Archive for the ‘Frame – Handling’ Category

XS650: K&J Swingarm   Leave a comment

Been busy lately. Summer (well not really much of one) riding. Work. And, best of all, play.

Our son turned 6. School. Need to get him there and pick him up. Started a while ago collecting bits to turn my SR500 into a sidecar. Velorex 562. Leading link forks. Box section swingarm. Steering damper. Better shocks. May yet even add a battery. Had a subframe made up – bolts directly to the frame. 4 point sidecar connection bolts to this – no welding to the frame – better load distribution. Easier to get certified.

Got a K&J box-section swingarm for a price I couldn’t refuse. Included all the bolts, bearings, axles … ca 5.7kg.

 

k&j box-section swingarm … shock mount bolts, axles and chain tensioners  not shown

 

Checked the existing bearings – OK. But the bearing races showed definite wear marks where the rollers have contacted. No internal spacer!! Checked their website. This is standard-no spacer. Means the bearings take all axial load. Anyone who has left the internal spacer out of their wheel when replacing bearings soon learns not to do this. Their instructions say to tighten the swingarm pivot to the point that the swingarm slowly lowers itself from a raised position. Fully loaded bearings – no wonder the races are marked. New bearings.

Measured it up. Figured there was 164.5mm space between the bearing centres. 16mm internal diameter. 22mm OD would fit inside the bearing cages. Cut myself a bit of pipe. Fitted it – too long – too much play. Remove. File. Refit. Did this 3 times before I got the fit I wanted. Now, there is no sideplay and the swingarm can move freely.

 

spacer … 164.5mm long …. 16mm ID … to the left is one of the bearing carriers, greased, ready for installation

 

Next problem. No chain-rub protector and the pivot tube has a larger OD than the original. Had a polyeurethane bread board the wife wont miss. Grabbed my holesaws and cut myself a new rub protector.

Mounted the chain guard. Shock mount bolt is in the way.

 

shock mount bolt blocking the chainguard

 

A bit of violent grinding soon fixed that.

For some reason K&J decided to reinvent the wheel. Put the brake plate anchor topside. Original is underneath. Must rotate the plate. The brake actuation geometry is now all fucked up. Bright. On researching they fixed this later – gave the choice of over or under. Later models are fitted for the original anchor. This didnt help me. Made myself a new anchor. A comprimise, but helps.

External dimensions of this swingarm are slightly larger than original – means the brake rod runs real close. A little judicious bending solved this. Also took the time to remove the brakearm pivot. Like the XS650, the SR500 has no grease nipple here and people forget to regularly repack it. Tends to seize when least desired. Fucking Murphy!!

 

brake arm pivot – getting a bit dry … caught just in time

 

Things to do:

  • Dechrome the swingarm – i hate chrome just as much as i do policemen
  • reposition the brake plate anchor
  • powdercoat it black
  • replace the missing grease nipple – swingarm pivot shaft
  • keep riding

If you’re wondering why I’m writing this, you may not have figured out that the SR500 and XS650 swingarms have the same pivot dimensions.

Advertisements

Posted August 31, 2012 by xscafe in Frame - Handling, SR500

Tagged with , , , , ,

XS650: Winter Tyres   Leave a comment

I don’t fit my neighbour’s norm. They’re all old. Mostly their kids never visit them. I have long hair. Work from home. Look after the kids (preschool) while my wife goes to work. Listen to ‘loud’ music (means: non volks-musik, non schlagermusik). And ride motorcycles. As do most of my friends. They really don’t understand that I choose to ride the whole year. Also in winter!

Mostly the weather is user-friendly. A few days of snow. Melts in a day or two. What really gets up my nose, literally, is the fucking salt. You don’t see it (until the bike begins to rust). But, you sure can taste it. Give me fish’n’chips any day. No vinegar.

