Topic: Newbie Building a Project '75 750F

[RSchaefer]

    Maybe you already know this but I will mention it anyway.  The petcock for the 75/6 will not fit the 77/8 tank so hopefully one came with your "new" tank.  The threaded fitting on the tank is different.
    I prefer paint on the frame.  It can be touched up and is more DIY.

Srust you also have been very very helpful and I thank you for that, I think you were the one who alerted me to this issue originally.  I did purchase the petcock from the 77/78 tank seller for that reason.  I'm seeing now that it seems the aftermarket does have replacements for the 77/78F tanks at a reasonable price, however NOT the 75/76F!

Also the issue is routing of the gas line with the 77/78F petcock and someone posted a great picture of the alternative routing.

[RSchaefer]

I sent my swingarm to Hondaman and had him rebuild it with the bronze oilite bushings.  I was able to source an older swingarm bolt from eBay and sent it along to Hondaman so he added the US zerks and had to get a new internal collar.

I was trying to post pictures but I use Photobucket and it seems to be super slow today, probably because of the New Years Eve party pic's

[RSchaefer]

I toiled over whether to paint or powder coat and finally bit-the-bullet and went for the powder coat.  I purchased a digital oven at a local used building supply for $40 and mounted it under my awning in the side yard.



I purchased the basic Eastwood PC kit which included 6-pints of various PC, I think I could specific 3 colors.  The basic kit included a gloss black and I then ordered a semi-gloss & satin black.  Process is very forgiving and pretty easy to do.  Here are some of the finished parts.

Before


After

[RSchaefer]

Also did allot of research on the engine paint on this forum and decided to go with the VHT silver caliper paint.  My '75 motor was painted from the factory.  I ended up soda blasting the block and fine sanding any scratches out.  I was able to purchase a spare engine and various other CB750 parts from a junk guy and decided to use the spare engine's covers to mask off those areas as I was polishing all of my side covers.

Getting ready to paint.  I purchased a small 1K lb lift from HF and had a location outside my garage to hang it.  I used the top rear bolt with some tie down straps to suspend it to paint.


Kinda close up of the original surface after soda blasting


Finished product.  I did two light coats in order to minimize the paint buildup as I'm reading to much paint will hold in the heat

[SOHC4 Cafe Racer Fan]

Looks beautiful

[Kickstart]

Looks nice!.... I'll be following your thread.
Thanks for your help on my valve clearance questions.

oh... one suggestion though... wire that oven up the proper way.  That looks like a bad accident waiting to happen.  (I assume that's 220V)

[RSchaefer]

Well turns out I am a home inspector and you know what they say about the cobblers kids not having any shoes    Anyway the oven is wired up properly, just that I have exposed wire nuts instead of them being in a J-box.  I have two plugs for the oven plugging into a 115V, quad extension cord (properly wired) to a 220V, RV outlet (properly wired).  So you plug one 115V into one side of the quad outlet and the other plug into the other side of the 115V quad outlet and vola 220V to the oven.  I also have the oven strapped to the wall so I think I'm OK.

[Jerry Rxman Griffin aka MuthaF'er]

Haven't checked in for a while. Looking good!

How much did the powdercoat kit set you back?

Aftermarket 75/76 F petcocks are available from CB750supply.ocm for $40. Looks pretty close to stock?  They also have a $20 non-stock looking one for the 77/78 F
http://www.cb750supply.com/products/6/fuel-system/67/petcock-parts-fuel-line

[RSchaefer]

OK so I felt like I should start updating this thing as I'm finally starting to put it back together and maaayyy get it running this year.

Here is its latest condition



I pretty much did everything HondaMan recommended for the low-cost upgrades to the motor.  I took the cylinders and head to a local motorcycle machine shop and had the cylinders honed as there was not any major problems there, only 12K miles on what appeared to be a not abused motor.  I had the machine shop take 9 thousands off the head to kinda level everything out and slightly increase compression and had them do a valve job and new valve seals.

Well let me backup a little.  Before I had the head work done I did all the recommend tweaks suggested by Mark i.e. I purchased a long stem diamond grinder bit set from Eastwood and started removing restrictions on the intake and combustion chamber.

I was really anal about taking picture of EVERYTHING.  I realized right away when I started taking it apart that the bike had never been seriously worked on since the factory build and I felt fortunate that I was not going to be finding surprises from a previous PO.  I also realized how important it would be for me to fully document the tear-down as this was, after all, the way it had come from the factory.







