Rebuilding camshaft gear drives - is it possible?

Hi, New member here. I have an Italian spec 1985 VF1000R and I am wondering if anyone has rebuilt camshaft gear drive units before? I have a couple of spare gear drive units for my VF1000R which show a lot of side to side movement in the larger gear and getting them refurbished before my rebuild. The bearing for the larger gear is a stock standard one but the needle roller for the small gear is a bit of an odd size. The manual says not to disassemble the unit but only 3 bolts hold it together - if anyone knows why they should not be taken apart please feel free to let me know. Thanks.

 

Of coarse it can be rebuilt. If it NEEDS it.

You did not tell us the mileage.
BTW all gears need some side play. The question is how much.

I think you are in way over your head. Sorry but just by the questions you ask.

 

Hi Donald
Thanks for the reply.
I do not know the milage on the spare gear drives which I got from the US, but my bike has done 44000km. I am setting up to do a cylinder head, camshaft and cam drive gear swap out in another six months or so. Valve stem seals are probably old and hard by now and the cams have some fretting on a couple of lobes.
Did you have any problems when you rebuilt your gear drives?
Could you post the source of the needle roller bearing so that I can order some - I have not had too much luck finding the bearing here.

 

Why the coarse reply?

I think the OP was asking if anyone has run through this rebuild on a kR. It is a valid question, IMO.

Of course I could be mistaken.

 

The micro fische sheets only show an assembly and not any seperate parts available. I only know the bearing sizes as I picked up a box of parts which had one disassembled gear drive and one complete.

 

Industrial supply house or industrial place that specializes in bearings will be much cheaper than the dealer & provide the same part (probably from the same source).

I'd be more worried about replacing the bolts and nuts that hold the assembly together. Be sure you use high-heat LocTite (or similar product) on the bolts/nuts when re-assembling the gear cartridges.

If you can't find torque specs on the bolts/nuts that hold the gearing cartridge together, I'd suggest tightening them evenly with a torque wrench (so you can be sure they're all the tightened equally) until you get to about the middle of the range of acceptable side-play in the gears and call that good.

 

If they have Japanese bearings than go with NSK or Nachi. Timken is a good USA bearing brand. I don't have a clue to what companies you have over there?

Was the bike ridden hard? I wouldn't think they would need to be rebuilt with only 44000km on them.

 

Rangerscott and tinker, all the normal brands of bearings are available but the difficulty is the sizing of the needle roller. I only use Japanese bearings as the Chinese ones fail in very short times (front wheel sealed roller bearings in a Bold'or failing in less than 10000km). I have found it is better to pay a few extra dollars for name brand Japanese than get some bargain bearings from "Cheng shing super extra luck happy joy" bearing company.

Dean, loctite is an excellent suggestion, the halves of the gear drive casing fit metal to metal, so it will just be finding out the typical torque value (range) for an 8mm bolt in a cast iron threaded hole. The side play is purely wear in the bearing and not to do with how much tension is on the case halfs.

My reason for rebuilding the spare units (with unknown history) is so I can replace mine as a service item when I do the heads. Mine maybe ok but if not, I don't want to be mucking about trying to replace/rebuild units with the motor apart. Much easier to have replacements ready to go. For the same reason I will be having a spare stock front head reconditioned in advance and have my NOS rear head fitted with valves etc ready to just drop on. Hopefully this will minimise the time engine is out of bike. I am planning on having the motor out heads etc replaced and back in over a weekend.

The big bearing is a standard ball bearing (a 6003) but the needle roller is a cage with rollers only and is an unusual length (11.7mm) the standard lengths are 12mm and 13mm. The needle roller is 18mm ID 24mm OD x11.7mm wide.

At the moment the bike is hanging from the ceiling (like some sort of advertisement for bondage) getting new rear shock (hagon), new front and rear wheel bearings, swing arm bearings replaced, swing arm powdercoated, new front fork legs with racetech springs, new genuine chain and sprockets, steering stem bearings replaced and new lower radiator. I have a complete electrical system (well at least the wire harness, coils, spark leads, alternator and handlebar switches, fuse box, and idiot light box) all of which is planned to go on when the engine comes out.

Donald has obviously done the rebuild before and I am hoping he (or someone else here) can chip in and give me some practical pointers on rebuilding the gear drives.

If I can work out posting photos I will put a couple of photos up of the gear drive units.

 

Great strategy, rebuilding core parts to replace existing before you dive into the rebuild.

If I could make a suggestion, give a shout out to Dave Dodge. I believe he is swamped with work on the bench (read long lead times to get parts back) but I have always found him to be very helpful, and timely, in answering tech questions, via e-mail.

This sounds like an interesting project. Please keep us posted on the progress!

 

Donald? Any help from your experiences with these gear drives would be appreciated.

 

What does "fretting"mean?
Need a good photo.

I would not rebuild the gear drives unless they need it.
They run in oil all the time. Think about that.
Make sure you get the one marked "F" and "R" in the correct position.
I would not rebuild the gear drives even if they had 50,000 MILES . KM's????
There has to be a reason to rebuild them.
Even if you put new bearing in them the teeth of the gears will always have some wear.

Check the clearances of the spares you have with the originals to see if there is a difference. There should be some side to side play.

 

Thanks Donald. The play on one of my spare sets is much greater than the other. I now have the correct bearings to replace the worn ones. I will clean them up and assemble them and see how they go. There is no visible wear on any of the teeth on any of the cam drive gears. I bought 4 of each type of bearing so I can rebuild 2 sets of gear drives.

 

Sounds good.

 

VF1000R chopper sold

Sorry wrong place.

 

Sorry double post.

 

As far as I know the gear sets are not considered to be "rebuildable". I think, as you guys are describing, the bearings can be replaced if damaged. Probably treading into uncharted waters - make sure to post your progress if you choose to tackle it!

 

If it can be welded ,machined, and info is available almost EVERYTHING is rebuildable.
Worn gears cannot be fixed. They must be replaced.
I would bet those gear drives can go 100,000 miles.

 

I have finally got around to a full rebuild on one of the gear drive cassettes (39 C saturday arvo with aircon on in garden shed so finding something to do inside shed was very attractive).
The small gear cog did not need the bearing replacing (play on the gear was the same with the old needle roller as with the new)
The 6003 roller bearing was replaced as the old one had maybe 1mm side to side play and the new one no detectable play. This bearing needed to be frozen and pushed in with a bearing press.
I used 15nm torque on the top bolt (6mm shaft with 10mm flange head) and 25nm on the 2 socket bolts. 222 super screw lock was applied to the 3 bolts before assembly as a bit of peace of mind insurance.
I took quite a few photos and will load then up when I get the time.