The last couple of winters were snowy. Last year was particularly cold. And I got caught a couple of times. 100-200mm fresh snow. Just as I was about to head home. A 20 minute trip took 3 hours. Mostly I laid the rear wheel in the gutter for traction. Driveways were a killer. Off-camber corners deadly. Rising and dropping slopes a challenge. Both feet skimming the ground. Tyres crunching virgin snow. Pedestrians and cagers both, jaw-dropping unbelievers. The worst were the last 200m. Our street. Never cleaned by the city. Underlaid by ice.  !!FUN!!

2010 the German Govt made winter tyres compulsory. Or did they? “ bei winterlichen Straßenverhältnissen geeignete Reifen zu verwenden sind ” by winter road conditions appropriate tyres are to be used.

  • winter road conditions … Glatteis, Schneeglätte, Schneematsch, Eis- oder Reifglätte … black ice, hard-packed snow, snow slush, ice or heavy frost
  • appropriate tyres … winter or all-weather tyres, marked M+S, M.S  … basically these have a higher silica content, hold better at lower street and tyre temps, deeper profiles
  • penalty … minimum €40 and 1 point … in practice this probably wont be controlled except if involved in an accident or your machine is left stranded
  • interesting perspective here … there is provision for road-tax reclamation for the days you are not able to use your machine if tyres are not available for it

Problem is, these are hard to find. Many bikes are simply not catered for.

For the XS650 I found Heidenau K60 Snowtex. 4.00/18 64S for the rear. 100/90-19 57H for the front.

The SR500 was more of a problem. Heidenau K60 Snowtex 4.00/18 64S for the rear (same as the XS). Heidenau K37 3.50/18 62P for the front (drum brake). Profiles don’t match but are a TÜV accepted match.

Not even bothering for the SRX600.

I found these tyres on offer in the internet. Reifen.com was offering the K60 for €71 and the K37 for €68. I went to my local branch to see if they would order them. Wanted €134 for the K60 and about the same for the K37. Just for the K60 – over €200 mounted! Cash up front. And they wanted to data-mine my name and address – said it was for warrantee purposes. What a croc-of-shit! All I need for that is the receipt. Needless to say I walked. Got back on the internet – €127 delivered. Total price. For both. From someone else.

So – Reifen.comgo fuck yourselves!!!!!!!!!!!!!!!!!!

Am interested to see how these perform. Good that I had an extra set of wheels for both.

K60 Heidenau silica

K37 Heidenau silica

When you get them make sure they have the MS sign on them. Summer and winter profiles are identical.

It’s been a while since I rode with enduro style tyres. The difference was startling at first. Especially the front. Until the block edges began to wear the wheel wanted to track straight. I literally had to slown down, steer and consciuously use my body to negotiate corners. A bit like sidecar riding. This didn’t last. But I wasn’t prepared for it.

And I’m still waiting for the snow!

Posted November 14, 2011 by xscafe in Frame - Handling, Frame - Tyres

Tagged with , , , , , , , ,

XS650: Sag   Leave a comment

Your body can and will tell you all about this. In time. Some parts more than others. Size. Weight. Time. Wear. All, factors.

The harder they come the harder they’ll fall, one and all

 

Amount of change in your motorcycle’s suspension travel with the rider on board-varies around 30% of your total suspension travel. Helps you choose correct spring rates. And correct spring pre-load.

Because suspension works under both compression and dampening a certain amount of preload prevents topping or bottoming out.

First check your springs. Correct rate. Not too progressive. Fork oil. Seals. Bearings. Set your gearing. Half tank of gas. Load when touring.

Have a look at this. For help choosing springs. From here. May need separate springs for touring or carrying a passenger. Or riding conditions.

Static Sag.

Best with a couple of mates. 1 to help you hold the bike up. The other to measure.

Paul Thede from Racetech advises to allow for stiction. Friction and inertia. Both serve to complicate correct measurement but can be compensated for.

Mark 2 points front and rear. Axle centres..2. Frame..2. One each above and below the spring. Front-lower triple clamp. Rear-as close to perpendicular as possible.

  • L1. Set the bike on it’s centrestand. Or racestand not interferring with the swingarm. So both wheels are at full suspension extension.

Measure and record.

