Topic: High Performance CAMSHAFT Chain tensioner for CB750(MessnerMoto)

[MessnerMoto]

This is one complete kit, chain does not go with the kit

But you get

1. CNCed back slider made from PA 66 + MoS2 plastic with laser cut stainless steel support plates
2. CNCed tensioner made from PA 66 + MoS2 plastic with laser cut stainless steel support plates
3. CNCed middle wheel bearing made from PA 66 + MoS2 plastic with NTN HK1312 high speed needle bearing
4. One fancy nitrated axel for middle wheel, hardened to 55RC
5. One Aluminum 8mm diameter pin. Sides of this pin are CNCed so it slides in upper hole of cylinders
6. One 6mm steel pin

You need this chain for this to work:

https://www.ebay.com/itm/CATENA-DI-DISTRIBUZIONE-DID-219FTH-96M-HUSQVARNA-350-TE-1990-1998/351761127274?epid=1658174043&hash=item51e698d76a%3Ag%3A8GcAAOSwzgRWua%7Ep&_sop=15&_sacat=0&_nkw=did+219+fth+96&_from=R40&rt=nc

It is DID 219 fth 96 links HD cam chain with two extra links(OEM is 94 links). It is endless but comes open with link that need to be riveted

This is straight side plates chain. Oval/peanut shaped chain will ruin sliding surfaces fast. Don't use oval shaped chain

Final price is 160EU

Shipping is 8EU for hole world(I checked for several countries from all over the world and it is always 8EU, maybe there is an exception...)
It is airmail with tracking number/info.... You should not pay import taxes but maybe there will be some exceptions....

The hole price is 160 + 8  = 168EU or by current rate 197USD You can choose EU or USD....

This is low margin for profit. I can't afford PayPal fee. If you want to pay like you are buying product I need to include also PayPal fee 5%.

Enjoy

Look at last five pictures in this post....

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Original post:

After several individuals from the forum expressed interest in buying my solutions for cam and primary chain tensioners, I decided to put in a production cam tensioner solution. Primary chain solution will follow. Initially I wanted to reproduce my original solution for all people interested. But this proved to be difficult because all original peaces are made on CNC using PA 46 plastic. It is hard to produce one set at the time and finding good source of PA 46 plates has proven to be complicate. I refined my original solution and I decided to make tooling for plastic injection of all plastic peaces for cam tensioner set.
 
This is an implementation of modern engine cam slider and tensioner design to cb750 engine, nothing is invented. This system of cam chain tensioner and sliders allows for total control of the cam chain. Due to the curvature of the guides and tensioner, all resonance is eliminated as the chain remains in full contact over its entire length. All of this will allow far better control and stability of timing across the rev range. For racing application this system will allow for higher rev range. Guides will be made from PA 46 or PA 66 polyamide, again this is just copying what major automotive companies are using in there high performance engines. Load on cam chain is decreased because of constant contact between chain and guides. Combined with state of the art material used in construction this will increase time use of cam chain and reduce wear of complete system. HD chain with straight side plates is a must for this system. Number of links in cam chain is increased from 94 to 96 links to achieve desired curvature in chain guides, compered to original cb750 cam chain. One beneficial side effect of this system is a lowered noise from cam chain.

Plates that hold plastic guides are laser cut from stainless steel. Wheel guid comes with HK1312 bearing and axis on which wheel rotates. Plates and plastic guides are riveted with stainless rivets. Set comes with two pins, one 6mm and one 7mm, for locating big slider part in engine. HD chain, DID 219 fth, with 96 links is available around the internet for around 25$.

Set is designed to be plug and play. There is no needed for modifications to head, cylinders etc…

Price should be around the price of OEM replacement set. Tooling for plastic injection is very expensive but I am hoping to cover that expense with volume rather then price.

I am inviting people from this forum to tell me, in this thread, if they are interested in this cam tensioner set.

Mirko

[slikwilli420]

Can you give an idea of price based on what you know right now? I know we discussed some things, but wanted to know what your thoughts were, even if its a range of prices. I missed out on this for 2018 but these might get implemented in my racer for next season. Best of luck and I'll be watching with interest.

