Rear Drive Unit

[GsBike]

I'm considering buying a rear drive unit off Ebay. I need it for a 79' standard and the one for sale is for a 79' special - are they the same unit?

Also, The unit looks in decent shape but, what questions should I be asking the seller? I'm a bit nervious buying something sight unseen from a stranger.

[John]

All rear drives are the same. The gear ratio's are the same also. There's not much to them.J ust ask how many miles are on it, how often he changed the gear oil, What type of oil he used, and why he's selling it, condition of the paint, etc... Same questions you'd ask if you were buying a used bike. Not much inside of them to go bad. I've got three final drives for sale, but so far, no inquires. Two of them are from XJ11's and one is from a 78 Standard. What is the price, if I may ask?

[Jerry]

Drives are mechanically the same, but there are a few color variations. The drive on my XJ is black, but the little 'bars' or 'ribs' cast in have a silver front. Some units are all silver. Only makes a difference if you want the bike to look original.

[GsBike]

I wish the seller could answer those good questions, John. Unfortunately, the guy who's selling the unit is a scrap dealer and he just got the bike (79' Special) a short time ago so he knows little about it...he's just taking it apart. He said the bike ran before he took it apart but he didn't ride it. I'll ask for the milage.

I haven't checked today but no one had bid on it as of yesterday. The guy is charging around$15 to ship it.

I'm keeping my bike as stock as possible so I do need one that is the same.

Did anyone bid on your drives, John?

[John]

Final Drives

I don't have my stuff listed on E Bay, only here in the classifieds, and nobody has inquired about the final drives yet. Sales have been very slow since first of the year. The only difference between the drives from an XS and and an XJ is just the color. The XJ is black. You said he wanted $15 for shipping? Is the price for the drive included? What was the bid price the last time you checked?

[GsBike]

There are a couple on ebay now and none have bids as of today (they are asking around $30 for them + shipping). I did send the seller some specific questions and he just replied "Drive is in good condition".

[John]

That is a good price. I would have asked for $50, plus shipping. My bike has over 90k miles on it, and I have had no trouble from the the final drive at all. I used to have a 79XS750 special, and had no problems with the drive on that either. I guess if you keep the oil changed regularly, they'll last forever. Better jump opn it if you need one. What is wrong with yours?

[GsBike]

I think I will bid on one.

The oil reservior cap on my rear drive was stripped by the previous owner (the one that uses an allen wrench). I tried drilling it and taping it but it would not budge. I cut a grove in it and tried using an impact driver...no luck. I asked a mechanic to try and get it out but he scraped up the finish on the drive working on it. My bike is in great condition so I'm looking for the same in a rear drive unit.

Thanks for your help, John.

[mitch]

Bigger Hammer

Try this hit the top of the cover quite hard with a ball pien hammer once or twice after letting it sit a few days with penetrating oil on it then take a chisle and make a indent in the rim of the cover, then take a flat punch and tap the cover as if you were turning it out it should start. Would be a lot less work to remove that and refinish the housing you have now than replacing it . Just my thoughts i havent met a nut yet i couldnt get out ( knock on wood ).................MITCH

[mitch]

Another option

Another way would be to get a welding shop to weld a bolt directly on to the cover and then while it is still hot use a wrench to remove it, hope this helps .....MITCH

[DarkAvenger]

"Skipping" in low gears

Can someone shed some light on this problem for me?
In 1st and 2nd (when taking off) as soon as I wind on the throttle (and not necessarily hard), the bike seems to skip a beat. Bad description, I know, but it reminds me of when I had a chain drive bike with a loose chain and it would "skip" a link across the cog-teeth.
I've had the gear-box stripped and it's in good nick, the clutch is a bit iffy - but I'd find it hard to believe that this metallic CLUNK is clutch related. I'm more inclined to believe that it is the final drive. Has anyone else had this problem? (I want to know before I strip the rear end).
If this is the problem does anyone have any rear drive units for sale (bearing in mind I'm in Ireland!), or can the components be bought or manufactured?
The bike is a 1982 XJ 1100 J Maxim - not in the best of nick, but I plan on getting it there.
Any help or suggestions will be very welcome,
Thanks,
Dave.

[ratbyk]

2nd Gear Skip

Dave, go over to the left side of this page. Click on Tech Tips. Then click on Repairs on the next window. Then scroll down to 2nd gear repairs. All of your answers are here complete with great accompanying pictures to walk you through the repair.
Your problem is in the transmission not in the rear drive.
Ken/Sooke
78E Ratbyk
82 FT500 "lilRat"

[DarkAvenger]

Thanks Ken, but I'm not sure that is the problem.
1st. On the first gear box (transmission?) strip down, the dogs on 2nd & 4th gear were worn, so I replaced the offending gears. After re-build, the bike worked fine for a little while (500 miles) then the same problem came back only worse!
2nd On the second gear box strip down, the gears were fine. There was wear on the clutch which I decided to do nothing about at the time.
3rd The problem happens in both 1st & 2nd gear.
4th Heavy metallic clunk seems to come from further back than the gear box (I could be wrong here admittedly)

I have looked at the item you recommend previously, and at that stage decided to strip the bike for the 2nd time.

Major problem now is, bike is too old for bike mechanics to want to work on it, and too new for classic bike mechanics to want to work on it. Looks like I'm gonna have to do it myself - some learning experience don't ya think? I don't want to have to go chasing the problem down, I need a mechanical magician here, someone who can successfully diagnose the problem ON-LINE!!

All magicians reply now PLEASE!!!
Dave.

[John]

Did you happen to inspect the shift cam, and shift forks? Any wear on these items can cause your symptoms. You say the skip only happens in 1st and 2nd gears? How about when you have 4-5000 RPM's in 3-4-5th gears, and twist the throttle? A final drive problem would show up in all gears. I had the same problem with my 80SG. I had to do the 'Black & Decker' fix to the gears, but I also found a lot of wear on the shift cam, and the related forks. Any wear on these parts is multiplied at the point of contact at the affected gears, and they may not mesh properly, and 'kick out' under load.

[DarkAvenger]

John,
The forks showed some sign of wear but not a whole lot. Not being the most mechanically minded sub-genius on the planet, I can't tell you if they are the culprits. If they are, I'm in trouble. I can't get parts for this bike here at all. Are they freely available in the US? What sort of cash is involved in a new transmission?
If (and I don't doubt it) you're right, this may be my only option.
As for your question about the higher gears - with a slippy clutch, I cannot tell, however, before the clutch needed attention, no, abuse in the higher gears did not give the same problem. I put this down to the probability that there was more pressure on the final drive when in the lower gears - just my uneducated assumption.
Dave.