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Rear Ride Height lowering find.


gregjet

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7 hours ago, markstertt said:

Yamaha didn't want to make it easy on us did they? On the Hugh's 500's I used to work on, the rotor blade links had steel heims with a phenolic looking liner that the ball rotated on...no lubrication necessary. Other aircraft heim joints can be had with a grease zerk but then even a plain old pregreased by hand type would be fine in this application I think. I mounted my gopro down there to watch the action of the suspension and linkage and that dogbone (Yamaha connecting arm) barely moves at all... especially the bottom.

 

 

Good info, thanks!  Cool what you did with the GoPro.

 

One negative with grease fittings is they weaken the rod end body.  Maybe one reason most don't use them in racing applications.  I used them all over when I designed the suspension on my Cobra replica race car.  The frame is on the jig in these pictures.

 

vpmframe1.jpg

 

vpmframe3.jpg  

Craig Mapstone
Upstate New York

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blackout, nice looking Cobra project...as far as heim joints go, I've never seen aluminum heims used in aviation so the ones I have with grease zerks are all alloy steel bodied and probably pretty hard to break. I'm not saying that aluminum heim joints aren't used in aviation but I've never seen one but I live to learn. Some of the greaseable ones have that very small pin point greaser so maybe not as failure prone.

 

If you lived down the street, I'd have to convince you that we needed to make a jig for a light wt. chromoly frame for our -07 street trackers/scramblers. I think an -07 powered scrambler (Duc desert sled) would be really nice. Still might go there but waiting to see T7.

 

The gopro proved to myself that what I thought was bottoming out really wasn't...hard to tell even in slo mo but an 'O' ring added to the shock shaft was proof positive of shock travel...

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1 hour ago, markstertt said:

blackout, nice looking Cobra project...as far as heim joints go, I've never seen aluminum heims used in aviation so the ones I have with grease zerks are all alloy steel bodied and probably pretty hard to break. I'm not saying that aluminum heim joints aren't used in aviation but I've never seen one but I live to learn. Some of the greaseable ones have that very small pin point greaser so maybe not as failure prone.

 

If you lived down the street, I'd have to convince you that we needed to make a jig for a light wt. chromoly frame for our -07 street trackers/scramblers. I think an -07 powered scrambler (Duc desert sled) would be really nice. Still might go there but waiting to see T7.

 

The gopro proved to myself that what I thought was bottoming out really wasn't...hard to tell even in slo mo but an 'O' ring added to the shock shaft was proof positive of shock travel...

You know your stuff for sure!  Aluminum is interesting because while it is light, it is not very strong, so most times you are better off running small alloy steel rod ends for maximum strength and minimum weight.  All the Formula SAE autocross cars that I saw while racing used very tiny alloy steel rod ends.  With pure tension and compression loads, they can be very small, and of course they did the math since it is a college project after all. :)  

 

The aluminum rod end made sense for the link on the FZ-07 because the Yamaha frame bolt was 12mm, so a sleeved 1/2" bore rod end needed to be used.  A 1/2" steel rod end is way stronger than needed for pure compression and tension loads, so aluminum it was.  The 5/8" shank matches the 16mm shank that the Nitron shock uses.

 

I'd be down for a custom frame for sure.  NY winters give you time for these projects. :)  I own a TIG welder as well, just need to practice. ;) I did my exhaust myself on the bike last winter, just because I could....

Craig Mapstone
Upstate New York

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  • 2 weeks later...
2 hours ago, firstyammerha said:

There are oil impregnated bronze bushings available. A bearing house could help find one. As I recall, they are machinable.

So true, there is barely any movement at the bottom pivot...I think even a high density urethane bushing like used in some automotive applications would work well and forever.

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My SOHC CB750's had a very thin "plastic" bushing in the swingarm pivot. Seemed like fiberglass reinforced nylon to me, but I can't be sure. The swingarm pivot travels much further than these linkage pieces, and mine looked great at 50k miles. Did it move as free as needles? Heck no. But like you say, these linkages are barley rotating at all. 

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