Help needed with my KR A2

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TurboStew
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Help needed with my KR A2

Post by TurboStew » Sun May 03, 2015 11:40 am

Hi all, my name is Stewart, I had this post in another section and was told it will get more views and feedback if I post it in this section. So I am hoping for lots of advice from you all.

I picked up a 1985 KR 250 A2 model about a bout 6 month ago. She is in a very bad way. Any way after lots of work on it I got it running, well sort off. Some times when it starts it runs perfect, sometimes it just won’t stars or starts on one cylinder or backfires out the exhaust. I have noticed when it is only running on one cylinder that the tacho is not working. I spent quite a bit of time working on it checking and cleaning connections and earth points but still the same. I got it started after my right leg had just about fallen off from kicking it to death. When it starts and runs I can rev it up and it rans perfect, anything from 20 seconds to half an hour she will run and then cut out as if I had turned it off. I am suspecting a faulty CDI. It is not a fuel issue causing the problem as I have cleaned the carbs and fuel system.

What do you all think is the problem?

Cheers 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

nigb
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Re: Help needed with my KR A2

Post by nigb » Tue May 05, 2015 12:09 pm

Stewart
My KR always starts on one cylinder & runs for a few minutes before 2nd cylinder kicks in. I have heard other owners say the same thing.
You say it can run perfectly for up to half an hour then suddenly cut out - it cant be a cdi unit as it would carry on running on one cylinder?
Also unlikely to be fuel given that you have cleaned out carbies & again it would run on one cylinder with one carb out unless there is a problem with fuel tap.
sounds like a dodgy connection - do the neutral/oil lights come on when motor stops suddenly? I had a problem with ignition switch on mine where it appeared to be in the on position but wasnt - tell tale was no oil or neutral light. Had to move the key around for it to connect properly.
Also check the side stand switch. Let us know how you go.
2008 Ducati 1098
2003 Triumph Sprint
2003 KTM 450EXC
1975 h***a 400-4 (fully restored)
1984 KR 250

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StrokerBoy
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Re: Help needed with my KR A2

Post by StrokerBoy » Tue May 05, 2015 3:48 pm

They're famous for being difficult to start Stewart. :D Everything needs to be spot-on for reliable starting, and there's so many parts whirring about in those cases that the timing can slip enough to cause a problem. See THIS for details of how to fix it, though I've still not got round to trying it myself. I just live with having to push-start it when it's sulking - try that with yours and see if it's easier to start.

Having said that, it sounds like you have a different problem. Once running on both cylinders, mine never misses a beat and certainly never cuts out. As nigb says, it does sound like a bad connection somewhere if it just cuts out dead like you've switched it off. And he's right to suggest the safety circuit as the first place to look - check out both the sidestand switch and the switch activated by the clutch lever. After that you'll have to trawl through the Wiring Diagram to find something dodgy.

Good luck !
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

TurboStew
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Re: Help needed with my KR A2

Post by TurboStew » Fri May 08, 2015 12:06 pm

Thanks nigb and oil injector for the posts. nigb I have previously bypassed the stand switch and yes the oil and neutral light come on when it stops dead. so don't look like the ignition switch. Couldn't be that easy could it :?: . Dam I wish, nice try though.
CDI????? correct me if I am wrong PLEASE, from what I can work out from the wiring diagram and manual is that the RH CDI unit has some input from the LH CDI unit and if I have a fault in the LH CDI unit/system it is possible that they can both shut down?

The CDI gets an input from the pickup coils and it decides on when to trigger the ignition coils to send the spark the spark plug. When it has its little hissy fit and dies and you try to start it again. Its like the ignition timing has gone out of timing and will not want to start and just backfires out the exhaust.
Oil injector, I will have a look at your subjection on the if the timing has slip enough to cause a problem. Will try to get some time to look at it this weekend. fingers crossed I can sneak out and have a play (do my head in a little more) #-o

Thanks guys I will let you know how I go.

