Author Topic: "Revive" (1985 K100 Street Scrambler Build, not a Cafe Racer)  (Read 178284 times)

Offline DJEwen

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"Revive" (1985 K100 Street Scrambler Build, not a Cafe Racer)
« on: February 25, 2018, 05:10:06 AM »
Fit like?

I’ve been lurking on the Forum since October 2017 and felt it was time to share. In September 2017 I purchased myself a couple of K100s, one 1985 K100 with 46,000 Miles, it has no keys but runs and hasn’t been on the road since 2012/2013. It’s unfortunately had had a small fire in the loom which a previous owner had repaired to some extent. The second is a 1987 K100 RT which is broken down, most of the parts are there with the exception of the fairings and lunch box.. Here’s a few pictures of the machines in question:










The Bricks making it home:








I’m planning on customising the running bike into a street Scrambler, the inspiration for this build is Sir Ulrich by NTC Motorcycles, some of you may be familiar:




I have a 3x3 meter section on the end of my garage that was used as a junk space previously, I spent time painting and building shelves in attempt of turning it into some form of workshop where the magic, or disaster will slowly happen. It’s small but it has great lighting, power and optional heat:









As I wasn't present for the collection of the Bikes I didn't get to see the runner running so the first task for me was to install a battery and get her started. After confirming the fuel tank wasn't filled with black sludge I siphoned the old fuel and added a squirt of new. I fitted a new 12V 14AH GEL battery which had no issues turning the big brick over. I eventually got her started but she was unable to idle by herself. The bike engaged first and drove forward with no painful sounds from the splines. Excuse the vertical filming of this shot:


Post start up I noticed there was one oily drip from the Oil/Water Pump weep hole.

The runner came with a 22ltr top box and RHS Touring tragkorb which I began to remove the mountings of last night (can be found on Gumtree for sale if anyone is interested) I got a little carried away during the removal and got this far, I got the seat from Texaviua:




From close inspection the brick is already already sporting some stainless front lines and all the hoses seem to be in un-cracked good condition albeit I intend to change the fuel lines regardless. I've spotted some rounded hex heads in the pinch bolts of the triple trees and the rear master cylinder is finished.

For the last 5 months I have immersed myself in this forum, a used Clymer manual and almost memorised Mr Chris harris's most helpful YouTube hits. I have purchased all fluids and assembly lubes including, Staburags, and made up my short fall in tooling. What would you guys absolutely say I need to change/replace during this build?

Thanks in advance
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline DJEwen

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Re: Triple S
« Reply #1 on: February 25, 2018, 05:24:21 AM »
In the 2 weeks leave I had, I managed to gain around 4-5 hours of wrenching on the K, about 3 of those hours were spent dealing with rounded, missing head or seized fasteners..

I built some more shelves in the garage and got some stuff a little more arranged. This is how the bike currently sits:







I have no more progress to show than this unfortunately.

All fluids except forks are now drained and the bike on the lift. I managed to get 3 of the 4 exhaust clamps up stream of the collector free but the hardest to reach one was solid and had to be cut out. I intend to get the silencer out next time home and remove the headers. The bolts on the manifold are terribly corroded, I had soaked them for a day or two in PlusGas and had an attempt at one after cleaning the surface as much as I could but it just rounded in the socket. Does anyone have any top tips for getting the exhaust headers off?


I've noticed there is quite a lot of oil from the the gearbox bell housing where the swing arm mounts, is that likely to be the output seal?


Thanks
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Boxermann

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Triple S
« Reply #2 on: February 25, 2018, 07:08:04 AM »
Welcome!

Maybe use a nut splitter or try forcing a slightly smaller socket on the exhaust header nuts? 15/32” or 12mm.

Edit: I read again and see that I you are talking about the bolts on the exhaust and not the exhaust to cylinder nuts? Heat and forcing a smaller socket on works most of the time anyway.

Yeah, oil in the bell housing does sound like a bad rear main seal.
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  • K100 / '87, K75 / '87

Offline Laitch

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Re: Triple S
« Reply #3 on: February 25, 2018, 07:08:53 AM »
I've noticed there is quite a lot of oil from the the gearbox bell housing where the swing arm mounts, is that likely to be the output seal?
It's a waste of time to guess the cause of a condition, especially when you understand that it will be uncovered during disassembly  Disassemble and inspect as you go.  At the end of the process, you'll have a list of what you might need after research and consultation. Keep posting photos as you make progress.

