First run out and it breaks down.

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peleno2
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First run out and it breaks down.

Post by peleno2 » Sun Jun 30, 2013 3:48 pm

:?: Right, new chain and sprockets on, new plugs etc etc, and we"re ready for a maiden voyage.
Start up the bike this morning, runs lumpy for app 90 seconds then fires correctly and sounds fine. Run it approx 40 miles, never misses a beat. Stopped for a minute, then tried to restart, ticking over like in the morning, but won"t rev at all.Took the panels off to get to the plugs, even found a "plug spanner", (well it says that on the spanner!), both plugs were firing??
Anyway found a cafe, had a brew and a butty, went back to it, same again for about 2 mins. I then drained the carb float bowl screws, just incase. Still the same again. I let it rumble along on sort of tickover, then it just burst into life again! Ran it another 25 miles again till it cut out, (near home). Pushed it 200 yards, then free wheeled it on tickover, put it in second gear, and it was off again. Got home ok, then tried to start it 2 mins later, same again. :?
Anybody any ideas? It seems electrical too me.


Also, the bellypan was full of oil, is it from the shock?? :?:
Oh almost forgot, i get a sort of whirring noise when its cold, could it be the waterpump impeller, its that kind of whirr, gets louder, then just stops!.

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Top-shaggy
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Re: First run out and it breaks down.

Post by Top-shaggy » Sun Jun 30, 2013 5:08 pm

Does the whirring sound stop when warmed up and also stop when you pull in the clutch?

Other stuff - Could be electrical or could just be muck in the carbs? Has it got fresh petrol in the tank? Is the tank cap breather clear? Water in the petrol if been left standing?

I've had all these problems over last couple years and all seemed like yours! Sometimes it's the simplest thing :wink:
If it takes more than 2strokes then your just playing at it..

peleno2
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Re: First run out and it breaks down.

Post by peleno2 » Sun Jun 30, 2013 7:44 pm

The whirring stops when it warms up, so is that normal?
As for the petrol, it came three quarter full, i filled up with Super unleaded and did add 100ml of some super carb cleaning stuff, that was recommened on the triple site, and it worked a treat on my Z650.
Do you think its the low speed pick up coils breaking down when hot? i know this is still a problem with the Kh400"s, and there is a kit, or maybe i could get them rewound?
Its frustrating, as you don"t know when its going to stall and not start again.
Its firing on both plugs, but just won"t rev, so the pick up coils seem the most obvious?

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Binetta Steve
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Re: First run out and it breaks down.

Post by Binetta Steve » Sun Jun 30, 2013 9:23 pm

Is it stopping when the sidestand is down? , these bikes are legends for ss switch problems. Make sure its up when you try to start it.

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the KR kid
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Re: First run out and it breaks down.

Post by the KR kid » Sun Jun 30, 2013 9:47 pm

In all my years of ownership of this bike I never had it cut out on me, and was quite reliable. The only issue was the cold starting, and by all accounts they all do that!

The petrol was fresh a few weeks before I sold it, so shouldn't be the problem. I started the bike at least once a week when it wasn't being used, let it warm up, and it revved freely; never cut out.

You changed the oil when you got the bike; did you torque the nut up properly? Might be the problem with oil in the belly pan, as I only ever had to wipe mud out of it.

I must admit I have never touched the carbs, so fuelling problem might be the answer there. Also, are you switching the petrol tap from prime to run once the engine has started? If you had the tank off to change the plugs are the fuel lines pinched, as there's not much room under there and is easily done!

The cylinders have seperate CDI boxes, one in each side of the fairing. As far as I know they are different and cannot be swapped over.
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StrokerBoy
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Re: First run out and it breaks down.

Post by StrokerBoy » Mon Jul 01, 2013 11:18 am

peleno2 wrote:Stopped for a minute, then tried to restart, ticking over like in the morning, but won't rev at all.
They all do that Sir ! :mrgreen:

Sounds like the infamous KR starting problem to me. The engine will fire and either tickover badly or just run on one cylinder but won't take any throttle and can't seem to wake up. Mine does it when it's warm. Try a pushstart - turning the engine over faster than you can manage with the kickstart seems to help.

Allegedly, all those cogs and dampers that mesh the two cranks together develop free play over time and because it's got disc valves that sends the timing out just enough for it to run but not rev. Try moving it in gear before you start it, you might take up the lash in the gears.

I've never bothered to strip my engine to fix it, I just live with it. I know that it'll start eventually, it just gets a bit embarrassing at the petrol station when you have to push it. But there's a section in the workshop manual that explains how you can correctly shim the crank dampers which - supposedly - fixes the problem.

I'll get round to it one day... :oops:
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Re: First run out and it breaks down.

Post by StrokerBoy » Mon Jul 01, 2013 11:31 am

By the way, once mine's running properly, it never cuts out, coughs or stalls, it'll run happily all day. It's only once you've stopped it that you get the restarting problem.

Someone suggested pickup coils breaking down to me too, I've never looked into it but I suppose that any minor electrical/fuelling/mechanical imperfection (the engine is almost 30 years old after all) will all add up to less than perfect running.

There's an awful lot of stuff whizzing round in the cases compared to an ordinary parallel twin, I suggest the whirring is normal.

The 2 CDI units are different and not directly interchangeable, but the only difference is that one has an extra wire for the sidestand/clutch safety cut-out, so with a bit of thought you can actually swap them if required.

Check the oil level and the sump plug. Mine gets a bit of oil in the bellypan, it's leaking from the gearlever shaft oil seal in my case.

