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SR125 will not start


r6demon
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Hi All,

My wife has just past her CBT so I bought her an old (97) SR125 that is in need of some TLC, so whilst trawling ebay I found another non runner (93 version with lots of new bits on) and snapped it up with the plan of swapping all the good bits on to my wifes and scrapping the rest.

However...... being inquisitive, I decided having never really played around with engines before, that I would like to get it running again as a mini project.

The issue is that the engine turns over but will not fire.

The 'Story' from the previous owner was that he filled it up with fuel on the way home and it cut out a couple of miles after, He managed to re start it but then cut out a little while later and that was the last time she ran.

I have checked the following:

Spark - good clean (blue) spark from plug - Even changed the plug from the running bike nothing - put non running

plug in running bike - fired first time.

Fuel - took the fuel pipe off the carb and there is a good clean flow - need to check fuel filter to be safe

HT Lead - Looks a little worse for wear - will try swapping running bikes lead over later

Carb - Cleaned it out with carb cleaner - inside looked very clean anyway

Fuse - This looks OK BUT its currently fitted with a 5A fuse???? I thought it should be a 20A

Wiring - there were two dodgy looking connections under the left hand panel (bare wires just wrapped around each other!!) so I re terminated these with spade ends and solder.

With the carb removed, if I put mu hand over the manifold 'hole' and turn the bike over there is good suction as the piston goes up and down, I assume this means that the piston is not shot??

Am about to try the fuel tank and carb off running bike on the non runner.

Any other suggestions?

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have you tried swapping the ignition coils? if thats blown then u wont get a spark

charge the battery this always helps

the blokes story sounds like he put diesel in it or bad fuel, try draining the engine of all fluids, flush it and refil with fresh

empty the petrol tank clean with fresh fuel and refill with new fuel.

and have you tried bump starting it? just push it down hill (or a flat) in second gear and see if it fires up

if it starts and runs then you know its just a starting problem.

hope this helps

.Paul.

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have you tried swapping the ignition coils? if thats blown then u wont get a spark

charge the battery this always helps

the blokes story sounds like he put diesel in it or bad fuel, try draining the engine of all fluids, flush it and refil with fresh

empty the petrol tank clean with fresh fuel and refill with new fuel.

and have you tried bump starting it? just push it down hill (or a flat) in second gear and see if it fires up

if it starts and runs then you know its just a starting problem.

hope this helps

.Paul.

Hi Paul thanks for the reply,

I have got a good clean spark at the plug.

Battery has been on charge all night to be on the safe side.

Have checked the fuel and it smells like petrol not diesel but will drain the tank as I have to check the fuel filter.

have not tried bump starting will give that ago when the wife gets home, good idea!

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I emailed the guy I bought it off and this is his reply:

so simply put: the bike ran out of fuel and I swithched to the reserve tank and drove home the 20 miles or so. I filled up the next morning on the way to work and drove to work and back fhat day and the next. On the next day drove to work and all was fine, on the way back had travelled about 10 miles (half way home) and the engine lost power at 40MPH and simply drifted to the side of the road and sopeed running......so after a little time I managed to get her started again and she drove for another mile or two and then again lost all power and coasted to the side of the road. This time she would not re-start (I tried everything from bump starting to changing the fuel back to main tank and then reserve etc and nothing worked.

The AA stripped the Carb and confirmed that the sparkplug was fine, the fuel was fine and the carb was not blocked or anything like that (he completelly stripped it down and blew it out with compressed gas).....so in therory he said that it should be running if the spark, fuel and carb are working (air/fuel and ingnition source), thus he assumed that something more serious had occured in the head, or crap had gotten through the carb and into the head and caused blockages or some kind.

He was discounting the serious failure as the bike did not simply stop running....she just lost power and coasted to a halt: an angine seize would lock the back wheel and I would have ended up on my arse (probablly as I was doing 40 at the time).

So it would be worth taking h the head oiff and having a look....the manual has a fault finding sectioin about not starting and it mentioned the rings and piston tapets and stuff I had not really heard off, these may be worth reading and exploring as potential probs

what do you think? The Fuel is just draining off into a can as I type!

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I emailed the guy I bought it off and this is his reply:

so simply put: the bike ran out of fuel and I swithched to the reserve tank and drove home the 20 miles or so. I filled up the next morning on the way to work and drove to work and back fhat day and the next. On the next day drove to work and all was fine, on the way back had travelled about 10 miles (half way home) and the engine lost power at 40MPH and simply drifted to the side of the road and sopeed running......so after a little time I managed to get her started again and she drove for another mile or two and then again lost all power and coasted to the side of the road. This time she would not re-start (I tried everything from bump starting to changing the fuel back to main tank and then reserve etc and nothing worked.

The AA stripped the Carb and confirmed that the sparkplug was fine, the fuel was fine and the carb was not blocked or anything like that (he completelly stripped it down and blew it out with compressed gas).....so in therory he said that it should be running if the spark, fuel and carb are working (air/fuel and ingnition source), thus he assumed that something more serious had occured in the head, or crap had gotten through the carb and into the head and caused blockages or some kind.

He was discounting the serious failure as the bike did not simply stop running....she just lost power and coasted to a halt: an angine seize would lock the back wheel and I would have ended up on my arse (probablly as I was doing 40 at the time).

So it would be worth taking h the head oiff and having a look....the manual has a fault finding sectioin about not starting and it mentioned the rings and piston tapets and stuff I had not really heard off, these may be worth reading and exploring as potential probs

what do you think? The Fuel is just draining off into a can as I type!

looks like your going to have to take the engine out and check the head and piston rings

you could also sort out the valve seats aswell. best get a manual and go from there

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looks like your going to have to take the engine out and check the head and piston rings

you could also sort out the valve seats aswell. best get a manual and go from there

Dont need to take the engine out and apart, just do a compression test of the two engines.

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Dont need to take the engine out and apart, just do a compression test of the two engines.

yeah didnt think of that

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