Short n sweet. Bike was running but right side sputtered a lot. Left cylinder was 140, right was 60. Found the intake valve on the right cylinder was not adjusted right (to tight), adjusted warm ( I know not recommended). Got right side up to 120, turned over multiple times and rechecked , still the correct gap. Then I started the bike, ran like crap again, rechecked and had 60psi compression in the right again. The left has been fine since I redid the headgasket so it shouldn't be the cam chain/ timing correct???? Anyone ?? Oh and before the tear down the right side was always the good side. (140 to 150 psi) All I did was replace the headgasket because of leaking oil and low compression on the left side. Right side was always fine. Thanks
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Compression woes
- Thread starter ggg2121
- Start date
I've used Seafoam on a running engine. Don't know if it helped, but it didn't hurt. Smoked a lot. Just follow the directions or look up on the web (Youtube) to see how to do it on a bike. The key is adding a bit at a time and not overwhelming the engine.
So I was Seafoaming the engine, everything was going good. Sounded like it was running better. Then I sprayed another shot into the side that probably didn't really need it .....and all of a sudden it started running like crap. Backfiring out that side. Compression is now 150psi in each cylinder, great, but......I don't know if I have an electrical problem and it's just a coincidence or what???? I only get to work on it maybe an hour a day so it's tough. Now I have to sit here all day thinking about what could be the problem while not in front of the bike. The spark on the points did seem pretty bad but I don't know why all of a sudden it would change unless I have a bad ground somewhere? I did try spraying them with contact cleaner and it didn't change anything. I did get shocked through one of the plug wires the other day. They should probably be replaced but I noticed it's all one piece to the condensor or whatever it is. I hope tonight to check all the grounds and main power wires.
How long did you run it after it started running rough?
A couple minutes. Then went back out about an hour later and tried starting it and it ran the same. Barely idles and backfires through the left carb. After the first minute of seafoaming the engine was running great, no backfires in either direction, smoothe idle etc. I don't think it's a matter of a little too much seafoam because I had sprayed in a decent amount before and when it started to die I didn't spray much at all.
new kid on the brat
new kid on the brat
my bike was running like crap yesterday also. i almost pulled the carbs off but i figured checking the plugs first would be a good idea. sure enough my right was sparking everywhere exept across the gap!!!
cleaned it with some starting fluid and a wire brush and it runs great now!!
try cleaning your points!! i have had more problems with points than anything else!! praise god for electronic ignition!!!
cleaned it with some starting fluid and a wire brush and it runs great now!!
try cleaning your points!! i have had more problems with points than anything else!! praise god for electronic ignition!!!
I cleaned my points with 400 grit sandpaper. Worked fine.
Cool, I can't wait to get this thing mechanically sound so I can start CHOPPING!!! I feel as though I'm close! I have a 98 BMW m3 that I turbo'd and put out 600WHP before I went a little crazy with the boost and blew the motor. Now that motor is at the machine shop and will be a while. That was mechanically easier for me than this. This 1970's motorcycle stuff is all new to me. This is my in-between project and I can't wait to ride again. Last year I sold a 2004 vtx1300, SWEET bike but it sat in the garage most the time so I thought it was a waste to have so much money sitting there so I sold it. That's why I'm trying to get something that I wont mind if it sits for a while. Cheap/cool little bike to putt around town on. All your help is much appreciated. I'll let you know what I find.
So yesterday evening, I cleaned the contacts and ran the bike, didn't run much better. I proceeded to go around cleaning every contact that I could . I redid the wire connections on the points themselves. I only found one ground on the motor that goes to the battery besides the front headlight grounds taht arent connected to anything right now. I also redid the spark plug cap connections. I have a funny feeling that my carbs may still be screwed up. I took them back off, took the bowls off, cleaned everything I could again with the little carb cleaner I had left and blew it out with my air compressor. I'm hoping to get everything back on the bike when I get home to try it again.
I'm going to agree that the issue is still fuel, not spark. Good luck!
So I put everything back together. The bike runs better. At idle it's pretty much perfect but if I rev it up at all I still get some backpressure out the front of the carb. Looks like some fuel spitting out also. I may have to do a complete overhaul on these carbs. I just can't seem to get them clean enough. Any new old stock carbs around?? =)
So I'm 99.9% sure I found the problem. Apparently when I was seafoaming the motor the first time and it "all of a sudden" started running like crap, was probably when the nut on the valve adjusting screw came loose and started working it's way off. When I went to check the valve clearances and the left side with the pressure coming out of the carb, the intake was fine........the exhaust side was completely screwed up. Literally, The screw was barely threaded into the rocker arm. Luckily the nut was still in the top end when I took the valve cover off. So now I just need to buy a new adjustment screw (it was kind of bent) and it should be good to go. But the exhaust valve definately was NOT opening. I'm sure this wasn't the original problem but hopefully the last haha.
Wow, that could have been a lot worse. That's good news.
wow, that was lucky!
