Author Topic: CycleX HiPo cam chain tensioner & primary chain tensioner (Read 37570 times)

gschuld · « **Reply #100 on:** February 01, 2016, 07:21:59 AM »

As a side note, and again thread drift, I recall reading an article(1973-4) about Yoshimura's work with their road racing cb750 engines where they specifically mentioned shimming up the cam towers, presumably to increase the distance between crank cam gear an sprocket cam gear. This would reduce the eccess play in the cam chain on the slack side, potentially reducing the tensioner issues.

If a custom chain length is reasonable, shortening a longer than stock chain from another source anyway, would it be worth it to consider shortening the chain to one link shorter than factory length?

This is, of course, referring to high rpm race engines rather than more stock applications.

George

Bill/BentON Racing · « **Reply #101 on:** February 01, 2016, 08:02:30 AM »

Can't take one, must take two, all gotta end in even numbers

madmtnmotors · « **Reply #102 on:** February 01, 2016, 08:13:07 AM »

Quote from: Bill/BentON Racing on February 01, 2016, 08:02:30 AM

Can't take one, must take two, all gotta end in even numbers

+1

or should I say +2!

Jerry Rxman Griffin aka MuthaF'er · « **Reply #103 on:** February 01, 2016, 08:15:54 AM »

Taking orders?

gschuld · « **Reply #104 on:** February 01, 2016, 08:25:17 AM »

Quote from: Bill/BentON Racing on February 01, 2016, 08:02:30 AM

Can't take one, must take two, all gotta end in even numbers

Ah right, sorry, wasn't thinking there....it's a Monday.

Anyone know how much Yoshimura shimmed up the towers? 1/16"? more? Too far and you start messing with the rocker geometry. I'm sure Pops Yoshimura raised those cam towers up for a reason, as cam tensioner service life is the only reason I can think of as to why it was done.

George

kmb69 · « **Reply #105 on:** February 01, 2016, 08:54:48 AM »

Quote from: gschuld on February 01, 2016, 07:10:30 AM

.....
I am interested in this as well. Forgive my ignorance(and continuing thread drift) but is Mark at M3 the only one who has developed, raced, and marketed a slipper type chain tensioner system specifically for the cb750?
.....

Mr. Magoo's (M3) POS doesn't work very well either. It does not address the issue Brent describes. Plus, pretty sure Mr. Magoo did not develop the one he sells for an arm and a leg. Made by RLRacing or some such.

Quote from: gschuld on February 01, 2016, 08:25:17 AM

Quote from: Bill/BentON Racing on February 01, 2016, 08:02:30 AM
Can't take one, must take two, all gotta end in even numbers
Ah right, sorry, wasn't thinking there....it's a Monday.

Anyone know how much Yoshimura shimmed up the towers? 1/16"? more? Too far and you start messing with the rocker geometry. I'm sure Pops Yoshimura raised those cam towers up for a reason, as cam tensioner service life is the only reason I can think of as to why it was done.
.....

The stock cam chain is not too long unless it is worn out and about to break. In fact, the chain probably needs to be longer to apply a solution similar to Brent's. Pretty sure Pops' mods were related to cam lift/clearance issues and/or intentionally changing the rocker geometry. Pops' tensioner solution was simple and it worked short of addressing Brent's discovery. Essentially, Pops' design is being CLONED by the two purveyors of such products that I am aware of.

gschuld · « **Reply #106 on:** February 01, 2016, 09:02:20 AM »

Interesting...

George

MessnerMoto · « **Reply #107 on:** February 01, 2016, 09:38:42 AM »

Thats very interesting

but can someone tell me what is the number of gear teethes on crankshaft cam gear. I have all the other measurements...

kmb69 · « **Reply #108 on:** February 01, 2016, 09:51:03 AM »

The stock, roller chain, crank has 17 teeth.

gschuld · « **Reply #109 on:** February 01, 2016, 09:53:19 AM »

Quote from: kmb69 on February 01, 2016, 08:54:48 AM

Quote from: gschuld on February 01, 2016, 07:10:30 AM
.....
I am interested in this as well. Forgive my ignorance(and continuing thread drift) but is Mark at M3 the only one who has developed, raced, and marketed a slipper type chain tensioner system specifically for the cb750?
.....

