Topic: The Quest for Brakes and Suspension: GSX-R Treats

[Retro Rocket]

Ah yes, modern frontend swaps; the new oil thread

I did some pretty bull#$%* rake and trail calculations on an online site earlier...I think there are too many variables. I'm gonna ride it regardless, and if Devin makes those adjustable trees, I may try those too.
I can say affirmatively, I wouldn't have anything to do with running a 19" wheel on this setup. Period. That's all I know, the rest y'all can speculate over it, or just try it yourself.

Have fun.

Seth

Gday Seth, I hope its nothing like an oil thread mate, there are measurements that are irrefutable in suspension geometry so hopefully this is a discussion, not a sh1t fight....

[sethdhawkins]

I'll give everyone my full input when I actually swing a leg over it. Keep in mind, my daily driver is a Dodge Ram 2500 cummins diesel....sooooo

[Retro Rocket]

I'll give everyone my full input when I actually swing a leg over it. Keep in mind, my daily driver is a Dodge Ram 2500 cummins diesel....sooooo

Haha, I drive a 2800 turbo diesel as well, only mine is an Isuzu...

[SOHC4 Cafe Racer Fan]

Assuming an 18" front as many run with a modern fork swap (thereby quickening steering), I wonder how the non-stock offset (slowing down steering) works out.  Is it a wash?  Does pairing it with an 18" help/hurt?

[Retro Rocket]

Lots of racers use 18 fronts, I am going to use 18 fronts on 2 of my bikes, on the F  i am going with 45mm offset clamps {stock is 50mm}and on the K i'm going with 50mm offset {stock is 60mm}. The F frame has slightly different rake to the K model frame...

[SOHC4 Cafe Racer Fan]

Thanks, RR.

[bwaller]

Anyone using longer than stock shocks introduces another variable in the front end geometry.

[sethdhawkins]

Don,

I'm running the 18" wheel in the front, but am limited to the least tall of the 18" tire profiles, due to header interference. I'm sure that changing tires three times on the front wheel was an exercise in humor for someone :-/ When I'm done, I'll go ahead and erase my build thread, so that everyone can screw up in the same manner I did

If anyone might be interested in the stock gixxer triple tree setup and 750 stem I have now, drop me a PM...I'm thinking I want the adjustable one, just because.

Seth

[SOHC4 Cafe Racer Fan]

I wonder if you use a tree with more offset whether you can run a larger selection of front tires.

[burlybear]

subsribed

[Terry in Australia]

I wonder if you use a tree with more offset whether you can run a larger selection of front tires.

You can, and then your top triple won't smash into your gas tank every time you turn your handlebars more than a few degrees. I've got the original FZR1000 triples that the PO tried to use on my gold bike, he took them off and made a set of custom triples with more offset when the bike tried to throw him down the road when the forks "tucked under" in tight corners. 

[timbo750]

Terry you have raised an interesting point, most of the time when are turning the bike it is leaning and we are usually either braking or accelerating which will shorten or lengthen the gorks and change all the geometry.  Then there is the profile of the tire, the weight of the bike, the centre of gravity, and I am sure there are plenty of other factors including the tightness of the sphincter.

Project 1 CB750 - http://forums.sohc4.net/index.php?topic=126864

[sethdhawkins]

I wonder if you use a tree with more offset whether you can run a larger selection of front tires.

You can, and then your top triple won't smash into your gas tank every time you turn your handlebars more than a few degrees. I've got the original FZR1000 triples that the PO tried to use on my gold bike, he took them off and made a set of custom triples with more offset when the bike tried to throw him down the road when the forks "tucked under" in tight corners. 

And would allow one to run a 19" wheel and tire combination, should they wish. I think I measured the fork lengths between the cb750k1 forks I had, and the gixxer forks...I think they were an 7/8" shorter, or something like that. I should probably do that again.

[Retro Rocket]

I wonder if you use a tree with more offset whether you can run a larger selection of front tires.

As long you don't end up with any more than the stock 60mm offset on a K model 750 frame and 50mm on a F model frame you'll be OK, more offset means less trail and less trail on a cb750 would make for an extremely nervous front end and prone to tank slappers, the Honda 750K has 3.7 inches of trail stock which, even by todays standards is not a lot, for example most modern sport bikes have around 4 inches of trail or slightly more. Thats the exact reason i'm going with a little less offset with the 18 inch front rims, to add a bit more trail to compensate for the slightly quicker steering 18 inch rim and half inch drop in front suspension height, this should make for a front end that still turns in but is also stable at speed.

[Syscrush]

BTW - I know 2 guys with those Ural sidecar setups (I think one of 'em even has the 2WD version), and they both love 'em.

I would suggest, though, that any mods to increase power is kinda missing the point of those rigs.

Hope you're having a blast on it.

[sethdhawkins]

BTW - I know 2 guys with those Ural sidecar setups (I think one of 'em even has the 2WD version), and they both love 'em.

I would suggest, though, that any mods to increase power is kinda missing the point of those rigs.

Hope you're having a blast on it.

It's the 650 model, not the 750. Cruising speed is around 50 mph, as opposed to 65 with the 750. I figure with the bigger bmw motor, and modifications, I'll have a reliable rig that I can take wherever I please. It'll be nice to be able to accelerate, and cruise for an extended period of time. I'm not looking for a total hot rod.

[sethdhawkins]

Spoiler alert:



My buddy set the tins on the bike, and I hope, gave himself a slap on the back for a job well done.

[Retro Rocket]

Seth, that is absolutely gorgeous paint mate, you should over the moon with that....

[SOHC4 Cafe Racer Fan]

Love it. I'd name her Ruby.

[sethdhawkins]

Love it. I'd name her Ruby.

You might have something there.

[rickmoore24]

I'd hit the 'Like' button if there was one. Nice!

Sent from my Desire HD using Tapatalk 2

[sethdhawkins]

I'm still at work for another 4 days, so these shots are as much of a tease to me as they are to everyone else!

[RAFster122s]

Ruby is quite the looker. Very nice job. Looking forward to the final pictures.

David

[Terry in Australia]

Looks beautiful Seth. Are you gonna get some padding on your seat, or just tuck your nuts under the tank for safe keeping? Cheers, Terry.

[sethdhawkins]

I've decided to forgo the seat padding due to the added weight of the foam Seriously, I can't imagine any type of seat pan for this thing is gonna be all that comfy.  We shall see.