Topic: Getting old girls back on the road

[Gearman]

Hello sohc/4 forum,

I'm the owner of 3 sadly kept cb 750's. I purchased a 76 and 78 together about 3 years back pretty much out of a field in WV and let them sit until this summer. I got the 76 to fire up but it's pretty rough condition. The 78 starts but is dead on #2. I suspect a stuck exhaust valve. Then a couple weeks back I purchased another 78 with no key and no title as a parts bike with only 12*** miles. It's been sitting for 30 years last registered in 87. But when I got her home I found the title under the seat tray with the registration and owner manual. Still trying to unseize the engine! I'll let you guys know how far I spray oil across my garage when I do!

Welcoming all advice and anecdotes along the way. Thanks everyone for your help now and in the future!
Cheers Matt

[Stev-o]

Welcome from Texas.

BTW - I have the record, my K7 shot it 17 feet once she broke loose!   
I used a 50/50 cocktail of ATF/acetone.

[calj737]

A mixture of 50/50 acetone and atf works pretty well. Keep filling it and use the bolt under the rotor and a breaker bar to get it unlock.

[Gearman]

You mean the bolt behind the alternator cover? I've been soaking for about a week now with wd40 and jb80 and tried rocking it to break loose but no progress yet. My progress is slow but sure.

[Stev-o]

You mean the bolt behind the alternator cover?

Yes, not the points side!

I like "rocking the boat" method, if it is a roller.

[PeWe]

Let the mixture soak and work for some days before using plenty of force. If rings are rusted into the bores, the pistons alu over and under the rings (ring land) might crack if using too much force too early. Use a heat gun warming up the cylinder block might be something in addition to the mentioned mixture.

[calj737]

If you pour the mixture into the plug holes, let it soak. Keep an eye on the oil pan drain. Set a small pan below the engine and as you see the mix drain out, refill it. Once its done that a few times, they'll come free with rocking or a breaker bar and some firm pressure. Works 99% of the time. Just may take a few days and a few refills is all.

[Gearman]

Been soaking a few more days now so I'm gonna roll her out and start the rockin'

[Gearman]

I had the alternator cover off the other day and had access to the large 23mm bolt but didn't feel comfortable torquing any more that I did. Also at the end of this after putting the covers back on I went to empty my oil pan and found a larger washer in there that I did not notice coming out I'll try to upload a picture of it. Does anyone know where this from?

[Gearman]

She's still stuck....stubborn pig. Really wishing I had a borescope right now to see if I'm wasting my time. Also is it common for these 4-1 headers to touch the oil filter housing? I'm thinking the bike fell over and tweaked things a bit

[calj737]

Washer is a mystery. Pipes shouldn't touch, could be due to how the rear pipe is mounted/supported?

[Gearman]

I suppose it's in the realm of possibility it was in the pan before

[HondaMan]

I had the alternator cover off the other day and had access to the large 23mm bolt but didn't feel comfortable torquing any more that I did. Also at the end of this after putting the covers back on I went to empty my oil pan and found a larger washer in there that I did not notice coming out I'll try to upload a picture of it. Does anyone know where this from?

That looks like the flat bearing washer for the starter gear?

[HondaMan]

Hello sohc/4 forum,

I'm the owner of 3 sadly kept cb 750's. I purchased a 76 and 78 together about 3 years back pretty much out of a field in WV and let them sit until this summer. I got the 76 to fire up but it's pretty rough condition. The 78 starts but is dead on #2. I suspect a stuck exhaust valve. Then a couple weeks back I purchased another 78 with no key and no title as a parts bike with only 12*** miles. It's been sitting for 30 years last registered in 87. But when I got her home I found the title under the seat tray with the registration and owner manual. Still trying to unseize the engine! I'll let you guys know how far I spray oil across my garage when I do!

Welcoming all advice and anecdotes along the way. Thanks everyone for your help now and in the future!
Cheers Matt

Finding that title and registration under the seat is like a dream I have had before!

[Gearman]

Thanks hondman that makes sense! Do you know the orientation how it goes in? There's a clear wear ring on one side

[Stev-o]

Do you know the orientation how it goes in? There's a clear wear ring on one side

The washer goes on the shaft of the starter gear and then the stator cover slides on the shaft.  Pretty simple.

[Gearman]

Gonna need a couple sets of tires do you guys have any economical recommendations?

[Stev-o]

Gonna need a couple sets of tires do you guys have any economical recommendations?

I like IRC for a budget tire, nice vintage tread pattern and made in Japan. [I avoid China tires]

I have them on a couple bikes.


https://www.amazon.com/IRC-GS-11-FRONT-3-25X19-87-5367/dp/B005IR2742

[Gearman]

Thanks Steve-o. Have you ever had the luck to get them wet? Wondering how they do in the rain. Also considering some dunlops since they've been decent on my fathers cx

[Stev-o]

Thanks Steve-o. Have you ever had the luck to get them wet? Wondering how they do in the rain. Also considering some dunlops since they've been decent on my fathers cx

Sorry, no.  I am a fair weather rider and cannot remember getting caught in the rain on the 550F or RD350.

I've had Dunlaps, good tires...

[HondaMan]

Thanks Steve-o. Have you ever had the luck to get them wet? Wondering how they do in the rain. Also considering some dunlops since they've been decent on my fathers cx

IRC don't grab in the wet. Not even on a 500-4.

[MauiK3]

As I have worked my way through my K3 project I have used several sources for information.
1. Hondaman's book
2. You Tube Hackaweek, Dean Segovia's rebuild of a K3
3. Haynes manual (it has some good images)
4. Honda shop manual for CB750
5. Downloaded and printed parts fiche
It takes all of it. I was assembling my shifter this weekend and Hackaweek saved the day.
Best of luck with your project(s), this forum is a great source for help.

[Gearman]

Well guys today I got the great experience of turning her over by hand. A little heat seafoam and leverage did the trick 👍🏼

[Gearman]

Looking at some different 4-1 exhaust systems today. Considering the delkevic. The only other thing I see in the price range is the mac which I'm not crazy about. Can anyone attest to the quality of these delkevic repos?

[Kemp]

Gearman,

Check out my site, ripplerockracers.com  I make performance exhaust systems for the SOHC Honda's and have a system for your CB750 that allows full access to oil filter, oil drain and centerstand. It's 4-2-1 for maximum torque and horsepower, all stainless steel and superlight. Looks real good and sounds awesome