Cheers 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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StrokerBoy
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Re: Help needed with my KR A2

Post by StrokerBoy » Fri May 08, 2015 7:52 pm

TurboStew wrote:Thanks nigb and oil injector for the posts.
I think that's my forum rating based on my number of posts, but you're welcome anyway ! :mrgreen:
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

nigb
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Re: Help needed with my KR A2

Post by nigb » Mon May 11, 2015 12:11 pm

Stewart the link between the CDI units you are referring to is actually a common feed from the exciter coil that provides the high voltage needed to generate the spark through the ignition coils. The independent pickup coils trigger the release of the high voltage in the CDI units.
It appears a bit clearer now that you probably have a faulty exciter coil or one of the connections to it are bad.
I think it is still likely to be a bad connection as when an exciter coils get an internal break or short they normally stop working. Worst case scenario is that you would need a 2nd hand stator.
If you have a multimeter there is a section in manual on checking exciter coil.
It would be worth checking resistance after engine has had one of its sudden stops.
Let us know how you go.
2008 Ducati 1098
2003 Triumph Sprint
2003 KTM 450EXC
1975 h***a 400-4 (fully restored)
1984 KR 250

TurboStew
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Re: Help needed with my KR A2

Post by TurboStew » Sat May 23, 2015 11:12 am

I had a little fun riding the bike for a short time last weekend on my parent’s property. I was quite impressed with the power the little 250 has. It was fun hanging on when the power kicked in and going through the gears for the first time. :lol: She was out of control going up and down my folks unsealed drive way, which just added to the excitement. Well until I thought I had better stop doing that as even though it was fun it was just a tad risky. [-X So rode it back and let it idle. After a few minutes of idling it just cut out again and wouldn’t start.

Ok here we go again. More pain, I did the following:
I have checked the stator coils all yellow wires 0.9 Ω specs 0.3 – 1.0 so that’s GOOD.
The Exciter coils that share the red as the common point, black – red =135 Ω (Specs 90-170) so good & red –white = 5.0 Ω (Specs 1.0-3.0) no good?
RED – WHITE is a little out of specs.

Funny though bike will run like this though and re testing the windings when the bike will not run and I get the same results.

So, go figure, my argument/confusion is: if the winding as tested are a few Ohms out but it runs then should I replace them?????? I think it will be fine, I don’t think this is the issue with the bike cutting out.

From my understanding is if the Stator failed this will not cause the bike to instantly cut out, however it will not charge the battery and when the battery goes flat then the bike will not run.
Pickup Coils are 119 and 121. (Specs 121-151 Ω) so that is very close.

Just came in from working ok bike this weekend. I went through the complete wiring again checking electrical connector terminal for tension etc. found one of two a little loose so I fixed them.

Tested ignition coils:
Primary side on both coils tested at 0.7 Ω (specs 0.17-0.25 Ω) so a little out.
Secondary sides couldn’t get a reading, so I tested the leads separately they were ok
Tested the spark plug caps on the leads couldn’t get a reading on them???? So took some of another bike I had and tested them and got continuity. Fitted them on tested for spark all was good. Two kicks and it fired up nice on both cylinders.

Had it running for five to ten minutes and was hoping all would be good but deep down I had this feeling that wouldn’t fix it. “DAM IT” Don’t you hate it when you are write she eventually cut out again. Funny thing though was when I touched the CDI unit with me finger it stopped. Coincidence or the issue? I am still scratching my head.

Also checked the timing marks and cylinder phasing and all is well.

