Topic: 1975 cb 550 throttle issues.

[ddamron]

I can't seem to get this one right and keep it that way.

The bike is slow to pick up when coming from idle and slow to come down. There's an occasional puff or crack from the exhaust. It's running kind of rough too.

I recently tried a 3000 mile tune up,  it was pretty much my first attempt at everything involved.

Any thoughts?

[goldarrow]

Did you tear your carbs apart during the 3k tune up?

[ddamron]

Yes I did.

[Randy]

I would say.. Pull the plugs first and see what they look like.. Resync the carbs, check timing.. check valve clearance.. Lube the carb moving parts " not the cables!... Clean the grease from the throttle handle and handle bar and regrease... then get back to us... worked for me..

[ddamron]

What kind of lube would you use for that?

[ANDY W]

Was it running like that before you did the 3k tune up? Sounds like its running rich. Did you check and adjust float hight or air screw?

[ddamron]

It was running pretty good but idle was hanging.


The screw is at one turn out. The plugs are a bit sooty, I was considering raising my needle clips.

Also, I'm not confident in my work with the 3k tune up fyi.

[ANDY W]

Needle position should have nothing to do with idle. it will only affect 1/8 to 1/2 throttle. If by hanging up you mean when you come to a stop and the engine idles high say around 2k to 3k then eventually comes back down to normal then i would say you have a rich idle condition. check your float levels, if the fuel levels are to high in the bowls it will cause a rich idle condition. if they are ok try turning out the air screws if the idle doesn't change the you could have a blockage somewhere.also is the bike stock?

[TwoTired]

When you did the carb vacuum sync, did you adjust each and every position?  If so, can you guarantee that the slides can reach bottom of travel with the idle knob backed out?

After idling for a few minutes, are all the head pipes the same temp?

[ddamron]

Ok so I did a few things today. Rechecked my timing and cam chain. Did a carb sync with the bike level, no luck.

Then I had a thought,  lean out the idle and loosen the idle screw. It worked a bit, not perfect.

Below is a video. The clicking is not nearly so loud in person. Maybe it can help you help me.

Also, is the clicking the tappets? I think I need to redo that bit.

https://www.youtube.com/watch?v=PuNKSp_QKvc&feature=youtube_gdata_player

[TwoTired]

Can't see video.  Says it's private and I have to login.  I don't have an account with them anymore because of the EULA.

[ddamron]

Fixed it!

[Ewan 500K1]

Fixed it!

what was it ?

[ddamron]

Fixed it!

what was it ?

Wow my post was so very unclear. I fixed the privacy on the video.

[Ewan 500K1]

Fixed it!

what was it ?

Wow my post was so very unclear. I fixed the privacy on the video.

acht ,, thought you'd sorted the bike out 

[ddamron]

I have done it! Lol

https://www.youtube.com/watch?v=81z8haF7n0s&feature=youtube_gdata_player

I completely re-did my 3k Tune up attempt, and based on some advice I adjusted the idle screws differently (set stop screw to
 desired rpm, lean air fuel screws out evenly until idle increases, slow down idle with stop screw, repeat in small increments until it didn't help anymore).