Cant go any faster than 30-35 mph

AzHonda

AzHonda

Coast to Coast
I swore I read something about this on here not to long ago and I cant seem to find it. I just picked up a 76 CB360T yesterday. It had sat for the last 5 years with fuel in it. The po drained the fuel and put new fuel in before he even sold it to me. I added Seafoam today to the fuel, drained front brake fluid and replaced with new and messed with the points to get it to idle (it is around 1900 rpms). I have a service mauel on the way but, what I am having an issue with (and I am thinking I need new points and condensor?) is at first I have plenty of power and then after 5 minutes of riding it gets real sluggish and I will have to open up the throttle just to get up to 30-35 mph.

Thoughts?
 
Sounds like you're running too rich. Also very possible your valve clearances are not properly set.

Start with the valves. When the engine is fully cooled off, turn the crank counterclockwise until you feel it rock back and forth with only a little bit of pressure (usually around the 90° ATDC range). Having the spark plugs removed can make this easier. Now open the valve covers and check the gap between the tappet and the valve stem. Exhaust valves should be .004" and intakes at .003". Adjust the tension while you're there.

Next, make sure your carbs are synced. Screw your mixture screws in all the way (not too tightly!) and then back each of them out 1.5 turns. Start the bike and let it warm up. Now turn each screw .5 turns at a time either in or out in order to achieve maximum possible RPMs. If your RPMs go up too much, use the idle adjustment to keep the RPMs below 2K and do it again.
 
I think Sonreir may be onto something with the valve adjustment. They get tighter as the engine heats up, so that would explain the loss of power once the engine is up to temperature. If you run it that way, you could burn the valves.

Not quite sure what you mean by "messed with the points." There is a very specific procedure for setting the points and timing. If you do a search on YouTube, you can find a video on how to do it, or any number of pages on the Web describe the exact procedure. I won't go into detail here, but in a nutshell:

[list type=decimal]
[*]Set the point gaps at 0.014"
[*]Remove alternator cover. (left side)
[*]Rotate engine forward to TL mark. The left points should just open. (a test light across the points helps) Adjust by rotating points backing plate.
[*]Rotate engine forward to TR mark. (May have to pass the mark once.) The right points should just open. Adjust right cylinder timing by tweaking the point gap slightly.
[/list]When you get your service manual, there should be some additional details on the procedure.
 
Thanks for the information guys.

Would needing a valve adjustment be a reason why I hear a pinging or rattleing kind of sound from the engine? I hear it on the right side.
 
AzHonda said:
Thanks for the information guys.

Would needing a valve adjustment be a reason why I hear a pinging or rattleing kind of sound from the engine? I hear it on the right side.
Click to expand...

Possible. Running too lean will cause that as well. Have you cleaned out the carbs since getting the bike? Old fuel can cause a varnish that clogs things up. For what its worth though, running lean is more associated with hard starting and idling; not with problems after heating up.
 
Cleaning up the carbs this week and when the manuel gets here I will attempt to adjust the valves and timing. I am new to motorcycles but have a background working on old International Harvesters. The mechanics is not my strong point but I can learn fairly quick once I have some direction. Thanks for all the help. I am sure I will have a million more questions if I cant find the answer(s) in the "search".
 
Thank you Teazer......I just downloaded it. Doesn't look to hard. I was working on the left side tonight and then couldn't find my feeler guage >:(
 
AlphaDogChoppers said:
I think Sonreir may be onto something with the valve adjustment. They get tighter as the engine heats up, so that would explain the loss of power once the engine is up to temperature. If you run it that way, you could burn the valves.
Click to expand...

Sorry, your wrong about that
Valve clearance increases when engine is hot, aluminium expands about 6 times further than steel (although the cam 'lifts'so the change isn't as grea as in a pushrod motor with alloy cylinder and head)
It's far more likely the air filters are scrap and restricting flow.
They are paper based and the fibers will have swollen from 30+yrs standing around (just from atmospheric water vapour)
It starts rich and gets riher.
If you want to check, just remove filters completely, it should run fine to around 4,500 rpm then go completely flat because it's too lean.
Messing with the points wasn't a good idea but there is a lot of information here to put it right.
The carbs need removing to clean, you also need to check diaphragms for tears, wear or holes
 
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