Set the bike on the ground. Sit the rider on the bike. In riding position. With full gear.

  • L2. Push down on the suspension. 25-30mm. Slowly release. Measure.
  • L3. Liftbike and rider. 25-30mm. Slowly lower to rest. Measure. Average. This is Static Sag.

Static Sag … L1- L2 + L3/2

Free Sag

Sag from bike alone. Only makes sense after Static Sag is set. Push down. Slowly release. Measure. Lift. Slowly lower. Measure. Split the difference. This is Free Sag. Used mostly setting up rear suspension.

Don’t ignore your stiction result L2-L3. This shows suspension condition. Front should be 10-20mm. Rear, 2-3mm. More or less than these? Time to start getting intimate with your bouncies.

Recommended Sag Measurements: mm …from Racetech

Road Race Street Dirt-full size Dirt-mini
Front
Sag 25-35 30-35 60-75 55-65
Preload 5-25 10-35 3-15 3-10
Stiction 5-15 5-15 10-25 10-20
Rear
Sag 25-35 30-35 90-100 80-85
Free Sag, Top-out bumper 2-8 2-8 15-40 10-25
Free Sag, negative spring 10-15 10-15
Stiction 2-5 2-5 2-5 2-5

Correct Sag numbers are personal. Will vary depending on the type of bike you ride, your individual riding style, your weight of the day, surface conditions….. This may help you get a baseline. Fine tuning is up to you.

Posted February 15, 2011 by xscafe in Frame - Forks, Frame - Handling

Tagged with , , , ,

XS650: Fork Rake Adjustor   Leave a comment

From Cheney Engineering:

 

rake adjustors…top, bottom or both

 

These give you the ability to quickly change your rake.

  • Insert one adjustor in the top of your fork head: -can position this for a +0.50 or -0.50 degrees over 30″
  • Add an adjustor in the bottom of your fork head: -gives an adjustment of ~ +1 or -1 degree over the 30″

Each Adjustor comes with Adjusting Offset, Race and Bearing.

You need to supply the diameter, thickness and length of your fork head.

Your stem probably requires machining to fit the bearing. Or buy one of theirs and press it into your bottom yoke.

They also have some nice trick stuff to adjust your offset-

  • Offsets provide the ability to make incremental adjustments to move your forks closer or away from your fork steering stem. Offsetting forks farther from the steering stem transfers more of the engine weight to the rear wheel…provides better hook-up. By modifying your offsets, you can improve your rear wheel hook-up. The trick is getting the right amount of offset for each style of track.

…and for dealing with shorter inverted forks.

XS650: Rephase   3 comments

I first heard whispers about rephasing listening to my older cousins discuss how they could improve their old Triumph race bikes. There are long discussions over at the brit forums.

Then I forgot all about it.

Some years ago I bought an old Special from a bloke in the Hunsrück. Don’t really know why. On a whim. An ebay joke-bid. Low kms. Clean. Been sitting for some years . MMM. As usual. The missus wasn’t happy. As usual.. And it sat. As usual.

Then I put my back out. Time on my hands. Found the aussie 650 site. Yes Terry, I know. You didn’t force me to read. And it got me off my arse. Actually I like the Yamahas. The only new bike I’ve ever bought was a ’77 XT500. My daily rides are my SR500 and SRX600. Growing up with British bikes you learn to think that‘s all there is. Later I was introduced to Italian bikes, falling in love with a ’75 Ducati 750. And with Guzzi Le Mans. They all, however, share one thing in common. They’re Thumpers.

Anyway reading that site opened my eyes to the versatilty of these bikes, and reintroduced me to rephasing. This little gif said it all.

