Kr 250 A Blowing smoke using gear box oil quick

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TurboStew
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Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sat Jun 30, 2018 3:40 am

Dear members, I purchased another KR 250 A a few weeks back. It had been sitting for years a took a lot to even get it running. All the jets in the carbs were blocker with set oil and I missed the impotent little ones the first time I cleaned them out, so I had to do it twice. HA HA. That's what you get when you don't stop and think and do things properly. Any way yes got it running. But the front cylinder is sucking the gearbox oil into the cylinder. Emptying the gearbox quickly and oil is now all over the rear of the bike and my driveway. So yes I know It's the crank seals.


My question is due to its age, should I change all 4 seals or take the chance and only do the clutch side seals????

Looking forward to your advice.

Thanks Stewart
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

Gerrit
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by Gerrit » Sat Jun 30, 2018 6:19 pm

If the bike were mine I'd strip the engine completely and check everything, then rebuild with new gaskets and seals. You will then know everything is as it should be. You could replace the defective seal only and solve the oil consumption problem, only to have another seal fail a few miles down the road and having to start all over.
The bike has been standing for years and presumably you don't know its history. Why chance it?
"Mine is a long and sad tale", said the mouse.
"Indeed it is", said Alice, looking at the mouse's tail.

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 01, 2018 2:24 am

Thanks, Gerrit for replying, Yeah, I am in to minds on what to do. Just the two seals and as you said only to have another fail latter. I will probably pull the engine. I also think the seal issue is why the bike was parked years ago as the lower pipe was already soaked in crusty old set oil. The guy I got the bike from has a lot of these bikes in various states of assembly most not running though. Well the bikes that he is willing to sell that is. I know he used to race these bikes in the day, and he still does a few track days. so I suspect this bike may have done a few hard laps. All the better I suppose a good reason to do a full strip down and inspect then. I'm keen to just get it running and tidy it up a bit.

This then leads to my next question then: Will the engine come out of the frame complete or do I have to take the heads and cylinders off to get it out. I ask this question as I have seen some posts when others that are doing a restoration put the bottom end in and then fit the top end.

So, what’s the go?

Thanks Stew
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

Skyeport
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by Skyeport » Sun Jul 01, 2018 4:47 am

Hi Stew,
The engine from memory can be removed and installed with the top end still on, bit of a juggle though. Much easier with the top end off.
Been a few years since I did mine.
Cheers
Skye

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 01, 2018 5:47 am

Cheers, Yeah it looked like it was going to be a bit of a squeeze. It's got to come apart anyway, so I will tale the top end off in the frame and then pull the bottom end. Iv'e just been studying it and started pulling off a few bits to get it out and got a bit of a surprise. It had an bad oil leak LHS and I assumed it would be the selector shaft seal. NO. It's dropped a chain at some stage and smashed the cover housing behind the front sprocket. The fun has begins as some people say. Looks like another trip to the guy I bought it of for some change over parts. I think this will be about trip 5 or six now but who's counting. At least He lets me come back and swap parts. Well until he gets sick of me to say the least.

I will keep you all posted on my progress.

Cheers for now and out to pull the motor.

Stew
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 01, 2018 11:49 am

Progress update:
The motor is out and on the bench. Head and cylinders off, the top end looks good, only some minor scuffing on the front piston back top ring land. But there is a few surprises of the negative kind as I started pulling it down further. The water pump was seized and had spun the impeller nut and the nut has vanished. The outer water pump cover is shot, corroded and unusable. On removal of the LH gear selector cover/output shaft cover that I already found was cracked and leaking due to dropping a chain in the past, I also found a stinky mix of water and oil sludge.

Stew.
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 01, 2018 11:59 am

I tried to upload some pictures but got this message:

"It was not possible to determine the dimensions of the image. Please verify that the URL you entered is correct".


I was trying to direst upload from my computer, File size was okay, but can not post pictures. :roll:


Stew
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

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JanBros
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by JanBros » Sun Jul 01, 2018 12:27 pm

you can't upload from your computer, you must use a picture-host site.
You know it's cold outside when you trip over dog shit instead of standing in it.

