Author Topic: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto) (Read 29201 times)

turboguzzi · « **Reply #100 on:** July 02, 2019, 12:49:44 PM »

sorry to hear mirko.... now you know the meaning of quality assurance in the procurement process

not that it will help any of the non auto 750 sohcs, but interesting read on the subject

https://www.cycleworld.com/driving-camshafts-roller-chain-silent-chain-morse-hy-vo-chain/

gschuld · « **Reply #101 on:** July 02, 2019, 05:56:35 PM »

Thanks for going the extra mile Mirko.

George

kmb69 · « **Reply #102 on:** July 02, 2019, 08:10:26 PM »

Quote from: gschuld on July 02, 2019, 05:56:35 PM

Thanks for going the extra mile Mirko.

George

+10 Mirko!
You're First Class Mister!

bear · « **Reply #103 on:** July 02, 2019, 08:59:06 PM »

Quote from: turboguzzi on July 02, 2019, 12:49:44 PM

not that it will help any of the non auto 750 sohcs, but interesting read on the subject

https://www.cycleworld.com/driving-camshafts-roller-chain-silent-chain-morse-hy-vo-chain/

It helps mine.

MessnerMoto · « **Reply #104 on:** July 03, 2019, 01:37:29 AM »

Thanks people really appreciate it!

Quote from: turboguzzi on July 02, 2019, 12:49:44 PM

sorry to hear mirko.... now you know the meaning of quality assurance in the procurement process

not that it will help any of the non auto 750 sohcs, but interesting read on the subject

https://www.cycleworld.com/driving-camshafts-roller-chain-silent-chain-morse-hy-vo-chain/

...the thing that interest me is why honda choose primary chain drive in SOHCs ? ....and more staggering why they kept using it for DOHCs. There needs to be some reasoning behind it. Economical ?

turboguzzi · « **Reply #105 on:** July 03, 2019, 04:17:20 AM »

DOHCs are Hy-Vo....

Honda moved to Hy-Vo already in the 500/4 in 72', just three years after the 750 for a reason i guess

gschuld · « **Reply #106 on:** July 03, 2019, 04:24:59 AM »

Over a 10 year period, Honda produced hundreds of thousands of Sohc 750s, at a rate averaging over 10,000 units per month. Chains/sprockets, one piece cranks, the decision to build a Sohc over dohc initially(plan was to go to dohc in 3 years) etc was logically driven by both production cost and production volume concerns.

For the most part, things worked well as intended. A stock engine had a conservative output and could often offer a long service live if well cared for. It’s when we inevitably try to extract far more power from these engines that we tend to get into trouble.

And that’s why your efforts are so appreciated Mirko.👍

George

MessnerMoto · « **Reply #107 on:** July 04, 2019, 04:27:41 AM »

But I dont see financial saving for Honda in keeping the chain. I would even argue that adding one sprocket and changing a little bit casting of a block is actually cheeper then chain system ?

PeWe · « **Reply #108 on:** July 04, 2019, 11:51:02 AM »

Vibrations?
Chains can forgive movements of the primary/ clutch shaft relative the crank and vice versa.

Sprockets all the way need stiffer cases?

turboguzzi · « **Reply #109 on:** July 05, 2019, 04:10:00 AM »

Quote from: MessnerMoto on July 04, 2019, 04:27:41 AM

But I dont see financial saving for Honda in keeping the chain. I would even argue that adding one sprocket and changing a little bit casting of a block is actually cheeper then chain system ?

Indeed, a few years later all the industry shifted to a gear carved on the crank web.

MessnerMoto · « **Reply #110 on:** July 12, 2019, 06:51:39 AM »

it is stamped with Nylon 4.6 so it must be it

fun fact for people who are not aware .... Polyamide is engineer/chemist term for Nylon....

Quote

As early as the 1930s, when Wallace Carothers produced Nylon for the first time, he noticed nylon 46 has a melting point (Tm) of 278 °C. Due to the intra-molecular deamination of butanediamine to produce pyrrole during heating, the molecular weight growth becomes difficult because pyrrole acts as a terminator in polycondensation. Without precise control over polymerization processes, one can only get a dark color low molecular weight oligomer without any commercial value. When he discovered the more valuable nylon 66, the development of nylon 46 was shelved.

In 1977, pale to white high-molecular-weight nylon 46 (Mw = 45,000, inherent viscosity 2.09 in 98% formic acid at 30 °C) was produced through a solid-state polymerization (SSP) technique by Gaymans et al.,[2] which gave hope to industrialization of nylon 46.

DSM cooperated with Twente University of Technology to accomplish the commercialization of nylon 46 in May 1984, and DSM announced that it had mastered the industrialized process of nylon 46. In late 1985, a 150 t/a pilot-plant was built; in 1990, a nylon 46 full scale plant was run in Geleen, The Netherlands. According to patents and the literature, one can conclude that the color of the product is key to the industrialization of nylon 46.

......
Although there are similarities between the molecular structure of nylon 46 and that of nylon 66, the higher number of amide groups per given chain length and the more symmetrical chain structure of nylon 46 result in the higher melting temperature of 295 °C, a higher crystallinity, and a faster rate of crystallization.

