New project: XS1100 endurance racer

[Mashermoto]

Mathh,

I've been following you're build here and have been watching the exhaust system build in particular

I don't want to highjack your thread, so if you get a chance and would like to comment, go here: http://www.xs11.com/forum/showthread...086#post255086

[daveyg]

When I worked as a technician at a local Yamaha stealership, I noticed almost all 4 cylinder bikes I worked on (From the R6 and R1, to CBRs, to GSX-R) almost all used a 1,2 and 3,4 tri-Y system, and all of which, from my research, were 180 degree engines with a similar firing order, if not just flipped, to our beloved XS11s (With the exception being the latest generation of R1 that uses a 90 degree crank) So if those wonderful Japanese engineers think it works so well... Maybe it does...

[Mathh]

@Diverray: I have made some calculations regarding the alternator/dynamo.

Rear Wheel Circumference = 202 cm = 2.02 meter > 1 rear whel rpH = 2.02 meter/hour > 1000 rpH = 2.02 kmh> 202 kmh = 100.000 rpH > 202 kmh = 1666.67 rpm > 1 rpm = 0.1212 kmh > 1kmh = 8.251 rpm
Sprockets 13:41 = 3.154

Now i tried really hard but I cannot post a spreadsheet in a topic so you have to take my word for it

At 235kmh my front sprocket will make 6116rpm (a lot less than I thought it would make). That means that at 50kmh it will make 1300rpm. Because a gsxr alternator/dynamo can safely make 11000 rpm I wil be able to alter the ratio so it will make 2400 rpm at 50kmh. However the ratio required is 1.8:1.
And i have no room for that because of the tiny front sprocket. Also the gsxr spec sheet shoes that the alternator starts to charge between 3500 and 5000 rpm (speed calculated between 75kmh and 105kmh, way too late). What i found on the internet is that most alternators start charging at these rpm apart from the race oriented chargers with high to very high output. These will already charge at idle. But I only need a small tiny alternator, now preferably with a 1:1 pully ratio, 1.3:1 max), maxing max 45 Amps. So I come back to the one I showed advertised on Ebay. But I need to make sure it will already charge at 1000 rpm. You mentioned alternators charging at 400 rpm. Which ones are these?

[DiverRay]

Just about every automotive alternator I've seen spec sheets on will charge at 400 to 600 RPM. They are also balanced to 14,000 RPM, at a minimum, if they use them on "small" for US engines. because you don't need too much amperes too keep everything charged, a physically small alternator should have plenty of output, and the mass is small so there will be no problems spinning it at close to 20K RPM.
I WILL check with an expert later today, but I am almost positive I'm correct on this. I do know I've just had a crank for my XS1100 balanced to 14K RPM, so I don't see why the alternator, that has it's mass rotating, and NOT reciprocating, can't hit over 20K new. A ten year old, used alternator I may be worried about. Some of the material used to build it may be starting to fracture from stress.

[Mathh]

I WILL check with an expert later today, but I am almost positive I'm correct on this.....

Any news? Just checking

Here's an update on the front forks. As you maybe know I chose the forks from an early Yamaha FZR1000 with 41mm stanchions because of the period look. These forks are reasonably well except for the fact that they use damping rods instead of cartridges. So it's about time to take them to a somewhat higher level. I took them to a friend of mine who has a Bitubo dealership. He also has a nice weblog filled with nice pics ranging from modern racers to classic racers and cafe racers:
BLOG (when you get to the bottom of the page just click "oudere projecten" and you will get to the next page..)

After disassembly of the forks I blasted and painted the outer forks, just to prevent them from getting oil stained. definitive painting will follow later.
As usual with these forks you don't know what to expect when you take them apart but these forks were the same as all the others as the internals were really dirty.



After a thorough cleaning the forks got inspected and serviced, got new seals, Motul "factory line" 10W oil and on top of that they got a YSS suspension valves treatment in order to get more damping in the forks.




Because of these valves a bit more work is involved: drilling some extra holes in the standard damping rods. That was not a problem, the big question mark was how much and how big....
After some thinking he decided to drill 3 extra 7mm holes.




Then the forks were assembled again and although a bit sceptical the end result was surprisingly good! More than enough damping without being "slow" anywhere.
In this pic you also see some Honda VFR1000 forks from another classic racer, very complex these. The owner wants to keep the anti-dive system intact, my fried wants to block it off and "throw the rest in the woods" hahahaha

[WMarshy]

All I have to say is, WOW. Totally epic. Keep up the great work.