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 01, 2018 1:02 pm

Some pictures Hope this works. The corroded pump housing and the oil sludge.

http://www.photobucket.com/user/bones-s ... t.jpg.html

http://www.photobucket.com/user/bones-s ... f.jpg.html
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

Gerrit
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by Gerrit » Sun Jul 01, 2018 2:10 pm

Yikes! Good thing you decided to strip the engine- who knows what mechanical misery would have been caused otherwise.
"Mine is a long and sad tale", said the mouse.
"Indeed it is", said Alice, looking at the mouse's tail.

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Mon Jul 02, 2018 8:27 am

Yikes! exactly, and more to follow. I split the bottom end today into two halves. I had trouble getting some of the bolts out as someone has had it apart before and some of the screw heads were a bit rounded off, I had to drill one bolt head off to get it apart. The main shaft is damaged. The circlip land is broken/missing. So I need a shaft.

Some pictures Below:

The damaged shaft

http://i1313.photobucket.com/albums/t54 ... 1530429761

http://rs1313.pbsrc.com/albums/t542/bon ... 1530429761

http://rs1313.pbsrc.com/albums/t542/bon ... 1530429759
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

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StrokerBoy
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by StrokerBoy » Tue Jul 03, 2018 4:20 pm

Sorry, I'm a bit late to this, but here's my 2p worth...

I've always been sceptical as to the need to replace crank seals on a two-stroke that's been left standing. I've rescued quite a few neglected bikes over the years and always managed to get them running fine without doing it. However, if I knew that one or two definitely needed swapping, I'd do them all at the same time, assuming I could get the parts.

I've been told that you can remove/refit the tandem-twin engine with the top-end still in place, but it's difficult and there's only one way in and out. However I've not had to do it myself.

It sounds like you've dodged a future bullet by stripping the motor anyway, at least you know it'll be right once it's done. :mrgreen:

PS. If you have a source of parts (new or used), grab as many as you can, they're not making them any more...
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

TurboStew
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by TurboStew » Sun Jul 08, 2018 11:18 am

Thanks for the reply StrokerBoy, it's never to late for some feedback. If you think you missed the boat this time well in fact your just early for the next one :lol:
Okay here my update. I went back to the guy I purchased the bike from today, he gave me another engine. Well no top end, lust the box minus the covers, started to strip this one down for the parts I needed and found the output bearing had a major failure. Anyway on dismantling and inspecting I found the same issue with this one too. That is the input shaft/main shaft has also broken the circlip retaining land on the end of the shaft (2nd gear end, end in the box).

http://s1313.photobucket.com/user/bones ... sort=3&o=0

http://s1313.photobucket.com/user/bones ... sort=3&o=2

So my question is what do I do? Is this normal? Do they all brake like this? They were obviously both running like this, so what's your thoughts. Try and find a good shaft or put it together like this? I also found the seals primary gear seals in the rotor/reed valve assembly installed one way in one motor and reversed in the other , what is the correct way? Its hard to tell from the PDF manual.

Looking forward to you opinions on this one.
Thanks
(2x) GPZ 750 Turbo, E1 1984 & E2 1985
KDX 175 B2
1997 GSXR 750 SRAD Blue/White
1984 KR 250 A Tandem Twin, Green
1985 KR 250 A2 Tandem Twin, Red

Gerrit
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by Gerrit » Sun Jul 08, 2018 2:32 pm

I'd say try and find a good shaft (part No. 13127-1112 according to my parts catalogues), a dealer might have a new one in his spare parts bin.
What Man has made, Man can make again and a gear maker can make a new shaft to drawing or pattern. I don't know if there are any gear makers in your part of the world but in Europe we have Nova and Ellis Moore to name but two.
I have no idea whether this is a common fault with the KR250s but two such failures suggest a potential weakness.
"Mine is a long and sad tale", said the mouse.
"Indeed it is", said Alice, looking at the mouse's tail.

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JanBros
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Re: Kr 250 A Blowing smoke using gear box oil quick

Post by JanBros » Mon Jul 09, 2018 11:20 am

no need for a new shaft, have new retaining blocks welded on. make sure the shaft is heated as much as possible before welding spots on the blocks. file them down so the gear can pass, they do not have to be perfect or have the same shape as the rest, just big enough to retain the clip.
You know it's cold outside when you trip over dog shit instead of standing in it.

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