77 cb750f2 915cc Updated Pics

tweakin

Beer and Grease
Monday was a Holiday so I day tripped from Seattle to Eugene OR to pick up my next project.

secret ninja 1977 cb750F2



After the first day on the bike;



Trashed parts.



I wanted to get the motor out asap because I want to tear it down first to were I am at. The bike ran strong but I could hear a "chain sound" when the bike was cold and it would go away when the bike warmed up.

any ideas?
 

rockcitycafe

I make things.
Re: cb750 -true believer

probably the valve tappets, check the clearances, but all the old sohc 4's sound that way when cold
 

tweakin

Beer and Grease
Re: cb750 -true believer

rockcitycafe said:
probably the valve tappets, check the clearances, but all the old sohc 4's sound that way when cold
Thanks man. I will know more once I tear into the engine.
 

JS550

New Member
Re: cb750 -true believer

The 750 gets a noise in the primary chains sometimes to. Mine does it in N, but if pull in the clutch it goes away. Fairly common, tensioner loosens over time. Did it do it in gear? Also if the carbs are out of sync it can cause the primary chain to slap.
 

tweakin

Beer and Grease
Re: cb750 -true believer

junkyard jon said:
pull the pipes out of the trash can! i'll pay shipping, don't care about condition.
lol. I pulled the pipes out of the trash can. think I am going to use them on the build. I will keep your info and they are yours if I decide against using them.
 

JRK5892

New Member
Re: cb750 -true believer

have to say... i am jelous... i had the same style CB 750 when i first got into bikes... rode it for a short time and sold it for something "cool" (a rocket) i am still pissed at myself! i had no idea what i had!!!
 
Re: cb750 -true believer

Right on Tweekin' this looks like its gonna be a killer build. I loved what you did with your hawk, wish my 81 looked that good! how did that gearing change work out? Is this 750 gonna be along the same lines as the hawk?
 

BCBarker

New Member
Re: cb750 -true believer

RIGHT ON!!!
My wife's uncle has a 750F model that is sitting UNCOVERED in NJ waiting to be plucked!!! I have serious dibs on it. When he wants to get rid of it, I can't wait to tear it up!!! I will be watching for Ideas etc.!
 

InkOverdoseD

New Member
Re: cb750 -true believer

Tweak, how's the SS looking? I need to follow ur build to learn from and not make novice mistakes....I felt guilty Cafe-ing the SS but your bike was actually in better condition so I don't feel so guilty now...thx

So between you, scrogg and DTT members I should minimize stupid mistakes on my build....
 

SrgtBear

The arsenic has oddly shaped feet...
Re: cb750 -true believer

Wow that 750 looks in great shape. I would hate to tear it apart other then to touch up the rusty spots.

Don't hurt her to bad.
 

tweakin

Beer and Grease
Re: cb750 -true believer

My initial plan was to just restore it until I got it home to the shop. The bike was / is in ruff shape. (pictures don't tell the hole story)

I am going through every bolt and inch on this bike and putting it back together with a slight cafe look and keeping all original parts I take off)

SrgtBear said:
Wow that 750 looks in great shape. I would hate to tear it apart other then to touch up the rusty spots.

Don't hurt her to bad.
 

slushie07

New Member
Re: cb750 -true believer

tweakin said:
My initial plan was to just restore it until I got it home to the shop. The bike was / is in ruff shape. (pictures don't tell the hole story)

I am going through every bolt and inch on this bike and putting it back together with a slight cafe look and keeping all original parts I take off)
What parts were in ruff shape, the internals?
 

tweakin

Beer and Grease
Re: cb750 -true believer

Finally got some wrenching time in. here is the case with the broken cylinder studs (what a bitch). Took it to a machine shop but they had no luck. Luckily I c=have a spare case for the build.



The second set of cases are getting media blasted. The internals looked pretty good considering how the outside of the engine looked.





New CAD plating system (www.caswellplating.com) works great to refinish old metal bits. I am re plating and polishing all the fasteners and small pieces.



The engine is getting:
New HD studs
New cam
New camchain
New rings
Hone
New high flow valves
New valve springs and retainers
New valve guides
mild port/ polish
Barnett Clutch

I also plan on installing the Gordon frame kit once it arrives so I will be able to work on the motor in the future ( big bore?) if I decide to.
 

Traveler

New Member
Re: cb750 -true believer

This "new project" of yours is the exact bike I need if I ever buy another. The lines are just perfect, it comes with mags, and the rear disc brake.

Really crappy deal with the head studs.....glad to hear you had a spare case available. Will you be painting the motor back to black?

I sure hope you will powder the frame. (Gloss black???)

The lines on this bike, with a 1/2 fairing and some clubmans or clip on's would be KILLER.

I'll be watching this build with great interest!

~Joe
 

tweakin

Beer and Grease
Re: cb750 -true believer (Update 4.20.10)

Put some time in today on the 750. Began working on the engine with the heads. Putting in some new highflow valves, guides, hd springs and retainers. I also dod some mild clean up of the chambers.










Tomorrow I will finish this up and start on the "Gordon frame kit"

I also was able to get the case halves media blasted and primed for paint.

 

Tim

Administrator
Staff member
Re: cb750 -true believer (Update 4.20.10)

I'm going to keenly watch your engine rebuild progress - hopefully you'll be able to post lots of pics. I'm contemplating building up a 2nd XS650 engine for my bike, including a complete tear down, paint etc. of the bottom end as well as the top. I only did my current engine's top end with new pistons, rings, valve job etc. with the cylinders and head blasted but left raw aluminum.

Not sure I have the wherewithal to do a proper job on the bottom end. I'm sure I could take it apart and put it back together, but I figure you'd want to be measuring things while you're in there unless you know it's a good running engine / tranny.

Anyhow - keep us posted!
 

tweakin

Beer and Grease
Re: cb750 -true believer (Update 4.20.10)

This is my first "bottom end" job. I have done multiple top end jobs on Harleys and Hondas and I am confident in my abilities. The tranny and bottom end internals are all with in spec and I am replacing all the bearings,chains ands tensioners while I am in there. I want to build a bike that will run strong for years to come with little surprises.

I will do my best to take pictures along the way. I have always been a believer of doing the engine correct first before you spend all kinds of time and $$ on cosmetics.

Tim said:
I'm going to keenly watch your engine rebuild progress - hopefully you'll be able to post lots of pics. I'm contemplating building up a 2nd XS650 engine for my bike, including a complete tear down, paint etc. of the bottom end as well as the top. I only did my current engine's top end with new pistons, rings, valve job etc. with the cylinders and head blasted but left raw aluminum.

Not sure I have the wherewithal to do a proper job on the bottom end. I'm sure I could take it apart and put it back together, but I figure you'd want to be measuring things while you're in there unless you know it's a good running engine / tranny.

Anyhow - keep us posted!
 
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