Kanzaki Clutch box failure

[thaisail]

I have a Beta 28 that came with a Kanzaki gearbox 2.33 to 1 reduction and each time I put it in forward gear now there is slippage and then it grabs as soon as the RPMs increase. It seems that this Kanzaki gear box is the same gear box used by Yanmar but Yanmar puts their name on it. The problem is only in forward gear with reverse operating normally. I have been informed that the problem is glazing on my drive cone on the forward side. I have also been advised to change the drive cone and the forward gear. Has anyone out their come across this problem or know where the parts can be found at a reasonable cost? The items on the parts list are item 2 and item 17. I am located in Thailand near Phuket.

[TheOffice]

start with the simple - have you disconnected the shift cable and shifted the tranny using only the lever?

[thaisail]

That was the first test it did. The results were the same. The clutch is still slipping exactly as before.

[lockie]

This is a normal event in the life of a Kanzaki cone-clutch transmission.

Look here: http://www.cruisersforum.com/forums/...nes-95325.html

You have to remove and disassemble the transmission. The hardest part about this will probably be undoing the various bolts that are probably corroded to buggery.

Then using valve grinding past rotate the mating parts together to remove the glaze. It is quite straightforward, and if your box is in good condition you can do it without any cost other than a few bucks for the paste. Of course prudence dictates replacing the seals and/or bearings while you are at it, but there really is no rush - mine ran fine for about 500 hours after an unfortunate ingestion of salt water. But it rumbled like a mother%^#^!

If you take the bearings and seal to a bearing shop to be matched with generic parts you will pay 1/2 - 1/3 Yanmar OEM prices.

You can do this!

Graeme

[fryewe]

If your prop is in an aperture between hull and outboard rudder, make sure you have at least a couple of inches clearance to pull the shaft aft so you can get the transmission stub shaft out of the damper plate to pull the transmission out.

If you don't, you could carefully pull your prop to allow the shaft to be moved aft.

Of course, if your prop isn't in an aperture, that won't be a problem.

[lockie]

Originally Posted by fryewe

If your prop is in an aperture between hull and outboard rudder, make sure you have at least a couple of inches clearance to pull the shaft aft so you can get the transmission stub shaft out of the damper plate to pull the transmission out.

If you don't, you could carefully pull your prop to allow the shaft to be moved aft.

Of course, if your prop isn't in an aperture, that won't be a problem.

You will probably find that removing the coupling flex disk and sliding the flange on the prop side back will give you enough clearance.

[Boston Blackie]

I just rebuilt the Kanzaki KM3A on my Yanmar 3JH2-TBE while on the hard with the mast out (1996 J42, 3600 hr) using the very detailed Service Manual for the engine and transmission. It was losing oil and ratcheting only at max rev anchor setting in reverse. Factory original according to PO. Had to hoist the engine forward onto a bespoke 2x8 cradle with twin checkstay tackles lead to the mainsheet winches to get the tranny out past the Seafrost lines. I discovered the locknut on the tranny output coupling was completly unscrewed and the o-ring loose and allowing oil to leak out at the output shaft. Disassembled and replaced both oil seals. No evidence of any wear at all on the drive cones. No wear shims were installed as the transmission was factory original.

I realized the ratcheting at max revs in reverse was due to bottoming out my PYI dripless seal bellows allowing the free floating coupling spline to slip on the teeth of the output shaft! No wear on the spline teeth either.

If you lap your drive cones you may need the shim washer kit to reassemble with proper positioning of the output shaft, as described in the service manual.

[lockie]

Originally Posted by Boston Blackie

If you lap your drive cones you may need the shim washer kit to reassemble with proper positioning of the output shaft, as described in the service manual.

Well maybe, but lapping only takes a few turns with hand pressure, and is only supposed to take the glaze off not a heap of base metal. You'd have to work very very hard to take a thou or more off such a large area.

I've lapped mine a couple of times and the measured gap is fine with the original shims.

[Ndavies]

These are great and helpful posts - very timely as I have my Kanzaki KB20 out at the moment with a similar issue. My damper plate was seized and I was thinking that may be the problem. I have occasional slippage in reverse but it "bites" with a push on the throttle. I will get my mechanic to check on the drive cones while its out!