Good luck with your project.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline DJEwen

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Re: Triple S
« Reply #4 on: February 25, 2018, 08:42:28 AM »
Welcome!

Maybe use a nut splitter or try forcing a slightly smaller socket on the exhaust header nuts? 15/32” or 12mm.

Edit: I read again and see that I you are talking about the bolts on the exhaust and not the exhaust to cylinder nuts? Heat and forcing a smaller socket on works most of the time anyway.

Hi Boxermann, no, you're correct, I am talking about the cylinder nuts. So you reckon a nut splitter should I not get a smaller socket on? I must add this to my top collection.
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline DJEwen

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Re: Triple S
« Reply #5 on: February 25, 2018, 08:52:27 AM »
It's a waste of time to guess the cause of a condition, especially when you understand that it will be uncovered during disassembly  Disassemble and inspect as you go.  At the end of the process, you'll have a list of what you might need after research and consultation. Keep posting photos as you make progress.

Good luck with your project.


Hi Laitch, new picture, nice! I'll admit I have been poor with my photo tracking. You detail a good system.


The bike will be be mostly stripped back without splitting the block and then painted and powder coated. I appreciate the law of "Everything works until it breaks and then it's broken", however, should costs allow, I'd like to replace anything thats prone to failure and sensible to replace whilst everything is apart to avoid having to go back in any tim soon after the build. If anyone has recommendations for must do's, I'm listening, I could sure use some direction.


Thanks
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Supershooter

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Re: Triple S
« Reply #6 on: February 25, 2018, 09:17:09 AM »
Great Goal, can't wait to see it take shape.


Supershooter
  • Liberty Township, O'brien County, Iowa
  • 85 K100 RT

Offline Boxermann

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Triple S
« Reply #7 on: February 25, 2018, 10:24:36 AM »
Servicing the water/oil pump, replacing rear main seal and of course lubing the splines is what I can think of off the top of my head.
  • Norway
  • K100 / '87, K75 / '87
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Offline Skunky

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Re: Triple S
« Reply #8 on: February 27, 2018, 09:40:24 PM »

All fluids except forks are now drained and the bike on the lift. I managed to get 3 of the 4 exhaust clamps up stream of the collector free but the hardest to reach one was solid and had to be cut out. I intend to get the silencer out next time home and remove the headers. The bolts on the manifold are terribly corroded, I had soaked them for a day or two in PlusGas and had an attempt at one after cleaning the surface as much as I could but it just rounded in the socket. Does anyone have any top tips for getting the exhaust headers off?


I've noticed there is quite a lot of oil from the the gearbox bell housing where the swing arm mounts, is that likely to be the output seal?


Thanks

Hi DJ , Exhaust headers AAAAAAARRRRRRRRGGGGGGGHHHHH!  :yow. Zinc Studs with Copper Nuts. One of the worst Jobs I've had to do. All bar one of the nuts on mine were rounded off and put in without anti seize. One of the penalty's of the quality of the exhaust is that you sometimes find they have never been off. I used nut splitters (useless at the back) grinders, drills, heat guns and allsorts and still ended up with two broken studs which had to be drilled out.  I had to fill and re-tap the engine for the new studs. My advice is, leave them on ifyou can. Just get the triangle can off and buy an off the shelf collector.

If you do have to get them off get a mattress and put the bike on its side on its side you will have much more working room. If your studs are long enough you could try running two nuts up. Tighten one against the other and turn the whole stud out. Also I found the headers to be welded to the head by corrosion as no gaskets were used.

Good Luck.
  • Derby GB
  • BMW K100lt
Rebuild it and they will come..
90 K100lt
Triumph Thruxton 900
Honda CB400F

Offline DJEwen

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Re: Triple S
« Reply #9 on: February 28, 2018, 08:41:58 AM »
Great Goal, can't wait to see it take shape.

Supershooter


Thanks Shooter! I had a thought once or twice when I first looked at the bike in the garage that I had taken on more than I could chew but once I got into it, I couldn't stop. Really enjoying it.


Servicing the water/oil pump, replacing rear main seal and of course lubing the splines is what I can think of off the top of my head.


Cheers Boxerman, do prompt me with anything else that comes to mind, please.


