. Everything looks smaller than it does on the internet.

http://plaza.ufl.edu/phillee/cbr/2.jpg

10mm for the bolts that hold the springs on... okay... I yank those off in a
star pattern and set them aside.

http://plaza.ufl.edu/phillee/cbr/3.jpg
http://plaza.ufl.edu/phillee/cbr/4.jpg

Here are the springs. Man, they're just itty bitty things!

http://plaza.ufl.edu/phillee/cbr/6.jpg

Check out that center locknut. Staked. Damn. Plus I only have a 1-inch
and 22mm socket max. Whip out the calipers... 27mm... jeez that's big. The
bicycle shop I work at doesn't even have anything that large.

Well, at least I can see the plates and discs. To my relief, the discs look
to be in great shape. Smooth, even wear, no bluing that I can see... the
outer lip isn't significantly thicker than the friction surface. Couldn't
get a good picture of it.

The plates are a different story... The outer one looks okay, but thin...
then I get to number 3 and 4... Yikes. The wear bars are almost all the way
worn. You can see 1 and 3 in the following pictures.

http://plaza.ufl.edu/phillee/cbr/7.jpg

I ask myself, "What's with this browned color of the aluminum? Too much
heat? The friction plates that I can see look glaze-free. Why would it be
that color?"

Clutch basket isn't notched from the plates; that's good.

So now I know the friction plates are getting pretty worn. Not too terribly
surprising knowing that the previous owner had the clutch lever adjusted
with no play.

I checked the Barnett clutch website last night. I find that there spring
kit for both the F2 and F3 are the same. I download the Honda F3 manual. I
find the specs there. I shoulda done this in the first place. Spring free
length is 49.7mm. Service limit is 48.3mm.

Since I got the springs out, I check one of the the spring's free length.
44.0mm. Given that the normal limit is 49.7mm, that's pretty damn short.
Since that's way under the service limit, I'm beginning to think that the
springs installed were the wrong ones, and the bike has gotten this far just
by pure luck. Maybe I could avoid buying a 27mm socket, another staked
locknut, and get by with just properly-sized springs.

I know, I'm being cheapskate to the max, but with an upcoming job offer, I
don't have much time to devote to this. I actually don't know if I'll be
keeping the bike after the job offer because it's in Orlando instead of
Gainesville.

So what do you all think? Pretend you're starving and can barely afford
food, and you want to do the least labor possible.

 

For future reference, 27mm is pretty much interchangeable with
1 1/16" SAE, which is more readily available and often cheaper.

 

"Phil, Squid-in-Training" <>
wrote:

[snip]

Two options:
1) Bolt everything back up, put a new gasket on the cover, close it up
and sell it as-is, immediately.

2) Do the job right: buy a full kit of springs and plates, locknut and
gasket-paper. You can probably find someone to borrow the socket from if
you ask around at work, local bike clubs, etc.

The advantage of #1 is the ease of the operation. You spend almost no
money, do almost no labor. The disadvantage is the lower selling-price
of the bike ("It's a great bike, but it needs a new clutch. I don't have
time to change it."), or knowing that you're mis-representing its
condition.

The advantage of #1 is the satisfaction of a job well done, the
experience, and not having to knock $100 off the price of the bike (I'd
certainly try to knock $1-200 off the price if I had to do a clutch
job). Depending on what sort of bike you end up buying down the road,
you'll also probably find that 27mm socket worthwhile.

I don't see much point at all to buying just springs. If you keep the
bike, you'll just have to go back in (running the risk of damaging the
new gasket, requiring a new locknut anyway) and do the job right soon
enough. If you don't keep the bike (and are honest), you won't keep the
buyer from demanding a discount because of the condition of the clutch
plates.

fwiw, my manual says that the locknut may be re-used, so long as the old
staked section does not line up with the staking groove on the shaft
(i.e. so long as you don't stake it twice in the same place).

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

Woah, cultural differences - I don't think I've ever seen a 1 1/16"
anything.

An acquaintance who just bought himself a Harley was a bit shocked to
discover that the back street workshop he's been using for the past 20
years don't have any tools to fit his new toy :-0

Do American built cars still use imperial fasteners?

 

Tempting, but I still need to get around at faster than scooter speed for
the next month.