How come no FEA of the front half of the frame? I would like to see how stiff it is! Any chance you would sell a set of tube prints to for the frame and swing arm?

[bikerphil]

they got a YSS suspension valves treatment in order to get more damping in the forks.

Those look nice, they control the compression damping, correct? How do you adjust them? Is the rebound damping adjustable on those forks? Sorry, a lot of questions, thinking of a set of those for my FJ forks that are on my 11.

[3Phase]

Here's an update on the front forks.

Okay, that was one excellent update. Well done!


Regards,

Scott

[Mathh]

Those look nice, they control the compression damping, correct? How do you adjust them? Is the rebound damping adjustable on those forks? Sorry, a lot of questions, thinking of a set of those for my FJ forks that are on my 11.

They can be adjusted by screwing them in 2-7 turns, change the springs with stiffer ones or use thicker oil. So to do adjustments you have to take the forks apart again. That is the only downside. The forks themselves are non-adjustable except for spring pre-load.

[Mathh]

How come no FEA of the front half of the frame? I would like to see how stiff it is!

No, I know it's a shame. But solidworks needs a lot of data to make these calculations and mr.Q is already designing another frame (Suzuki TR750 replica). But don't worry, tube wall thickness and diameter is way more than in those days, that combined with superior steel and welds, this thing is absolutely overkill

I had the special in front of the racer and the differences are very obvious.... The racer has its engine sitting 1.5 inch higher from the floor than the stock bike. And the headstock has been lowered 4 inches from stock height.....

Check lower triple tree clamp vs valve cover on the special and the ones from the racer:





This week I fabricated some small things like the rear brake bracket (rear brake caliper is 4-piston MV Nissin):







And I machined 2 extra slots in the upper triple clamp... The smaller ones..




I shortened the chain and put the rear wheel in line, just have to measure how much the rear wheel has to move to the right now (to get both wheels in line) and make up a spacer that comes between the wheel and the cush drive..
Here 2 more pics with both feet on the ground, without any tank or seat it is still incredibly low...

[WMarshy]

Any interest in selling the tube prints? BTW, what carbs are you using on this engine and, why didnt you go with some more modern forks? Looking nice, keep it up.

[Mathh]

Any interest in selling the tube prints? BTW, what carbs are you using on this engine and, why didnt you go with some more modern forks? Looking nice, keep it up.

No tube prints, sorry. All ideas were put in a chassis design program that was based on a different engine (see pics in earlier postings) just to visualise things. By looking at the drawing the tubes were bent and added (and changed if not nice or good) then spotwelded and welded later. Only minor measurements were made for basic things. Carbs are from a 93 GSXR750 (36mm). It will be a classic racer replica (with some updates on brakes and wheels, but not visually disturbing). Modern forks have way to big fork diameters, like 45 -50mm, definitely not classic looking. Upside downs are therefore a no-no as well.
Classic racing rules define forks max diameter to be 37mm. Mine are 39mm, and looking at the wheels and brakes.... I cannot join official racing. But i can participate with free riding during these days.
I think I will change back to 18 inch 5-spoke campagnolo's as soon as I have a set complete.

[Mathh]

well, I got a complaint on the UK forum about my machined upper clamp being no longer safe...



So for sake of safety I called in some experts help.. here's the result:

As seen below... the forks with the machined upper clamp.... max stress is in the outer rear side of the smaller openings: 297N/mm2. A good piece of alu can handle 240 N/mm2 pulling force. Damn!


Thanks guys
So... I'm off looking for another upper clamp or.... weld the smaller holes shut again..
Here's how it looks with only the two big slots on the front. Stress peak moves back into the fork legs. Max stress in the upper clamp does not exceed 110N/mm2.



Tiny small update... I swapped the more modern gold coloured Brembo calipers and brake discs for these older ones. Not period but almost.. :tongue: These were once standard fitment on Ducati 851 superbike ('87-'92). I blasted the gold inner of the discs with aluminum oxide. That gives a very nice, almost painted like finish. Then I have to make up some brackets (easy this one)..

[81xsproject]

DAMN! Those things are HUGE! If I ever do a front end swap, I will keep those in mind. With those on, I could have a non XS11 front wheel and no one would ever know it didn't match because they could never see it behind those rotors! They look awesome, by the way.

[cywelchjr]

Imagine the braking power they give. The closer to the edge of the tire the calipers are the better braking power they give. You could probably do stoppies with those rotors, if the forks would hold the weight of the bike.