[voxonda]

Hi Mirko,

I , for one, am interested. Just rebuilding my engine now with a new oem primary tensioner and a camtensioner with special wheels from Over Racing in Japan. But fro future builds surely like your solution.

Regards Rob

[Medyo Bastos]

Yes, more than 1


Sent from my iPhone using Tapatalk

[MRieck]

I'm in for 3 but I am curious about what happens when a cylinder and head have been really decked/milled. I'd imagine the 94 link would work??

[gschuld]

I'm in for 3 but I am curious about what happens when a cylinder and head have been really decked/milled. I'd imagine the 94 link would work??

I’ve read in an old article about Yoshimura that they would shim up the rocker towers a small amount in an effort to improve cam chain life with whatever adjuster they were using at the time.  Odd solution, but the towers could be shimmed up the same amount as any decking would reduce.

George

[livefast_dieold]

Interested!

[MessnerMoto]

Mike I can calculate this. Tell me how much is your maximum decking? 1mm or 2mm?

George this is good solution. I can laser cut shimmes.

Also I checked clearance if you deck head up to 4mm. Guides will clear the chain. I made a picture. Yellow line is how chain will follow if you deck the head 4mm.

Based on my calculations 1mm deck will work with 96 links

[MRieck]

Mike I can calculate this. Tell me how much is your maximum decking? 1mm or 2mm?

George this is good solution. I can laser cut shimmes.

Also I checked clearance if you deck head up to 4mm. Guides will clear the chain. I made a picture. Yellow line is how chain will follow if you deck the head 4mm.

Based on my calculations 1mm deck will work with 96 links

I'd say 2mm is the maximum between head milling and cylinder decking. Be careful with cam tower shimming as it changes the rocker arm relationship to the valve tip.

[MessnerMoto]

Mike I can calculate this. Tell me how much is your maximum decking? 1mm or 2mm?

George this is good solution. I can laser cut shimmes.

Also I checked clearance if you deck head up to 4mm. Guides will clear the chain. I made a picture. Yellow line is how chain will follow if you deck the head 4mm.

Based on my calculations 1mm deck will work with 96 links

I'd say 2mm is the maximum between head milling and cylinder decking. Be careful with cam tower shimming as it changes the rocker arm relationship to the valve tip.

It will work with 2mm deck and 96 links. But it will demand small modification to tensioner guid. What I can do is to make steel plates that hold plastic of tensioner to follow 2mm deck flow of chain. or 1mm deck etc. You will then need just to remove a little bit of plastic and you will be guided by steel plate(second picture)

[gschuld]

Mike I can calculate this. Tell me how much is your maximum decking? 1mm or 2mm?

George this is good solution. I can laser cut shimmes.

Also I checked clearance if you deck head up to 4mm. Guides will clear the chain. I made a picture. Yellow line is how chain will follow if you deck the head 4mm.

Based on my calculations 1mm deck will work with 96 links

I'd say 2mm is the maximum between head milling and cylinder decking. Be careful with cam tower shimming as it changes the rocker arm relationship to the valve tip.

I wondered about that as well.  An added lash cap or valve seat depth change would also alter the rocker to valve tip contact geometry a small amount.

George

[kmb69]

I'd say 2mm is the maximum between head milling and cylinder decking. Be careful with cam tower shimming as it changes the rocker arm relationship to the valve tip.

The stock rocker geometry is less than optimum to start with. Raising the cam towers makes it worse.

[slikwilli420]

The stock rocker geometry is less than optimum to start with. Raising the cam towers makes it worse.

Now there’s a new part that would be of enormous interest to many: re-engineered rockers!

I used Rockerarms Unlimited in California for the ones I just had hard welded. They do everything rocker related. They may be able to do something reasonably priced. Considering what they charge for hard welding vs other vendors, its a good possibility.

[kmb69]

The stock rocker geometry is less than optimum to start with. Raising the cam towers makes it worse.

Now there’s a new part that would be of enormous interest to many: re-engineered rockers!

I used Rockerarms Unlimited in California for the ones I just had hard welded. They do everything rocker related. They may be able to do something reasonably priced. Considering what they charge for hard welding vs other vendors, its a good possibility.

