Author Topic: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)  (Read 11281 times)

0 Members and 1 Guest are viewing this topic.

Offline mick7504

  • Old Timer
  • ******
  • Posts: 3,734
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #25 on: October 13, 2018, 03:05:11 am »
Sorry Mirko,

I was only dreaming. Not of the Harley type Rachet adjuster either. More of a variable rate or two stage spring assembly that just the spring assembly could compensate for chain and substraight wear and not impede or limit total tensioner travel. The lighter stage spring would address the harmonics you describe in detail and wouldn't lend to accerated sub-straight or chain wear. The second heavier spring rate, only to slow or dampen the sudden torque reversal shock the chain transfers to the tensioner assembly when it becomes the tight side.

Probably all here have witnessed an out board spring loaded chain adjusters used in various other applications and their reactions to sudden torque reversals.

 Without installing a camera in the cases, it's all theoretical conjecture based off of available known knowledge-technology and their applied failures.

My own thoughts, as mentioned above, the original tensioner design (Honda Idle Noise Bandaid) and location on the outside of the chain circle can only effectively address acceration torque slack.

 With space being the killer, I think the compromise may lie within the chain circle where both torques could be addressed.

All dreams are unique and some like me have trouble expressing what we visualize. You have taken yours to reality. I believe your on top of your game and will succeed within the restrictions Honda has placed. I will be patient and quietly watch (gear Idler too).

Thanks for your efforts

Thanks for your support. I will try to explain why I think I addressed some of the issues with my solution.

When you "power downshift" there is no torque reversal... Typical scenario when you prepare bike for a corner etc...
In a race, driver will never/'try not to' get his bike in a position where there is a torque reversal. One can conclude that weakness in OEM primary chain system, regarding the racing, does not come from torque reversal. So my system will address all the weak spots in OEM system in racing conditions.

When you "coast downshift" aka. break with engine... down shift, close the throttle and let the bike slowdown.. torque will reverse but torque amplitude will be several magnitudes smaller from the torque that engine can produce.

I agree that my system does not solve second scenario perfectly but addresses it. Firstly buy introducing artificial slack in upper side of the chain by curved guide. That curved upper guide will also absorb oscillations introduced by torque reversal. Secondly by designing lower guid with big sliding area I was able to put spring that is several times stronger than OEM spring because big sliding area reduces friction and lower shoe will not wear out. This much stronger spring is able to cope with change of slack lower chain side to lower tight side of chain, by not allowing that lower side looses to much curvature and by that not allowing slack to form in upper side of chain.

Maybe I am wrong, and this is not perfect solution, but from first 3000km I can say it is definitely much better then OEM system.

I take it you have never raced a bike then , if you had you would know that you do exactly that entering every corner . It's known as engine braking .
Congratulations you have designed a solution for a problem you don't understand .
Sarcasim is the lowest form of wit Simon.
If I was you
I'd be worried about me.

Offline simon#42

  • Master
  • *****
  • Posts: 2,228
  • liverpool
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #26 on: October 14, 2018, 07:56:02 am »
believe me mick i deleted what i really think

Offline Rod

  • Enthusiast
  • **
  • Posts: 153
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #27 on: October 16, 2018, 05:47:32 am »
I take it you have never raced a bike then , if you had you would know that you do exactly that entering every corner . It's known as engine braking .
Congratulations you have designed a solution for a problem you don't understand .

[/quote]Sarcasim is the lowest form of wit Simon.


Its a saying that is often misused because most people only know the first part of Oscar Wilde's quotation, which he actually intended to be a compliment - the second part being "but the highest form of intelligence"   ;)
« Last Edit: October 16, 2018, 07:34:27 am by Rod »

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #28 on: October 23, 2018, 07:09:40 am »
I disagree

------------------------------------------------------------------------------------

It took me 3 working days to completely disassemble and assemble the bike



you cant here any sound coming from the engine. Completely quiet like modern bikes... Expect clapping noise from MIkunis... I have problem with noise Mikunis RS34 carbs. They are killing me with the noise. Will try to retune them. Or even redesign flat shibers inside the carbs
« Last Edit: October 23, 2018, 07:55:39 am by MessnerMoto »

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,218
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #29 on: October 23, 2018, 07:15:34 am »
All looks very good so far! Excited to hear more about testing it on the road and what you learn from real testing.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline gschuld

  • Master
  • *****
  • Posts: 2,096
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #30 on: October 23, 2018, 08:59:17 am »
All looks very good so far! Excited to hear more about testing it on the road and what you learn from real testing.

