Poor head light

Cexley · Post by **Cexley** » Sat Dec 05, 2009 10:44 pm

Flywheel bolt seems tight. There is verrry slight play when rocking the rotor back and forth - maybe half a mil at most (big end play - great). No up/down or end float. No debris inside the cover and coils look good. The two wires to the pickup at the bottom look ropey. I'm suspecting everything now!

How do you test if ignition coil is packing up. Could it be a load based issue, that only manifests itself at higher revs?

I'll investigate further in daylight.

smithyrc30 · Post by **smithyrc30** » Sun Dec 06, 2009 12:06 am

Cexley wrote:Well....

Only thing I couldn't check was the regulator (needs a load of batteries connected in series etc), the CDI and the ignition coils.

Just put it all together and went for test ride in the pi$$ing rain (will it ever stop?). Anyway it was a lot better. All the lights, indicators etc behaved normally with slight dipping of headlight at idle and steady headlight strength at all revs. The indicators also flash 'normally'. They were flashing faster and faster the higher the revs and the headlight went bright when I put the brakes on (weird).

From an electrical viewpoint, all is normal. However, although better, the engine still won't pull cleanly thtough the revs. It feels like it is holding back. Occasionally it will all chime in and the show starts to take off like a 2-stroke should, then it goes off song and starts bog down. It feels like the ignition timing is randomly retarding the ignition.

I need help. This is now turning into some sort of forensic exercise! Is it the CDI or coils?

Ok it sounds like your electrical system is working ok in respect of charging. You don't need all the battery nonsense if you have a meter with a diode checker on it. It will be a symbol with a solid triangle with a bar at the pointed end. If you look at page 14 of the electrical section 15a, there is a circuit diagram of the regulator.

To check your regulator, set it to diode check, put the positive connection to one yellow wire and the negative connection to the white one. If it bleeps god. Reverse them, it should not bleep, if it does the reg is screwed. Repeat for the other two yellow wires. Do not connect to the brown wire there is a thyristor in there which limits voltage and it will give you a false reading.

Not sure how long your has been standing, but mine had been standing for over a year. When I put it all back together, it ran poorly, had no pick up and then when it hit 9000 spitting and coughing it took off like it should. A few wide open blasts through first and it gradually came good. I guess it was just a build up of crap, seals not working to their best etc. I would say that using it seems to keep it healthy.

One thing to be very careful of, and I'm not sure if yours has been apart, but if it has it most likely has not been put back together right. The wire bundle that comes from behind the rotor needs careful positioning, otherwise the wires can rub on the rotor, wearing through the insulation. This eventually will short out and then proceed to fry one or other of the coils behind the rotor. Believe me an 8km push is not ideal in 30 degrees... Not that you will get that there at the moment....

The pick up wiring is a bit susceptible to corrosion, so that is a good call.

Checking to coil under load is very tricky unless you have a tester. Best way with the coil is substitution for a known good one. Don't know if anyone lives near you who would/could loan you one to test on your bike.

If your meter has a diode checker, you need to check the diode block. Not sure where it sits on the bike (I think it is near the regulator, a black box), but basically its function is to protect the CDI from the back EMF from the coil, it is connected to the coil feed, the side stand switch and the kill switch. The two switches are connected to the CDI and so need protection through them so they don't blow it up. When your coil field collapses, it generates about 40000volts at the plug electrode, the trouble is it develops about 125 to 250volts in the primary when it does so. This is for a very brief period, micro seconds, which bulbs and the like can handle easily. Electrical bits like CDI units can't so they need protection. This is what the diode block does. You need to check across the block with it disconnected it the same way you did the rectifier. Meter on diode, then put the positive onto the brown/white wire position, and the negative on any of the outputs. You should get a bleep. Reverse them and you should not. Check the other two.

Personally I would not suspect the CDI until everything else has checked out. In my experience they either work or they don't. I'm not saying it never happens, but I have never seen one break randomly, i.e. be good then bad and vica versa.

