Topic: 1975 Supersport, performance cafe

[Jerry Rxman Griffin aka MuthaF'er]

Hey guys, just a FYI. The man, Big Jay, himself does all the work on our 750 stuff at APE. He doesn't let the young guys touch it. Plus, he has to run the place as an owner too. So, be patient, it could take a little longer than expected but it'll be done right. Just be glad he's still enjoying working with his expertise on this stuff.

[sangyo soichiro]

Hey guys, just a FYI. The man, Big Jay, himself does all the work on our 750 stuff at APE. He doesn't let the young guys touch it. Plus, he has to run the place as an owner too. So, be patient, it could take a little longer than expected but it'll be done right. Just be glad he's still enjoying working with his expertise on this stuff.

Thanks Jerry.   

[tweakin]

Great build! 

Can you recommend a Seattle area machine shop to bore my jugs for my 836 kit?  I also sent you a email.

Thank you,
Tige (tweakin)

[Doctor_D]

I really like Johnnie at Autosport Seattle.

Though he's not doing my CB750 work, which has gone to Mike Rieck and APE, he's done most of my other work - including that for my Norton.

[Doctor_D]

Well, at least the forks are done.



New 1" shorter stanchions
Racetech cartridge emulators and springs
New OE seals
New OE studs, nuts and washers
New OE copper sealing washers
Stainless triple-tree, brake and fender fasteners
175cc's of Redline 15wt suspension fluid per leg
All Balls tapered steering bearings
Overhauled brake caliper relocated to right side

They won't give a modern cartridge fork much competition, but they're certainly an upgrade over stock.

[sangyo soichiro]

Hey David, looks nice.  How will the gaiters attach at the top?  Are you sticking with the standard fork ears?

[Doctor_D]

Not sure what to do with the gators.  Thought they would be snug to the stanchions, but they're loose.  I may need a universal brit-bike type set like I have on my Norton. The ones I bought were pricey K0-K1 repros, so I don't really want to hack them up.

As for headlight ears, the absolute best I've found for the money are like these GB Cafe Headlight Bracket Set, found on the MikesXS page, here: http://www.mikesxs.net/products-77.html They're solid aluminum and pretty nicely made.  Seem like a steal at $39. I've also got a 7" Emgo halogen headlight to replace the squashed flat looking Honda one.

[Doctor_D]

Finished polishing the rocker-cover and couldn't resist mocking up the motor.

Before:



Part way:



Barrels have been bored and honed, but not blasted as I'm waiting to see how much I'll have to surface the barrels to achieve Mike Rieck's suggested squish.

The crank is on it's way back from APE and should be here Monday.  Given that, I could potentially get the bottom end more or less together before the end of May - almost on schedule.  I'm sure there are lots of bits I'll need that will delay assembly, but that's the plan for now.

[MRieck]

Looks mint David. Can't wait for the finished product.

[MRieck]

 Is that some whiskey I see   What's up with all the Web cam boxes too??

[Doctor_D]

Thanks for the kind words.  I'm sure you've seen many motors at least as nice, and many much better -- but I appreciate the compliment.

Yep, that's a bit 'o rye in the picture. Little nip on Friday afternoon to celebrate the supposed end of the work week. Now I just need to actually "end" the work week.

The other cams aren't mine.  Working on this at a friend's shop that's just a few block's from my house, and they're his. Think they're all 41a's.

While you're here, your squish recommendation was 0.004 down the bore -- including the head gasket, correct? Is that going to keep me around 10.25:1 or bump the CR a bit?

Thanks again.

[tweakin]

Looks great david, you did wonders polishing up the rocker cover.

[Doctor_D]

Like Soichiro, I received my crank from APE.  Needless to say - it's beautiful.



In case anyone's wondering, not everything with this build is a bowl of cherries.



I was removing the starter clutch from the rotor.  The damn thing broke the head off my impact driver... and the head (hardened steel that's a match for any drill bit, by the way) was firmly embedded in the phillips head screw. Torch, drill, chisel, you name it... nothing. Arghh.

Anyway, modded the rocker towers per Hondaman's suggestion, eight oiling holes where the casting marks are.  Though I've heard some disagreement on the issue, I plan on leaving the 5mm rocker-shaft fixing bolts out during reassembly.



