Why do bad things happen to good motorcycles?
 

My Dommie has done about 40-45000 miles, 20,000 of them across Africa.
Valve clearances were adjusted about 8000 miles ago.
Everything has been great until last week.

First I got the occasional misfire. Soon it got worse and would idle fine, then cut out as I applied the throttle.

Replaced spark plug and CDI.

Still misfiring. Seems to start when it gets warm. As I tried to ride it to a garage yesterday it was groaning and ticking (with spark frequency). Cutting out and no power. There's new oil in it and plenty of it! I took the oil filler cap off and there was some bizarre smoke (steam?!) curling out. Never seen that before...

Leaving it to cool allowed me to get it to the garage. The bike was not overheating according to the oil temp gauge - normal operating temp seems to be 220 f., yesterday only reached about 140 f.

Help appreciated, especially if it turns out to be something easy I can do myself....

did you check the spark plug lead itself and the ignition coil (check it's temp, v hot means v knackered).

what about the fuel pump? when it's cutting out take the fuel pipe out (the bit that goes from fuel pump to carb) to check it's not on the blink. Point it away from the engine and your lit ciggie!

it's not your air blockage thing again? Fuel tank breather is clear?

Hello mate

Gonna change coil/lead. Was gonna do that in malawi but 2 coils got "lost" in the "post"...

Howzabout some lager soon? Email me with your availability mate...

getting the hell out of the smoke at the end of the month. man, so many "oh my god" stories from the nhs...

up for a beer anytime this month, pretty much. you still idle?

at least you know it's not gonna be water in the tank, with the lack of rain.

Still idle. Can't knock it. Will email you re. booze...

Sime,
Check the carb to head rubber manifold for splits and make sure the carb hasn't popped off it's flange.A bit of "smoke"(it's vapour really)is pretty normal when you open the oil cap when the motor is hot,don't worry.If still no joy,re-check the valve clearances to be sure one hasn't tightened up.
Jon.

When this happened to me on an XRL, the temp looked normal because the oil level had dropped off the end of the dipstick!! Still, if you say there's oil in it ;-)

Had mega problems trying to get a Suzuki DR200 to run properly (high rev misfire and felt like it was running out of fuel), turned out to be the sidestand switch, easy to bypass and got to be worth a look.

Phil

Doug / Simon,

Let me know if / when you guys are going for that beer. Keen to catch up and have a few.

cheers
Matt

Thanks for all suggestions so far...

Misfiring problem is gone after new coil fitted, and was running perfectly for 20 miles yesterday, then unpleasant ticking/clunking noises and loss of power.
Basically sounds like something complicated, expensive and nasty, but seems to be intermittent. When it's not doing it, it runs grrrrrreat.

I just had a few problems with the bike not running properly and it turned out to be the main earth wire by the battery might be worth checking.

Embarrasingly I had to call out the AA to a drizzly M3 hard shoulder when I was delivering my '89 Dommie back home. One of the wires in the suppressor circuit just above the coil was grounding against the frame intermittently, causing misfiring and dying.

I went through all of the stuff discussed by the road - earthing nr battery, carb jets blocked, you name it. Eventually the AA man twigged that he could force it to cut by turning the bars, which pulled the wire and touched it on the frame. Frustrating. Perhaps you have a problem like this?

...unless there really is some obviouslyt mechanical noise going on... PS > I think when the bike is running you can (carefully!) take off the oil tank cap and shine a torch down - you should be able to see healthy oil flow from the returnn pipe. Might put your mind at rest about faulty oil scavenger pump.

Keep us posted, eh?

It will be the stator I think.

I come from an XR600 background and the stators crap out after many mnay miles.

Bascially swap out a stator and give that a shot.

unless the battery is boiling, I doubt its the stator/regulator/rectifier, but check the battery. an XR6, having no battery, might indeed have these symptoms from a failing stator.

if its taking a while to go wrong, it sounds likely something is heating up and breaking down. as you've already done the coils, its likely to be something else - CDI, dodgy switch etc. some have "potted" components that take a while to get hot and bothered. if you're unlucky, one thing will have caused the other and it used to be said that you had to swap coils and CDI/ignitor together

CDIs generally do not get hot.

The classic symptons of a stator failure are very hard to start and then when hot cutting out.

Spark is also very weak.

I did not mention regulator/rectifier. They normally never go out.

The oil soak that the domi uses for it's stator is not healthy to stators. The insulation comes off and makes it useless.

If it was the regulator/rectifier then he would be blowinglights and genrally not be intermittent. It would be a black or white issue.

Apart from obvious (like all wires are connected) then I'll stick with the stator .

Even though the domi/XR650L have entire diff electrical systems, the oil bath destroys stators.

XR600 riders on long trips know to carry a spare stator as replacement.

Anyway the real test is to swap one out. Inspect it and see if thw wires are going.