BTW, the headlight getting brighter when you pull the brake on is quite normal with old electrical switches. As they age the copper corrodes and the resistance across the contacts increases, reducing the voltage to the bulbs. When you pull on the brake, you add another earthing path to the circuit, hence increasing the voltage, so the bulbs glow brighter. You might see the same with the indicators, but there are multiple connections there and so the effect will be smaller.

In the other post about electrics, you mentioned 4volts.... Is that from the battery before you re-filled it? If so that is one well phaarked battery.

Cexley · Post by **Cexley** » Sun Dec 06, 2009 1:02 am

Hi Smithy. The 4volts was what the generator/regulator was sending to the battery without the battery connected and revving to 4k. Battery was suspect earlier in this saga, so I have now replaced with a new one. Today I cleaned up the connections in the fuse box and both earths and did all the other checks mentioned. Now reads 12-14v as specified, so must have had cr@p connection somewhere. Anyway, thanks for a load more helpful advice and tips. I will have another round of forensics tomorrow and see what I find.

Also, yes the bike has been stood for years. Not sure why a good thrashing should sort it. But as you say, seals go hard etc. I torched out the spannies thinking they were blocked up and causing too much back pressure. I still suspect them as bike seems more willing to rev since burning them out, but things still aren't right. When I raced TZ's back in the eighties (showing my age now) I rememeber getting a lot of heat seizures on one particular TZ250G. It would pinch up when flat out down straights (very bowel losening experience). A fellow racer freaked me out by taking a hacksaw to the tailpipes where they joined the expansion chamber. The exit diameter was less than half what it should have been due to carbon build up on the weld where the tail pipe met the expansion(nasty side affect of Castrol R). Anyway, a new set of expansions (ouch) and the thing went mental.

Anyway, I'll go for an early morning thrash and see if the old dog can clear its lungs out. Thanks, Craig

smithyrc30 · Post by **smithyrc30** » Sun Dec 06, 2009 3:43 am

Yeah the 80's.... I remember them too.

250LC's in the proddy class...

A mate of mine raced a TZ250, I think it was an F, the last one with the wire wheels. at the Darley Moor club (localish track to me) there were about 6 bikes in that class, and 4 of them were out because it was a Sunday. He nearly always got a 1st or 2nd.... Except for the time he forgot to put the retaining pins back in the brake calipers....

The 250 production was nearly always over subscribed. If you didn't get your entry in early then you weren't racing... Mad sessions, elbows knees, barging, anything to get through the first corner ahead.

I don't know why they go funny if left for a while. I think what you have done so far has been small pieces of it, the pipes, the electrics, and I'm guessing the carbs need to get some air and fuel through them and the reeds need to get some oil over them to make it all sing along. I never could work out why they went better if you thrashed them. Brings back memories of 'running in' the LC down the A38 at 10000 in top.....

Ah the good old days of Pro2, total loss ignition systems (ahem), crap tyres, crap brakes and youthful invincibility.

Cexley · Post by **Cexley** » Sun Dec 06, 2009 10:57 pm

My head now hurts. Took KR1 out this morning for a serious thrashing and things looked promising as it cleared its lungs and smoked out the A3. It even reluctantly revved up to the red line and then went back to its old habits and limped home all bogged down and refusing to rev or pull cleanly.

It is just like the ignition has retarded or the CDI has lapsed into 'limp home' mode. It also seems to be heat related as well as it shows signs of running cleanly when the engine is cool and deteriorates as it get hotter.

All electrics and instruments etc are working normally. KIPS valves working normally. There is no misfiring or spluttering - it just goes gutless and refuses to rev out. If I try and 'force' it up the revs, sometimes it will clear and show signs of taking off, but mostly it gets worse and worse the more you try and force it to clear. I'm at a loss. Has anyone else experienced these exact symtoms?

JanBros · Post by **JanBros** » Mon Dec 07, 2009 1:15 am

maybe just the carb settings are completly wrong ? a bit too rich when cold, and going to way too rich when hot ?

checked the colour off the spark plug's ?

