Topic: Did anyone see this? -- Honda CB750 16 Valve Twin Cam Head. Piper

[Camrector]

George-
What was the price in the catalog?

[gschuld]

Sorry, I didn't get a price list with that catalog.

Grorge

[Tintop]

On the CMR web site there are more photos of the Piper bike that Denis built for a customer.  I remember asking him about it and he said it required a lot of machining.

Here's a link to an article about it and also the Vincent special that Jay Leno now owns. - http://curtisracingframes.com/articles.html

[Sam Green Racing]

On the CMR web site there are more photos of the Piper bike that Denis built for a customer.  I remember asking him about it and he said it required a lot of machining.

Here's a link to an article about it and also the Vincent special that Jay Leno now owns. - http://curtisracingframes.com/articles.html

That was a great read Brian and I think that was as far as I got when I was researching the Piper head some years ago.
After reading it all again, the guy must have been off his head to spend all that time and money just to create a 100bhp
Street bike but I'm sure it would have won BOTM had he been a member here,  .

Sam.

[H2Eric]

I've got a copy of the Piper Winners Handbook from 1975, but there is no mention of the 16 valve CB750 cylinder Head. I've seen an article in a magazine from the period, hope I've still got it. However, I seem to recall that Piper invited Honda to look at their handiwork, probably with a view to selling them the rights to manufacture, but the men from Honda just took loads of photographs and went away and did their own thing resulting in the CB750 DOHC, which I think first saw the light of day in 1979 .

Eric

[Tintop]

I've got a copy of the Piper Winners Handbook from 1975, but there is no mention of the 16 valve CB750 cylinder Head. I've seen an article in a magazine from the period, hope I've still got it. However, I seem to recall that Piper invited Honda to look at their handiwork, probably with a view to selling them the rights to manufacture, but the men from Honda just took loads of photographs and went away and did their own thing resulting in the CB750 DOHC, which I think first saw the light of day in 1979 .

Eric

Toyota did something similar.  When I was re-building the Seven we had a Lotus TC head, an Alfa head and a Toyota 2TG on the bench (was building a 2TG for Solo 1).  You didn't have to be very knowledgable to see the Lotus & Alfa in the 2TG head design.

[kmb69]

I've got a copy of the Piper Winners Handbook from 1975, but there is no mention of the 16 valve CB750 cylinder Head. I've seen an article in a magazine from the period, hope I've still got it. However, I seem to recall that Piper invited Honda to look at their handiwork, probably with a view to selling them the rights to manufacture, but the men from Honda just took loads of photographs and went away and did their own thing resulting in the CB750 DOHC, which I think first saw the light of day in 1979 .

Eric

Honda had been building world class, championship, 4 valve road race motors for years. Seriously doubt if they needed much help from Piper other than they may have copied Piper's geared camshaft drive. Not sure what year Piper produced these. In fact, Honda's RCB1000 endurance racer in 1975 was a DOHC on SOHC cases. It also had a geared primary drive. Check out the double row cam chain.

[Big Jay]

MTC had one of those heads in their lobby when they were in Calif. As the seller is in Calif, that is probably it.  Piper cams is a current customer of ours.

[MessnerMoto]

Does anybody have more info about geared primary drive? Pictures etc....

[Captain]

 Created for the DOHC 900-1100

 Captain

[MessnerMoto]

Created for the DOHC 900-1100

 Captain

Thanks!

And where do you bolt sprocket. To oil pan?

[turboguzzi]

very nice period piece, talk about the only kid on the block with one  
what strikes me is that with all the extra valve area, the thing peaked only at 8000.

[Captain]

Created for the DOHC 900-1100

 Captain

Thanks!

And where do you bolt sprocket. To oil pan?

 It bolts into the cases........ There is extra material and machining required but all the engineering problems were solved with this.

 Captain

[slikwilli420]

Created for the DOHC 900-1100

 Captain

That would be a killer upgrade to a SOHC bike. To be able to ditch the chains for a permanent solution would be a dream realized.

[kmb69]

.....
That would be a killer upgrade to a SOHC bike. To be able to ditch the chains for a permanent solution would be a dream realized.

We are currently working on one for the SOHC 750A using Brent's idler gear but it requires switching to a DOHC 900 crank which is "wrong ended" if you will. The SOHC 5 speed can be done also with a crank change but it is not as well suited for it. The SOHC 750A already used a Hy-Vo crank, so the Hy-Vo primary style is already in place. Still requires a lot of crankcase and primary mods to get it right - more so than the DOHC engines.

[kmb69]

Does anybody have more info about geared primary drive? Pictures etc....

This is the only viewable picture I have ever found of it. If you find more, please share.

[bwaller]

Brent or kmb69 is the tooth pitch similar for all Honda's cranks using Hyvo?

[kmb69]

Brent or kmb69 is the tooth pitch similar for all Honda's cranks using Hyvo?

The pitch is the same. The width differs.

[Captain]

Brent or kmb69 is the tooth pitch similar for all Honda's cranks using Hyvo?

 Keith is quickly becoming more experienced with "other" Honda HyVo cranks and can talk more about this than I can as all my efforts have been directed at the DOHC.  Until he does I will provide some back ground of what this is about and it's pending application to the SOHC.

