News:

We rely on our supporters to help keep us running. Thank You!

Main Menu

Joining The Club

Started by Chris Duncan, September 07, 2019, 12:34:08 PM

Previous topic - Next topic

Chris Duncan

Hello

I bought an '82 Vision a couple months ago, looking to build a cafe racer out of it. Originally I had decided on an XS650 but I've already had one of those and this Vision looks more interesting. When I was working in a bike shop as a teenager in the late 70's it would have been a dream bike for me. Water cooled, 4 valves per cylinder, mag wheels etc. The best bike I had at the time was a '75 RD350.

So far I have a Triumph rear shock, an '83 Seca Turbo front fork set and some clubman bars

the plan

front fork conversion with 300mm dual front discs (R1?)
2 pot or 4 pot calipers with adapter brackets
fork brace
delete center stand
lighten or replace muffler/footpeg brackets
cut off rear frame and put smaller hoop
de-bracket frame
mod rear wheel to fit disc brake, or swap with XJ900 wheels (with rear disc)
cafe half fairing with round LED headlight
cafe seat
possibly modify tank or swap, or paint it to hide the bottom edge.

I really like the Italian designer Oberdan Bezzi when it comes to cafe bikes. I think the Dutch guy Maartin Poodt that built the yellow cafe XZ550 copied one of his designs.
I want to do one of his designs but with a smaller budget than Poodt's bikes.



This forum has been really helpful so far but I do have a couple of questions

What 2-pot or 4-pot front brake calipers fit with clearance to the stock wheel?

build threads I've found so far

Vision Tracker
P.O.D.'s Going Racing
John Clemens XZR650

Haven't had much luck searching, if anyone could point out some more build threads that would be nice.

The Prophet of Doom

Quote from: Chris Duncan on September 07, 2019, 12:34:08 PM
What 2-pot or 4-pot front brake calipers fit with clearance to the stock wheel?
None I'm afraid.  You can upgrade to a XZ550 83 setup (dual caliper) or run adapters to fit other calipers. 
I did once fit a pair of Brembo brakes and R1 rotors on my bike.  Looked great, but then I abandoned it for legal reasons.


Have a long look at the vision tank and the big airbox underneath.  You will really struggle to get lines like the Bezzi on the XZ.  The Poodt bike on the other hand seems to be an unmodified stock tank, but with cleverly concealing paint.


Good luck - post lots of pics

cvincer

Visione Cafe Racer Update   (note the extra   'e')   was an interesting post by   'Saddle Bums'

Finished product at    https://www.youtube.com/watch?v=1r2BZMTnIZk

.

fret not

Check out the "PARTS AND UPGRADES" section and look for "Front Brakes".

It is always easier if you can find a part that just bolts on without modification, so do it if you can.  I usually have to make things, or at least modify something so it fits.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Chris Duncan

Quote from: Prophet Of Doom on September 07, 2019, 07:29:47 PM
You can upgrade to a XZ550 83 setup (dual caliper) or run adapters to fit other calipers. 
I did once fit a pair of Brembo brakes and R1 rotors on my bike.  Looked great, but then I abandoned it for legal reasons.

The Poodt bike on the other hand seems to be an unmodified stock tank, but with cleverly concealing paint.


Yes some of the write-ups say Poodt used a stock tank but I'm not sure, I can see some of the stock lines like the front triangle but the top edge does not match. If he used a stock tank it's modified and has concealing paint.

I knew you had R1 rotors but I only saw the stock calipers with brackets (because of the larger rotors). Didn't see the Brembos will have to go back and re-read your thread.

Yes I have Seca Turbo front forks and will be using adapter brackets, the question was what clears the stock wheel when you center a 2 or 4 pot caliper on the stock rotor position.

The Prophet of Doom


Chris Duncan

#6
This project is going to have 3 main goals

1. Build a good looking and performing cafe racer

2. Build with a minimum budget

3. Concentrate on adding lightness (reducing weight)

I'm finding out when upgrading/ swapping parts that there are certain years of sport bikes that are more numerous thus leading to an oversupply and a reduction in pricing. An example would be the 3rd gen R6/R1. Higher tech and usually lower miles than older models.



Things to reduce weight
change exhaust
de-tab frame and shorten rear hoop
li-po battery
mod/replace footpeg/exhaust brackets
remove center stand
remove balance shaft??
aluminum radiator
remove rad fan
change fenders
change seat

Things that will increase weight
wider XJ900 wheels and tires
larger tube XJ900 forks
dual front rotor swap



Some weights so far (has anyone posted weights before?)

bare frame with brg races 
36.2 lbs.

stock exhaust
25.5 lbs.

stock rad fan
2.3 lbs

stock single brake rotor (300mm)
3.55 lbs

'02 R6 R1 front brake rotor (300mm)
3.15 lbs

footpeg/muffler brackets each
2.2 lbs

front fender
1.7 lbs

stock forks w/o top triple tree. (35mm)
19.75 lbs

'83 XJ900 forks w/o top triple tree. (37mm)
23.2 lbs

swingarm with drive
28.05 lbs

centerstand w/spring
3.35 lbs

stock front wheel
11.75 lbs

stock rear wheel (w/ solid bolted drive hub)
15.75 lbs

XJ900 front wheel
11.7 lbs

XJ900 rear wheel (w/ rubber damped drive hub)
16.6 lbs




jefferson

I would not do with out the radiator fan. If you get caught in traffic or just numerous traffic lights, you will overheat. That will not do your engine any good.