I pretty much refuse to sell the bike in any state other than fully working
everything. That way they can't leverage anything to make me budge from my
asking price, especially with the high labor rates in this town. I bought
this thing with lots of stuff wrong with it and had fixed or fixed myself
lots of things that were wonkered. I'm proud to say that other than this
clutch issue, everything on it works properly as if it were stock.

I'm guessing you mean #2. And the job well done/experience/personal pride
aspect is really important to me. A Craftsman unit from Sears is only $7
retail. Not so bad.

IMO, with a 5mm difference in spring length, that's definitely a reason to
replacing just the springs.

In this town, you could sell navel fuzz for a pretty penny.

Cool... The nut's probably not double-helix, so if I have to go in,
hoepfully it won't match up.

 

American stuff is still largely SAE. I've got decent sets
in both. SAE is still more common than metric, though
metric nuts and bolts are now found in the corner hardware
store.

The one I haven't seen for a long time is Whitworth.

 

Clutch kit came in today. The new springs measure 49mm. I throw them in,
and retorque the bolts down... *snap* *swear*

One of the bolts holding the lifter plate snapped on me... and I only had a
tiny bit of torque on it. I may have overtorqued it upon the previous
reinstallation. I'm used to having a nice firm ramp-up of torque as bolts
get tightened. On these, they just kept going... Gotta ez-out and replace
those bolts.

Do you think they made them soft because they'd rather have the bolts fail
than the female threads (not sure if they're aluminum or steel) get buggered
up? Makes sense. I will have a torque wrench upon reinstallation.

I go out for a 100-yard ride... clutch is stiffer, but it's still not enough
to keep it from slipping. I'm not going to ride it anymore because I'm
afraid the fragment of bolt is going to work its way out due to vibration.

Looks like an oil/filter change, friction plate replacement, and bolt
replacements are up on the list of things to do.

 

That's a pretty nasty feeling, all right. What's even worse is when you
have the experience to feel when you're shearing a bolt, and feel it
starting to go, and knowing that it's already too late.

BE _extremely_ careful with the EZ-out when you're trying to get that
bolt out. If you don't get it exactly in the center, and precisely
parallel to the hole, you run the risk of snapping the thing off, or
drilling the EZ-out into your case/cover. Neither option is pretty.

Yeah, both make sense. fwiw, one of the first tools I invested in when I
got started wrenching on cars was a torque wrench. In ended up with two
Craftsman wrenches: a 1/2" drive beam-break wrench with a range from
24ish-110ft-lb, and a 3/8" beam-break with a range up to 20ish ft-lb. I
really like having a "high-range" and a "low-range" wrench, because it
means that I spend less time on the edges of the ranges (which is where
that sort of wrench is least accurate). Put another way, it gives me the
beef to get my wheels on at 100 ft-lb, but also the sensitivity to get
my clutch slave-cylinder bolts at 8 ft-lb.

Bummer that it turns out to be more work than you thought it might be;
keep after it and you'll have that thing sorted out nicely.

--
Later,
John



'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

 

It happens....

Did you use a torque wrench or not?

Oh Jeez - those things fail as often as they work. If you can get to it,
a better solution is just to spot-weld a small socket head or something
to the protruding bit of bolt.

Ah, so you didn't.......

Whaaat!?

 

Yup, the Haynes air-cooled Kawasaki 750 series manual had the same error
for the camshaft caps. Quoted something like 73ft/lbs, IIRC. Like you
said, I read the torque reading and thought: "No, wrong....."

They'd misplaced a decimal point.

 

Or, as happened to me on the bolts holding down a Kawasaki camchain
tensioner, using precisely the right recommended torque - very low, as
it happens - and the thread *still* strips.....

 

I generally try to compare and contrast the Haynes and Clymer
manuals before I start. I figure it's a little less likely that both
manuals have produced identical stupidities.

 

I got a drill from work and used my drill bits to make a 5/64ths shallow
hole and ez-out the bolt fragment. Took me 10 minutes, where normally such
a job ends up requiring cursing, yelling, and general mayhem. It came out
easy as butta. Now at least I can ride.

Speaking of welding, a group and I were going to take a human-powered
vehicle up to competition this weekend, but the trailer we were going to
take got sold out from underneath us. I had to MIG some tubing together.
My first real welding experience.

Now time for the clutch plate replacements... I'll be tackling that in a
few days.

 

Good news.

Heh. Did you manage to weld any tools to each other?

The crowd is hushed... expectant...