Need help with engine knocking/electrical problems

[Nessism]

Loose valves won't cause the problem you describe. Something else is wrong. You might want to check the compression to see if there is anything noticeably wrong.

[pjm204]

well I re-did the valves, they were way off. That helped with the loss of power and it no longer burns any oil, but there is still a noise.
I am not sure I'd call it a knock. It happens every few seconds during idle, may happen while riding but I can't hear it. It could be cam chain slap...not sure. any advice?

[pjm204]

I rode the bike and had a mechanic listen to it. Of course when I get there the bike isn't making a sound. He said his best guess is that the bike is only firing on one cylinder at start up and then once it is warm the second cylinder kicks in and it stops knocking.....

it seems to only do it when it is below around 1700 rpms. It seems to blow some smoke out the left pipe until it warms up. Could this be an electrical problem?

[Suzuki mad]

Well first I will start by saying hello, i've been reading here for awhile but just decided to join. I'm a regular over at GStwins.com but that is pretty much just a gs500 site. Considering I have some older GS's now, I figure the right answers will be found here.

I recently picked up a second gs400, a 1977. The bike was in somewhat rough shape when I got it. Missing lots of nuts and bolts, the front brake caliper was frozen together and hanging from the bars. It had no paint on the tank or tail, no battery, fuel lines disconnected, and other random things wrong with it.

Since then, I have done the following to it:
1. Adjust valves
2. change oil
3. paint tank/tail
4. bleed front brake/attach
5. switch bars
6. replace lots of screws
7. fix some wiring


Here is what still needs to be done:
1. recover seat
2. get horn to work
3. Brake lights only go on when pressed HARD
4. find an air filter
5. find a right sidecover
6. Gear indicator identifies wrong gear, says 4,8,9...neutral does not light up.
7. Fix engine knocking


The engine knocks while idling until it is warmed up. It is coming from the top of the engine and is pretty loud. I am not sure what it could be. Once the bike warms up awhile, it seems to go away. The bike does seem to vibrate a bit more than my other gs400 when idling. Anyway, if anyone has any advice for this or any of the other things I still need to finish, please let me know. Thanks, here are a few pics of before, and now

One area you haven't talked about or done. Fuel and carbs.

They probably could do with a strip and clean.

I suspect that its a blocked or clogged fuel filter inside the carb.

Suzuki mad.

[pjm204]

I've been thinking about the carbs as well. I think I may have a blocked pilot jet since it only happens at low RPMS. I took the ignition cover off and found that the points for the left cylinder were out of spec, gap was too wide. I'm currently trying to adjust the timing since one of the screws was real lose, I think the guy I bought it from was attempting to do work on the bike and stopped.

There was no filter in the bike at all so I bought some uni filter foam and put it in the airbox and then made a cover out of lexan for the airbox. I couldn't find a stock filter.

Also the air/fuel screws were waaaay too rich, plugs were really black, now they are started to clean up.

I really don't want to take the carbs off but I guess I have to, I hate messing with the airbox.