Hi DJ , Exhaust headers AAAAAAARRRRRRRRGGGGGGGHHHHH!  :yow . Zinc Studs with Copper Nuts. One of the worst Jobs I've had to do. All bar one of the nuts on mine were rounded off and put in without anti seize. One of the penalty's of the quality of the exhaust is that you sometimes find they have never been off. I used nut splitters (useless at the back) grinders, drills, heat guns and allsorts and still ended up with two broken studs which had to be drilled out.  I had to fill and re-tap the engine for the new studs. My advice is, leave them on ifyou can. Just get the triangle can off and buy an off the shelf collector.

If you do have to get them off get a mattress and put the bike on its side on its side you will have much more working room. If your studs are long enough you could try running two nuts up. Tighten one against the other and turn the whole stud out. Also I found the headers to be welded to the head by corrosion as no gaskets were used.

Good Luck.


[Plugs Ears] Oh the joys, sounds like I've got a fair task on my hands, Skunky! On this advice I think I'll leave the headers until the bike is fully stripped and I can rotate the engine upside down. I'll give everything a good soaking in Plus Gas for a day or two before I walk into battle, I'm armed with a blowtorch, heat gun, freeze spray and Chris harris vocabulary. Good suggestion on just leaving the studs in, I'll likely do that should I not damage any too badly with the splitters or such like, good idea on the double nuts!


Did you have any issues removing the triangle can? I have all 4 clamps free and gave it some gentle persuasion with a block of wood and hammer but it didn't budge. I hadn't planed on selling it so don't mind cutting right through it with the grinder.


Any other complete nightmares that you expect me to encounter? (with the exception of wiring) I noticed a couple of those shallow headed hex pinch bolts on the triple trees are already completely rounded from one of the POs.
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Skunky

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Re: Triple S
« Reply #10 on: February 28, 2018, 07:06:31 PM »



Did you have any issues removing the triangle can? I have all 4 clamps free and gave it some gentle persuasion with a block of wood and hammer but it didn't budge. I hadn't planed on selling it so don't mind cutting right through it with the grinder.


Any other complete nightmares that you expect me to encounter? (with the exception of wiring) I noticed a couple of those shallow headed hex pinch bolts on the triple trees are already completely rounded from one of the POs.


To Be honest there were various bolts which had to have the heads grinded off where over zealous mechanics had tightened with air gun's, but as long as you have a bolt removing set and an extractor set you can normally get them out. I found it easier removing bolt studs once the heads were off which takes the force off the thread. When your dealing with 30 year old bikes that have eons of corrosion you're always going to have issues. I have invested in a pot of copper anti seize and torque wrenches to make sure I don't over tighten.

I had to drill Two of the Triple tree bolts. I guess PO's are worried about decreasing ground clearance.  :hehehe

Like you mine is still on blocks and probably will be until May. I have a life to lead as well as a bike build.
  • Derby GB
  • BMW K100lt
Rebuild it and they will come..
90 K100lt
Triumph Thruxton 900
Honda CB400F

Offline DJEwen

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Re: Triple S
« Reply #11 on: March 01, 2018, 08:10:08 AM »
Cheers, Skunky.


I’ve just ordered a set of Irwin bolt nut grip removers and a cheap set of extractor screws. My tooling expenses are escalating quite rapidly  :mbird [size=78%], I’m still within budget though![/size]
[/size]
[/size][size=78%]So no advice on the exhaust can itself? I’ll maybe just pay it a visit with the grinder.[/size]
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Laitch

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Re: Triple S
« Reply #12 on: March 01, 2018, 08:17:25 AM »
[size=78%], I’m still within budget though![/size]

[size=78%]So no advice on the exhaust can itself? I’ll maybe just pay it a visit with the grinder.[/size]
I'm wondering if you go to the Look and Layout section of your Profile on this site, then choose the WYSIWYG option, those random characters in this post won't appear in your next. Maybe I'm the only person seeing them.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline DJEwen

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Re: Triple S
« Reply #13 on: March 01, 2018, 08:36:47 AM »
I'm wondering if you go to the Look and Layout section of your Profile on this site, then choose the WYSIWYG option, those random characters in this post won't appear in your next. Maybe I'm the only person seeing them.
Nope, I see them too. That’s what I get for not previewing. Just checked, WYSIWYG was already checked, I’ve unchecked and saved  :dunno
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Skunky

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Re: Triple S
« Reply #14 on: March 02, 2018, 02:41:12 AM »
Cheers, Skunky.


