Hi All,

I bought a cheap 1989 K100LT off of a friend with the intention of pulling it all apart and putting it back together, fixing and cleaning up as I go. I wanted to start this thread to capture the progress and also to hopefully get some advice from you guys on what trouble areas to look at as I go through.

I decided to start with the transmission am working through Chris Harris' 6 part "K100 Spline Lube" videos - very nicely done. So here goes...

So I collected the bike looking like this:



First job was to pull off the fairing, damn they weighed a ton. Plus the previous, previous owner had used all kinds of wood screws to hold it together

Best advice I can give is use plenty of sandwich bags and a marker pen and take heaps of photos unless you have a memory like an elephant.
If you need bits ask on the forum first as many of us have 3-4 spares bikes
If you want a manual send me a PM

Much appreciated. I have already raided the kitchen and stolen the sandwich bags. That lesson I have learned the hard way!

Then I yanked apart the final drive to find this:



and this



Not good. I contacted Brunos in Canada and he suggested that the pinion is fine but the spline is shot and I need a new drive shaft. About $500 here in Aus new. I am trying to source alternatives but if there aren't any other major problems then it's not too bad.

An interesting looking bike - judging by the tyres and raised front mudguard the PO used it for some off-roading.
 
They are reasonably straightforward bikes to work on but it is worth having a good read through the "just bought a K" articles on the portal page. Unless you are going for a show bike or money is no object, don't go looking for problems where there are unlikely to be problems. Stick to the fundamentals of cleaning up electric connectors, oil & lub changes, coolant change (including cleaning up the radiator cap) and filters. Some rubber components and hoses may need changing, but many will not. Stop Press - Ok and perhaps do something about the drive shaft splines and seals....

When you've done the basics, get out and ride and let the bike tell you what else needs attention. I fear that too many bikes get the strip down treatment, with the best intentions in the world, and then just never come back together again.

Enjoy the project

Get the spline from Motobins in UK and weld it on. I have done 3 now for friends. If the uni is suspect you can take your pick of 3 I have here with good unis and shagged splines.

Anyway, so I keep stripping down...




Wow, wonder if these are OEM pine battery planks?



Shock is not OEM, need to look into these IKONs.



Exhaust removal was easy. But 2 of the header pipe clamps were missing  Lots of dirt down there too

RicK G wrote:Get the spline from Motobins in UK and weld it on. I have done 3 now for friends. If the uni is suspect you can take your pick of 3 I have here with good inis and shagged splines.

Thanks again Rick - I have just sent an email through to them. I think the UNI is ok but I'm not 100% sure what to look for - I believe that they get 'notchy'?

Hold the shaft in one hand and push down on the uni and rotate it and any wear will become apparent.

Born Again Eccentric wrote:An interesting looking bike - judging by the tyres and raised front mudguard the PO used it for some off-roading.
 
They are reasonably straightforward bikes to work on but it is worth having a good read through the "just bought a K" articles on the portal page. Unless you are going for a show bike or money is no object, don't go looking for problems where there are unlikely to be problems. Stick to the fundamentals of cleaning up electric connectors, oil & lub changes, coolant change (including cleaning up the radiator cap) and filters. Some rubber components and hoses may need changing, but many will not. Stop Press - Ok and perhaps do something about the drive shaft splines and seals....

When you've done the basics, get out and ride and let the bike tell you what else needs attention. I fear that too many bikes get the strip down treatment, with the best intentions in the world, and then just never come back together again.

Enjoy the project

Sounds advice. I plan on checking the clutch plate then doing the spline lube and cleaning and sealing it all back up. Then I will focus on exactly the type of things you are talking about. Hoses are in reasonable condition but clutch boot is shot and some other grommets have been torqued to hell. Touch wood - i have not had a single seized bolt.

So I got the swing arm off and the bell housing. Now I noticed something odd. In the Chris Harris video he pulls off the clutch boot, removes a spring and a "puck" and then a bearing. I did not seem to have one of these bearings...

In this video https://www.youtube.com/watch?v=YCnQE4vQTcs at 5:43 he removes the 'puck' and then pulls out a bearing.

All that came out of mine was



Nothing else in there...



I might be as thick as 2 planks though and missing something obvious...

The little piston is the bearing and sometimes (well most of the time) it falls apart and comes out like Harris pulls it out. When they do that just put them back in and all is fine.

mikerogers74 wrote: Now I noticed something odd. In the Chris Harris video he pulls off the clutch boot, removes a spring and a "puck" and then a bearing. I did not seem to have one of these bearings......

The video shows the early version alu piston where the bearing was a separate part.
In your picture is the later plastic piston where the bearing is integrated.

So I got the transmission off. I have a thin coat of black oil in the clutch area and on the transmission block. This is not 'normal' no? Is it likely to be coming from the transmission? Should I replace the transmission gasket?

