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SR125 I'm in engine trouble deep


Joffie
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Hi folks,

I'm in a particularly nasty patch with my routine maintenance schedule...

This time I've really blown it.

PLease advise.

Here's the sit-rep.

Earlier this week I was having trouble shifting gears in my SR125. I figured that either the clutch cable needed adjusting 'down below' or, the gear chamber itself needed lubricating. Unwisely I put it off. Lesson no.1 learnt already.

Anyway, after getting up a small hill I thought I had shifted up gears and gave it some, but I was in first by mistake and literally blew the engine.

So now she won't run at all.

What damage has been done, and how may I repair this pls?

I guess we're talking an engine rebuild?

Where do i start?

Thanks

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Hi Oldgitonabike,

Here's the low-down...

1) Recent maintenence history. 2 days prior to this engine failure I had changed the oil, being carefull to put in the right amount and check circulation by loosening the allen-screw beside the oil pump, to see it glisten withi a minute of starting the engine.Like it says in Haynes Everything there, seemed fine AOK

2) On the day itself that morning I took the bike out and the back wheel was siezed up completely. Having noticed it was stiff the night before after work I figured it was just cack in the drum brake, which our tutor told us sometimes happens when I done a course in Feb/Marcxh this year. The drum was wyped clean and all seemed good-to-go after that. One thing though, since I got some spray grease from Taz I noticed that the sprocket nuts etc. have now locked... will the same thing happen to my axel?? Yikes.

I read the thread about copper grease this forum and I think I'm ising the wrong stuff.

Anyway continuing with the current tale of woe and hardship...

3)Luckily the day before this engine failure I bought a cheap car coz' I was worried about givin my ol bike a hammering, what with riding all thru winter and now, itching to get out more. ROll on my full licence...

So in essence I felt that there was certainly stuff to be doing on the bike that I wasn't... little thinkgs here and there.

4)I had been suffering from periodic power loss on the SR125, when it used to do 65+ no probs I was now struggling to get past 58.

Checked spark plug:CHECK

Oil levels;CHECK

Timing:CECK

Air Filter:CHECK

Probelm: Last oil change there were one or two tiny bits of swarf in the sump filter. SO I guess that's because in Februaury when changing oil I flushed out the engine with petrol and then put the wrong amount of oil in.

But rode a good thousand miles in the meantime, after righting the above mistake. To work, to college, to my girfriends (100 mile round trip) a few times etc.

5)The moment of breakdown. 5 minutes from home. Over the roundabout, up the hill cranking the clutch and gear select something chronic, definitely a problem there, not enough play in the clutch I suspect....

6)The gear select was stixcking, not shifting gear easily or predictably so that It becomes a thinking matter to know what gear you're in...I kept falling back into neutral but going at some speed, so tried to change up quickly, but I was only in first. I revved like hell and the engine responded, I was slow to react, before a brief popping sound i think, and then it died.

7)I still have compression, and there's a ratchety noise instead of the engine firing up.

But I've drained the tank and removed the battery for now.

That's all i know.

Any ideas???

Many thanks

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Right as i'm not familiar with your bike I know its a four stroke single and assume its an overhead cam engine. The power loss you mention will possible be due to the stiff rear wheel rotation you mention, your bike will only be a low power output in the first instance so anything that saps any of this will result in a loss of speed., you need to get the wheel rotation free, remove the wheel, wipe out the drum with a rag and some brake and clutch cleaner spray, if there is a build up on the outside edge of the drum, then rub this away with some fine emery cloth but only stick to built up part. also whilst the wheel is off, check the wheel bearings, that about covers the wheel problem.

Now as for the engine it doesnt sound good does it, the ratchety noise you describe is a bit of a worry and why was the gear select awkward? at this stage i'm thinking if its a chain driven overhead cam has the chain jumped a cog..has a valve clouted the piston? I suggest you check your cam timing as per haynes manual but really I think youre heading for an engine strip to identify whats wrong here. ... :(

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Hi Oldgitonabike,

Here's the low-down...

1) Recent maintenence history. 2 days prior to this engine failure I had changed the oil, being carefull to put in the right amount and check circulation by loosening the allen-screw beside the oil pump, to see it glisten withi a minute of starting the engine.Like it says in Haynes Everything there, seemed fine AOK

2) On the day itself that morning I took the bike out and the back wheel was siezed up completely. Having noticed it was stiff the night before after work I figured it was just cack in the drum brake, which our tutor told us sometimes happens when I done a course in Feb/Marcxh this year. The drum was wyped clean and all seemed good-to-go after that. One thing though, since I got some spray grease from Taz I noticed that the sprocket nuts etc. have now locked... will the same thing happen to my axel?? Yikes.

I read the thread about copper grease this forum and I think I'm ising the wrong stuff.

Anyway continuing with the current tale of woe and hardship...

3)Luckily the day before this engine failure I bought a cheap car coz' I was worried about givin my ol bike a hammering, what with riding all thru winter and now, itching to get out more. ROll on my full licence...

So in essence I felt that there was certainly stuff to be doing on the bike that I wasn't... little thinkgs here and there.

4)I had been suffering from periodic power loss on the SR125, when it used to do 65+ no probs I was now struggling to get past 58.

Checked spark plug:CHECK

Oil levels;CHECK

Timing:CECK

Air Filter:CHECK

Probelm: Last oil change there were one or two tiny bits of swarf in the sump filter. SO I guess that's because in Februaury when changing oil I flushed out the engine with petrol and then put the wrong amount of oil in.

But rode a good thousand miles in the meantime, after righting the above mistake. To work, to college, to my girfriends (100 mile round trip) a few times etc.

5)The moment of breakdown. 5 minutes from home. Over the roundabout, up the hill cranking the clutch and gear select something chronic, definitely a problem there, not enough play in the clutch I suspect....

6)The gear select was stixcking, not shifting gear easily or predictably so that It becomes a thinking matter to know what gear you're in...I kept falling back into neutral but going at some speed, so tried to change up quickly, but I was only in first. I revved like hell and the engine responded, I was slow to react, before a brief popping sound i think, and then it died.

7)I still have compression, and there's a ratchety noise instead of the engine firing up.

But I've drained the tank and removed the battery for now.

That's all i know.

Any ideas???

Many thanks

Hmmm,

you replaced the oil filter I do hope you got it the right way round !! it is possible to fit the filter either way, if backwards serious engine damage may occur (weather it bled out or not). just ensure the filter is the correct way round .. but I guess that the clutch & g/box have not been lubed and there will be quite a few parts that need replacing

Regards Jim

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Well that's given me some food 4 toughrt , Thanks,

I've a feeling it'sgonna be awhile before I'll fix this but will report back then.

Cheers for the noo, Aha!

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Well that's given me some food 4 toughrt , Thanks,

I've a feeling it'sgonna be awhile before I'll fix this but will report back then.

Cheers for the noo, Aha!

Hi Joffie,

just fire the motor down here (pack it in a good box) and an honest appraisal of what you may have done to the motor will be done .. if you don't want to do that strip it down & send piccies and the same appraisal will be done.

Regards Jim

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