[LeaseOnLife]

Originally Posted by Ndavies

These are great and helpful posts - very timely as I have my Kanzaki KB20 out at the moment with a similar issue. My damper plate was seized and I was thinking that may be the problem. I have occasional slippage in reverse but it "bites" with a push on the throttle. I will get my mechanic to check on the drive cones while its out!

in you mean "Kanzaki KBW20", it doesn't have cones, but clutch discs.

Dirk

[Ndavies]

yes, it is a KBW20. Can the plates be "unglazed" in the same way you describe for the cones? I am a complete novice when it comes to transmissions. So sorry if this is a dumb question!

[LeaseOnLife]

Originally Posted by Ndavies

yes, it is a KBW20. Can the plates be "unglazed" in the same way you describe for the cones? I am a complete novice when it comes to transmissions. So sorry if this is a dumb question!

I never heard of the clutch plates being glazed, they are a mix of alternating bare metal and friction material plates. Since the transmission is out, your mechanic will have to disassemble the transmission and check the plates for thickness. Since it is apart, have the bearings changed too..

[a64pilot]

I am no expert on the KBW-20 although I have one too. It's my understanding that we have clutch packs very similar to the multi plate wet clutches most motorcycles use, if so those are way more likely to slip under high load not light load, and if allowed or continue to slip will eventually overheat and warp the steel plates. Every other plate is a steel with the other ones friction plates.
It seems sometimes that mine does what you are talking about, that is when I place it into gear at first no movement, but move the lever a little more and clunk, it goes into gear so to speak. I had assumed it was the shifter cable adjustment, but am real interested in finding out what your issue is.
The clutch packs ought to be real ,real tough as long as fluid is changed regularly. I change mine every 100 hours and have not noticed and change in color or burnt smell like you get from a slipping clutch pack.
If you have ever overhauled automatic transmissions, you know that smell well.

All this is theory though, but I have been around multi plate clutch packs for a long time, and they are tough.

Actually now that I think about it, I believe that the more torque you put through our transmissions, the more the packs are compressed and are able to carry more load, and I think maybe that our transmissions are actually Hurth and maybe Kanzaki owns Hurth or something?

[SV Bacchus]

Originally Posted by LeaseOnLife

Since it is apart, have the bearings changed too..

Yup, out and apart is the hard part. When that is done you certainly want to replace all those little pieces that can cause problems later. No sense pulling it again after a couple hundred hours because you saved a few bucks now.

[thaisail]

Originally Posted by lockie

This is a normal event in the life of a Kanzaki cone-clutch transmission.

Look here: http://www.cruisersforum.com/forums/...nes-95325.html

You have to remove and disassemble the transmission. The hardest part about this will probably be undoing the various bolts that are probably corroded to buggery.

Then using valve grinding past rotate the mating parts together to remove the glaze. It is quite straightforward, and if your box is in good condition you can do it without any cost other than a few bucks for the paste. Of course prudence dictates replacing the seals and/or bearings while you are at it, but there really is no rush - mine ran fine for about 500 hours after an unfortunate ingestion of salt water. But it rumbled like a mother%^#^!

If you take the bearings and seal to a bearing shop to be matched with generic parts you will pay 1/2 - 1/3 Yanmar OEM prices.

You can do this!

Graeme

Thanks to all of you for the very helpful posts. I just have a couple of questions. First, I need to find a service manual for this job. Is there anything available on the Internet? Second, I need to know which oil is the best for this type of gearbox? Third, I would like to know which is the best way to protect and preserve the gearbox while under sail. Is it better to lock the gear in reverse which prevents rotation while sailing and the other 2 options allow the shaft to rotate while under sail forward and neutral. My practice has always been to lock the shafts from rotating by putting the shift lever in reverse. How often should the oil be changed?

Originally Posted by lockie

This is a normal event in the life of a Kanzaki cone-clutch transmission.

Look here: http://www.cruisersforum.com/forums/...nes-95325.html

You have to remove and disassemble the transmission. The hardest part about this will probably be undoing the various bolts that are probably corroded to buggery.

Then using valve grinding past rotate the mating parts together to remove the glaze. It is quite straightforward, and if your box is in good condition you can do it without any cost other than a few bucks for the paste. Of course prudence dictates replacing the seals and/or bearings while you are at it, but there really is no rush - mine ran fine for about 500 hours after an unfortunate ingestion of salt water. But it rumbled like a mother%^#^!

If you take the bearings and seal to a bearing shop to be matched with generic parts you will pay 1/2 - 1/3 Yanmar OEM prices.

You can do this!

Graeme