Mr. Magoo's (M3) POS doesn't work very well either. It does not address the issue Brent describes. Plus, pretty sure Mr. Magoo did not develop the one he sells for an arm and a leg. Made by RLRacing or some such.

Quote from: gschuld on February 01, 2016, 08:25:17 AM
Quote from: Bill/BentON Racing on February 01, 2016, 08:02:30 AM
Can't take one, must take two, all gotta end in even numbers
Ah right, sorry, wasn't thinking there....it's a Monday.

Anyone know how much Yoshimura shimmed up the towers? 1/16"? more? Too far and you start messing with the rocker geometry. I'm sure Pops Yoshimura raised those cam towers up for a reason, as cam tensioner service life is the only reason I can think of as to why it was done.
.....

The stock cam chain is not too long unless it is worn out and about to break. In fact, the chain probably needs to be longer to apply a solution similar to Brent's. Pretty sure Pops' mods were related to cam lift/clearance issues and/or intentionally changing the rocker geometry. Pops' tensioner solution was simple and it worked short of addressing Brent's discovery. Essentially, Pops' design is being CLONED by the two purveyors of such products that I am aware of.

Keith,

For reference, this is what I was referring to. February 1973 Motorcycle Riders Guide for Honda Fours. "The Yoshimura 750" article on page 50.

MessnerMoto · « **Reply #110 on:** February 01, 2016, 10:17:29 AM »

Quote from: kmb69 on February 01, 2016, 09:51:03 AM

The stock, roller chain, crank has 17 teeth.

Thanks! I have all the parts around me expect the crankshaft.... so 5 min later I am starting to see the problem.... need to model slider

kmb69 · « **Reply #111 on:** February 01, 2016, 10:19:33 AM »

Quote from: gschuld on February 01, 2016, 09:53:19 AM

.....
For reference, this is what I was referring to. February 1973 Motorcycle Riders Guide for Honda Fours. "The Yoshimura 750" article on page 50.

Interesting. I would guess that results from milling/surfacing the head and/or cylinders if the chain length is really the issue. Shimming the towers would not reduce the compression ratio as would a thicker base or head gasket. Would definitely change the rocker geometry even if they used longer valves. Still does not address the issue Brent discovered.

Bill/BentON Racing · « **Reply #112 on:** February 01, 2016, 08:25:21 PM »

This the one I took out last night.....who's? Chain was way tight. ..but it was definitely making contact! Bill

MessnerMoto · « **Reply #113 on:** February 02, 2016, 03:16:51 AM »

I recreated in CAD configuration of chain, slider and tensioner. Everything is up to 0.5mm precision. We can see clearly where is the problem Brent talked about.

bwaller · « **Reply #114 on:** February 02, 2016, 04:15:14 AM »

I might have created some misunderstanding. My slipper tensioner failures were with the 550 part. It's a reasonable design but with increased revs it doesn't survive. Like Captain claims an "arched" guide in the front would be far more useful. The smaller engines guide faces the opposite direction of the 750 but with same results. It was suggested by one of our members in the Netherlands I try a unit he has used successfully last race season. It's spring loaded & I think I'll give it a go. He was suffering OEM tensioner breakages every race as well.

That piece Bill shows is a problem if the material doesn't hold up. All that material ends up somewhere. Maybe if they were "pre-worn" so both links & rollers made contact it would be better, but for how long?

Captain · « **Reply #115 on:** February 02, 2016, 04:43:05 AM »

A PDF of what these items are and how easy it is to install in a DOHC.

Captain

kmb69 · « **Reply #116 on:** February 02, 2016, 07:42:54 AM »

Quote from: Bill/BentON Racing on February 01, 2016, 08:25:21 PM

This the one I took out last night.....who's? .....

That's Mr. Magoos's (M3) tensioner that I mistakenly called RLRacing. Mr. Magoo's tensioner is the KA Performance product.

cbr954 · « **Reply #117 on:** February 02, 2016, 08:00:35 AM »

The tensioner I got from Cycle x also said ka performance...it was placed in the scrap iron pile.

kmb69 · « **Reply #118 on:** February 02, 2016, 09:32:41 AM »

Quote from: cbr954 on February 02, 2016, 08:00:35 AM

The tensioner I got from Cycle x also said ka performance...it was placed in the scrap iron pile.