It's not the rockers by themselves. The rockers and pivot locations relative to the camshaft and valve stems are not "optimal". They have excessive sweep across the valve stems than is considered "optimal" by the "expert valve gurus". Honda "shrunk" the whole setup to keep the height down and the valve angles were made wide to fit the 61mm bores. It's adequate for many thousands of miles as is evidenced by some high miler bikes but could have been done better.

[MRieck]

The stock rocker geometry is less than optimum to start with. Raising the cam towers makes it worse.

Now there’s a new part that would be of enormous interest to many: re-engineered rockers!

I used Rockerarms Unlimited in California for the ones I just had hard welded. They do everything rocker related. They may be able to do something reasonably priced. Considering what they charge for hard welding vs other vendors, its a good possibility.

It's not the rockers by themselves. The rockers and pivot locations relative to the camshaft and valve stems are not "optimal". They have excessive sweep across the valve stems than is considered "optimal" by the "expert valve gurus". Honda "shrunk" the whole setup to keep the height down and the valve angles were made wide to fit the 61mm bores. It's adequate for many thousands of miles as is evidenced by some high miler bikes but could have been done better.

I think you should figure out a solution and bang it out brother. You got machines! It does create side loads which wear the guide bore much faster. Modern bikes with shallow valve angles don't have that problem. The shim/bucket arrangement certainly helps too.

[gschuld]

I dug this out for reference.  On the last section of the article it mentions shimming up the camshaft pedestals. I’m not endorsing this by any means, just passing old info along regarding what Yoshimura was messing with back then(January 1973 article BTW)

Carry on.

George

[MRieck]

That's the article I read years ago about the shimming.

[madmtnmotors]

Subscribed. 

[gschuld]

Back in the early road racing days, the cam chain/tensioner system appeared to be the most obvious weak link.  The 1970 Daytona bikes seemed to chew up tensioners and chains way too fast.  Mann’s bike limped in for the victory, the rest blew up long earlier.

I’m guessing Pops Yoshimura decided that any potential improvement to a fatal flaw to the factory design of their high revving engines was worth any presumably modest extra wear on the guides and valve tips. 

Who knows, but I enjoy the history aspect of the early teething issues/ problem solving.

George

[kmb69]

Back in the early road racing days, the cam chain/tensioner system appeared to be the most obvious weak link.  The 1970 Daytona bikes seemed to chew up tensioners and chains way too fast.  Mann’s bike limped in for the victory, the rest blew up long earlier.

I’m guessing Pops Yoshimura decided that any potential improvement to a fatal flaw to the factory design of their high revving engines was worth any presumably modest extra wear on the guides and valve tips. 

Who knows, but I enjoy the history aspect of the early teething issues/ problem solving.

George

No disrespect to Pops but I'm not sure they actually knew where the source of their problem was nor did Honda. He tried to solve it by leaving no slack in the chain. It has been explained to me that the cam chain destruction comes from harmonics generated as the chain leaves the sprocket on the pull/front side. The Honda front guides were not designed properly and only kept loose chains from hitting other engine parts. Same thing was happening on the Hy-Vo chains that may have actually been worse. Captain (Brent) has solved this on the DOHC's with his redesigned front guide that extends up to the sprocket and has a gentle curve the chain has to follow as it leaves the sprocket. Kenny (Cycle-X) is about to release a similar version for the SOHC's that will probably do the trick. Most folks have focused on the wrong side of the chain IMHO. The key to long term success with these new guides is the material being used. I know Brent's material has held up on his racer for over 2 seasons now but unfortunately he keeps the material specification, as does Kenny, secret.

I should add that the Daytona bikes were purportedly coil binding some of the valve springs, a condition that will destroy any chain no matter what guides/tensioner is used. Mann's bike barely made it because he had the lowest tuned bike using a lower lift cam.

[gschuld]

Kieth,

Good points.  Yes I agree on the preference for a long and curved fwd guide.  Brent’s custom work along with plenty of more modern examples drives that point home.

I’ll be keen to get a look at Kenny’s cb750 curved front guide solution.

