So I bought an 87 that was in great shape last year from a guy cheap who didnt know what he had (or did he) Spent a bunch of time (and money) getting her back into shape. Basically just cleaning it up, new tires, chain, sprockets, rebuilt calipers, new fluids, etc. Basically a total restoration. But I guess I should have concentrated on the motor first. When I rode it last year, sounded like it had a misfire but I just thought it was becasue the carbs were gummed up, bad plugs etc from sitting so long. So I disasembeled the carbs, soaked them, cleaned them, and put them back together. Installed new plugs, and a new battery and attempted to fire it up. Runs great on the left 2 cylinders, the third is warm and the right one is ice cold. There is spark on those 2 cylinders, and it is getting fuel. Actually I think it is getting too much fuel becasue if I pull the plugs and crank it over, fuel shoots out to the cieling. So if I have spark, air and fuel, why is that cylinder not firing? Also I noticed that while I had the header off, looking inside the exhaust port, that one of the valves looked a little oily (not wet to the touch, just looked different) and the others were completely dry with carbon. Dont know if this has anything to do with my problem. Could it be that the carbs on that cylinder are just dumping too much gas? When I took the carbs off to clean them, there was fuel just laying inside that intake track of that right cylinder. But I took the carbs apart and put them back together and they seem to be working ok. I am at a loss.
Motor trouble... Please help!!
Luch
1 - 11 of 11 Posts
So I bought an 87 that was in great shape last year from a guy cheap who didnt know what he had (or did he) Spent a bunch of time (and money) getting her back into shape. Basically just cleaning it up, new tires, chain, sprockets, rebuilt calipers, new fluids, etc. Basically a total restoration. But I guess I should have concentrated on the motor first. When I rode it last year, sounded like it had a misfire but I just thought it was becasue the carbs were gummed up, bad plugs etc from sitting so long. So I disasembeled the carbs, soaked them, cleaned them, and put them back together. Installed new plugs, and a new battery and attempted to fire it up. Runs great on the left 2 cylinders, the third is warm and the right one is ice cold. There is spark on those 2 cylinders, and it is getting fuel. Actually I think it is getting too much fuel becasue if I pull the plugs and crank it over, fuel shoots out to the cieling. So if I have spark, air and fuel, why is that cylinder not firing? Also I noticed that while I had the header off, looking inside the exhaust port, that one of the valves looked a little oily (not wet to the touch, just looked different) and the others were completely dry with carbon. Dont know if this has anything to do with my problem. Could it be that the carbs on that cylinder are just dumping too much gas? When I took the carbs off to clean them, there was fuel just laying inside that intake track of that right cylinder. But I took the carbs apart and put them back together and they seem to be working ok. I am at a loss.
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393 Posts
You still have a carb problem. Did you check the float heights?, replace the float valves if they're bad?, make sure that every passageway was clean and flowing?, remove the idle mix screws and make sure their passageways were clear? After cleaning the carbs, always bench test them by hooking up a fuel supply and checking to see if the float valves are closing as they should. Just a few thoughts.
I am kind of new to tinkering with carbs. So this whole part is a learning process. But I did everything above except checking the float valves. Forgive my ignorance but I am not sure I know what this means. I took the floats out, inspected them, and then there was a little metal thing that looks like a mini plumb bob that is spring loaded that the float sits on. Took that out cleaned and inspected everything. I guess I am just not sure how else to tell if the carbs are working properly other than them being totally clean.
Forgive my ignorance again, but which o-rings, and where?
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2,560 Posts
read the carb sticky and it'll show u exactly what u need to do. I assume that's an american market bike and u hav CV carbs. The float carriages r held in place with o-rings which perish over time and allow fuel to effectively bypass float valve thingy leading to to much fuel in bowl irrespective of float height. Replace the o-rings as a precaution and set float heights as per sticky.
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838 Posts
and watch what you're doing until then, cranking the bike while its dumping lots of fuel into the cylinders is a recipe for hydrolock and bent rod badness
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