Topic: hyvo chain conversion

[tony sawyer]

 hi all thinking of doing a hondamatic crank hyvo conversion to a gl1000 cushdrive conversion
the questions are
1. is there a stock chain that fits
2. is it tensioned with the standard tensioner
any info about
regards tony

[kmb69]

hi all thinking of doing a hondamatic crank hyvo conversion to a gl1000 cushdrive conversion
the questions are
1. is there a stock chain that fits
2. is it tensioned with the standard tensioner
any info about
regards tony

1. No
2. No

It can be done but requires custom chain and tensioner.

[Retro Rocket]

Do you already use the HD primary chains..? I'm pretty sure they are stronger than the hyvo conversion, and far less trouble, you can get heavy duty rubbers for the cush drive too......

[bear]

Do you already use the HD primary chains..? I'm pretty sure they are stronger than the hyvo conversion, and far less trouble, you can get heavy duty rubbers for the cush drive too......

Sorry Mick, can't agree.
We couldn't  get fifty hours out of a bottom end on the chair before we went with the HI-VO setup.

Tony,
It is a pretty big job though. The bottom half of the crankcase has to be modified to accept a DOHC type tensioner.
As Keith has said it's a reasonably big job.

Cheers,
Brian

[Retro Rocket]

Do you already use the HD primary chains..? I'm pretty sure they are stronger than the hyvo conversion, and far less trouble, you can get heavy duty rubbers for the cush drive too......

Sorry Mick, can't agree.
We couldn't  get fifty hours out of a bottom end on the chair before we went with the HI-VO setup.

Tony,
It is a pretty big job though. The bottom half of the crankcase has to be modified to accept a DOHC type tensioner.
As Kieth has said it's a reasonably big job.

Cheers,
Brian

Was that using the heavy duty primary chains Brian..?   

[bear]

Yes it was Mick, but the loads we put the driveline through can't be compared to a normal solo really.
Although a  drag bike with a wide slick and a bit of grunt might go close.

The weak link is the cush drive.

As soon as you get some stretch in one of the chains the cush rubbers get chopped up, the pins in the cush drive start banging into their stopper and you either break chains or more likely damage the gear dogs in the tranny.

If you weld up the sprockets on the cush drive one of the chains would usually fail.

Cheers,
Brian

[Retro Rocket]

Yes it was Mick, but the loads we put the driveline through can't be compared to a normal solo really.
Although a  drag bike with a wide slick and a bit of grunt might go close.

The weak link is the cush drive.

As soon as you get some stretch in one of the chains the cush rubbers get chopped up, the pins in the cush drive start banging into their stopper and you either break chains or more likely damage the gear dogs in the tranny.

If you weld up the sprockets on the cush drive one of the chains would usually fail.

Cheers,
Brian

Hmmm, so if you manage to find chains strong enough, you then have to look at beefing up the primary drive, is the goldwing drive much stronger..? Sorry for all the questions, inquiring mind and all...

[kmb69]

The Goldwing conversion still uses the same primary inner cogs but the dampers are spread across the whole drive with a single Hy-vo chain gear versus the independent sprockets as Brian mentions.

[bear]

Yes it was Mick, but the loads we put the driveline through can't be compared to a normal solo really.
Although a  drag bike with a wide slick and a bit of grunt might go close.

The weak link is the cush drive.

As soon as you get some stretch in one of the chains the cush rubbers get chopped up, the pins in the cush drive start banging into their stopper and you either break chains or more likely damage the gear dogs in the tranny.

If you weld up the sprockets on the cush drive one of the chains would usually fail.

Cheers,
Brian

Hmmm, so if you manage to find chains strong enough, you then have to look at beefing up the primary drive, is the goldwing drive much stronger..? Sorry for all the questions, inquiring mind and all...

It's not really a matter of getting strong enough chains.
The two chains linked to the twin sprockets driving the cush drive is the weak link.
As soon as you get a little bit of wear you end up creating a disproportionate load on the cush drive rubbers and they fail.
With the Hy-Vo drive the load on the cush drive rubbers is allways even regardless of the chains condition.

[bear]

There you go, Keith explained it in two sentences better than I could in half a page.

[Retro Rocket]

There you go, Keith explained it in two sentences better than I could in half a page.

Thanks guys, I see now, so when you see it being talked about welding the drive, that takes the individual sprocket problem out of the equation.. I do have this right, the two sprockets on the primary drive work independently from each other..?  Sorry, I don't have one to look at up close..

[kmb69]

That's correct. The sprockets are mounted independently but share the dampers - each sprocket using half of each damper. Honda obviously did it that way for a reason. It apparently allows the dual chains to wear differentially and last longer under normal riding conditions. But like Brian said, it is the weak link in serious power applications. Brian's 135+HP motors definitely found all the weak links. Manual below from: http://honda60-70s.net/Pieces/pieces.html

[Retro Rocket]

That's correct. The sprockets are mounted independently but share the dampers - each sprocket using half of each damper. Honda obviously did it that way for a reason. It apparently allows the dual chains to wear differentially and last longer under normal riding conditions. But like Brian said, it is the weak link in serious power applications. Brian's 135+HP motors definitely found all the weak links. Manual below from: http://honda60-70s.net/Pieces/pieces.html

Interesting, I would have thought that the rubbers would take up the stresses of driving off the crank, the chains should nearly always carry equal load, would welding the two hubs for the cush drive really reduce chain life that much ? , and with using heavy duty chains, wouldn't' that almost cancel that worry out..?  Give me a gear drive bottom end any day...   {without the exorbitant cost} 

[bear]

Brian's 135+HP motors definitely found all the weak links.

And  I just about got 'em all fixed too, but the last one got me in the end......................it was  the nut attached to the handle bars.

Cheers,
Brain

[Retro Rocket]

Brian's 135+HP motors definitely found all the weak links.

it was  the nut attached to the handle bars.

Cheers,
Brain

Yep, same problem with the wife driving, loose nut behind the wheel....   Looks over shoulder...!!

[kmb69]

1. Interesting, I would have thought that the rubbers would take up the stresses of driving off the crank, the chains should nearly always carry equal load, would welding the two hubs for the cush drive really reduce chain life that much ? , and with using heavy duty chains, wouldn't' that almost cancel that worry out..?  2. Give me a gear drive bottom end any day...   {without the exorbitant cost} 

1. I am not an engineer so your assumption certainly makes sense to this shade tree, but apparently it does not work that way.
2. Amen brother! Been part of my SOHC heartburn for some time. They could have also spaced the cylinders a little farther apart for obvious reasons. They would have been THE performance kings for some time. And then along came the Z1's, geared and big.

[bear]

Sorry for getting a little off track Tony.

I have found a couple of photo's but I can't post them in one go.
I will try it over a couple of posts.

[Captain]

 For those of you that have fitted the Hy-Vo cranks in order to handle increased loads.  I'm well aware that the following is all about the DOHC engine but what I'm showing you contains lessons that can be applied to the SOHC.
 Here is my Gear drive conversion for the 900-1100 DOHC engine and has proven to be an effective and viable solution to eliminating the primary chain failure.  In addition it has shown a reduction in parasitic losses and oil temps dropped with this conversion fitted. Without question it has proved to be a major advance over anything else in this area.
 The story behind this is that we have progressively developed the DOHC engine to a point that we can no longer keep the primary chain in them when road racing.  Our engine now exceeds 180 RWHP and operates between 11500 -12000 RPM and during sustained operation the chain would fail and this Gear Drive development solved the problem.

 Brent
https://www.facebook.com/100004676028806/videos/551798074986055/
 
https://www.facebook.com/100004676028806/videos/551773721655157/
 

[Retro Rocket]

What a tease Captain  I would love to see some pics of the gear drive...

[Captain]

 Have a look at the last "IMG" link in my previous post.  This was the first mock-up being turned.
 Captain

[bear]

Good stuff Brent,

Will the Vance & Hyde crew make an appearance at Phillip Island next year?

Cheers,
Brian

[Retro Rocket]

Have a look at the last "IMG" link in my previous post.  This was the first mock-up being turned.
 Captain

Thanks mate, I missed that. I'd like to see how you mounted the slave gear to the lower case...

[bear]

We haven't forgotten you Tony.

What's your time line for this project?

Brent and Keith will probably roll their eyes to the heavens but I think there may be a simpler way to do this.

Rather than tig welding mounts and fabricating tensioners I beleive it may be possible to mount a resin block just to dampen the chain on it's over run.(no guarantees with this, it's just a thought bubble)

I was going to give it a try on my next motor but it didn't happen.

I'm pretty sure there will be a Morse dealer up your way some where.

I can give you the specs for the chain thats not a problem.

If your not confident attacking the primary drive I'm happy to put one together for you.

Cheers,
Brian

[kmb69]

We haven't forgotten you Tony.
.....
Brent and Keith will probably roll their eyes to the heavens but I think there may be a simpler way to do this.
Rather than tig welding mounts and fabricating tensioners I beleive it may be possible to mount a resin block just to dampen the chain on it's over run.(no guarantees with this, it's just a thought bubble)
I was going to give it a try on my next motor but it didn't happen.
.....

Sorry Tony. Thanks Brian.

Can't speak for Brent but I'm not rolling my eyes at all. Been thinking along those lines myself. (great minds think alike?)   

That's how Honda did the Automatic. Seems to work fine in that bike, at least on the street. Been looking at the tensioner on the Goldwing also. It appears much simpler than the DOHC and it works really well.

[Retro Rocket]

We haven't forgotten you Tony.
.....
Brent and Keith will probably roll their eyes to the heavens but I think there may be a simpler way to do this.
Rather than tig welding mounts and fabricating tensioners I beleive it may be possible to mount a resin block just to dampen the chain on it's over run.(no guarantees with this, it's just a thought bubble)
I was going to give it a try on my next motor but it didn't happen.
.....

Sorry Tony. Thanks Brian.

Can't speak for Brent but I'm not rolling my eyes at all. Been thinking along those lines myself. (great minds think alike?)   

That's how Honda did the Automatic. Seems to work fine in that bike, at least on the street. Been looking at the tensioner on the Goldwing also. It appears much simpler than the DOHC and it works really well.

Did you look at that gear driven Dohc Keith.... me likey....