stevearama
New Member
Bought 1972 Yamaha LS3 from ebay. I'm not sure why. Really I did heaps of motocross when I was younger and I really loved my '88 CR 125. I'm not very experienced mechanically, so I figured a small displacement two stroke was simple enough for me to restore.
I live in Sydney Australia if it's important.
The bike is registered, and runs okay. I've bought plenty of new parts, that are slowly arriving form partzilla and CMSNL. I need help with a few things though. I'm hopeful you guys will reply with some tips.
Firstly. The muffler was full of oil and carbon. I pulled the muffler off and washed out the oil with solvent, but how do I get the carbon out? .. I know with steal pipes I could just burn it off, but this muffler is chrome, and I didn't want t ruin it.
Secondly, gee it's difficult to repack the thing? ... there isn't any rivets or whatever to pop, and while I've got the silencer (baffle think) out, the circumference of the hole it goes back into is quite similar to the baffle... how do i solidly repack the muffler without needing to cut a hole in the thing? Should i use the matt type material around the silencer, or the kind of shredded paper looking stuff (it had the shredded paper looking stuff when I pulled it apart).
The other exhaust option is to buy a new one. I can't find the LS3 exhaust (new) anywhere online. However I can find the '75 RS100 muffler at CMSNL. This muffler uses the same stay to attach it to the frame, and uses the same nut to attach it to the exhaust pipe. But it isn't identical. It seems to be perhaps 1 inch longer between the front attachment bolt and the thread at the front end of the muffler. I wonder whether or not it would be suitable?
Thirdly ... the engine runs really terribly at low RPM under load (so second gear going up a hill). It is perfect at idle, and perfect at high RPM, but horrible down low. There are no gaskets in the exhaust, and so I don't think it's sealed very well and might be letting in plenty of air. Could this be part of the reason? .. if so I should probably fix that before moving on to the carb? .. So yeah, I'm in need of some tuning tips. I have already pulled the carb apart and cleaned it. I put it back together identically to what it was before. As for the tuning, I'm more than happy to take it somewhere to get it tuned, but I kind of wanted to fix a few things first so that the mechanic has a reasonable place to start.
I live in Sydney Australia if it's important.
The bike is registered, and runs okay. I've bought plenty of new parts, that are slowly arriving form partzilla and CMSNL. I need help with a few things though. I'm hopeful you guys will reply with some tips.
Firstly. The muffler was full of oil and carbon. I pulled the muffler off and washed out the oil with solvent, but how do I get the carbon out? .. I know with steal pipes I could just burn it off, but this muffler is chrome, and I didn't want t ruin it.
Secondly, gee it's difficult to repack the thing? ... there isn't any rivets or whatever to pop, and while I've got the silencer (baffle think) out, the circumference of the hole it goes back into is quite similar to the baffle... how do i solidly repack the muffler without needing to cut a hole in the thing? Should i use the matt type material around the silencer, or the kind of shredded paper looking stuff (it had the shredded paper looking stuff when I pulled it apart).
The other exhaust option is to buy a new one. I can't find the LS3 exhaust (new) anywhere online. However I can find the '75 RS100 muffler at CMSNL. This muffler uses the same stay to attach it to the frame, and uses the same nut to attach it to the exhaust pipe. But it isn't identical. It seems to be perhaps 1 inch longer between the front attachment bolt and the thread at the front end of the muffler. I wonder whether or not it would be suitable?
Thirdly ... the engine runs really terribly at low RPM under load (so second gear going up a hill). It is perfect at idle, and perfect at high RPM, but horrible down low. There are no gaskets in the exhaust, and so I don't think it's sealed very well and might be letting in plenty of air. Could this be part of the reason? .. if so I should probably fix that before moving on to the carb? .. So yeah, I'm in need of some tuning tips. I have already pulled the carb apart and cleaned it. I put it back together identically to what it was before. As for the tuning, I'm more than happy to take it somewhere to get it tuned, but I kind of wanted to fix a few things first so that the mechanic has a reasonable place to start.
