Really helpful video, cheers! I'm doing this exact job on my '99 SR125 but coming across all sorts of bloody challenges. I can't get the cam sprocket bolt out so will need to use an impact driver as you did I think. Could I ask what one you used please and if it's a good all-rounder for bike jobs? Cheers
Hey Pete. That bolt shouldn’t be mega tight. Maybe someone has been there before and used some sort of thread lock compound. In which case a little heat may help. I agree it can be difficult without an impact, but I’ve only just started using one, and it’s just a luxury really. Try and lock the sprocket place somehow, put the engine in gear with spark plug in. Hold the crankshaft bolt tight with a socket and bar then undo the bolt. Will be a lot easier with a 2nd person. Failing this you may be able to lock the camshaft sprocket by carefully inserting a screwdriver in one of the holes or teeth and locking up against strong part of casing. This later method is just theory as without the engine in front of my it’s hard to remember. Just get creative. Even jamming some fabric in the cog will stop it turning. Still too tight? Use a longer ratchet handle :-) I use a dewalt dcf887 impact driver. A very useful tool. A little expensive if just starting out with them as you need the charger and batteries. I bought as a bare tool as luckily my brother in law gifted me a drill with all the accessories. Loads of other brands available. I even hear good things about the ones from Lidl or Aldi. Completely up to the job for most home diy tasks. Hope this helps, any questions let me know.
@@TRISTANorTRIS Hey Tris, thanks a million for that advice. I tried everything, including the screwdriver-through-the-sprocket idea to jam it in place and no luck. I got the DeWalt impact driver and even then it wouldn't budge initially! Your suggestion of heating up the bolt coupled with the impact driver finally did the job. So much is seized up on this bike that i think I'll get my moneys worth out of this impact driver :) Cheers!
That wasn't a light run with the honing stone, it was oversized and should be soaked in the oil you intend to run for 24-48 hours. It was too tight as you had to scrape it to get it out, 1-3 runs down the barrel should be enough to hone as you said when you finished that it was a bit much, much more than that and yourw starting to bore. Using the oil you intend to run isn't exactly important but just so long as your oilstones are saturated with an oil, the closer the better, spraying a bit on 10 seconds before you do it isn't enough. The saturating your oil stones applies to any oil stone whether you're sharpening knives, chisels, honing barrels or anything
Also, the wall doesn't really matter when gapping your pistons rings. The wall is the wall and the wall determines the ring gap. So long as it's flush, you've got it right. Push the ring in and then use the piston to make sure it's square with the barrel, then measure. The same goes for your base and deck surfaces. You aren't supposed to scrub them with sandpaper like a madman. You're supposed to smoothly run a flat oilstone over them with significant lubrication, ie. engine oil to get a perfect mating surface
Need more sr125 videos ❤️👌 good work
Really helpful video, cheers! I'm doing this exact job on my '99 SR125 but coming across all sorts of bloody challenges. I can't get the cam sprocket bolt out so will need to use an impact driver as you did I think. Could I ask what one you used please and if it's a good all-rounder for bike jobs? Cheers
Hey Pete. That bolt shouldn’t be mega tight. Maybe someone has been there before and used some sort of thread lock compound. In which case a little heat may help.
I agree it can be difficult without an impact, but I’ve only just started using one, and it’s just a luxury really. Try and lock the sprocket place somehow, put the engine in gear with spark plug in. Hold the crankshaft bolt tight with a socket and bar then undo the bolt. Will be a lot easier with a 2nd person. Failing this you may be able to lock the camshaft sprocket by carefully inserting a screwdriver in one of the holes or teeth and locking up against strong part of casing. This later method is just theory as without the engine in front of my it’s hard to remember. Just get creative. Even jamming some fabric in the cog will stop it turning.
Still too tight? Use a longer ratchet handle :-)
I use a dewalt dcf887 impact driver. A very useful tool. A little expensive if just starting out with them as you need the charger and batteries. I bought as a bare tool as luckily my brother in law gifted me a drill with all the accessories.
Loads of other brands available. I even hear good things about the ones from Lidl or Aldi. Completely up to the job for most home diy tasks.
Hope this helps, any questions let me know.
@@TRISTANorTRIS Hey Tris, thanks a million for that advice. I tried everything, including the screwdriver-through-the-sprocket idea to jam it in place and no luck. I got the DeWalt impact driver and even then it wouldn't budge initially! Your suggestion of heating up the bolt coupled with the impact driver finally did the job.
So much is seized up on this bike that i think I'll get my moneys worth out of this impact driver :)
Cheers!
Good to hear you succeeded. Like I said, any other problems let me know.
Hi,
Would you say the SR125 is a sound selection for a newbie bike mechanic rebuild project?
Yes why not. They are relatively straightforward to work on. Only down side being some parts are expensive to buy.
My sr125 is a 1994 and it's a little bit of a tap but it's on 45000 miles never had anything other then tyres and oil change
They will last ages if looked after.
Hi do you have any yamaha sr 125 engine parts please?@@TRISTANorTRIS
That wasn't a light run with the honing stone, it was oversized and should be soaked in the oil you intend to run for 24-48 hours. It was too tight as you had to scrape it to get it out, 1-3 runs down the barrel should be enough to hone as you said when you finished that it was a bit much, much more than that and yourw starting to bore. Using the oil you intend to run isn't exactly important but just so long as your oilstones are saturated with an oil, the closer the better, spraying a bit on 10 seconds before you do it isn't enough. The saturating your oil stones applies to any oil stone whether you're sharpening knives, chisels, honing barrels or anything
Also, the wall doesn't really matter when gapping your pistons rings. The wall is the wall and the wall determines the ring gap. So long as it's flush, you've got it right. Push the ring in and then use the piston to make sure it's square with the barrel, then measure. The same goes for your base and deck surfaces. You aren't supposed to scrub them with sandpaper like a madman. You're supposed to smoothly run a flat oilstone over them with significant lubrication, ie. engine oil to get a perfect mating surface
Increasing friction to get your rings to stay put is dumb as shit because you want the exact opposite of that