I’ve just ordered a set of Irwin bolt nut grip removers and a cheap set of extractor screws. My tooling expenses are escalating quite rapidly  :mbird [size=78%], I’m still within budget though![/size]

[size=78%]So no advice on the exhaust can itself? I’ll maybe just pay it a visit with the grinder.[/size]


I didn't have a triangle exhaust on mine it came with a stainless steel motad unit which, ( don't tell the purists) I chopped up and shortened. You will find yourself buying all sorts of tools and stuff you don't need. There seems to be two types of builders. Those who throw loads of no eyes at their project. And those who want to do everything themselves on a budget. What you have to remember is that you can spend a lot of mm money but you will never get it back. There's a nut and bolt rebuild on EBay that they want 14k for. Yes it's like a new bike, but it's still a 30 year old bike that's been chopped. They will not sell for 6k let alone 14.
  • Derby GB
  • BMW K100lt
Rebuild it and they will come..
90 K100lt
Triumph Thruxton 900
Honda CB400F

Offline DJEwen

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Re: Triple S
« Reply #15 on: March 02, 2018, 05:00:21 AM »

I didn't have a triangle exhaust on mine it came with a stainless steel motad unit which, ( don't tell the purists) I chopped up and shortened. You will find yourself buying all sorts of tools and stuff you don't need. There seems to be two types of builders. Those who throw loads of no eyes at their project. And those who want to do everything themselves on a budget. What you have to remember is that you can spend a lot of mm money but you will never get it back. There's a nut and bolt rebuild on EBay that they want 14k for. Yes it's like a new bike, but it's still a 30 year old bike that's been chopped. They will not sell for 6k let alone 14.

Oh well, I think it’ll be the angle grinder.

Aye, you probably mean this one, been for sale for an age: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F172456651375

Sir Ulrich build sold for €18k
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Laitch

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Re: Triple S
« Reply #16 on: March 02, 2018, 11:42:22 AM »
I didn't have a triangle exhaust on mine
K100 stock mufflers are rectangles—a Teutonic symbol indicating four cylinders. The K75 has a stock triangle muffler. Are mufflers not being discussed here at all? Clarity is eluding me again.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Martin

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Re: Triple S
« Reply #17 on: March 02, 2018, 01:32:57 PM »
Pictures speak a thousand words. Please include some we do not want a cloudy, confused  Laitch.  :nono
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.
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Offline DJEwen

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Re: Triple S
« Reply #18 on: March 02, 2018, 08:57:48 PM »
K100 stock mufflers are rectangles—a Teutonic symbol indicating four cylinders. The K75 has a stock triangle muffler. Are mufflers not being discussed here at all? Clarity is eluding me again.

Sorry, Laitch. Yes, the rectangle muffler. It was the last thing I attempted removing before I went on hitch, I’ve removed all 4 clamps at the collector, soaked in releasing fluid and gave it some heavy persuasion but it wouldn’t budge. I’m considering cutting it out with the angle grinder.

Pictures speak a thousand words. Please include some we do not want a cloudy, confused  Laitch.  :nono
Regards Martin.

 :yes



Rectangle
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Martin

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Re: Triple S
« Reply #19 on: March 02, 2018, 11:07:14 PM »
Have you tried heating it and spraying with a good penetrating fluid. Wait for it to cool a bit before spraying as you do not want the Brick to erupt in a ball of flame and don't breathe in the resulting smoke. Not all penetrating fluids are created equal WD 40 and some others comes to mind, they are water displacement fluids. The best fluid for penetrating is a mixture of 50% ATF fluid 50% acetone.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: Triple S
« Reply #20 on: March 02, 2018, 11:32:01 PM »
Have you tried heating it and spraying with a good penetrating fluid. Wait for it to cool a bit before spraying as you do not want the Brick to erupt in a ball of flame and don't breathe in the resulting smoke.
If that doesn't work the first time, do it again, wait a couple of minutes, freeze spray the header pipes a couple of inches away from the muffler coupling then pound and twist the muffler. There's always the grinder though.   :yes
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider
Winner Winner x 1 View List

Offline DJEwen

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Re: Triple S
« Reply #21 on: March 03, 2018, 12:04:44 AM »
Have you tried heating it and spraying with a good penetrating fluid. Wait for it to cool a bit before spraying as you do not want the Brick to erupt in a ball of flame and don't breathe in the resulting smoke. Not all penetrating fluids are created equal WD 40 and some others comes to mind, they are water displacement fluids. The best fluid for penetrating is a mixture of 50% ATF fluid 50% acetone.
Regards Martin.