 

360° crank

 

270° crank

 

Changing the crank set up so the pistons dont travel together. Rephasing doesn’t so much give a power increase. Rather it uses the existing power more efficiently. The torque wasted overcoming the inertia of having both pistons stationary at TDC and BDC is made useable

  • power saving
  • less vibration, the motor runs smoother
  • better responsiveness
  • slightly torquier
  • if you do this weld the pins to the flywheels…balancing helps too

 

split crank…you want another #2 disc

 

and one of these 90° offset centre pins

 

#2 disc modified…dont forget to renotch for the cam chain gear locator … this is only necessary when doing a 277° rephase as the sprocket is relocated onto the splined rephasing shaft for a 270° and is positioned properly when re installed

 

to be assembled so

 

and so

 

to look like this

 

so right leads left…makes timing easier as you can use the original marks

 

tolerances

 

tolerances

 

mmm

 

There are 2 ways of doing this
277°

  • split the crank at the centrepin-rotate the right hand side 3 splines and press back together…277° rephase

270°

  • split the crank, replace the 2nd flywheel from the right with a slightly modified 3rd flywheel (remove 7mm from the pin boss where the cam sprocket seats … Distance between centre flywheels is 54mm, unmodified flywheel is 25mm cam sprocket is 11mm leaving 18mm for the modified flywheel therefore 7mm is removed. This just happens to be from the end of the bearing mounting section to the bottom of the circlip groove.), use a 270° pin and press together 90° out of phase…270° rephase.

Was talking with Heiden a while ago. They were tying to explain their new method. I couldn’t exactly understand what was being said. What I did get was that they use an offset pin…do the 277° swap and a 3° offset pin to get the rest. Saves sourcing and machining the other crank disc.

These require a suitably modified camshaft and ignition system…a good time to consider installing a permanant magnet alternator. Originally I used a modified points plate

Yamaha missed a golden opportunity to produce a truly extraordinary motor by turning this idea down. Todays TDM.

Anyone interested in spending the effort wont be disappointed. Virtually all modern-day parallel twins are built this way.

Last time I went home I took with me the bits necessary to do this. Airport security and check-in were not happy. Complete 533 crank. Already set-up. Back home we get 447 motors. Rephased 256 cam. That hurt, I had around 8 or 9 of these. All got destroyed trying to weld them together. Except for that last one. What a waste. And a modified points plate. Fortunately I had my 2 year old with me and got to use his baggage allowance too.

My initial test ride was the Scenic Drive. This winds its’ way along the Waitakere Ranges west of Auckland, separating it from the west coast. A nice ride. Couldn’t get the smile off my face. Had to turn around and run again. This time taking the Piha Kare Kare road. To the beaches. In the old days this used to be gravel. Great for testing. What a blast. Couldn’t stop. Back. To Huia and Whatipu. Then. Shot across the city. South and East. Through Kawakawa Bay, Orere, down the Kaiaua Coast road, stopping for fish and chips at my cousins. And along the Coromandel Coast Road to the commune at Coro. There I changed the oil, got super wasted and spent the night. Next day across the Hauraki Plains, out to Port Waikato and down the back way to Raglan. Then time to go home. Had forgotten my poor son. Although he was with my family he doesn’t speak english. He was not happy. Ouch.

I was converted. My son was concerned.

Bits can be sourced from Daryl promctun@bigpond.net.au ph: aus 03-9330-4909 …  and Heiden -not on their site-u need to ask for these

Webcam will regrind your stock cam to any of their profiles, and for a rephase motor. Megacycle will do this too, they need to know which piston you lead with & what profile you want. See Heiden also for billet cams. If anyone in kiwiland is reading, contact orb, he will point you to a grinder.

The crank was split and reassembled using a press. Safe. Controlled. I have seen photos where this has been done on the garage floor. It can be done. I’ve seen similar in Africa, Sth America, Asia, India etc.

Don’t know about you. But. I like my eyes.

 

if these get loose i dont want to be in the way

 

there are parts of me that wish i’d never seen these 2 photos..hugh says ..’The 2 picture you posted of a crank being split and pressed together are mine. I did that several years ago when no one else in the US was willing to build a crank for me, nor had anyone had any real experience doing so that they wanted to share. Low budget, and not a highly recommended method, but it worked and has worked for over 10,000 miles now. I do recommend welding the crank at all pressed joints though, as they tend to seperate at high rpm’s.’

