Xs250 Cuts Out When Hot And Leaks Petrol Through Air Filter?

[Jamie S]

Hi , the Xs250 is all back together and running after having new piston rings , any way the bike cuts out when hot ( used to do this before the rings were done) any idea what it could be ?
The bike runs fine for 20 or so miles then cuts out and refuses to start ,if we leave it 30 mins or so it will fire straight back up , any ideas what it could be??
(I'm thinking something electrical braking down when hot ?)

Also fuel is leaking out of the air filters when the bike is stationary (both air filters), so I stripped the carbs down and gave them all a good clean out but it still does it , it never used to do this before the rebuild.


Any help much appreciated.

Jstokes.

[halo123.]

hi jamie
I would suggest check that you have the correct sparkplugs.
For extended use as my gs did same put in new plugs and problem gone.
Cause its like it over heats plug, not the correct heat range or some thing.
edit
check here
https://www.ngkspark.com.au/part_index.htm?https://www.ngkspark.com.au/PartFinder/spark_plug_vehicle_type.php

YAMAHA 250cc XS250PK/SK/R
Spark Plug Part No. Plug Gap
Recommended Plug D8EA 0.7
Iridium Option DR8EIX 0.7
or
YAMAHA 250cc XS250/C/H/RH/SE/SH
Spark Plug Part No. Plug Gap
Recommended Plug BP7ES 0.8
Iridium Option BPR7EIX 0.8
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Halo123. =Techie/geek and bike rider ,
current bikes owned ,fix me upper gs 500e missing cdi
cbr 250 virgin colours

[Nath]

Check your float valves are sealing shut. Take the float bowls off one at a time, and hold the floats up whilst turning on the petrol. When you let the float drop petrol should start coming out, and stop flowing when you lift the float again. If both the floats are working fine you might have to adjust the heights. Could also be a punctured float.

When the bike cuts out, is it at normal running temperiture, or is overheating and running like a bastard and then stalling?
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Hard livin', hard luck.

[Andyco11]

[Paddy Blake]

When the bike stops open the petrol cap and if it sucks in air then the
breather in the cap or tank is blocked.
Check if there is a spark as the coil can stop for a while when hot and
work again when it cools down.

Paddy.

[Jamie S]

There is a really week spark when it cuts out.

Checked the tank breather and that is ok and does not suck air in when opened.


Never heard of a vacuum advance ? Bear in mind this is a 1980s bike.

[Jamie S]

[Paddy Blake]

Hi Jamie.
Well if it is the coils then you could match some second hand ones off
many different bikes.
A lot off bikes will take a good few different types of coils.
I have stuck the CG one on a few bikes.

Paddy.

[MaybeGuy]

when it stalls, try push starting, see if that works...
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

[Jamie S]

[Andyco11]

[Andyco11]

And if you are selling it PM me and maybe we can do a deal
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XS250 Special - XS250 US Custom - XS250 Special Jap Import with YICS Engine
The Florida Forum

[Jamie S]

Hum, the two inlet rubbers have a pipe linking them but I didn't think it had a vacuum fuel tap , could this cause the problems I'm having ?

[Andyco11]

The vacuum hose comes from the right hand (as you are siting on the bike) inlet and pushes on to the back of the fuel tap.

Could be your problem if not connected as it need the vacuum to suck open the membrane in the tap to allow full flow of fuel.
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XS250 Special - XS250 US Custom - XS250 Special Jap Import with YICS Engine
The Florida Forum

[Jamie S]

The rubber hose off the rh inlet is connected to the lh inlet.

There is only one pipe that comes from the petrol tap.

[Blau Zedong]

Coils are the same as RD250 and 350 points models as far as I'm aware. In which case they are likely your source of trouble as they are crap.
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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

[sickpup]

If it still has the original points ignition when was the last time the two condensors were changed?

[Jamie S]

[Caft Dunt]

have you checked the points gap? sounds like theyre closing up when warm. where are you btw might be interested wher your selling it

[Jamie S]

[Jamie S]

It seems the bike is sold to Andyco11, cheers for your help guys.

[Jamie S]

The bike went today.

Thanks Andyco11, hope she brings you as much fun as we had with her.

[Andyco11]

Thanks dude

No-doubt i will be giving it a good kicking later
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XS250 Special - XS250 US Custom - XS250 Special Jap Import with YICS Engine
The Florida Forum

[oz spudgun]

I just bought an 1980 xs 250 in OZ and its been giving me a bit, Anyway I noticed that there is meant to be a vacuum pipe connected to the rh carb inlet rubber brass port. As mine didn't have this I have been having all kinds of trouble keeping it running fro more than 5 mins. It floods. I changed the petcock rubbers and all but it still flows a bit when ON position. I am quite excited about this believe me its past 3am. It must be whats wrong because everything else has been checked fifty times. Thanks in advance I'll let you know how I go.
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sometimes i fly others i slide

[bikenut]

want some spares for this bike, rods with pistons and rings ( little ends worn out as well as crank )), g/box parts, side panels, tank, seat, some electrics and other bits.

alloy wheels and rear disc/swing arm going on the rd250.

north wales.