Topic: Vintage Speed Part Mashup - 1976 CB750F

[slikwilli420]

Final stage of getting the seat mounted. I found the aluminum threaded posts at the hardware store yesterday, and figured that 6 of those and 2-6mm bolts should be enough to hold it to the steel pan, which is bolted to the sub-frame up front and to the hoop via two tabs at the rear.

I really need to decide on a tail light and have narrowed it to two options that I think will fit the vintage feel and the shape of the tailpiece. Links to both below.

http://www.tcbroschoppers.com/ford-duolamp-model-a-stainless-steel-tail-light-1778.html
http://www.tcbroschoppers.com/stop-tail-light.html

Both would be mounted flush with the license plate light being recessed so the plate doesn't hang out so far. Thoughts on the seat or tail light?

[seanbarney41]

Those tail lights are chopper stuff...not right for your build at all imo.  I got an extra early, small, cb tail light that would fit right in that tail, I would guess...You can have it if you use it.

[slikwilli420]

I really liked the vintage look like a Vincent but I'm still open to any light. Got a pic or link to a pic?

[Retro Rocket]

I like these twin round lights.. 4th from top...

http://www.airtech-streamlining.com/miscpages/lights.htm

[seanbarney41]

I really liked the vintage look like a Vincent but I'm still open to any light. Got a pic or link to a pic?

no...just take the big ole' stock cb750 light and shrink to about half size and round it a bit

Retro, thanks for that.  I have been looking for those for my f.

[slikwilli420]

Like this?

http://m.ebay.com/itm?itemId=360677284009

[seanbarney41]

That's exactly what I was talking about.

[Retro Rocket]

What is the smallest cb looking tail light..?

Sean, you can get those lights in small square lights as well, just google twin square motorcycle tail light, if you go to images and look around you'll see both the square and round lights   

[slikwilli420]

Got a small CB tail light from Sean so I will need come up with a way to mount it securely.

Also finished up making a rear caliper torque arm out of some square tube and a few pieces of strap steel. Should look the part sitting over my box section swing arm after its powdercoated.

The last thing is my new kickstand. I probably could have come up with a replacement from another bike, but I love one-off parts. I started with some 1/4" strap steel for the fork that goes around the frame, with one side drilled and the back tapped like the stock one. That is attached to a 3/4" solid bar that was notched to take the two tabs up top, welded together and shaped with a grinder. The bottom foot is a take on the stock one, shaped from 7/8" round bar with a  flat bottom. I may or may not put a foot plate on the bottom for a larger area to keep from sinking in. The overall length is about 3/4" longer than stock to keep my bike from leaning too far over from longer forks up front and shocks out back.

[seanbarney41]

It was good to meet ya last week and to see all the nice fabbed and vintage parts in person.

[slikwilli420]

I have gone back and forth a bunch lately trying to decide on how far to take my engine build. I have decided to go for a 915 build similar to one others have done on the forum. I really want something that rips but will be working toward a reliable engine as well. Here are my thoughts, but please let me know if I forget anything.

From top to bottom:
Head will be stage 3 from JMR with oversized valves, new guides, spring kit, seals, cam/chain/roller/tensioner
915 kit with new sleeves and cylinder fitting/boring by Cycle X
Balanced/lightened crank with Cycle X rods all fitted together by them with lightened alternator
New primary chains
Undercut tranny
New fiber clutch plates, steel ones if needed
All new gaskets/seals, and any bearings that are suspect
This will be breathing through Weber DCOE 40’s as well as a Kerker with comp baffle.

My question to those in the know is how do you recommend attacking this? I don’t have the cash right now to do everything so what makes sense to do first? It seems that sub-assemblies would make sense, so Im thinking head or crank first, then tranny/bottom end, and all they cylinder/piston stuff. This is my first 750 build but I have done basic rebuilds on dirt bike engines in the past.

[calj737]

If it were me, and it is with respect to a 500 build or comparable caliber, I start by getting the head work done. Mike is a busy guy, and his work is in high demand. Nor, does it happen quickly. What he does takes a lot of time, and is critical for the rest of the bike to run to its potential.

I would then commence purchasing the components, rods, pistons, carbs,  etc. once accumulated, then send your cases for machining. If you have the means, acquire a second motor and send the assemblies in stages and build the motor on the side while you keep your bike running.

Machined cases, heads and components can sit on the shelf for months or years if that's what it takes. Lots of spare motors around to get as donors for rebuilds.

[Retro Rocket]

I won't offer any build advice but, i wouldn't take too much off the crank, with the lightened alternator you'll already improve revability, you still want torque as its a street bike, the 915 will easily spin up a fairly stock weight crank, i'd slightly lighten it and balance it for sure and do the oil passages in the crank, I think Cycle x do that anyway....