 

Vibration was noticeably less. Was not an XS any more. Neither sounded nor responded the same.  Begged to be cut loose. Yamaduc.

Generally crank vibration depends on such-like: balance factor, stroke and rod ratio. She will run smoother the closer you get to a balance factor of 50 to 53%. I didn’t balance mine. Pressed her together. Mic’d her up and slammed her gently into the cases. Ride.

I want to do this to my ride here too. Wont tell the wife unless she notices. Time to start collecting the bits again. This will complement the 750 well.

Interesting. Was talking to Jerry Heiden this morning. Was saying he doesnt like, or more to the point, is not as fond of the 270° conversion. Too time consuming for the extra gain? Says he has been having problems matching crank parts. Seems there are variations in castings and machining between the years. Puts the balance out. To minimise the problems you need to get the extra crank parts from a machine as close as possible to your production run/engine nr. All for only a 2% gain. Or stick to a 277° rephase. He welds them up. But not fully. 2 x 1cm tab welds. Makes it easier to resplit.

Posted January 25, 2011 by xscafe in Frame - Handling, Motor - Cam, Motor - Crank

Tagged with , , ,

XS650: Inbuilt Limitations   Leave a comment

When you talk with people who play with these engines, they will mostly tell you how solid they are. How destressed and strong they are built.

To a degree they’re correct.

This was the first 4 stroke motor built by Yamaha. So they were careful. Didn’t want expensive mistakes. The heritage was of course German. It was pretty solid to begin with. Add a little nervous over-engineering and you get the XS1. Built as a street engine. It didn’t have years of racing development behind it.

Many of the ideas were reworked into their second 4 stroke. The XT500. And look where the French took that. Bet Yamaha considered making Olivier an honoraray Japanese.

The fascination for Motocross and Enduro killed Yamahas’ interest in Flattracking while they were at the top. A real shame for Shell Thuet. Also for Bob Trigg.

The XS1 was immediately improved. Clutch. Forks. Crank. Brakes. Later, Percy Tait showed how to improve the frame geometry.

With some improvements the motor basically stayed the same for years.

XS1s make good restoration projects, although the heads breathe somewhat better. 447s make good café racer bases. And Specials lend themselves, with their layed forward rear geometry, to choppers and bobbers. Everyone’s happy.

Restorers will debate the interchangeability and logic of XS1 headlight bracketry or fork internals vs XS1B or XS1F and XS2. Corner carvers will relish the Standard frames improvements. Commuters the electric start. Easy riders the lower-slung specials. Sidecrossers and hillclimbers the simplicity and grunt.

They will all see strengths and weaknesses depending on the design problems they meet and the level of customising they do.

The further you go the closer to the limitations you come. The machines’. The machinists’. The mechanics’. The riders’. And your pockets’.

The problem is that, unlike global finance, the trickle down effect actually works in the real world of mechanics. Any changes you make here directly effect how that there works. Every action has an opposite and equal reaction.

In reality the reaction can be plural and the effects cummulativly overwhelming.

Means, you start playing with the motor, increasing the cubes, playing with the squish zone, allowing her to breathe, changing the timing and you begin experiencing the limitations.

Same with any system in balance.

Talk to the big cube and torque blokes and they tell you head design and the crank centre pin are the ultimate limiting factors. No matter what you do to the rest-it’s that pin that goes.  Some talk about converting the cases to take conventional bearings and running high pressure oiling. Or machining 1 piece auto style cranks and 2 piece conrods.

It’s not going to change the fact that they simply don’t like being shifted over 7500. The little end stretches. Any piston pin play and you have problems.

Fine. What gives next? Cylinder stud anchor points in the crankcase. Aluminium.

Liner thicknesses. Pistons.

Increase cubic capacity? RPM? You’re talking air. Has to come from somewhere. And go there too. Carburetion. Exhaust. Only as good as the head.

Also here the talk is porting. Cylinder centres and stud patterns. Machining existing DOHC heads to fit? Or making your own.

Got good flow? How to get it to the rear wheel? In a way you can control it?

