Honda 1972 SL125 Project
Posted: Thu Dec 26, 2019 5:28 pm
Hi folks - I'm working on this to ride with my grandson on some trails but I've been stumped for a month or so. I thought I would at least run it by the mechanics on this site!
Background: the bike was locked up when I got it but I got the crank moving again by pouring acetone and transmission fluid in the crankcase after taking the cylinder off and realizing the head was not the problem.
Put new rings in and put her back together and back in the bike. Decent compression - about 125 or higher. Timing was interesting since I had not worked on "points" bike in while - but finally got it.
She fires on the first kick and runs but will not take throttle. As soon as you give it the least bit of throttle, she dies.
I've been searching on the internet a good bit and of course I'm thinking carb and floats and such but no matter what I try, she will not take throttle. She will idle pretty good, maybe a little rough but not bad at all. I have the service manuals but they have not been much help to me at this point.
I've set the float many times with no change. This was the original carb so I ordered a new one (china I'm sure) and put it in. The jets are new obviously in the new one and I was able to clean the old carb jets just fine but none of that has ever helped. No real smoke issue either.
Same exact issue with the new carb. I have noticed that the air mixture screw in both carbs seems to have little effect, which is interesting. The plug become sooty and somewhat damp in 5 minutes of idling. I understand that should be a "too rich" condition but I cannot seem to lean it out. Working with the float does not seem to matter until I set to where it's no longer getting any fuel and then it stops:). I've tried several plugs to no avail.
I'm missing something - if you have any ideas, please shoot them my way!
Thanks!
Background: the bike was locked up when I got it but I got the crank moving again by pouring acetone and transmission fluid in the crankcase after taking the cylinder off and realizing the head was not the problem.
Put new rings in and put her back together and back in the bike. Decent compression - about 125 or higher. Timing was interesting since I had not worked on "points" bike in while - but finally got it.
She fires on the first kick and runs but will not take throttle. As soon as you give it the least bit of throttle, she dies.
I've been searching on the internet a good bit and of course I'm thinking carb and floats and such but no matter what I try, she will not take throttle. She will idle pretty good, maybe a little rough but not bad at all. I have the service manuals but they have not been much help to me at this point.
I've set the float many times with no change. This was the original carb so I ordered a new one (china I'm sure) and put it in. The jets are new obviously in the new one and I was able to clean the old carb jets just fine but none of that has ever helped. No real smoke issue either.
Same exact issue with the new carb. I have noticed that the air mixture screw in both carbs seems to have little effect, which is interesting. The plug become sooty and somewhat damp in 5 minutes of idling. I understand that should be a "too rich" condition but I cannot seem to lean it out. Working with the float does not seem to matter until I set to where it's no longer getting any fuel and then it stops:). I've tried several plugs to no avail.
I'm missing something - if you have any ideas, please shoot them my way!
Thanks!