Me too.👍

George

Offline RAZZ

  • Enthusiast
  • **
  • Posts: 119
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #31 on: October 23, 2018, 10:51:10 am »
All looks very good so far! Excited to hear more about testing it on the road and what you learn from real testing.

Me too.

George
+1


Sent from my iPhone using Tapatalk

Offline PeWe

  • Really Old Timer ...
  • *******
  • Posts: 10,684
  • Bike almost back to the 70's 2015
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #32 on: October 23, 2018, 11:34:15 am »
Good looking bike Mirko!
I like the exhaust pipes, nice bends from head, art.
- You used Loctite 518 as case sealer?
About clattering carbs, my Mikuni TMR clatter very loud at idle. When jets and ignition are OK with carbs in synch, music!
- No additional case breather?

Offline MRieck

  • Really Old Timer ...
  • *******
  • Posts: 10,046
  • Big ideas....
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #33 on: October 23, 2018, 12:46:18 pm »
Good looking bike Mirko!
I like the exhaust pipes, nice bends from head, art.
- You used Loctite 518 as case sealer?
About clattering carbs, my Mikuni TMR clatter very loud at idle. When jets and ignition are OK with carbs in synch, music!
- No additional case breather?
RS', FCR's, and TMR's all clack and all 3 use different slide designs. It's not as bad as a Ducati dry clutch at idle.
Owner of the "Million Dollar CB"

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #34 on: October 23, 2018, 01:18:06 pm »
Good looking bike Mirko!
I like the exhaust pipes, nice bends from head, art.
- You used Loctite 518 as case sealer?
About clattering carbs, my Mikuni TMR clatter very loud at idle. When jets and ignition are OK with carbs in synch, music!
- No additional case breather?
RS', FCR's, and TMR's all clack and all 3 use different slide designs. It's not as bad as a Ducati dry clutch at idle.

annoying... and for me mistake in design

Mick do you think I can lower the clapping sound by tuning the carbs better? By listening the sound in videos.... I mean I spent 4h tuning them with manometers maybe there is more to be done... cx-7 is the cam and everything is more or less open both ways

Offline calj737

  • Really Old Timer ...
  • *******
  • Posts: 19,986
  • I refuse...
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #35 on: October 23, 2018, 01:50:29 pm »
Mirko if you can hear your carbs clacking, you’re riding too slowly! Twist the damn throttle  ::)
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

*** Currently experiencing life at 60 WTFs per hour ***
I always thought getting old would take longer

Offline T1m32sh1n3

  • Full Member
  • *
  • Posts: 71
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #36 on: October 23, 2018, 04:28:03 pm »
Im interested.

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #37 on: November 07, 2018, 07:30:06 am »
This is a final version for production.

Compared to version that is in my engine there are two differences.

1. There are two M8 bolts for upper slider. That means mounting of upper slider will demand just 2 holes in upper case instead of 4 in previous version.

2. Lock mechanism of lower tensioner is added for when torque is reversed. This is not just simple lock mechanism. I added Polyurethane Spring rubber(brown in images) of 90 Shore to act as spring when torque is revered. This rubber spring is adjustable in the sense that it can be changed without taking the engine apart. But it will demand taking out the pump probably. I don't think this mechanism is necessary, but some people with experience complained in this thread. So why not added it. If you want to completely lock tensioner you can replace rubber with piece of aluminum or whatever you prefer. With time as chain lengthens you will need to insert rubber with more thickness end so on. But that Polyurethane Spring rubber is not expensive...

This is expensive collection of parts and there is a lot of manual work involved. Material is expensive, PA46 etc.... A lot of complicated CNC, laser cutting, custom heat treated spring,  heat treated axel, demands welding.... And do on....

I will offer to people now this tensioner system and if there is at least 5 people willing to pay in advance I will make just for them because this is expensive collection of parts like I said. Also I bagged my CNC shop to do this small series of parts like I am making 50 sets. I already invested so much money and personal time in to this primary system that I doubt that I will ever return my investment. But for love of cb750 and engineering here it is;)

Later on if somebody wants, this system can be made per one set. But price will be multiplied by factor of 2 at least.

