Another Smoker - KR250 (1984)

[metaltriumph]

You do not need a comliance plate - my z did not have one when it was registered. But they will do a check on your engine and frame numbers to see if there was a compliance plate on there at some stage. If there was - good - if not - they may not be able to trace its history.

[Bogan]

I'm also thinking that after my mighty SAINTS smack the Roosters into next week on Sunday I might even paint this up in this scheme:

[ProblemChild]

cool mate , go green but the red & white looks like a hoooooooooooooda.

[Bogan]

OK so the green paint scheme will probably get a guernsey but in other news guess what!!! Paul dropped over today and we got the old drain plugs out of the carby bowls and put the new ones in. One of them still leaks but guess what we made it do anyway...





Now yes, it runs, but it sounds like a tractor and as you can see from my furious wrist action it won't rev. The tacho doesn't register anything above about 1000rpm. And when I go clicking the first related item on Youtube I find this:



The one above sounds more like my RGV and less like a tractor, I'm assuming that a carby rebuild could be on the cards, or maybe pull the chambers off and clean them out? I'm not sure how long since its been run, anyone got anything to offer on whether this sounds normal for an old smoker who has had a long rest and what to do next to get it running something like normally?

[Damon Z1000]

Fark, that brings back some memories, I had an '84 AR125 first roadie in '93, man that farking thing took some getting going right but fark when it did, it used to hustle even for a 125! Holed a piston at 75mph and thank fark the engine didn't seize. Was back on the road in a week, you gotta love 2 strokes for ease of repair.
Good luck and I reckon you are up for a carbie rebuild.

Enjoy, I'll be watching this thread

[the kid]

Is that firing on 2 ?
You have to be a bit carefull of old seals leaking air on strokers that have been sitting for a while . They will lean out and burn pistons . Don't know much about those tandems tho .
Will PM you a phone number of a bloke in Melb who has a couple of these and done a fair bit of work with em .

[Bogan]

I'm pretty sure it's firing on two, there's pressure coming out of the top can, and even a bit of smoke sometimes, but I guess that could be due to leaks between the crankcases (if they're separate but joined)?

Both plugs have spark and both carbies are getting fuel...

[the kid]

Feel the header section on each of the pipes when you next fire it up .

[Bogan]

OK, so the carbies are Mikuni VM28SS, which looks to be the same as a Z1R (Z1000D). Can I use these repair kits on the two stroke carbies or are they different?

http://www.carbkitscapital.com/Merchant ... de=48-1415

http://www.carbkitscapital.com/Merchant ... de=48-1416

http://www.motorcyclecarbs.com/CARBURET ... 61C695.cfm

It lists the Z1R as 1978 but the KR is 84 or 85?

[the kid]

I thought the KR 250 came with Keihin carbs ? , and a fairly uncommon carb as it angled through itself . The needle jet / emulsion tube is different in 2 stroke carbs to 4 stroke carbs .

I don't think you will find too much stuff for the KR in the states as they didn't get them .

Show and Go in SA will have carb parts .

[Bogan]

I thought the KR 250 came with Keihin carbs ? , and a fairly uncommon carb as it angled through itself . The needle jet / emulsion tube is different in 2 stroke carbs to 4 stroke carbs .

Thanks Billy. It depends where you look, I found this page (Keihin) and this page (Mikuni).

Also these pages state Mikuni:

http://www.kr250.org/manual/KR_manual_chapter_2.pdf (workshop manual scan)
http://motorbike-search-engine.co.uk/cl ... cation.php

The best bet would be to look at the carbies I would guess, I'll probably pull them off this weekend and try to rebuild them.

[Bogan]

Rightyo there's been some progress today. The easy simple bit was putting some brake fluid in the front brakes and bleeding up some sort of feel to the lever. It's sitting in the shed with a cable tie on it now we'll see how it is tomorrow.

I got the carbies off and cleaned them up as much as I could, got the floats off, needle and seats out, main and pilot jets out, choke plungers out, blew everything out with air and carby cleaner, and reassembled them and put them back on.

Replaced the spark plugs, which it looks like the previous owner did as well, the ones that came out looked pretty new so I have a good pair of spares .

Pulled the exhausts off as well, and bought some caustic soda to flush them out with. Interestingly when I was moving the bottom one (the one that runs, the front cylinder) into the garage to start the cleanup this happened:



There was quite a bit of oil in there...



The baffle I don't think will come out...



I'm gonna fill the chambers with caustic soda and see how much weight they can lose, I had to undo the rear subframe to get the rear exhaust off, this pic is looking forward towards the engine with the battery box and right hand coil removed, it's fun to get out:



Oh yeah and if anyone tells you that the only difference between one battery and another is that the vent pipe is on the other side make sure you don't just settle for the wrong one, I had to cut the vent outlet off:



This big hole is for the vent pipe bit to stick out and there's no big hole on the other side .



Once the exhausts are clean and back on I'll kick it in the guts again and report back...

[Bogan]

Still more progress, not as much as there was going to be but some important things have still been done this weekend.

Cleaned the chambers out with some petrol, to get all (or most of) the oil sludge out. The caustic soda treatment to remove the carbon will come soon, but they've been cleaned up inside and out with some fuel and it removed lots of gunk from both inside and out:



I was blowing them through with compressed air and little bits of this came out, it's no big deal right?



So while the chambers were drying I fished around with the electrics, doing some little or low cost things while I don't know if it will run right. I found the wiring for the front blinkers and rear lights under some black tape:





And I also found bits and pieces of the number plate light and rear lights in the box of bits:





And three of these in reasonable nick:



The fourth one that I have looks to be a little dodgied up and semi permanently connected to the front fairing already:





I figure once I get it running again I can plug it all in and see how much of the electrics works, I know the horn and kill switch work, I can just hope that all the other wiring and switches work, and maybe I might just have to replace a bulb or two...

[Bogan]

So after a bit more than 48 hours full of caustic soda I rinsed out the chambers tonight, and had to rinse my arm and leg off too (oops).

Anywho, I haven't dried them out, or rinsed them with vinegar to neutralise the alkali, but here's a before and after shot of the caustic soda mix, 500g of NaOH to 1.5 litres of water:

Before:



After:

[metaltriumph]

Wow - thats alot of sludge.

Im restoring a yami 2-stroke from 69, i think it might be a good idea to do this same process. 40 years would create alot of buildup

Was the petrol step necessary you reckon? And did you just plug one end up? what with? and where did you get the caustic soda?