 

8 valve head … wim mellendijk

 

And frame geometry.

None of this is new. Each pushes the envelope. Each tests the limits of it’s partners in crime. All is linked…ommmmmmm

Bud Aksland talked about..

‘…rephasing cranks, different firing orders, hundreds of valve, cam piston crown profiles, welded up ports,…the list was endless…the basic … was a stock set up with a weighted crank…the stock head casting was the limiting factor…is why the OU-72 was commissioned…purpose-designed casting with more favourable valve angles etc.’

‘…it is an engine with built-in performance limitations and if you are going to be successful in your attempt to extract more user-friendly power, it will have to be done with a systematic, integrated manner.’

Kenny Roberts talks about it too.

‘…Accepting the deal from Yamaha meant we had good roadracing bikes —real roadracers built by Yamaha.

But the dirttrack bikes weren’t so good. We had to make do with Yamaha’s XS650 twin, a steetbike, as the basis for a dirttrack racer…

…we struggled with the XS650 that first year. Still, I earned enough points that year to move from junior to expert.

In our struggles with the XS650, we too often resorted to using pistons from here and a cam from there and these valves trying to make the bike fast. We also managed to blow it up a lot!

…in ’72 Yamaha decided to get serious and added Shell Thuet to the team. Shell was an established motorcycle dealer in Los Angeles; he was very experienced, and he knew how to build a racebike. Like all good tuners, Shell knew how to make all the parts work together. He made sure to build reliability in before trying to build horsepower. Some things never change. This is still the best approach to building a competitive racebike’

Posted January 24, 2011 by xscafe in Frame - Handling, Motor - Breathing, Motor - Head

Tagged with ,

XS650: What Could Have Been   Leave a comment

I don’t require a bike to be clean. Mine mostly aren’t. I do require the lines to be though. And the feel. That must be right.

Many of my bikes have been what most might call rats. Now I don’t take that negatively. After all, rats fulfil their niche conditions perfectly. Evolutionary survivors.

 

a prime example of what was being produced in the mid 70s…this 6T chop of my cousins took out the cold kiwi hill climb in 1977 when many specialised bikes failed

 

If form and function are observed, a bike is not supposed to remain clean.

This is one of the things I like about the XS650. And not just me. This is a machine that simply wont die. A ghost returning to haunt Yamaha.

3 clean platforms. None perfect. All with recogniseable soul.

You met Bob a while ago. He helped create the Ténéré 650 prototype. He came from Norton, NVT. Did little jobs for Yamaha.

“We were trying to create extra business. The British motorcycling industry was sort of collapsing, and tried to generate money by doing engineering contracts for other companies. We did several contracts for Yamaha while I was technical director at Norton. Yamaha wasn’t the big international company it is now, and they did not know about Europe as they do now.”

Development of the HL500.

 

HL500 .. cool singles

 

“At Norton we did the HL500 motocross bike with the TT500 engine. We developed the chassis, it was the first one with an aluminium swingarm. It was a very exclusive bike, only 300 units were produced.”

And the NVT650.

 

..NVT650 … often called the Ascot TT, according to Ludy Beumer from Yamaha Netherlands ‘The Amercano’s (YMUS) had absolutely nothing to do with this project.’ Bob Trigg himself said that the american flat trackers – ascot – was only the design concept

 

“Also we did a good styling concept for the XS650, styled as an American flat-tracker, the Ascot TT. I still have the bike, it still works great, it’s a real pure motorcycle. When I ride it, people still ask me where they can buy it.”

I’m sure I’ve seen this bike. In the French Alps. Doing what it was designed to do. Leave me in the dust.

Halco, I believe, used to knock these off. Even caught some of the magic.

It’s not perfect. But. Bob is right. It would have sold.

Too bad the French were still to learn their rally marketing lessons.

What could have been.

…nicely written-up in Classic Bike Dec 1996 p102-5…

XS650TT Bob Trigg Ascot TT

Posted January 23, 2011 by xscafe in Frame - Design, Frame - Handling, XS Pics

Tagged with , , , , ,