'76 cb360 Tappet Confusion

10277 Views 56 Replies 10 Participants Last post by Brly, Apr 22, 2009

Brly

Discussion Starter · Feb 16, 2009

I'll do my best to keep this short, but no promises. My brother picked up this 360 a couple years ago. It was not running when he got it and we knew nothing about it. It did come with a Clymer manual. I cleaned the carbs, twice, and did some of the other tune ups out of the Clymer manual, but I was stupid and impatient and skipped some of the more important things. We got the bike running once, but it was only running on the right cylinder, and only with the choke on. We kinda jumped into it without any knowledge of bikes and shortly thereafter, my brother lost interest. Now the bike is basically in my hands. After reading tons about these bikes, I know a tiny bit more about them so I'm pretty much just trying to start over from scratch.

I checked the compression today. Right cylinder was at 150 psi, left was at 145 psi, everything good there. Then I went to valve adjustment and ran into a problem. I followed the Clymer manual which states turning the alternator until the intake valve opens completely and then starts to close, then continue turning until the LT mark lines up with the index mark. "Note that both valves for the left cylinder are fully closed at this point."....... They're not.

When my brother and I worked on this bike, I did pretty much all of the mechanical stuff except for one part that I wasn't around for. The head gasket was leaking, and since he had a gasket for it, he decided to put it on. I honestly don't know what the top end of that motor looks like, but I'm thinking the cam was not oriented correctly when he put it back together. Any thoughts on this? What else could it be?

Also, if this problem gets worked out and I can actually adjust the valves, where exactly do you put the feeler gauge? The Clymer manual says insert a .002 inch feeler gauge between the tappet adjuster screw and valve stem but I just don't get it. Am I having trouble with this because of the above mentioned problem?

If there's any more information needed, let me know, I'll see what I can find. Any help will be greatly appreciated.

Ben

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tbpmusic

· #5 · Feb 16, 2009

First off, do yourself a favor and put the Clymer in the outhouse where it belongs.
Here's the Honda Manual -

Much better descriptions of the tuneup procedures here...

Secondly, on page 30 of this manual, it states that 171 psi is the desired compression, and 149 pounds is the "red flag" that indicates a top end job.
So measure your compression again - engine warm, throttle wide open, NO CHOKE.
If you still see the same readings you got before, you have overriding problems to deal with, because the readings you posted would be considered marginal.
Could be caused by tight valve tappets, but more likely bad rings/valves.

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tbpmusic

· #7 · Feb 17, 2009

Check the compression again, as I outlined. A warm engine will give you maybe +5 pounds or so.

The cam/crank timing cannot be "adjusted" at all. It can only be checked.
With the alternator rotor "LT" mark lined up, the two lines on the cam sprocket should be perfectly horizontal - if they are not, the bike ain't gonna run.

When you put it back together, be sure to observe the Manual's comments about filling the cylinder head's oil bath reservoirs, it's important.....

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tbpmusic

· #9 · Feb 17, 2009

It may barely run if it's a little off up there, but usually not.
It would affect the compression readings.
Check it and report back.....

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tbpmusic

· #14 · Feb 23, 2009

Ben -

Lots of folks proceed with compression like that, and the bike runs fairly well for a while.
The time is not far away though when it will get hard to start and run crappy.

Yeah, that discussion about compression readings over at SOHC is a good one.
I re-posted it at the now-dead 450 DOHC forum and instantly got flamed severely for my trouble. :? :x :|

So I never posted it here... enough flamage for me.
There's certainly merit to the argument, you can't simply ignore the logic of it.
It's not really an issue with me personally, because my compression gauge is a real old one, one of the very short-stemmed ones with a rubber tip that you jam into the spark plug hole. You wouldn't be able to use it on the Fours because of access, but works fine on the Twins.
Using it, I read over 180 psi on my recently re-built 450 project (valve job, new pistons/rings /bore job).
But compression is one of my pet peeves, so i always harp on it.... you can feel free to join the legions of folks (including Wifey) who ignore most of what I say....

Anyway, Mike's XS shop offers a pretty good deal on replacement coils - I think there's a post with photos I made a while ago in the 450 section here. Almost a bolt-up, just had to make a couple of little mount plates for the 450 - should be about the same on a 360.
I can recommend them highly, they work great, and you can get rid of those nasty old coils for not much money - get some new wires and caps too.

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tbpmusic

· #17 · Mar 1, 2009

Sounds like your carbs are not synched and balanced - that can cause the idle to hang up.
So can tight intake valves.

You may or may not have to re-jet, don't just assume you need to.
Get those carbs synched up first.
You've been messing with the choke, so you need to put in clean plugs and get some plug readings.
Then think about jets, if required.

There are lots of inexpensive aftermarket mufflers - for about $50 each you can score some real nice, shiny mufflers that work good.
http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

Many times aftermarket mufflers will leak at the exhaust pipe/muffler joint.
Gotta stop that - way down at the bottom in this link you'll see how I did it....
http://home.comcast.net/~tbpmusic/id54.htm

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tbpmusic

· #24 · Mar 8, 2009

Brly said:
Anyway, this got me thinking about what the bike needs to pass inspection. Some of the bikes I've seen don't have front or rear fenders, turn signals, mirrors or whatever else. How do they pass inspection? Do they bolt the needed parts on and then take em off afterwords? Ben

It varies with the State you live in.
Personally, I live in a state of chaos, mainly.......

Go to your State's DMV website, you'll find answers there.

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tbpmusic

· #32 · Mar 22, 2009

You took apart the starter solenoid, not the regulator.
Neither of them has anything to do with the spark circuit.....

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tbpmusic

· #40 · Mar 22, 2009

Brly said:
How could I run the bike without frying electrical components without the regulator. I have been blowing one of the 7 amp fuses. One of the wires from that 7 amp fuse goes to the hi/lo beam switch on the left handle bar, the other goes to the right handle bar control, which is brand new.
Ben

Like Steve says, look for a new harness, it will make life easier.
One of the 7 amp fuses is for the headlight circuit, the other 7 amp fuse is for the taillight circuit.

Here's the Honda manual - wiring diagrams in there......

http://home.comcast.net/~tbpmusic3/Honda_CB250_CB360_CL360_CJ250T_CJ360T_Shop_Manual.pdf

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tbpmusic

· #50 · Apr 5, 2009

Brly said:
Also, I've looked all over, Honda manual, Clymer, Google and I can't find what size forks are on this bike ('76 cb360t). Can somebody help me out? (I don't have a micrometer).

Thanks,

Ben

33 mm

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