You can see the obstructions of slight walls in the combustion chamber in this photo that Mark talks about in his book







You can see here that I did not have much of a ledge in the cylinder above the top ring and thus no need to do a bore

[RSchaefer]

I had asked Mark about this stuff oozing out around the intake manifold and apparently it is the glue Honda used when they screwed these guys into the head and I could remove the excess.



This was my attempt to take a picture of the original intakes and the bumps left over from the original Honda technician



Here you can see the residual glue on the inlet tract and less visible is a "step" between the nozzle and the intake 



Also in the distance you can see the ridges around the valve stem

[RSchaefer]

Some more pictures of the intakes, valves, etc.

I ended up buy a soda blaster nozzle from HF and a bag of soda and cleaned everything up



Ridges/obstructions in the combustion chamber are much more visible after soda blasting





Valve seat







You can clearly see where the Honda technician took a swag at removing some of the intake obstructions



Here you can see the nozzle glue and some flash bumps in the intake molding





Looking into the inlet tract from the intake valve side and you can see obstructions





Look how big the ridge is where the nozzle meets the casting



Valves and seats and the need for a valve job



I was careful to label the valves but then my machinist said it was not necessary when doing a valve job as he was grinding each valve into a new seat.

[RSchaefer]

So this was the result after I, lets say, ported the intakes.  Mark does not recommend polishing as the rough surface of the intake assist in mixing the fuel air mixture.

All intakes ported and obstructions removed





Was concerned about removing to much shrouding around the valve stem but my machinist says it should not be a problem as I am not going to be racing the engine and the additional inlet flow should help keep the valve stem cooler



Biggest concern I continue to have is having significantly changed the volume of each inlet tract and the inability to adjust the carbs due to the variations.  I tried to remove the same from one tract to the next but I'm sure my eyeball is not that well calibrated, will see!!







This is my version of the "bowl" that Mark describes in his book



Notice how bunged-up the valve seat is.  The diamond grinder got away from me a couple of times and I couldn't sleep a couple of nights thinking I had just blown-up the head!!  When I showed the nicks to my machinist he said "no problem" he would be taking that out as a result of the valve job.







Getting ready to paint the engine





Painted!  I used the side covers off a donor motor to mask those areas of the engine

[SOHC4 Cafe Racer Fan]

I cannot begin to critique your port job -- leave that to the true experts like Mike Reick -- but you definitely smoothed out some of the casting obstructions.  You did a solid on that paint job -- good work!!

[RSchaefer]

OK I got it started, took almost 4 years and the current balance is: $6,887.  I tore it down to every last bolt and did lots & lots of stuff.  I realized early on it did not make sense for my to keep a blow by blow on the forum as my starts and stops were all over the place.  Waiting for parts, waiting for shops, running out of money, on and on and on.  In the last few weeks I started to try and get back into it.  I have gotten it up on its wheels and rolling probably a year ago and then spent time cleaning more parts, sourcing parts, etc.  Today I finally got to the point where I could put a little gas to it and see what happens.

I also was super stressing because of others experiences with god knows what when it didn't start, broke something, no oil to the top end, etc. - kept me up at night wondering if maybe I forgot something, put something in wrong, or whatever.  I pretty much did ALL of the work myself including all of the powder coat, except for the frame (sent it out).

Anyway I put a little gas in and it started right up, 1st hit of the started button.  Oh my god!!!!

[Jerry Rxman Griffin aka MuthaF'er]

Congrats Rich!! You beat me on #2. My powder wasn't ready when I got home. There's always 'next week' haha.

Looks great but we gotta work on the routing for the wire coming off the solenoid ;-)

Oil pressure, running good??

[RSchaefer]

I'm concerned about oil pressure as it was a little noisy.

OK I give up, what about the solenoid wire routing, reference?

[Kickstart]

Excellent work!... and congratulations on getting her started!

Glad to see you're still working on it, even if it's sporadic.  My rebuild is also stalled but I hope to make some progress this winter.

I think Jerry is referring to the starter wire coming off the starter solenoid... I believe it should be routed a little differently - tucked behind some of that other stuff?

[RSchaefer]

OK, I sorted out the wiring!

[Jerry Rxman Griffin aka MuthaF'er]

 

Oil pressure gauge? Tune up procedures including adjusting valves, sync'ing carbs, adjusted cam chain and clutch?

Now you have all winter 

[RSchaefer]

Valves are adjusted, bench sync'ed carbs before I installed, have already adjusted the cam chain & clutch - installed the oil pressure gauge today.