Nylon 46’s crystallinity is approximately 70%, compared with 50% for nylon 66. This results in a high heat distortion temperature of 190 °C for unreinforced nylon 46 and 290 °C for glass fiber reinforced nylon 46.

These features give nylon 46 a technical edge over other engineering plastics like polyamide 6 and 66, polyesters and semi-aromatic polyamides (PPAs) with regard to heat resistance, mechanical properties at elevated temperatures, wear and friction behavior. Due to an advantage in cycle-time, improved processing economics, nylon 46 has significant characteristics of a high amide group concentration and a high rigidity of molecular chain, leading to a high degree of crystallization, good rigidity at high temperature and higher water-absorption.

next week cnc

gschuld · « **Reply #111 on:** July 12, 2019, 08:27:39 AM »

Good progress. Looking fwd to the finished result.

George

MessnerMoto · « **Reply #112 on:** July 27, 2019, 05:42:03 AM »

If nothing goes wrong shipping is next week

gschuld · « **Reply #113 on:** July 27, 2019, 08:09:31 AM »

Quote from: MessnerMoto on July 27, 2019, 05:42:03 AM

If nothing goes wrong shipping is next week

Nice work Mirko. Thanks for correcting the issue 😉.

George

MessnerMoto · « **Reply #114 on:** August 06, 2019, 06:42:47 AM »

first batch has been shipped... rest goes out tomorrow. A lot of work went in to this.

kmb69 · « **Reply #115 on:** August 21, 2019, 03:01:01 PM »

Received mine today. Very, very nice!

Mirko, do you have a drawing for drilling the holes in the upper and lower cases?

MessnerMoto · « **Reply #116 on:** August 22, 2019, 06:02:17 AM »

Quote from: kmb69 on August 21, 2019, 03:01:01 PM

Received mine today. Very, very nice!

Mirko, do you have a drawing for drilling the holes in the upper and lower cases?

working on it;)

MessnerMoto · « **Reply #117 on:** August 26, 2019, 05:34:02 AM »

I added instructions at the first post in this thread.

For now for upper chain guide installation.

I am making instructions for manual adjuster.

gschuld · « **Reply #118 on:** August 26, 2019, 08:12:31 AM »

Mirko,

Thank you, that helps a lot

George

MessnerMoto · « **Reply #119 on:** September 23, 2019, 03:24:50 AM »

I have added instructions for installation of manual adjuster.

Go to first post of this thread.

gschuld · « **Reply #120 on:** September 23, 2019, 09:42:28 AM »

Excellent thx. 👍

George

Skoti · « **Reply #121 on:** October 22, 2019, 11:31:46 AM »

Quote from: MessnerMoto on March 12, 2019, 01:04:53 AM

Quote from: kmb69 on March 11, 2019, 11:40:21 PM
Quote from: MessnerMoto on March 11, 2019, 09:06:33 AM
.....
They are not any special chains.
.....

What makes them "special" is CCC had IWIS run a batch in the correct 68 link size.
Not saying you cannot buy them here but that eBay seller will not ship to the USA.
I had IWIS US Rep quote some after CCC sold out and you have to have several 100 made to get the price down.
Granted, it's easy enough to remove 4 links.

so they are not specially made like it is stated in brochure that is heavily misguiding cb750 community that they are some specially engineered chains just for cb750.

you can find them locally in US or from other buyer on ebay

If I order locally 100 SWAG-30-93-9962 like a distributor and get them shorten 4 links by specialized company it will not cost me more then 20-25eu per chain.

and shortening the chain is 15min job... if I do it with home made tool

...................

and now back to the topic

Is it possible to buy the correct Iwis rivet link connector to rejoin this G68HPF-2 chain after you shorten it by 4 links?

Skoti · « **Reply #122 on:** October 22, 2019, 11:38:36 AM »

Has anyone managed to buy the correct Iwis rivet link connector to rejoin this G68HPF-2 chain after you shorten it by 4 links?

MessnerMoto · « **Reply #123 on:** October 22, 2019, 11:49:31 AM »

there is no special rivet link. U just rerivet the chain.

Phil · « **Reply #124 on:** October 22, 2019, 01:31:22 PM »

I've been following the saga of CB750 primary chains for over 10 years now. Back then I bought a pair of (astronomically priced) chains from M2 (?) in the US. I'm convinced modern chains are hugely superior to those in 1969. I had a CB750 in 1970 and had to change the huge and heavy (530?) drive chain every 3 - 4000 miles. It's amazing to think that a 300 BHP Moto GP uses a 420 chain. I believe the chains I bought from M2/USA are Regina chains so I'm confident they can handle the 90 BHP my race engine will make. I listen closely to what Brent (V&H) says about chains and have fitted his cam chain guides in my 1100F race bike engine. Its very interesting to follow this thread because, I've been collecting the parts for my CB750 SOHC race engine for 10 years and now I'm finally putting it together.

I bought the Cycle X primary chain tensioner some years ago - but now see the recommend the standard tensioner?? Bit worrying ...

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Author Topic: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto) (Read 29201 times)