fret not

The important thing about making a custom street bike is to be able to ride it.  Your focus on reducing weight may be less important than you may think.  If you are going racing with this bike then yes, reduce weight as much as reasonable, but if you are not racing the bike there is very little reason to really cut weight.  My reasoning is that for racing ANY benefit that aids going faster is worthwhile (mostly) because less weight allows quicker acceleration, but at what cost.  Those brackets and tabs you mentioned have (had) reasons for being (holding side covers, wiring, etc.) that may be useful on the street.  I have witnessed riders (racers) drilling parts to lighten them to shed a pound or two but they still weighed more than 160lbs themselves before they put their leathers on.  It is easier to shed a kilo of your own weight. 
The most important aspect of weight I think is the sprung vs unsprung weight.  How heavy are your wheels, brakes, suspension etc. compared to the overall weight of the bike that rides on the springs/shocks?  The point is that the wheels (unsprung weight) need to be very light compared to the rest of the bike (sprung weight).  This allows the wheels to rise and fall very quickly as they encounter irregularities in the road surface while the bulk of the weight floats along on the springs and pushes the wheels down to the road surface.  This means tires are in contact with the road surface more of the time, which means more control.  Heavy wheels hit a bump and are lofted a bit, but their inertia slows their return to the road, and when the tires are not touching the road you have NO control.   Focus on making your wheels and brakes as light as you can manage and leave the rest unless it is really necessary. 

I had a race bike a long time ago, (1970 Yamaha TR2) with heavy brakes/wheels, and it was exciting to ride.  Skittering along through the turns on the verge of disaster, bouncing a bit and always in the 'regain control' mode.  Then I got a bike with very light wheels and brakes, and the difference was like the thing was on a rail.  It just rode over the bumps and followed the line I set.  You can go a lot faster when you have control, and it is much more relaxing.

I am in the process of adapting a set of FZR1000 forks to my Vision, and choose to use one 320mm disc on the front precisely to avoid adding too much unsprung weight, and still have decent braking on the street.  If this bike were to be raced it would have more brakes and lighter calipers, but it is not a race bike, and I don't ride like that any more.  Suit your bike to your intended use for best results.  If you just want to look at it then all restrictions are off, but if you want to ride it very much you might benefit by making it more comfortable and easier to use.

I have seen a lot of custom bikes, and many of them are not practical, they just 'look good'.  Having a bike that you can ride and enjoy is the goal. 
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Chris Duncan

Quote from: jefferson on September 21, 2019, 09:39:25 PM
I would not do with out the radiator fan. If you get caught in traffic or just numerous traffic lights, you will overheat. That will not do your engine any good.

It will be a Sunday driver. But then again there sometimes traffic on Sunday. So I may just put a lighter fan, because the stock fan is antique and very heavy.

Chris Duncan

Quote from: fret not on September 21, 2019, 11:29:36 PM
The important thing about making a custom street bike is to be able to ride it. ...I have seen a lot of custom bikes, and many of them are not practical, they just 'look good'.

I understand the unsprung weight issue. I think some of the control factor may be superior adjustable (and tuned) damping. Like most sport/race bikes have dual front disc and wide wheels and tires and they somehow manage to handle well.

Most of the fun for me is the build itself. Building light and on a budget is an engineering challenge. And I'm small so don't want a heavy bike.  And the stock Vision has a lot of weight that's easy to cut. I've built a lot of cars, and I've ridden bikes a lot but never really built a full custom bike. I'm looking forward to it because it's quicker and less expensive than a car. For the time and expense of one car I can have two or three bikes.

And I agree there's a lot of custom bikes out there that probably don't perform all that well. But there's also some that look good and perform good. But when you see someone build a bike and call it a "cafe racer" and they still have a centerstand and stock brakes I just cringe.

fret not

I look forward to seeing what you do with the XZ, and hope you enjoy the challenge more than you expected. 8)
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Chris Duncan

Quote from: fret not on September 23, 2019, 03:00:59 AM
I look forward to seeing what you do with the XZ, and hope you enjoy the challenge more than you expected. 8)


The single biggest weight saving will be the exhaust. The double walled twin downtube pipes running from the front cylinder will be eliminated. I think it's just for looks.  If you think about it for tuning it should go two into one right out of the head to match the rear cylinder, which has to be that way for clearance reasons. That and single wall .035" stainless should cut the exhaust weight by more than half.


A pleasant surprise, the XJ wheels are lighter than the stock wheels even though they are wider. The rear wheel with the drive hub is a little heavier because the hub has the rubber dampers unlike the stock wheel where the drive hub is bolted direct. But weighed without the drive hubs the XJ wheel is a half pound lighter. Apparently Yamaha was evolving their wheels to be lighter.

This brings up another question. Why did they have a non-damped drive setup on the Vision and a damping setup on the XJ? What purpose does the damping system serve?

jefferson

There is a damper in the drive shaft on the Vision so they didn't need to do one on the wheel.