[gt alex]

I would like to share my build and get feed back and discussion.
I started with my desire to build a cafe racer but due to budget I found my first choices of bikes were to expensive.
Then I was offered a gen1 sv650 for $500 dollars.

I knocked it back at first because it didn't match the picture in my head, but a friend said their a great bike .

So over the next week I came up with a plan, which to date I have more or less stuck with.
First step get the bike fix up register it and see how it goes.

It only needed a chock cable, clutch switch bypass. fork seals and the speed drive repaired.

It has since been styled to match the drawing I did while making my plan, and I have been riding it 6 months.
All that is left is a cafe racer tank which I have but will be moding it to match the plan. and performance mods to match the plan.

then strip it down for paint and polish. pictures are rubbish I know

 

[gt alex]

 

[Kenneth]

You have almost no clearance between your tire and rear fender. Also the swing arm angle appears too flat, both suggesting your shock is bottomed out and/or too short. Is that a remote shock reservoir just above your heel?

 

[gt alex]

You have almost no clearance between your tire and rear fender. Also the swing arm angle appears too flat, both suggesting your shock is bottomed out and/or too short. Is that a remote shock reservoir just above your heel?

No problems, it has min 100mm travel at the wheel before the bump rubber, the shock is 330 mm instead 338 mm which lowered the frame approx 24mm, standard dog bones and the custom rear frame lowered the seat, but the tray is on top of the frame and bowed up so thats an extra 20mm clearance. I was unsure if I would need put a spacer under the bump rubber but not even the rear fender (added for legality) has scraped. The static sag is 10mm and total sag is 35mm, spring rate i think was 510lb not much harder than the stock spring
P.S. performance is the goal if it proved a limitation I wound raise the seat frame. I have done about 600km on it pushing harder all the time and some has been on terrible roads, fingers crossed no rubbing yet and I have kept the rubber side down.
That is a remote shock reservoir just above my heel, Front and rear are tune-able jounce and rebound.

 

[Kenneth]

The optimal shock length on a gen 1 is said to be 352mm, according to the racers on this site whom I consulted when setting up my suspension a year ago. I ended up with 349mm on my used gen 1 specific Ohlins. Raised the rear quite a bit, so I lowered the tops of my stock fork tubes (modified with gsxr cartridges) to flush with the upper triple, instead of the spec in the FSM which calls for the tops protruding 2mm above the top triple, which also raised the front a tad. The bike does sit a lot higher than it did before, but the handling is so vastly improved I'd never go back. If performance is your goal and your shock allows for length adjustment you might want to play around with it some.

 

[gt alex]

To keep the geometry balance the front has been pushed through 32mm (by memory) and .9 spring rate so the total sag is 1/3 of the remaining travel. If it was pure race bike I have am sure I would follow a more conventional route.
This bike is just my bit of fun and since its all custom if I don't like something I am free to change it, but at this time I am happy with the handling, however all feedback is welcome, and it all is filed away in my thoughts for a rainy day. My brain can be a bit like a bag of snakes.

 

[Kenneth]

It's all good man, part of the appeal of motorcycles happens on a glandular level. If that weren't so we'd all ride BMW's and the world would be a boring place. Please excuse my comments and carry on, I'm looking forward to seeing the finished product!

 

[gt alex]

Me too, Despite having a plan I still don't know how it's going to turn out. It may end up with a ram tube through the tank. I would like lighter wheels, I've been checking out some super motard wheels but that's not affordable a this time.

 

[gt alex]

The optimal shock length on a gen 1 is said to be 352mm, according to the racers on this site whom I consulted when setting up my suspension a year ago. I ended up with 349mm on my used gen 1 specific Ohlins. Raised the rear quite a bit, so I lowered the tops of my stock fork tubes (modified with gsxr cartridges) to flush with the upper triple, instead of the spec in the FSM which calls for the tops protruding 2mm above the top triple, which also raised the front a tad. The bike does sit a lot higher than it did before, but the handling is so vastly improved I'd never go back. If performance is your goal and your shock allows for length adjustment you might want to play around with it some.

The 8mm shorter shock (I could not find a standard length fully adjustable shock I could afford) stole about 24-25mm But I am revisiting the standard dog bones I am running. If I run shorter dog bones I can regain the standard swing arm angle although the travel will not change.
However I am uncertain if the side effect of reducing head angle another 1 deg will be too much (that would be a total reduction of 2 1/4 deg from standard)
Here's a clearer pic

 

[Kenneth]

There are reasons suspension tuners argue about an acceptable range of swing arm angles that are beyond my comprehension. The obvious one, however, is that a lack of ground clearance compromises safety. This is something I don't understand about cafe racers, a willingness to accept compromises in safety and performance in pursuit of a certain look. By all means, get a proper length shock or at minimum use different dog bones to return it to stock height. Then design around that. In terms of its chassis and motor your G1 is a factory race bike, and is only relegated to the commuter class by reason of its price-point suspension. Seems odd you'd start off by making that worse.