This system will work only with straight plated, 68 links, HD chains. You can buy pair of HD chains directly from ebay for around 100eu or you can buy from somewhere else with multiply factor greater than.

The price is 350eu plus shipping 15eu(maybe it will be 8eu if I keep the weight below 1kg for package). You get everything in pictures expect the chains.

And sorry for not that high quality renderings ;)
« Last Edit: November 07, 2018, 07:32:52 am by MessnerMoto »

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,218
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #38 on: November 07, 2018, 07:52:34 am »
Very interested. A bit short on cash right now but I can manage since I have been one watching since day one. What is involved in the installation? I am going to split my cases this year to take a peek but dont want to break the whole thing down to make this work. If I need more complete disassembly I will probably reserve this kit for my next build.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #39 on: November 08, 2018, 04:02:01 am »
Very interested. A bit short on cash right now but I can manage since I have been one watching since day one. What is involved in the installation? I am going to split my cases this year to take a peek but dont want to break the whole thing down to make this work. If I need more complete disassembly I will probably reserve this kit for my next build.

Matt it would be possible to install it without disassembling complete top end. Nit easy but not hard. I did it without disassembling top end look in previous pictures. You only need to open and than re-rivet chains. But I used a tool from aliexpress to do that. Tool costs 10$ with shipping. It took me 45min to open and re rivet chains.

The only other thing for you would be to drill two holes in upper case. I will think of some  simple guide tool so you can drill with hand drill while top is on ;)

Offline slikwilli420

  • Master of Disaster
  • Master
  • *****
  • Posts: 2,218
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #40 on: November 08, 2018, 08:54:14 am »
Very interested. A bit short on cash right now but I can manage since I have been one watching since day one. What is involved in the installation? I am going to split my cases this year to take a peek but dont want to break the whole thing down to make this work. If I need more complete disassembly I will probably reserve this kit for my next build.

Matt it would be possible to install it without disassembling complete top end. Nit easy but not hard. I did it without disassembling top end look in previous pictures. You only need to open and than re-rivet chains. But I used a tool from aliexpress to do that. Tool costs 10$ with shipping. It took me 45min to open and re rivet chains.

The only other thing for you would be to drill two holes in upper case. I will think of some  simple guide tool so you can drill with hand drill while top is on ;)

If I have the cases opened up, I should be able to move the primary drive out of the way without splitting the chains (not willing to do that) and fit both pieces. The upper guide will obviously be the challenge to get it aligned and keep chips out of where they dont belong. How precise does hole placement need to be for the upper guide? Does you kit have a template that can be used? A drill guide from the outside would be ideal since you could locate off the case half bolts near the cam chain tensioner.
All you gotta do is do what you gotta do.

Vintage Speed Parts Mashup: http://forums.sohc4.net/index.php?topic=133638.0
Rickman CR Parts Kit Refresh: http://forums.sohc4.net/index.php/topic,154837.0.html
AHRMA CB750 Racer: http://forums.sohc4.net/index.php/topic,158461.0.html
AHRMA Superbike Heavyweight Racer: http://forums.sohc4.net/index.php/topic,173120.0.html
'76F CB750 Patina Redemption: http://forums.sohc4.net/index.php/topic,174871.0.html

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #41 on: November 09, 2018, 01:43:54 am »
Very interested. A bit short on cash right now but I can manage since I have been one watching since day one. What is involved in the installation? I am going to split my cases this year to take a peek but dont want to break the whole thing down to make this work. If I need more complete disassembly I will probably reserve this kit for my next build.

Matt it would be possible to install it without disassembling complete top end. Nit easy but not hard. I did it without disassembling top end look in previous pictures. You only need to open and than re-rivet chains. But I used a tool from aliexpress to do that. Tool costs 10$ with shipping. It took me 45min to open and re rivet chains.

The only other thing for you would be to drill two holes in upper case. I will think of some  simple guide tool so you can drill with hand drill while top is on ;)

If I have the cases opened up, I should be able to move the primary drive out of the way without splitting the chains (not willing to do that) and fit both pieces. The upper guide will obviously be the challenge to get it aligned and keep chips out of where they dont belong. How precise does hole placement need to be for the upper guide? Does you kit have a template that can be used? A drill guide from the outside would be ideal since you could locate off the case half bolts near the cam chain tensioner.

yes you are correct. I was not thinking. I had to shorten the chains because they were longer for 2 links than OEM because of previous tensioner design. Yours are of correct length.

