XJ650 Final Drive Unit

The FD unit on my 1980 (UK) 4K0 XJ650 is leaking oil past the oil seals and making it's way on to the rear wheel.

Unfortunately the unit will require to be overhauled with new seals. The Haynes manual suggests that the work is rather complicated and for these reasons must be entrusted to a Yamaha dealer. I believe some specialist tools are required. Is there anyone in the UK who can overhaul the FD unit.

Any help or advice would be much appreciated, as without repair, the bike is obviously not fit for use, thank you.

 

Have you looked at eBay for a used unit? Might be a better option than rebuilding your unit. Don't know who repairs them.

 

I've found a 1980 XJ650 Yamaha factory workshop manual on ebay UK. Does anyone have a copy and if so, does it give details for overhauling the FD unit including listing any specialist tools required.

 

Have found a Maxim FD unit, does anyone know if this will be the same as that for my 4K0 model.

I'm aware that the rear wheels are different diameters which may mean different crown wheel and pinion gearing.

 

Took the plunge and bought a used FD unit from Huggy's Speed Shop. It was listed for a Maxim but after checking the OE part numbers, the same unit is fitted to many bikes.

I'm pleased to be able to say the bike is back on the road and looking good so far.

It's looking like Padgett's at Batley will be able to refurbish the original FD unit as a spare.

 

Padgetts have declined to carry out the work on the FD unit.

So, with help from a very good friend, the FD unit has been partially disassembled. Now I need some special tools to remove and replace a collar, oil seal & bearing from the main housing. These tools are not available from Yamaha and have to be manufactured. Within the UK, please has anyone got the tools or have any recommendations as to where I might get them manufactured. Preferably, somewhere in the NE of England.

 

Had a recommendation from a VJMC member, now getting the tools made locally.

 

Hi mate, might be too late but it’s not very hard to replace the main seal and oring. Just standard hex bolts and a cover to remove. As long as you have some mechanical know how you shouldn’t have an issue

 

The oil seal which was leaking is #7, in fact, when the FD unit was overhauled, the seal was fitted facing the wrong way.

 

I don't know if this information is posted elsewhere within the forum but thought while I had it in front of me, I'd post it here for future reference.

Found this in The Venturers - Tech Library, The Venturers - Yamaha Venture Technical Support Library it shows the pinion being removed and replaced.
The set-up is the same as that for my XJ650.

The Special Tools are available from CMS.
Coupling Gear Tool, 9089001229: Tool, Coupling Gear/m. Shaft Yamaha - buy the 90890-01229 at CMSNL
Pinion Bearing Retainer Remover, 9089004050: Pinion Brg Retainer Remover Yamaha - buy the 90890-04050 at CMSNL

With the machined tools manufactured above, I think these are all those which are required to overhaul a final drive/gear unit.
I've got a genuine Yamaha XJ650 Factory Service Manual which seems to confirm that this is the case.

 

Found the tools are available in the UK from Yamaha via Fowlers.
Coupling Gear Tool, External 9089001229 TOOL COUPLING GEAR/M. SH (fowlersparts.co.uk)
Pinion Bearing Retainer Remover, External 9089004050 PINION BRG RETAINER REMOV (fowlersparts.co.uk)

 

if its just the main seal leaking why don't you just replace that only with its o-ring? You only need those tools if you plan to remove the pinion gear which can stay in place if you just replace the main seal...

 

The seal which is leaking (previously fitted the wrong way around), is internal behind the crown wheel needle roller bearing. This is going to be replaced next week using the machined tools I had made. I'll then have a serviceable spare FD unit on the shelf in the garage.

The reason for looking at the pinion tools was should I need to get the FD unit which is currently on the bike overhauled sometime in the future.