1980 cb750f Project

[80cb750ff]

Sees, thanks for the info.  Ill pull the exhaust and pan this week.  Speaking of, do I need to put in new copper gaskets each time I remove and install the exhaust?

You might be right about 900 cams, as I noticed my number 7 or 8 intake lobe looks like it had some contact with a shim, there is an obvious indentation.  Ill try to get some pics this week.  There was clearance between the shim and the lobe when I checked the valve clearance, so not sure how it happened.  I assume this happened when the previous owner was working on it, which means I have been riding it around/testing it ever since.  Am I ok starting the engine/riding with this issue, or could I be causing further damage?  I'd love to be able to ride it this season then upgrade to 900 cams in the winter, but I don't want to break anything!

Any clue what a good set of 900 cams go for?

[seestheday]

It shouldn't do a lot of damage to ride like that. It'll just wreck your cams faster. That said, those rubber oil deflectors are like $10 from honda for 2. Why not buy them?

I rode for about 3k kms without one and one of my lobes was past spec after I took them out.

As for the price of 900 cams, you should be able to get some for less than $100. I got mine locally for $50.
One of the good things about the 900 cams is that if the lobes are past spec for a 900 they're still a significant upgrade to a 750. As long as they aren't rusty I would go with any pair. I also recommend asking in the buy sell section of this site and the cb1100f.net site.

[80cb750ff]

I will definitely get a pair of the deflectors.

Not too bad at all!  I was thinking they wold be closer to $200.  Definitely sounds like a worthy upgrade!

[80cb750ff]

It's been a while since I updated! I have cleaned the rust from the tank, stripped it, and put primer on it.  I think my carb insulators are leaking so I ordered a new set, should be here next week then I can start dialing in the carbs.  I also ordered a new rotor and reg/rec which should solve my charging issues from the tests I did.

Picture of the primered tank on and my license plate/integrated tail light mounted.  Just ignore the mess...

[mk3brent]

4 deflectors ey?

Both of my engines only had 2. Haha.

Maybe I'll look in the pan to find the missing ones?

[80cb750ff]

I'm pretty sure there are only 2.  I found a diagram somewhere else on the net (of course I can't find it now), and I only saw 2 on there.

This isn't what I saw before (it was better), but it only shows 2 oil stoppers, then there are 2 plates.  I could be wrong, but I think that is what Sees meant, that there are 4 different oil plates/stoppers.

http://www.partzilla.com/parts/search/Honda/Motorcycle/1980/CB750K%20A/CYLINDER%20HEAD/parts.html

[seestheday]

yep, that is what I meant.  Two oil "deflectors" per that diagram, and two oil "plates" that also deflect the oil...

[80cb750ff]

Well I ordered a new rotor and reg/rec as well as carb insulators, as the bike will idle for a little then slowly die if not revved - which I assumed was an air leak.

I have not changed the rotor yet because the rotor removal tool I ordered from dennis kirk didn't quite do the job.  I read to screw it it hand tight, whack it with a hammer then repeat until the rotor falls out.  Unfortunately after whacking it with a hammer a couple of times, the threads on the rotor tool got warped.  I ordered a spare read axel for cheaper, so hopefully that will do the job!

I did install the new insulators, but unfortunately I am still having the slowly dying issue! Any idea what the problem could be?

[TOOLS1]

Hand tight will not do it!!! You need to snug that thing down tight, and then smack it.
TOOLS

[80cb750ff]

Good to know!  Ill be sure to do that when the axle comes in.

Any ideas on the bike stalling?

[Johnnylevi]

do you have a fuel filter in your line? mine did that for awhile and it was cause my idle circuit was clogged up a bit..

[80cb750ff]

Yes I do, although my #2 carb was leaking last week which appears to have been a stuck float - so I replaced the filter as it seems like something was getting through.  I just gave it a decent whack with a screwdriver handle (read that on another site), and everything was good.

[80cb750ff]

With Tools advice I got my rotor out.  I replaced it with a new rotor and a new reg/rec from Ricks.

Carbs are still behaving poorly around idle.  I took it out for a quick trip to get fuel yesterday (my first real ride in months).  If I have to choke fully closed it idles better, but it much worse when I rev it up.  I opened the choke slightly for the ride, and boy was it a blast in the mid to upper RPMS!  Unfortunately, with the choke opened a little bit I couldn't let the rpms drop too far or it would die.

[80cb750ff]

Does anyone know if there are direct bolt on spoke wheels that will work with my existing disc brakes?

[Ba5sKing]

Hey sees,

I really like how you moved your peg back farther on your back, I have always wanted a sportier stance on my cb750, however do you feel that it affects the comfort of longer rides? One of my favorite qualities of my bike is being able to do 2+ hour trips comfortably. I am tempted to copy you, however I'd like to hear your opinion.

Thanks,
-Ba5sKing

[seestheday]

I have drag bars, and am 6 feet tall. Everybody's body geometry is different and your bars probably aren't exactly the same as mine, but for me, the switch to rear sets make long rode soooooo much more comfortable.

Try to spend a little time on the highway with your feet in the back pedals to see how it feels. Make sure you do it on wide open stretch without much traffic though, because you will have to move your feet to brake and change gears.