Honda XRV Forum banner

1 - 3 of 3 Posts

·
Registered
Joined
·
35 Posts
Discussion Starter #1 (Edited)
Looking to strip and replace the countershaft on my RD03 in the next couple of weeks, Bike is currently in a 8x6fr shipping container so I;m moving to a 8x20ft container closer to home where I'll have space to take the engine out and strip it down, the 20ft is also cheaper.

The bike has only done 3750Km, previous owner imported it and left it partially stripped, under a tarp for 18 years.
165179
replacing the worn RD03 countershaft 23220KW9000 with a good 23220MN8000 from a NT400 Bros, think the whole gearbox cost £85, being from the little 400 this shaft has no wear on the sprocket splines.

165180
165181


Was looking for a guide but can't seem to find one...

I've rebuilt C90 Cub engines and gearboxes before so it should be similar, just larger with an extra piston.

Found this on Rugged Rugged roads as a guide to what needs replacing.
165182


I have an Athena gasket kit P400210850652 Complete Gaskets Kit - Complete Gaskets Kit » Athena Aftermarket Division
165183


Is there anything else I need, thinking gearbox bearings and oil seal for output shaft

Do I need any extra special tools, flywheel/clutch pullers?

Is it just a case of heads off, cylinders off, clutch and generator covers off, clutch and flywheel out then split casings and replace shaft?
This time it's just a quick rebuild to get the bike running and on the road. I bought it 28 months ago and it's just sat there until now, but I'd like to ride it to the Malle Mile in August.


Over winter I'm going to strip it back down, get the frame blasted and powder coated, and strip the engine and get it vapour blasted and the covers Cerakoted burnt bronze.

Should I fit a Honda or KKBike Superpinion front sprocket?
 
  • Like
Reactions: een705

·
Registered
Joined
·
23 Posts
After a few decades of experience with early Transalp and the RD03 (very similar with interchangeable parts) there is still, to my knowledge, no one who has actually tested the Rockwell hardness of the Honda output shaft, the Honda output shaft sprocket and any aftermarket sprockets.

My strong opinion, however is that excess spline wear is caused by the following factors: Primarily it is the fault of owners and shop techs ignoring the correct chain slack as stated in the owners and service manuals. This slack will look excessive when the suspension is at full droop with the bike is on the center stand. This is particularly true if the owner is coming from a road bike background. In order for the RD03 to provide the rear suspension travel is has, the chain will look much too loose when on the stand (to road riders eyes). So most riders will set their slack too tight. This also happens at times when the bike is taken in for a tire change and a tech will “eyeball” the chain slack without regard to correct specs. This puts enormous strain on the chain, countershaft (output shaft) bearing and sprocket as the suspension compresses due to rider weight, load and bumps.

Next on the list is the question of “hardness” and addresses the question you pose in your post. While I have never seen any real specification on the hardness of the outputshaft and sprockets, wisdom suggests that it is best to use the official Honda sprocket on this shaft. You are assuming that Honda got it right and the sprocket is actually a bit “softer” than the shaft. Much better to wear the part most easily replaced. Aftermarket sprockets are a gamble since you have no idea if they are harder or softer than the shaft. Now a “hardened” sprocket sounds, at first, to be a good thing. Don’t want that thing wearing out too so00n, right? But if it’s harder than the shaft, the wear will occur on the part that requires case-splitting to replace.......not good.

To provide a direct answer......use the official Honda sprocket. I have done this with a 1989 ( 67000 miles) and a 1990 Transalp (108,000 miles) and a 1988 RD03 (41,000 miles) with no spine problems at all.

Lastly, you will notice that the sprocket mounting system used by Honda will allow a small amount of lateral movement of the sprocket on the splines. I always clean the splines at sprocket change time and very lightly lube with Honda Moly 60 grease. I’m sure any good grease with a high moly percentage will work just as well. I’m in California but with your climate in winter, I’d have the sprocket off at least once during the wet months for a clean and spline lube.

All the above is opinion based on experience. If anyone has any real data on this, I’d be happy to hear it.
 

·
Registered
Joined
·
23 Posts
After my last post, I took a longer look at your photos.

I’m almost positive that the output shaft from the 650 Bro’s (NT650 in the USA) is exactly the same since I’ve used the 16T sprockets from that bike before but have no experience with the 400. The output shaft also has other splines cast into it for two other gears, Make certain that these spines will fit the RD03 gears if those are to be re-used. The internal ratios of the 400 may be different than the RD03 with internal gears being larger, smaller or even thinner in width. Be sure everything is the same if mixing parts. Study parts diagrams between the 2 models to be certain part numbers and the number of gear teeth are the same. Also pay attention to the small holes in the shafts that are oil passages for gear lubrication. Make certain these holes line up if mixing parts.

If this were a normal rebuild, I’d advise removing the clutch and flywheel while the engine is still in the frame so one can use the transmission/chain/rear brake to help hold these parts while removing large nuts that have a high torque value. With your bad splines (which by the way are AMAZINGLY bad with only a few thousand miles on the clock) I don’t believe this would be posssible but if the splines hold you might consider it.

You should certainly replace the output shaft bearing. With the wear evident on the output shaft, I’m shocked the bearing is still in one piece.

Without this, you’ll need a tool to keep the transmission from spinning while you remove the central nut holding the clutch basket in place. A pneumatic or electrical impact wrench may also work in that application without the need to hold anything since those tools can put enough force into the fasteners to spin them out before the shafts spin. DO NOT pry on the “ears” of the clutch basket to hold it in place. They WILL snap off !!

Pay particular attention to a very small oil jet in the right side case half. It is only held into the case by an O-ring and MUST be placed into the case in the same orientation in which it was removed.

On some models, the front or rear axle has the same threads as the flywheel puller tool and can be used (prudently) as a bodge to avoid purchasing a puller. Be careful here.
 
1 - 3 of 3 Posts
Top