75 CB400F SuperSport

Kanticoy said:
Stock only four of the valves had seals.
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Thanks. This has been a bit confusing. The Honda owners manual AND the parts fiche both show seals on the intake and exhaust sides, but most people say they are only on the intake side and there were no seals on the exhaust side when I disassembled it so that's how I'll be putting it back together.

BTW, if anyone is rebuilding one of these heads, I've got four extra brand new valve seals for you.
 
I'm missing one of the bolts to connect the cam gear to the shaft. It appears to be a M7x1.0, weird. I'd really like to keep making progress on this bike. Can I install the engine into the frame and install the valve cover after I get the bolt in?
 
the head's together

8063706188_1096aeaf6d_c.jpg
 
What are these small rubber tubes far? They are slightly smaller than a dime. They were in the bag with bolts for the head, but that doesn't necessarily mean they go on the head.

8063703635_76dfd8d17a_c.jpg
 
Also, I'm having problems with the cam chain tensioner. It doesn't seem to be taking up the slack on the chain, even when I release the tensioner lock bolt. When I pull out the bolt that holds the tensioner spring in place, the spring does not seem to pop up at all. Suggestions?

PS. Thanks for all the advice so far. It has been very helpful.
 
Hi Pablo. Do you have a parts manual/fiche? One is available here:

[/url]http://www.dansmc.com/cb400f.pdf[/url]

It's invaluable to assist in determining where things go, or if you are missing parts.

I believe those are o-rings that encircle a dowel in the cylinder head.

With regard to the tension on the cam chain - it's best tightened with the engine running. The camchain tensioning system on the 400f is one of its weak points, and by now most don't function as designed. Have a look at the parts diagram to see how it's meant to function - if there is no movement it could be that the pivot is seized. Here's a thread that discusses this issue:

[/url]http://www.dotheton.com/forum/index.php?topic=38781.0[/url]
 
sorry if those links don't work. Just remove the [/url] bits and copy and paste into your browser.
 
She's ALIVE !!!

I've spent about four hours on the bike today. Compression on cylinder 3 was 55 PSI. I adjusted the valves (they were terrible) and compression went up to 110! Compression in all cylinders is now between 110 and 120. There was also a bad condenser for the left coil so I replaced that and a spark plug boot and she fired up! All I had in the shop was 2-stroke pre-mix so she made a lot of smoke. She also leaks lots of fuel out the carbs. It appears to be coming from between the bowl and and carb body on all four carbs which is weird because I just replaced all of those gaskets. Anyone else had this problem?

8081005188_01ca051dfd_c.jpg
 
Nice to hear you have it running!

Regarding the fuel leak, I had this happen to me. Check a couple of things. If your gasket was the round one, it's likely to have came out of the groove when it was installed. Check for a pinch. If you ever have to take a bowl off, it can be a real bitch to get the gasket to seat properly after it's swelled with fuel. I found that washing the o-ring with detergent and placing it in the freezer for 15 minutes will allow it sufficient time to shrink back to new.
 
Check for smooth operation of ALL choke butterfly's. if one hangs up even slightly on those wire clamp bands, it's going to start badly. ...I know.
 
Owned said:
Check for smooth operation of ALL choke butterfly's. if one hangs up even slightly on those wire clamp bands, it's going to start badly. ...I know.
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I'll check it out.
 
Now for the fun part: trying to figure out what other people have done to the wiring harness over the years.

8093649486_f2ef523de0_c.jpg


I've found two wiring diagrams on the internet for this bike. Both of them show a single fuse for the system. My bike has a main fuse, plus a fuse box with with 5 fuses and more wires than either of these diagrams say I'm supposed to have. Can anyone point me to a correct wiring diagram for my bike?
 
I found the problem:

8097493612_af554d344e_c.jpg


I was also able to find a US model CB400F wiring diagram which matches the bike. I think I've fixed all the electrical issues.

I see projects like this (just buckets of parts) for sale on Craigslist all the time and I always wonder what type of person would buy something like that. I would never get into something like this unless there were something really special attached to the deal. So I've got to admit I've been sandbagging a bit. I'll have pics soon...
 
If you need a 400F wiring harness let me know. I happen to have an extra one that i'd make you a hell of a deal on.
 
BCBarker said:
If you need a 400F wiring harness let me know. I happen to have an extra one that i'd make you a hell of a deal on.
Click to expand...

Thanks, but I think that one wire was the only real issue with the stock harness. There were some new components wired into the system, but a replacement stock harness wouldn't help me there.
 
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