Anyone got a spare brick wall they won’t to lend me so I can bash my head against. That will be more fun than trying to fix this bike. :(
Cheers 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: Help needed with my KR A2

Post by TurboStew » Sat May 23, 2015 12:17 pm

Came in and had tea and wrote the above message. Was feeling a little curious about the CDI unit and bike cutting out when I touched it. Went back out and started the bike as it had cooled down. So I touched the CDI and the bike cut out again. Did this a dozen times and it stopped every time. Fiddled with wiring and connectors with bike running and it didn’t miss a beat. Touched the CDI unit one last time and the bike cut out. I don’t think I will be needing that brick wall. LOL just a CDI unit 21119-1135 ND 070000-1270. :D
Anyone got one for a good price?
(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: Help needed with my KR A2

Post by Skyeport » Sat May 23, 2015 10:48 pm

Hi Stew,
I'll have a look at what I have. Think I might have a few spare CDIs.
Which side CDI is it left or right?
Glad to hear the bike is up and running, mostly.
My project has stalled a bit, all bearings & seals replaced in bottom end though.
Skye

TurboStew
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Re: Help needed with my KR A2

Post by TurboStew » Sun May 24, 2015 5:12 am

Its the RHS when sitting on the bike, the one with the white connectors. You can also check my last post for the part number. Thanks

While I have you all I also have another question about the bike. She blows a lot of smoke, it gets a little better when wormed up. I have had 2strokers before but running this bike smokes out my garage - drive and the neighbours place. I have had a bit of a look on YouTube at the posts of them running some have hardly any smoke and some quite a bit.

My top exhaust pipe is the worst, rear cylinder, its smoking really bad. I was talking to a guy a while back about the bike when I firs got it. He told me these bikes were known to blow some seal in the engine/gearbox or something to that nature and will empty the oil into the rear cylinder and eventually the crank will spin the main bearing because they run out of oil.

Anyone know what seal this bloke would be talking about? is it easy to check?, Replace it? Pictures would be good if anyone knows about this.

Note: I have checked the oil pump injection system for adjustment, its good at idle but a little advanced on full throttle at the moment. I have tried to adjust this out by adjusting the slack out of the throttle cables. adjustment is a little better but still a little advanced. but still smoking like an olden day smokers convention.

Thanks again all for your support and assistance
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: Help needed with my KR A2

Post by Skyeport » Sun May 24, 2015 6:30 am

Hi Stew,
There are a few CDIs on ebay?

I have 3 sets, but don't know if any work yet.
Could always send a coupple down for you to try out?

As for seals I don't know which one might cause the excess smoking, but all are readily available from bearing shops, they are not strange sizes or anything. I seem to recall that there was only one seal in the engine that was only slightly too thick off the shelf, but there is enough room to make it work.
If it is the crank seals I think it's a split the cases job to replace. Only did it a few weeks ago but couldn't tell you if it can be done without splitting cases? Memory fading :roll:
Skye

TurboStew
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Re: Help needed with my KR A2

Post by TurboStew » Sun May 24, 2015 6:43 am

Hi Skye, Yes I saw the ones on EVIL BAY, price a little steep I think but if no one can help I will bite the bullet. I will send you a TXT. Have you got those CARBS freed up yet????

Found a post on the smoke/oil issue and if it's a seal yes sadly it looks like it's a case split. Was trying to avoid doing the engine. :evil:

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: Help needed with my KR A2

Post by Skyeport » Sun May 24, 2015 7:01 am

Just today I was cleaning up my pigsty/shed & applied heat to the carbs as you sugested. Bingo freed up the stuck slide. Still one choke stuck but hace soaked it with inox to see if that helps.

TurboStew
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Re: Help needed with my KR A2

Post by TurboStew » Sun May 24, 2015 7:15 am

Well done Skye, top effort. =D> I am so glad for your success with the carbie, a little heat on the choke as well and it should also come free. I am happy my trick worked for you as well. Keep it soaking then hit it with heat.

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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StrokerBoy
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Re: Help needed with my KR A2

Post by StrokerBoy » Thu May 28, 2015 8:54 am

Glad you've probably found the cause of it cutting out. =D>

For info, although the 2 CDI units are different, you can interchange them with a minor change to the wiring, it's only the sidestand safety cut-out that one has and the other doesn't.
Kawasaki KR250 Tandem Twin (x4) & KS-II 80,
Yamaha RD350LC,
Suzuki GSX-R750RK & RB50 Gag.

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