Topic: CB550 tuning help

[JTknives]

So I’m a bit stumped as this is my first CB550. This build has been 2 years or so in the making and things are just now coming together. So my question is on timing and jet size for my set up. Long story short I got the motor running good as it sat with a carb bank replacement. The motor that came with the bike was a 500 but it was thrashed. I rebuilt the carbs and thy just sat till I picked up this 550 motor. The carbs on this motor where great except carb 4 which was rotted out so bad it could not hold a main jet. So I bought a replacement #4. Once I got it I inspected it and noticed the jets where a different size then my 550 carbs. So I pulled out the 500 bank and thy where the same as those. So I ended up saving some rebuild and soda blasting time and just used the 500 carbs. The jets in the 500 are 100 & 40, and the 550 jets are 100 & 38. Had it running good and seamed quite snappy with very little smoke.

So the next step was to drop in the 650 can I scored a year ago. I got that in tonight and it fit perfectly and I did not have to remove any of the cylinder head for clearance. Got it back together and gave it a quick valve adjustment using some .002 thick stainless foil I have. The exhaust side was just about good but the intake side had to be backed off. I then got the battery connected up and fired it up. It seamed to run a tad different and did not spring to life as it had before. I would give it a quick snap of the throttle and at first it would bog down. As it got hotter it did not bog down but it also seamed less snappy as the idle seamed to drop slower. I also noticed I could see visible smoke from the exhaust and the temp at the exhaust valve was much higher then the past test runs with the 500cam. Thy where all about identical in temp but you could feal that everything overall was much hotter. I temp gunned the pipes a few times and it thy kept getting hotter. First read was 250° and thy where going up. I think by the time I called it thy where in the 300-320 range. The shop was completely full of smoke. 

What has me concerned is the idle responsiveness and excessive heat from the motor. The smoke has me wondering if I have a timing issue as well as I did not go back and check my timing on my points after I did the cam install. A few added insights into the motor is I am running a stainless 4 into 1 with a baffle. I also kept the intake Manifold and adapted it to the documented K&N cone filter. I did not want to change to much at once so I have been trying to do o e thing at a time. I do have a complete electric Dynatek ignition set with coils and wires ordered. But I would like to sold these issues first before I add another link in the chain of questions. here is a picture of the motor on its stand if that helps.

Thank you guys for any info you can provide. I have searched and searched and it seams like info is scattered all over and I felt like my brain was going to melt. Oh and I included a picture of a plug before the cam swap. 

[scottly]

How about pics of the plugs After the problems started?

[bryanj]

Are you 100% sure the cam timing is correct?

[JTknives]

Here is a picture after installing the cam and before I replaced all the seals. You can see the notch is aligned on the right and the timing was on the First | on the T| F| 1-4. When I first aligned it the cam was not far enough so I had to advance it one link to get the notch parallel and inline.

[bryanj]

It may be the picture but if that is on the T mark the lobes at both ends do not look "even" I.E. same amount stuck up on each lobes at one end and same down at other

[flatlander]

valve clearances should be .002in / .003ex. why do you measure with foil, don't you have feeler gauges?
cam alignment should be at the T mark. if you want to share a  pic of the notch, please take one that's looking at it horizontally so that we can see how it aligns with the gasket surface.

[Scott S]

 Also, these engines need air flow. Run a fan on it at the least.

 Reset valve clearances using .002 IN, .003 EX. Set the timing. Get some air flow on the engine.
 You used a lot of oil/assembly lube (which is good), so don't be too concerned with a little smoke coming off it just yet.

[JTknives]

I did not have any feeler gauges on hand. I will be taking care of that and getting a set, looking for an offset set so I can get in on the ex. Yeah I used a good amount of assembly lube. I guess I will pull the cover back off and double check the timing and take a picture of the notch location to surface and the timing marks.

[JTknives]

Oh and after the cam swap I have anywhere between 1 to 5 pops on fuel let off. It never popped befor the cam swap.

[bryanj]

Pops on overun usually air leaks on exhaust

[JTknives]

Pops on overun usually air leaks on exhaust

that’s what I had read but it just started doing that after the cam swap. I did not remove the exhaust and it’s just as it was when it was running good.

[JTknives]

I pulled the cover and snapped a few pictures. I then went to pull a plug and discovered it was loose. Looks like I was just finger tight and I did not tighten it down. I pulled it and it was a bit darker which I’m guessing is from less compression as the other cylinders. I pulled another one and snapped a picture of that.

[JTknives]

Pictures

[Scott S]

 Cam timing looks right. What about dynamic timing? Have you used a strobe light on it yet?

[flatlander]

yes the cam is right.
i guess he only installed the cam, did not change anything else. so if the ignition timing was good before, it should be the same now. but it doesn't hurt to check with a strobe light.
but you'd have to remove the spark plugs for timing the cam so installing them correctly may be all that's needed.

[bryanj]

You really should have reasurched or asked as the charging system is marginal enough that dyna ignition can push you into discharge

[scottly]

Did you use rubber bands to hold the rockers up when you re-installed the cam cover? Have you done a compression test?