Might get the head together today. Foul weather this memorial day weekend in Seattle.

[traveler]

Looks like progress is being made.

Might be better off sourcing a new rotor/stator setup off of eBay and let that one find the dumpster.

I assume you will use stock gearing?

~Joe

[tweakin]

Excellent progress and that crank is a thing of beauty.  I hope to get my tins painted this "crappy weather" holiday weekend in Seattle.

[Doctor_D]

Yep, that rotor's toast.  It'll be my test mule for lathing a little weight off the inside edge.

My plan is to convert to a 520 x-ring chain, keeping the stock ratio.  Why do you ask?

[Doctor_D]

I hope to get my tins painted this "crappy weather" holiday weekend in Seattle.

It's pretty pathetic, ain't it.  The wife had a furlough day on Friday, so I took the day off hoping we could go somewhere -- but it's cloudy and cool all the way down to southern Oregon.

Good luck with your painting.

[sangyo soichiro]

Anyway, modded the rocker towers per Hondaman's suggestion, eight oiling holes where the casting marks are.  Though I've heard some disagreement on the issue, I plan on leaving the 5mm rocker-shaft fixing bolts out during reassembly.

Good idea.  Somehow, that Hondaman mod slipped past me.  I suppose I'll do mine too while I got everything apart.  Thanks for the tip.   

[traveler]

Yep, that rotor's toast.  It'll be my test mule for lathing a little weight off the inside edge.

My plan is to convert to a 520 x-ring chain, keeping the stock ratio.  Why do you ask?

Curiosity, Doc....nothing more.

I have played around with gearing on most of the bikes I have had, and wondered if you were going to drop a tooth or two on the front cog, or maybe go up a few on the rear.

With the power you will be making, I guess stock gearing will be perfect.

The 520 chain setup will free up a bit of HP.....I would think the 520 chain will handle 90 HP.

~Joe

[traveler]

Anyway, modded the rocker towers per Hondaman's suggestion, eight oiling holes where the casting marks are.  Though I've heard some disagreement on the issue, I plan on leaving the 5mm rocker-shaft fixing bolts out during reassembly.

Good idea.  Somehow, that Hondaman mod slipped past me.  I suppose I'll do mine too while I got everything apart.  Thanks for the tip.   

First I had heard of it as well....if it dosen't affect oil pressure having extra passages used...then it could only help, IMHO.

~Joe

[jaguar]

yeah is that from hondamans book or am i missing a hondman thread somewhere?/

[Doctor_D]

yeah is that from hondamans book or am i missing a hondman thread somewhere?

Might be in a thread, but it's also in his book.

In short, leaving the retaining bolts out allows the rocker shafts to rotate, decreasing drag and wear.  The older 750's didn't have the 5mm retaining bolts and, according to Mark Paris (Hondaman) the valvetrain was a little noisier, but far more durable. (With open megaphones on my CR replica exhaust, I sincerely doubt I'll hear it anyway.) Since the shafts can rotate, one taps oiling holes to spray-lubricate the now-free spinning rocker shafts.

It was fairly simple and will hopefully produce the desired result.

[754]

Rotor should be saveable, grind out bolt head with carbide burr..
 The screws are heavily staked to prevent loosening, if you have replacements, it may have been easier to drill heads off.


 You gaiters, do you need something made to hold up gaiter ends? If it can be 1 pce, ie , musy be slipped over forktube, price will be lower..

[Jerry Rxman Griffin aka MuthaF'er]

Doc,

I hate to ask but did you drill off the "keeper punches" (for lack of better word) or staking as Frank says on each screw before removal? I just pulled my rotor off and found one of those damned screws broken off with the head floating in the recess and the other 2 loose but they hadn't turned due to the original punches. Apparently the thread holes have worn without the screws turning. I have a spare to use and an anchor now. Dime a dozen. Shipping should be more than the part. Screw trying to save it. Sounds like we could have to order Franks' carbide burr or anything else to save something that can be easily and cheaply replaced.

[Doctor_D]

I hate to ask but did you drill off the "keeper punches" (for lack of better word) or staking as Frank says on each screw before removal?

Not that I looked hard, but I didn't see that they'd been peened or staked into place.  First two came out with effort, but nothing out of the ordinary.

Live and learn, I guess.