 There is no reason to believe that this gear drive conversion technology cannot be transferred to the SOHC (in a modified form) and the results will be well in advance of the OEM set-up when this is achieved.
 The part to solving this was finding a way to engage with the HyVo tooth form of the crank which is not your conventional in-volute gear shape. Honda manufactured cranks and associated components this way as it is quicker and easier to broach the HyVo form during manufacture as it requires less material removal. This HyVo tooth profile presented unique problems that required a lot of investigation and testing but eventually I managed with a special hybrid idler gear to solve the engagement issues and further an innovative way of locating and anchoring the assembly.
 This has proven to be a game changer for the DOHC engines as we are now free to RPM well beyond the limits previously imposed by the chain.

 Captain     

[kmb69]

I just received my DOHC gear drive and cases from Brent last week. It is absolutely a work of engineering ART.
Almost a shame to try to destroy it in a drag bike but that's where they're going! 
Brent is the expert! I thank him very much for the generous help he's been providing for the 750A conversion.

[bwaller]

Hummm the 550's coming apart shortly. 

[kmb69]

Hummm the 550's coming apart shortly. 

Haven't looked at the 550 other than the primary cush. I am using a modified 550 inner with a custom outer to cush the torque converter in the 750A. I think I have a set of NOS 500 or 550 cases on the shelf. Will try to take a peek this weekend and check out the possibilities. 

[MessnerMoto]

Brent or kmb69 is the tooth pitch similar for all Honda's cranks using Hyvo?

 Keith is quickly becoming more experienced with "other" Honda HyVo cranks and can talk more about this than I can as all my efforts have been directed at the DOHC.  Until he does I will provide some back ground of what this is about and it's pending application to the SOHC.

 There is no reason to believe that this gear drive conversion technology cannot be transferred to the SOHC (in a modified form) and the results will be well in advance of the OEM set-up when this is achieved.
 The part to solving this was finding a way to engage with the HyVo tooth form of the crank which is not your conventional in-volute gear shape. Honda manufactured cranks and associated components this way as it is quicker and easier to broach the HyVo form during manufacture as it requires less material removal. This HyVo tooth profile presented unique problems that required a lot of investigation and testing but eventually I managed with a special hybrid idler gear to solve the engagement issues and further an innovative way of locating and anchoring the assembly.
 This has proven to be a game changer for the DOHC engines as we are now free to RPM well beyond the limits previously imposed by the chain.

 Captain   

... It is a shame that I haven't seen the picture of Honda solution before or your solution. I had this exactly idea of making a mid sprocket on my own without seeing your or Hondas solution. But I was thinking that it is not that easily possible. So I went with my chain solution

And this is working much better then OEM solution but this sprocket solution is way better and cheaper to make.

What bearing do you use for this ? You say that sprocket for HyVo chain is not perfect. I was thinking of copying it to be exactly the same like on crankshaft.

[Captain]

 Chains are cheaper which is why they are used, but they have their limits when RPM and HP climbs.
In our case we are now beyond that limit /window and reached a point that we could only expect to keep a chain in it for one race, not a weekend meeting, but one race. If we went and tried a second we lost the chain and the resulting damage is very costly and too costly to continue (ask me how I know) and so the gear drive conversion was born. With gear drive there are no practical limits to what it can take in the way of RPM and power and opens the door to further increases.
On the journey to this point I've done it all from stock OEM tensioners through to our own custom manual versions and did manage to keep pushing back the limits to chains tech but in the end it was not enough and the gear drive became the only practical way forward....................So I did something about it and built a prototype, tested it, made changes, built a second and tested the changes and then built the final and commercial version as shown in my posted picture.
 Your two questions:
 1/ I am assuming you are referring to the idler gear, then the answer is Hybrid Ceramics.
 2/  The crankshaft gear form is "NOT" a fully formed in-volute tooth and although strong enough and hard enough (60 HRC) it requires a customised idler to engage the crankshaft and the more conventional primary gear.

 Captain

[MessnerMoto]

Chains are cheaper which is why they are used, but they have their limits when RPM and HP climbs.
In our case we are now beyond that limit /window and reached a point that we could only expect to keep a chain in it for one race, not a weekend meeting, but one race. If we went and tried a second we lost the chain and the resulting damage is very costly and too costly to continue (ask me how I know) and so the gear drive conversion was born. With gear drive there are no practical limits to what it can take in the way of RPM and power and opens the door to further increases.
On the journey to this point I've done it all from stock OEM tensioners through to our own manual versions and did manage to keep pushing back the limits to chains tech but in the end it was all over and the gear drive become to only practical way forward....................So I did something about it and the picture I posted is part of that result.
 Your two questions:
 1/ I am assuming you are referring to the idler gear, then the answer is Hybrid Ceramics.
 2/  The crankshaft gear form is "NOT" a fully formed in-volute tooth and although strong enough and hard enough (60 HRC) it requires a customised idler to engage the crankshaft and the more conventional primary gear.

 Captain

thanks for the info once more. And I am sure you have great result with your solution!

1/ I was asking about size of bearing(6205 ? etc? ) and is it needle or ball bearing.

2/ I think I know what are you talking about. Honda did not remove all the material so probably some was left in pockets between teeth.
I would need to see how primary drive sprocket from gl1000 looks(needed for this conversion). If it was machined in same way like DOHC crank sprocket(and I dont see the reason why would HONDA machine bigger sprocket all the way if they saved on crank sprocket). Than solution is simple. I would just copy DOHC crank sprocket(leave same imperfection)... not just copy but also shorten sprocket teeth