Cexley · Post by **Cexley** » Mon Dec 07, 2009 10:44 am

Good point. It starts 2nd kick every time and is off choke within 30 secs. I dropped the needles to the 2nd slot. Carbs are running standard jets. Could it be float heights? There is no sign of flooding. Also swapped from iridium back to standard plugs with no improvement. Could it be reed valves? I'm scratching around at anything that I haven't yet checked or replaced etc. It does seem to be fuel, but it is the way it turns 'on' & 'off' that makes me think it is ignition. Fuel is usually more gradual, this seems to be like a random retarding affect.

I'll give it another thrashing and do a plug chop.

scooble · Post by **scooble** » Mon Dec 07, 2009 11:11 am

Not sure if it is an ignition/retarding problem.
I once had a problem with my TZ ignition once where it would not advance at high revs. The engine would still run and rev to 12K+, but only produced 60bhp. I had the system checked by an ignition specialist (wish I could remember who), they put it on a rig and the 'curve' was flat at the top.
Did you say you changed the coils? I know others have done so and noticed a big improvement, trouble is, if the coil is on its way out, it will probably misfire and then 'oil' the plug which could also mask caburation problems.

A very silly thing happened to me on a proddy KR1 when I put the air filter under the plastic grid and the foam eventually got sucked into the inlet - figured it out eventually. Also had a dodgy fuel tap with a 'birds nest' in it. It would flow fine at low load, but as soon as it ran the float bowls dry it would splutter. Slow down and it was fine for a while and pulled to the redline and then died again

Bikemike · Post by **Bikemike** » Mon Dec 07, 2009 10:19 pm

scooble wrote:. Also had a dodgy fuel tap with a 'birds nest' in it. It would flow fine at low load, but as soon as it ran the float bowls dry it would splutter. Slow down and it was fine for a while and pulled to the redline and then died again

That's interesting, I have had the same problem. I very rarely hold her on full throttle for too long (licence), but there is a nice long uphill straight nearby so I thought I would really open her up. I got exactly the symptoms you describe above.
I'm of to ebay for a fuel tap rebuild kit now.....

Mike

kwackman12 · Post by **kwackman12** » Mon Dec 07, 2009 10:23 pm

Blocked exhausts?

Cexley · Post by **Cexley** » Mon Dec 07, 2009 11:10 pm

So does turning the fuel tap to 'prime' prove the point? If it still chokes up, then it has to be exhausts. Failing that, it is back to ignition system forensics.... This is turning into Ground Hog Day! OCD could be a distinct advantage in KR1 ownership.

smithyrc30 · Post by **smithyrc30** » Tue Dec 08, 2009 4:32 am

On the KR the tap has a vacuum diaphragm to operate the on and res positions. The prime does not require the vacuum take off.

However thay are all fed off the tubes in the tank. If these are blocked then no, being on prime will not prove it. However if it is the vacuum hose or the diaphragm leaking then yes it will.

The vacuum gets lower as you open it up more, and if there is a leak in the vacuum system than it will have a bigger effect as the throttle is opened more.

Cexley · Post by **Cexley** » Sun Feb 07, 2010 6:22 pm

Right. Having convinced myself it is not electrics, I have returned to carbs & expansions. Stripped the carbs and meticulously set float heights and also replaced stock KR1 spannies with some KR1S expansions. Carb needles set to 2nd slot (from top) and now it actually revs out, but it still goes sick in the mid range and still randomly goes off the boil (like half way past overtaking someone - nice....). It still aint right, but a lot better. It is driving mental. I just can't put my finger on whether it is electrical or fueling. Are all KR1's posessed?!

Bikemike · Post by **Bikemike** » Sun Feb 07, 2010 8:25 pm

Cexley wrote: Are all KR1's posessed?!

Yep.

Cexley · Post by **Cexley** » Sun Feb 07, 2010 9:54 pm

Does anyone's KR1 fuel cleanly? Am I wasting my time on this SOB? Do these damn things ever run right?