I hadn’t tried heat yet, only a soak or two in penentrating fluid and a bit of brutality with a big hammer. I have WD40 but I was using PlusGas as I read somewhere it’s the best off-the-shelf penentrating product... to be honest it seems identical to WD40  :dunno2: I’ll look to put a mixture together, I have a few spare spray bottles anyway. Well noted on not breathing in the smoke. Thanks, Martin.

If that doesn't work the first time, do it again, wait a couple of minutes, freeze spray the header pipes a couple of inches away from the muffler coupling then pound and twist the muffler. There's always the grinder though.   :yes

Alright, go twice. I have some freeze spray so I’ll spray the header pipes, heat the muffler and give it yah hoo with the hammer while twisting as directed! Hopefully the grinder will remain parked. Cheers Laitch.
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline DJEwen

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Re: Triple S
« Reply #22 on: April 23, 2018, 08:12:57 AM »
Got back from my hitch and managed to find a full 8 days to strip the brick down. I’m not sure if I’ve achieved enough for 8 days but I reached my target of complete strip, frame welded and everything away to  blasters, painters and powdercoaters. I’m now purchasing the rebuild items from the long list that was populated during the strip. I have been really lucky in some places and less so in others, all splines have been immaculate, I forgot to take any pictures but I shall in the next couple of weeks.

One getting the tank off it was apparent the “small fire” had been slightly worse that the PO had indicated. The botched repair job was so poor I’m surprised the bike was running so well. There were sections of wire where the sheath was completely melted off but where the PO couldn’t reach to poorly wrap insulating tape around, the cables were just left bare in the frame. I have a lot of hours ahead of me going through the loom with a fine tooth comb.





The fire has managed to completely melt the fuel sender plug on both the tank and loom side. BMW don’t make this part anymore and it’s proving difficult to get a hold of, not to mention pricey.



Of course the 1988 spare bike has the later float unit so unfortunately no joy in swaps here :(



I removed 140mm from the rear of the frame to meet the proportions of the new seat, fabricated new bracketry for the seat, tank and rear light then de tabbed and dressed ready for welding at a local shop.
















Progress continued nicely and I got down to the heart of the beast, listing parts as I went.





I was lucky to get the exhaust off with little effort, thankfully only needed a smaller socket hammered onto the #1 cylinder outlet, the rest came off with little persuasion.



Then the water pump driven gear decided to shear and the oil/water seal, which I expected was original was nearly welded in the pump housing. I couldn’t get at it with my seal puller and was getting minimal purchase with a drift via the smaller diameter hole in the opposite side. In the end I ended up carefully using a dremmel to make a nick in the remainder of the old seal and managed to lever underneath it.. 1 hr later.



Continued the breakdown, logging and parts listing.



And current state. Top and bottom end half painted in gloss black.





  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Skunky

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Re: Triple S
« Reply #23 on: April 23, 2018, 05:35:08 PM »
Moving along at a cracking pace. Due to circumstances beyond my control mine hasn't made much progress at at all sinceDecember. Hoping to get back to it in May .

  • Derby GB
  • BMW K100lt
Rebuild it and they will come..
90 K100lt
Triumph Thruxton 900
Honda CB400F

Offline DJEwen

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Re: Triple S
« Reply #24 on: April 24, 2018, 06:32:49 AM »
Moving along at a cracking pace. Due to circumstances beyond my control mine hasn't made much progress at at all sinceDecember. Hoping to get back to it in May .

Thanks, Skunky. Looking forward to your updates. Unfortunately due to circumstances outwith my control (not knowing a part number, even if a number exists) I can’t see my build going much further. Until I can get a replacement snap ring on the output shaft business end of the cases (the one that controls float) then this build is going nowhere. I can’t seem to find a part number anywhere and tinterwebs producing nothing. #LooseEnd
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT