Topic: New to Sohc 4 Forums

[gsalter]

Hello; Everyone

I too am a SOHC junkie.  I feel like this is a 12 step program with that first sentence?  But in all seriousness I love the Honda CB750.  So much so I have started to make it a part of my day job.  My best friend and I started a business together building these bikes and improving the available parts. So I thought we might as well get some feedback from some of the talent on this site. 
We have designed a new swing arm for the Honda CB750.  Our current bike is a 1978 CB 750K.  This swing arm will be a direct replacement to the current one and it weighs 2lbs less than stock.  It will also have Sealed Roller bearings and our own Stainless Steel swing arm bolt. We are in the process of doing FEA test then some real world testing.  The swing arm is also being designed around Progressive Suspension's 970 rear shocks.  This will allow for maximum tune ability to the bikes suspension.

Sorry for the sales pitch but since so many people have so much old / new world experience I would love the feed back. Play nice please. It could be a give away some day...

grant

[Greggo]

Welcome to the forum.  That 'arm looks nice.  You may want to post it in the classifieds, either in parts for sale, or in the services offered section.

[MoMo]

Welcome to the forum, that is one very nice piece of engineering...Larry

[MCRider]

Yeah, welcome, and that's purdy!

It's not going to be something everyone has to have, so you won't get rich off it. But some will have it if you sell it. Some people are buying Carpy's Dresda look alike arm, which doesn't appeal to me at all vs yours.

[DJ_AX]

... Carpy's Dresda look alike arm, which doesn't appeal to me at all vs yours.

+1
True dat.

[ekpent]

Looks nice. I have never had a 750 newer than a 1976 though. Do these swing arms fit the 69-76 K model bikes also?. Just from a business standpoint I would think that there would be larger numbers of these machines out there as potential customers than the 77-78 K bikes.

[Spanner 1]

Good luck with your business.... nice looking swingarm... but needle rollers ?, to date all signs say they don't last any time in a road bike ( good for racing ? ) Also is their a 'stop' mechanism to hold/adjust the axle as chain action will pull it forward no matter how tight you tighten the axle bolt.... happens on a stock swingarm when you leave the 2 adjusting bolts/ locknuts loose ( backed-off ). ?

[fastbroshi]

  Wow is that a cast piece or machined?  Spanner it looks like there is a hold for a bolt to run through with a modern style axle adjuster to be placed by.   Hole looks kinda small though.  Maybe they haven't drilled/tapped yet. 

[Danno]

welcome and beautiful piece of engineering but I agree with some of the others that cyntered bronze  impregnated bushings would probably be the best and of course a way to grease them

[MCRider]

Good luck with your business.... nice looking swingarm... but needle rollers ?, to date all signs say they don't last any time in a road bike ( good for racing ? ) Also is their a 'stop' mechanism to hold/adjust the axle as chain action will pull it forward no matter how tight you tighten the axle bolt.... happens on a stock swingarm when you leave the 2 adjusting bolts/ locknuts loose ( backed-off ). ?

All modern bikes have needle rollers in the swingarm. My 1988 hawkGT and my 2003 FJR do. The service intervals are very generous. I think the key is that they have to be sealed, which the OP says their's is. The CB750 original design, if executed in the HondaMan way, is as good as it can get for what it is. But ultimately a sealed roller is better.

I'm sure they have an adjuster mechanism, looks to be pretty sophisticated just not in the picture. Closing the end of the swingarm is the better design over the open dropouts we have with the stoppers. But not having open ends precludes the use of this swingarm with 4-4 exhausts. Or at least you'll have to remove the exhausts to get the wheel off.

As to the axle, i submit to you and everyone, a properly tightened axle, that is 65-70 ft lbs is the only way to hold the axle. There is no way any adjuster mechanism is designed to or intended to hold the axle from moving. A properly tightened axle will never move and the adjuster bolts can be removed and stowed in one's pocket until they are needed again.

Asking those adjuster bolts to act as a backup to a properly tightened axle is asking for disaster, IMO. If the axle does move, the adjuster is there and its bulk will act to retard the movement, and it will bend, but that was never an intended piurpose.

If the axle moves there was a problem tightening it up, or something else is not right.

They are "adjuster bolts", not "wheel stays".

I'd be polite and say OCICBW, but this is a safety issue and I'll say I'm right. I've seen and read of too many people wanting to line up the cotter pin hole rather than get the nut tight enough. Take it to full torque and if the hole doesn't line up, make it tighter not looser.

[johnrdupree]

That's a pretty rendering.  Do you have a real part yet?  How will it be manufactured?  The rendering makes it look like a controlled fill die cast part, which would be waaaayyyy expensive for a limited market like this.

~john

[gsalter]

Thanks for the warm welcome guys!  The coolest thing I see is so many MI people.  Was born and raised in MI moved when I was 27 to NY.  Love the Mitten.

To answer some of the questions about the swing arm.  We decided to use Sealed Roller bearings because of the load they can withstand.  The ones we are using have a load capacity of 2300 lbf per bearing and there will be two of them.  If anyone is putting 4600 lbs of force on their bikes please video tape that for me. So in the words of McRider (They are better). The other thing you don't see is the chain tensioner's. Their not pictured in this image.  We designed some that will be just like what Honda use's on the CBR 900RR bike.  Ours will be made from Stainless steel.

Some one asked questioned about the yr of bike that its going on.  We want them to fit earlier models too.  If anyone on this forum knows if the swing arm from the pre 77, CB750 is different than than the later models let me know.  I may pm you for some critical measurements to make the appropriate swing arm.

The swing arm will be machined from solid billet aluminum.

The one thing I am surprised no one picked up on was the clevis mount for the suspension.  That will actually be a post mount / ETE mount.  This is just a rendering on Solid Works of a rough design. We made changes today to a few things and that was one of them.  No pics yet.  I will post a pic mounted with shocks once we cut it.  So stay tuned.

Keep the questions coming it's very helpful.

 p.s.  I posted something else we are working on too.  Whacha think?







grant