And get some photos up ! =D>
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peleno2
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Re: First run out and it breaks down.

Post by peleno2 » Mon Jul 01, 2013 12:10 pm

Ok, i don"t think its petrol related at all, due to the fact it doesn"t misfire, cough or splutter when its running on both cylinders. As for the starting procedure, i would only use the Pri position, if i"d just filled up the tank and the carbs have been drained. The on position relies on the vacuum from the engine, so if the bike is used regularly there is no reason for the carbs to be empty, am i correct? I have a similar set up on my Z650 and never use the pri position.

I understand you on the starting Tim, but when i pulled up at a set of traffic lights it just cut out on one cylinder then wouldn"t rev. This does seem strange when its already running.
This was why i thought of the pick up coils, breaking down when hot, which was a common problem on the Kh400 CDI.
I"m not sure how long Gary ran the bike for, when he started it once a week, maybe it didn"t get hot enough for the fault to appear.
I did try it out Sat aft for approx 2 - 5 mile runs, and it ran faultlessly then, but Sunday i did cover 40 miles before stopping it.
As for the oil leak, i"ll take off the bellypan and see if its coming from the gearbox shaft. :?

Thanks for the info, i"ll see if it starts either tonight or tomorrow, which surely will indicate something is breaking down when warm.

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StrokerBoy
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Re: First run out and it breaks down.

Post by StrokerBoy » Mon Jul 01, 2013 12:27 pm

peleno2 wrote:when i pulled up at a set of traffic lights it just cut out on one cylinder then wouldn"t rev. This does seem strange when its already running.
I do tend to blip the throttle a bit at traffic lights, just to prevent the revs dropping below the point at which it might not pick up again.
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JanBros
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Re: First run out and it breaks down.

Post by JanBros » Mon Jul 01, 2013 2:09 pm

StrokerBoy wrote:
peleno2 wrote:when i pulled up at a set of traffic lights it just cut out on one cylinder then wouldn"t rev. This does seem strange when its already running.
I do tend to blip the throttle a bit at traffic lights, just to prevent the revs dropping below the point at which it might not pick up again.
that would mean your air-screw is set too rich
You know it's cold outside when you trip over dog shit instead of standing in it.

peleno2
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Re: First run out and it breaks down.

Post by peleno2 » Mon Jul 01, 2013 7:12 pm

I"ve pulled off the bellypan, and the oil is coming from an overflow pipe, (there"s a bunch of about 4) its the thickest one, engine breather pipe? :?:
Put the new plug back in, kicked it up, took about 4 kicks, burst into life 1 cylinder again, let it rumble on for the best part of 2 minutes, then a different tone, lovely back on two, let it run for about 5 mins, stopped it, then started it again, no problem fired on two.
This certainly is one quirky bike! :)

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the KR kid
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Re: First run out and it breaks down.

Post by the KR kid » Mon Jul 01, 2013 8:01 pm

Attaboy! :lol:

That sounds normal (for a KR) to me. Just remember, NNNOOO throttle while it's running on one, and the 2nd will join in when it's ready. Have to think slightly differently with a KR, it's a completely different animal to your KH's, lol!

Check the manual I gave you, it'll have what each of those pipes is for in there.

Incidentally, only use prime on the fuel tap when starting from cold; all other times just leave it on.

When I very first got the bike many years ago it wouldn't idle properly. Had a play with the idle screws on the carbs and that sorted it out, ran sweet ever since. Wouldn't hurt to take a look at them again if it's cutting out at a standstill. They are very touchy to adjustments, so may have vibrated out of adjustment over the years.

Quirky is good!!!! :D
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Top-shaggy
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Re: First run out and it breaks down.

Post by Top-shaggy » Mon Jul 01, 2013 11:02 pm

I'm still promising myself a 'quirky ' KR250A 8)
Agree quirky = character... It's got soul :wink:
If it takes more than 2strokes then your just playing at it..

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Re: First run out and it breaks down.

Post by Cexley » Sat Sep 29, 2018 9:09 am

I have ALL these problems on my KR250A. Is it the same bike?...

I also had a leak from the gear shift shaft oil seal, which I’ve replaced (Part still available from Cradley and an easy in situ job). However, gearbox oil is still appearing in the belly pan, which is also coming from the gearbox breather. The gearbox oil level is on the high side, so I assumed it was dumping a bit of excess out of the breather, so I reduced the level to nearer the ‘low’ mark on the glass, and it still does it (along with all the cold and hot starting problems described here!). Is it due to leaking crank seals or disk valves increasing pressure in the gearbox?

I’m reluctant to start a major strip down only to find it is some new ‘quirk’ I didn’t know about.....

In all othe respects, once it gets over its cold start sulk, it runs like a scalded cat, ticks over fine, starts first time, every time when hot, but returns to being a total PITA as soon as it is left more than 10 mins.

So frustrating trying to do root cause analysis on these unique machines! Can anyone help re the gearbox leak? I’ll move onto the infamous starting issues once I’ve sorted the leak, (or be forced to do the crank shim adjustments if it means crank seals....).

All advice on this latest querk would be appreciated.
KR250 Tandem - Love It
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Binetta Steve
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Re: First run out and it breaks down.

Post by Binetta Steve » Sat Sep 29, 2018 9:22 am

If you pm peleno 2 if he is using the same email as in 2013 he will get a message. It might be the same bike! The above advice in the thread gives you some startling points. Re top shaggy comment fom 2013 quirky = character I disagree quicky = pia. Thats why i sold my classic BSA i just never knew what trick it would pull next!

Good lucknwith your root cause analysis

Steve

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