Xs 250 dies after a run out.

[Jamie S]

Our Xs250 dies after a run out, well in fact it dies if you stop it (I meen it doesant start again ) Ok so we did 30 miles on it with the tick over turned up a bit so it wouldant stop(my dad has a tendancey to stall the bike at junctions lol ) , It was fine when runing, As soon as the engine is shut off it just wont start till the next day. I think it could be:
1. the coils braking down.
2.sompthing to do with the points.
3. sompthing electrical ?

^Any advice would be apriceated^

Also I did a compresion test ( because I found our mislayed compresion tester) And the right cyinder is loseing compresion so I take it the piston rings have gone on that side ?
the left is fine.

^any advice would I would be grate full of^

Also were could I get a set of piston rings if it is them ? and how much do you think it could be ?

plz note i couldant get the spell checker to work just now so dont have a go at me !

[Blau Zedong]

It's punishment for owning an XS250 .

Seriously, these bikes are known for having ignition systems based on entropy rather than common sense, I would suggest attention to timing and coils / condensors. You'll need to give us some figures for the compression before we commit to anything....could be a valve issue rather than piston rings. Have you set the vale clearances properly?
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Jamie S]

thats a thought I havent even looked at the valve clearances.

[Dalemac]

sompthing = something
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YBR125 -> GPZ500S -> SL1000

[Jamie S]

Any help with the problem ? no ? didant think so.

[Dalemac]

yes. i helped with your grammar problem.
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YBR125 -> GPZ500S -> SL1000

[Jamie S]

if you say so, right now go away unless you can help with the problem with the bike.

[Whosthedaddy]

[Dalemac]

[WavyGravy]

the bad hot starting might be down to something expanding when hot and settling back when it cools down, could be anything in the electrics, check the connectors that carry current when the engines running, if its points ignition check the condensor, try fresh plugs, has the bike got the correct plug caps fitted? avoid temptation to buy new rectifier etc until youve really established where the problem lies, it only makes spares suppliers rich.

low compression could be the rings, or the valves not seated properly, or worn valve stems/guides or missing valve stem oil seal (if it has them). it doesnt cost anything to loosen off the tappets and redo the compression check, might just be a tappet is too tight.


The problems could be linked, what's the condition of the plugs? oiled up?


just some ideas
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1975 CB125s, 1991 GN250, 1990 Ducati Paso 906
"Don't wake him up - He's got insomnia - He's trying to sleep it off"

[finpos]

I'd go for a new condensor first.

finpos.

[yambabe]

I think this may be a common thing with these bikes, the XS250 we used to have did exactly the same thing. We could run it for so long (I was learning on it at the time so it was mostly 1st-3rd gear stuff on a car park) then once it got to a certain temp it just wouldn't re-start.

Himself reckons it was because the fuel was vapour-locking.

We certainly didn't have to wait til the next day to get it going, it usually took about a 10-15 minute wait for it to cool off a bit and then a BIG handful of throttle as you pushed the starter button next.

If that's what is wrong with yours too there isn't really a lot you can do about it except wait for it to cool off.
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Sod falling in love, I wanna fall in chocolate.

[yambabe]

There's some quite detailed stuff about the cause and effect of vapour lock on Wiki: https://en.wikipedia.org/wiki/Vapour_lock

It's not so common in modern engines apparently, but was still quite rife when your XS250 would have been built!

[yambabe]

He also says check the valve clearances cos they may be too tight.

Apparently the main problems with these bikes is to actually set the ignition timing properly. Although it's a points system so fairly simple you have to make sure the cylinders are running the same or the bike will never run right. He says, and i quote, "Getting the advance and retard set up correctly is a real bastard, you have to do it one cylinder at a time".

One last thing, your dad turning the idle up could actually be contributing to the not-starting problem as it may be flooding the engine once it gets hot.

He says check and clean your float bowls too, that may help.
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Sod falling in love, I wanna fall in chocolate.

[Gradog]

As Finpos has suggested, the condensor would be the first place to check, re the restarting, and as far as compression, the XS was always prone to valve problems, and needed careful setting up. It was one of those bikes that you can tell if it is right by the murmor of the valves, getting louder meant they were coming loose again, but almost no noise and they were over adjusted. I used to have to loctite the valve locking nuts to keep maintanance down.
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Grey haired bikers don't get that way from pure luck. Only a biker knows why a dog sticks his head out of the car window.

[Jamie S]

hello, i think i have sorted it ( one of the points wasent opening all the time, only some times ) but got a new problem after playing with the air/fuel mixture screw (i have a new thread on it called can some one help me in the workshop section)
cheers
jamie stokes

[Jamie S]

here is a link to the new problem


https://bikechatforums.com/viewtopic.php?t=107618