Holes does not have to be positioned in 0.01mm precision range. but +/-0.5mm error is ok. Let me think about template. And dont worry about drilling and chips. I have a simple trick to keep everything clean

Offline gschuld

  • Master
  • *****
  • Posts: 2,096
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #42 on: December 03, 2018, 03:21:40 pm »
I thought this older post by Mark Mcgrew regarding engine breaking in a high level road racing environment would add to this topic.

George

Offline Tracksnblades1

  • My Son was a collegiate competition Trap, Skeet, and sporting Clay
  • Hot Shot
  • ***
  • Posts: 688
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #43 on: December 04, 2018, 09:37:35 am »
I thought this older post by Mark Mcgrew regarding engine breaking in a high level road racing environment would add to this topic.

George

The Verdict is in. Now there is evidence why Semi truck transmissions were never synchronized.
Good archival find George....
Age Quod Agis

Offline gschuld

  • Master
  • *****
  • Posts: 2,096
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #44 on: March 07, 2019, 06:43:02 pm »
Mirko,

What’s the current status on your chain tensioner design?

George

Offline eli

  • Full Member
  • *
  • Posts: 49
  • Life is hard if you cannot work on your bike...
    • Seeley-Honda
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #45 on: March 11, 2019, 01:29:23 am »
I thought this older post by Mark Mcgrew regarding engine breaking in a high level road racing environment would add to this topic.

George

The Hy-Vo conversion was of course done, e.g. by Stefan Beck in his Moto Martin racer. I have more pics somewhere, but it is well documented even in this Cycle-X booklet. Have a look.

eli
Will my patience hold till the thing is finished???

Seeley build:
http://forums.sohc4.net/index.php/topic,171911.0.html

Offline JamesH

  • Enthusiast
  • **
  • Posts: 100
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #46 on: March 11, 2019, 08:32:00 am »
Mirko - also interested to hear an update where you are with this? Have you commenced production yet?

Offline kmb69

  • Master
  • *****
  • Posts: 1,974
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #47 on: March 11, 2019, 08:54:34 am »
I thought this older post by Mark Mcgrew regarding engine breaking in a high level road racing environment would add to this topic.

George

The Hy-Vo conversion was of course done, e.g. by Stefan Beck in his Moto Martin racer. I have more pics somewhere, but it is well documented even in this Cycle-X booklet. Have a look.

eli

These are actually from Classic Cycle City, not Cycle-X, and the CCC chains are VERY good. One slight misstatement in their brochure regarding the last version of the RCB. Honda's last version RCB using the SOHC lower engine was gear driven!

Offline MessnerMoto

  • Hot Shot
  • ***
  • Posts: 706
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #48 on: March 11, 2019, 09:06:33 am »
I thought this older post by Mark Mcgrew regarding engine breaking in a high level road racing environment would add to this topic.

George

The Hy-Vo conversion was of course done, e.g. by Stefan Beck in his Moto Martin racer. I have more pics somewhere, but it is well documented even in this Cycle-X booklet. Have a look.

eli

These are actually from Classic Cycle City, not Cycle-X, and the CCC chains are VERY good. One slight misstatement in their brochure regarding the last version of the RCB. Honda's last version RCB using the SOHC lower engine was gear driven!



They are not any special chains.

Those are chains made by IWIS for Audi/WV cars from 2006. They are used like cam chains in cars. It just happened that they fir our CB750s
because pitch and roller diameter are industrial standard frequently used in industry. \

G68HPF­2 is iwis catalog number

http://souzimport.ru/upload/files/iwis_Motorsysteme_Automotive_aftermarket_Ersatzteile_DE_EN.pdf

you can buy them for fraction of the cost... 48eu per chain

https://www.ebay.it/itm/Steuerkette-SWAG-30-93-9962-/161555573484

I made a topic about it long time ago

search for SWAG-30-93-9962

you need to shorten them for 4 links
« Last Edit: March 11, 2019, 09:11:48 am by MessnerMoto »

Offline kmb69

  • Master
  • *****
  • Posts: 1,974
Re: High Performance PRIMARY Chain tensioner for CB750(MessnerMoto)
« Reply #49 on: March 11, 2019, 11:40:21 pm »
.....
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.