[SOHC4 Cafe Racer Fan]

I have that spec head - Stage 3 with oversized valves - as do a bunch of other members. Some call it a Stage 4 with those valves. It is a thing of beauty. Go with MR.

Cycle X for the slightly lightened and balanced crank, and undercut trans. Balanced rotor. You may want Super Rods, too.

[slikwilli420]

I agree with you RR on not taking too much off the stock crank weight. My thought is just to shave a bit and get things cleaned up and polished, as well as have the Super Rods installed while its there. I will also get the alternator lightened but not so much to lose e-start.

Couple of parts questions to everyone. What flavor of primary chains are recommended? Im guessing the more expensive set would be a race use, high-stress application and that I can get away with the normal replacement ones Cycle X sells.

For the sleeves for the 915 kit, does the upper case need to be bored or not? I might be misunderstanding what the Cycle X site says, but it seems they mention both boring and no bore for that size.

I have an email out to Mike on the head and asked for some cam recommendations based on wanted good streetable power first and formost, meaning good torque. Im not as concerned with top speed, redline power. What is a good cam for the 915 based on what I intend to use the bike for?

With regard to cam chains and the associated roller/sliders. Is a stock replacement a good choice for chain? For the roller/slider, it looks like Cycle X rebuilds them and that seems like the way to go. Thoughts on that?

Planning on the main/cylinder stud kits as well. I see only one main kit but two cylinder ones, a Cycle X and Kibblewhite w/ and w/o nuts. I would really like to do the one without nuts and get 12pt ARP with some nice thick washers for the head and main studs. Is there any downside to that approach and which cylinder studs are better?

Lots of questions but I want to buy once, cry once on this build and not have to buy the same thing twice.

[SOHC4 Cafe Racer Fan]

Matt,

With a ported head, cam and big bore kit, I would spring for the HD primary chain and tensioner, Tsubaki HD cam chain and HD cam tensioner.  Definitely go with HD studs.

[calj737]

I used ARP nuts with my HD studs. Mike is a great source for much of what you want to buy too. And invaluable advice.

[Retro Rocket]

Matt,

With a ported head, cam and big bore kit, I would spring for the HD primary chain and tensioner, Tsubaki HD cam chain and HD cam tensioner.  Definitely go with HD studs.

+1

[slikwilli420]

Which cylinder studs,  Cycle X our Kibblewhite? Also there are a few options for primary chains that seem similar. The ones with oiling holes sound like the ticket to me.

[Retro Rocket]

Which cylinder studs,  Cycle X our Kibblewhite? Also there are a few options for primary chains that seem similar. The ones with oiling holes sound like the ticket to me.

I have the heavy duty primary chains from classic cycle city, they {CCC}were the ones that did all the R&D on these type of primary chain and had them made,  they say their chains are better that CycleX's chains and I have no reasons not to believe them, now, I have had quite a few conversations with both Ted {cycle city USA} and Thomas, {cycle city Germany}. There were good reasons why the solid chains were better but I can't remember at the moment, It was a while back that it was discussed. I will continue to buy the Classic Cycle City chains, that is no reflection on Cycle X, they are a great shop as well...

[SOHC4 Cafe Racer Fan]

I don't think there is any marked advantage between the HD studs made by APE, Cycle X/Kibblewhite (it's my understanding that Cycle X and Kibblewhite have some type business relationship where KB provides/manufactures parts for Cycle X).

I think that any HD primary chains -- Cycle City or Cycle X -- will be better than the OEM chains. 

[Retro Rocket]

I don't think there is any marked advantage between the HD studs made by APE, Cycle X/Kibblewhite (it's my understanding that Cycle X and Kibblewhite have some type business relationship where KB provides/manufactures parts for Cycle X).

I think that any HD primary chains -- Cycle City or Cycle X -- will be better than the OEM chains.

The only reason i'm go with Kibblewhite studs, is I have had an APE stud break, there are a few reports of them breaking here, It may be a rare occurrence but I just thought i would give them a try... I agree, both primary chains will be better than stock. 

[SOHC4 Cafe Racer Fan]

RR,

Good to know that about APE studs.

[Jerry Rxman Griffin aka MuthaF'er]

I have that spec head - Stage 3 with oversized valves - as do a bunch of other members. Some call it a Stage 4 with those valves. It is a thing of beauty. Go with MR.

Cycle X for the slightly lightened and balanced crank, and undercut trans. Balanced rotor. You may want Super Rods, too.

The Stage 4 actually uses the lighter 5mm Kibblewhite valve stem conversion (stock = 6.5) and the intake is 34mm. Extra work and more expense.
 

[SOHC4 Cafe Racer Fan]

Correctomundo. But worth it!