The unit being discussed on this thread is a pretty impressive bit of engineering and cad design.  I’m really digging the effort that has been put forth.  I have no opinion on how well it will work in practice as I know just enough to know how much I don’t know regarding cam chain issues.🙄

Reading with the interest of getting smarter...🧐

George

[PeWe]

Modified rockers and adjusting cam holders height were mentioned....
I had problems with dimples in the valve stems when my K6 head had F2 inlet valves. I blamed the different angle when stem was shorter so the Honda adjuster could dig dimples when adjusters are almost flat.

I had ideas to find something like Porsche 911 adjusters, elephant foot model. This is too thick for CB750 rockers

[MRieck]

Back in the early road racing days, the cam chain/tensioner system appeared to be the most obvious weak link.  The 1970 Daytona bikes seemed to chew up tensioners and chains way too fast.  Mann’s bike limped in for the victory, the rest blew up long earlier.

I’m guessing Pops Yoshimura decided that any potential improvement to a fatal flaw to the factory design of their high revving engines was worth any presumably modest extra wear on the guides and valve tips. 

Who knows, but I enjoy the history aspect of the early teething issues/ problem solving.

George

No disrespect to Pops but I'm not sure they actually knew where the source of their problem was nor did Honda. He tried to solve it by leaving no slack in the chain. It has been explained to me that the cam chain destruction comes from harmonics generated as the chain leaves the sprocket on the pull/front side. The Honda front guides were not designed properly and only kept loose chains from hitting other engine parts. Same thing was happening on the Hy-Vo chains that may have actually been worse. Captain (Brent) has solved this on the DOHC's with his redesigned front guide that extends up to the sprocket and has a gentle curve the chain has to follow as it leaves the sprocket. Kenny (Cycle-X) is about to release a similar version for the SOHC's that will probably do the trick. Most folks have focused on the wrong side of the chain IMHO. The key to long term success with these new guides is the material being used. I know Brent's material has held up on his racer for over 2 seasons now but unfortunately he keeps the material specification, as does Kenny, secret.

I should add that the Daytona bikes were purportedly coil binding some of the valve springs, a condition that will destroy any chain no matter what guides/tensioner is used. Mann's bike barely made it because he had the lowest tuned bike using a lower lift cam.

Funny....I was watching a film on Youtube which had the 70 Daytona 200. Mann's engine was ready to implode (or explode) with oil puffing bad on downshifts and under acceleration. A fella questioned Mann about the smoke (the guy knew what he was talking about too) and Mann said they wanted "extra" oil in the top end. The guy says...."so...it was done on purpose?" Mann says yes.
 What a load of horse $hit.
 I think those no seal exhaust guides were responsible for 50% of the ongoing smoke during running and the coil bind brother Keith mentioned the other half (big puffs of downshifts with heavy vacuum applied).
 It really begs the question....if you have coil bind who in Gods name assembled the engine as the builder is directly responsible for that kind of BS. Also makes me wonder if they just shimmed stock valve springs???

[kmb69]

.....
Funny....I was watching a film on Youtube which had the 70 Daytona 200. Mann's engine was ready to implode (or explode) with oil puffing bad on downshifts and under acceleration. A fella questioned Mann about the smoke (the guy knew what he was talking about too) and Mann said they wanted "extra" oil in the top end. The guy says...."so...it was done on purpose?" Mann says yes.
 What a load of horse $hit.
 I think those no seal exhaust guides were responsible for 50% of the ongoing smoke during running and the coil bind brother Keith mentioned the other half (big puffs of downshifts with heavy vacuum applied).
 It really begs the question....if you have coil bind who in Gods name assembled the engine as the builder is directly responsible for that kind of BS. Also makes me wonder if they just shimmed stock valve springs???

They all started with the same factory hardware. Bob Jameson, of American Honda, built Mann's bike. Yoshio Nakamura, factory racing guru, was in charge of the other three Hondas. There was very little oil left in Mann's bike at the end of the race which I got to see in person by the way! Got to ride the first Sandcast we ever got at Pasadena Honda from Houston to Daytona and back. Too KOOL!     

I heard from a pretty reliable source, they were using Massey Ferguson valve springs!     

[BPellerine]

so you think all the oil went out the exhaust guides?I can see the idea of some smoke but not that much oil consumption,but I could be wrong.bill