Wow that clutch spline looks like you have got there just in time. How are the splines on the shaft, in the pic they look OK but its hard to tell.
The gearbox oil will have a very acrid sulphury smell to it. It looks to me like the oil will be coming from the engine output shaft seal because there is no oil on the clutch yet.
You will need to remove the clutch plates and carrier to get to it. Take care removing the 6 clutch bolts, the hex hole is shallow and easily rounded out. If that does happen use an 8mm or 5/16 drill and dril the head off and the remainder will come out easily. I replace them with hex head bolts from REPCO and usually need to cut them down to the correct length so next time its easy. In behind the nut on the shaft is a big O-ring use a sharpened 3mm screwdriver to cut it into 4-5 pieces which makes it very easy to get out.
If you buy a seal locally get a viton seal to stand up to the heat and when they try to charge $80 for it squeel like a stuck pig and say you only paid $32 for the last one and usually they will give in. The seal is 80 x 50 x 8 which works well but OEM is 80 x 50 x 10. I have used the 8mm seals many times and never had an issue.

RicK G wrote:Wow that clutch spline looks like you have got there just in time. How are the splines on the shaft, in the pic they look OK but its hard to tell.
The gearbox oil will have a very acrid sulphury smell to it. It looks to me like the oil will be coming from the engine output shaft seal because there is no oil on the clutch yet.
You will need to remove the clutch plates and carrier to get to it. Take care removing the 6 clutch bolts, the hex hole is shallow and easily rounded out. If that does happen use an 8mm or 5/16 drill and dril the head off and the remainder will come out easily. I replace them with hex head bolts from REPCO and usually need to cut them down to the correct length so next time its easy. In behind the nut on the shaft is a big O-ring use a sharpened 3mm screwdriver to cut it into 4-5 pieces which makes it very easy to get out.
If you buy a seal locally get a viton seal to stand up to the heat and when they try to charge $80 for it squeel like a stuck pig and say you only paid $32 for the last one and usually they will give in. The seal is 80 x 50 x 8 which works well but OEM is 80 x 50 x 10. I have used the 8mm seals many times and never had an issue.

 
Thanks Rick. It does not smell sulphury so I guess not transmission. Attached are pics. Hopefully they are ok...

The gearbox input spline looks OK but not the spline in the friction plate.
To lube the splines I use Rocol GA50 you can get it from Blackwoods. There are quite a few brands with 50% or more moly, Honda make one and Staburags is what factory use but I am not sure if you can get it in Oz apart from a Dealer
 Also check the steel plates by puting a straight edge across the flat surface and check if they are dished.

RicK G wrote:The gearbox input spline looks OK but not the spline in the friction plate.
To lube the splines I use Rocol GA50 you can get it from Blackwoods. There are quite a few brands with 50% or more moly, Honda make one and Staburags is what factory use but I am not sure if you can get it in Oz apart from a Dealer
 Also check the steel plates by puting a straight edge across the flat surface and check if they are dished.

So you reckon I should replace that clutch plate? 

I bought some of this to lube: http://www2.munichmotorcycles.com.au/product_info.php?products_id=515

Boy was it a mission to get the clutch out! Hex hole is indeed shallow but I stripped none. Pulling the clutch was a different story - tapping with rubber hammer, swearing at at, sweating, begging. Stopping for a beer did the trick.

Yeah that Optimol is the good stuff. Definately replace the clutch plate you are lucky there is no real damage to the input shaft of the gearbox.

Hi Guys,

Do these clutch plates looked too dished? I'd say about .5mm, maybe less...

The first plate is definately had it and the other is not as bad but on the way out.

With both plates like the first one you only get about 6mm at the edge of the friction plate that holds. I have probably 10 maybe 12 plates like that. I repaired a pair about 5 years ago for my K1100 but it took hours to set them up and grind them so it really isn't worth doing. I have put a few back together with a friction plate that matched and they kept going well but with your plate in that condition it's not a proposition worth considering.

Thanks Rick. Sigh... I guess it's time to hit up beemer boneyard or motorworks...

I'm going to go out on a limb here and say my main seal is indeed busted

My new guts arrived courtesy of Munich Motorcycles. Super fast delivery from Perth to Sydney. 

So I had to get the seal out. First I tried the old screws, sledgehammer and wire trick.



And ended up with broken wire.



Then I tried my own variation. The patented vice-grips-on-a-rope-to-a-sledgehammer-tug. I ended up with a vice grip in the shins.



So finally I bought a tool called a seal remover. To remove the seal. It removed the seal.

So I decided to remove the air box to see what was under there. A lot of oil muck. What other expensive seal could possibly be broken to allow this crap to exist?

Nothing to be concerned about there, it's fairly normal and this is quite possible the first time it's been cleaned or seen in 30 years.

So I think I have a filthy plenum. Is it just me or do you all have filthy plenums?

We're all dirty buggers around here . Seriously though, that one looks like a lack of air filter.

Just found a thread here http://www.motobrick.com/index.php?topic=4408.0 which suggests this is 'normal' due to oil from crankcase breather hose. Will clean and maybe get a hose filter.

Oil sludge build up is fairly normal but there is a dust build up there as well. Make sure the filter is working as intended and seals well on the outer edge and there is no splits in the paper. If you have a reuseable filter like K&N get rid of it as that is where the dust is getting in. I have found and the US military also found that K&N usually dont even stop fine sand.