 

[gt alex]

Riding this bike is a lot of fun the way it is. Its lighter and faster than standard, Its sure footed although a bit harsh on very rough roads because the suspension is tuned, it is a bit lower but I a have set it up allowing for that. I may raise the rear 1" back to standard swing arm angle to try, but over all I have no problems. I like the cafe racer style and love doing as much myself as I can. One of the main reasons cafe racers and gp bikes use to be lowered was to reduce frontal area (drag ). There's more mods to come some results will be very unknown until done for example my single throttle body manifold. So from where I sit it's not worse just different.

 

[Kenneth]

Only worse from the standpoint of dragging stuff sooner and crashing at lower speed than you would with a properly set up suspension. If you're more into the cafe side of cafe racer, and plan on riding slow and not doing track days then carry on, and may the Force be with you.

 

[gt alex]

My goal is art and function with no need to ride slow. Not an easy balance but that's the fun.
I've seen many things that on the surface I've thought that won't work, only to see things I would not have considered, succeed. As I said it's all fun and the best way to learn is from doing. Sticking to what is safe will teach nothing new.
I will try shorter dog bones to restore original swing arm angle and clearance but it may it may shorten the trail too much.

 

[Kenneth]

My goal is art and function with no need to ride slow. Not an easy balance but that's the fun.
I've seen many things that on the surface I've thought that won't work, only to see things I would not have considered, succeed. As I said it's all fun and the best way to learn is from doing. Sticking to what is safe will teach nothing new.
I will try shorter dog bones to restore original swing arm angle and clearance but it may it may shorten the trail too much.

It would unless you raised the front back up. Art and function are a delicate balance, but if it were my ass I'd want to utilize and enhance the handling of one of the very best sport bikes ever built. Put the art in the details. With the amount of money you're spending you could end up with a really desirable motorcycle, but what do I know anyways? I'm a just a paint-by-numbers artist.

 

[gt alex]

Guys on the cafe racer net are giving me a hard time over the bike being too low and the swing arm too flat, I can't disagree the swing arms a bit flat but since it's riding well no rubbing I am happy with it over all. But My goal is performance and style and I think both could be served but raising the rear a little. I made mock bog bones for the rear 5mm shorter(100mm) and fitted them raising the rear a smig over 20mm(3/4") a bit more than expected.

I felt Looking at the pics the ass is dragging a bit, and raising will help handling(i hope)

This is a copy of my cafe racer forum reply

Its quite common to run shocks up to 13mm(1/2") longer rear shocks on this model for performance applications that equates to approx 40 (bit over 1 1/2") higher rear I think (having not done this myself), and I am extrapolating the effective difference of mine will now be approximately 1" (25mm) with preload wound all the way out with 2cm of bike sag which I could reduce to 1cm,

Overall I could have an effective difference front /rear as little as 15mm.

Front like the rear has been set to 100mm to make this work I am running cartridge emulators, spring upgraded to achieve appropriate sag and 15w castrol oil and oil height was increase to create progressive bottoming if need.

So the front is purpose made not lowered and fingers crossed.

Of course I have to ride it and see how it goes with the latest planned change.but double checking the numbers. I am more confident it's all coming together.


As always feed back is welcome; It all helps, I listen to everything but ultimately decide my own path and sometimes I later change my mind.

 

[TeeRiver]

... As always feed back is welcome; It all helps, I listen to everything but ultimately decide my own path and sometimes I later change my mind.

Build it, break it, change it, change it back... there is a lot to discover and learn along the way.

So long as you are having fun with your bike, that is all that counts.

 

[gt alex]

thanks

 

[gt alex]

SV650 Cafe Racer
Latest changes are the 520 DID track day sprocket chain set 14t front 45t rear.
Red Back Gen3 race full system with old school reverse flow muffler.
New levers with 17.5 radial brake master cylinder
The brake master has a good feel better than stock, next is front and back new brake pads
There is a bit to much free play on the brake lever before the brakes start working it only a issue because of my short fingers, I am thinking of fitting a grub screw as a return stop on the lever.

 

[gt alex]

Dyno day with single TB. Got 62hp 8800 rpm and 44.5 ft/lbs torque 6300 rpm

64.2 hp (47.9 kW) @ 9000 rpm[12]
42.3 lbf⋅ft (57.4 N⋅m) @ 7200 rpm[12] from Wikipedia

So I am both disappointed and pleased
with a single throttle body and a home made manifold I have a better better mid range torque and max power only rolls off 200 rpm early and sacrificing 2hp.
I really think I will stick with this and add cams to see what that does. Also the muffler is nothing flash but I like the look at this time.

 

[gt alex]

Just got my e-marked bar end mirrors, so I pulled off the "better looking" 75mm mirrors and banged on the new legal sized mirrors.
On a custom bike it doesn't feel right but I don't want to attract the wrong attention