They are definitely JUNK!
I have one that Mike removed from one of his engines and the guide is burned to hell.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #119 on:** February 02, 2016, 09:40:42 AM »

Weren't the KA's all the rage not long ago? There just have not been good options. Good attempts perhaps but not the best outcomes. If you seriously race your bike perhaps the best practice is yearly maintenance of the engine components.

bwaller · « **Reply #120 on:** February 02, 2016, 10:05:31 AM »

Captain, what's the pin to pin length of your curved chain guide? I modified a CBR600 manual tensioner for use in my 550 and fastened an OEM slipper to the arched CBR steel back. Once rivoted & epoxied in place I realised I had arched the tensioner too much and could not change it...1st failure.

Both Gerrit & turboguzzi used the CBR tensioner for a short period. This picture is one Gerrit sent of the CBR sliding surface which didn't hold up. I deduced that it may be the difference in material used for a hyvo vs. roller chain, but I'm not sure. I'd like Captains thoughts on this.

I'm not trying to confuse the 750 chain tensioner issue with the smaller engine, but I'm sort of in the same boat here.

MessnerMoto · « **Reply #121 on:** February 02, 2016, 12:01:23 PM »

The problem with slider setup is that number of links need to be increased to 96 links to accommodate chain to curvature of sliders.

This is currently the best setup I can come to. I eliminated middles wheel... But the space between opposite ends of chain is 11mm. I don't now how much chain will starch over time.... Sliders are optimized for 219th DID chain.

kmb69 · « **Reply #122 on:** February 02, 2016, 12:07:27 PM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on February 02, 2016, 09:40:42 AM

Weren't the KA's all the rage not long ago?.....

Sure were - by those SELLING them.

Captain · « **Reply #123 on:** February 02, 2016, 01:53:04 PM »

Quote from: MessnerMoto on February 02, 2016, 12:01:23 PM

The problem with slider setup is that number of links need to be increased to 96 links to accommodate chain to curvature of sliders.

This is currently the best setup I can come to. I eliminated middles wheel... But the space between opposite ends of chain is 11mm. I don't now how much chain will starch over time.... Sliders are optimized for 219th DID chain.

The overall curvature and amount it protrudes into the chain path is excessive and I recommend you reduce it. This will also allow more room for the tensioner side which is required in order to build a workable adjustment mechanism. Also make both the entry to the front curved guide more closely aligned to the natural chain path bearing in mind that the chain tends to "throw" out further as it leaves the cam sprocket even when it is under load. It would also be advisable to increase the vertical height of the guide so it overlaps the sprocket at a point where the roller of the chain is still fully seated in the sprocket. If this is not factored into the design it will show up as heavy wear at the entry area of the slipper. (These points are incorporated into the design of my Curved Guide and AHM Tensioner used in the DOHC engine).
But essentially the Cad drawing design is correct and will provide the capacity and life that has been missing since these engines came into being.

Captain

Captain · « **Reply #124 on:** February 02, 2016, 02:07:42 PM »

Quote from: bwaller on February 02, 2016, 10:05:31 AM

Captain, what's the pin to pin length of your curved chain guide? I modified a CBR600 manual tensioner for use in my 550 and fastened an OEM slipper to the arched CBR steel back. Once rivoted & epoxied in place I realised I had arched the tensioner too much and could not change it...1st failure.

Both Gerrit & turboguzzi used the CBR tensioner for a short period. This picture is one Gerrit sent of the CBR sliding surface which didn't hold up. I deduced that it may be the difference in material used for a hyvo vs. roller chain, but I'm not sure. I'd like Captains thoughts on this.

I'm not trying to confuse the 750 chain tensioner issue with the smaller engine, but I'm sort of in the same boat here.

I have no first hand knowledge of your application nor the modifications that you are referring to, but I do know that the damage you are seeing is not the material of the guides themselves but the uncontrolled "whipping" of the chain during operation. Get this under control (perhaps incorporating the principals I have disclosed) and you may have the reliability that you are currently missing.

Captain

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Author Topic: CycleX HiPo cam chain tensioner & primary chain tensioner (Read 37570 times)