Thursday, 27 August 2009

Angle of dangle.

My Supertrapp exhaust arrived yesterday and I'm now trying to decide on the optimum position for it. I've tried quite a few different angles and found that a slightly forward sloping angle works best (see image).

Marcus of Marcus Moto Design, gave me some feedback on my first attempt and suggested that I put the exhaust as high as possible in order to show off as much as possible of the wheel. A valid point and I have now moved it up as close to the seat unit as I dare
(I don't want the heat to spoil the paint). Looking at the image now, I think I'll try to lessen the angle a little bit further to make it a little bit more parallel with the seat unit (also one of Marcus' suggestions). But I still want to keep a little bit of forward lean. I tried the fully parallel route but it looks to static and "slow". What do you think?

I may add a laser cut polished stainless heat shield with the same style holes as in my radiator guards, for that old school scrambler look. More on that later.

Tuesday, 25 August 2009

Spot the difference?

Have you ever noticed that 99% of all bikes have the speedo drive on the left side of the front wheel? Neither had I. Well, at least not until I started to look for a new speedo drive to replace the original one on my Husqvarna, which for some unknown reason was mounted on the right side.

Since my new front wheel spindle has a diameter of 25 mm – in order to fit my Gixxer forks – the old 20 mm speedo drive wouldn't fit, and couldn't be modified (like enlarged/drilled or something like that). After a lot of digging in the intertubes, I found that some Ducatis use a 25 mm front spindle and I finally found a drive from a 996 at my local breakers in Fleninge outside of Helsingborg, who incidentally is THE least service minded and friendly establishment I've ever had the displeasure to visit. Anyhoo, the problem is, as you can see in the image, that the Ducati drive is meant to be mounted on the left side and can't be flipped over and mounted on the right side, since it then spins the speedo wire backwards. And there is simply not enough room on the left side where the disc carrier gets in the way of the speedo cable...

At this point you are probably asking yourself; why the hell doesn't he stop this nonsense and mount a modern little magneto driven speedo instead? Well, first of all: I like a challenge, and secondly: I really want a nice looking proper mechanical speedo, and not some poncy liquid crystal, glorified pedal bike computer. I know that the 996 drive won't be very exact since it's calibrated for a 17 inch wheel, but that a compromise I can live with.

I sat wracking my brains for hours on how to modify the drive gear or the spindle in order to make it all fit. Then it suddenly struck me. What if I simply flip the wheel over? After all, I can just as well run the brake disc on the right side... I'm not entirely sure if this means that I have to exchange my Tochico brake caliper for a right side one, or if mine can be used, but that's a small issue. Time to start looking for a nice looking speedo. Any suggestions?

Saturday, 22 August 2009

Let there be light.

After yesterday's realization that I had made a mess of my gearing calculations, it feels good to be able to report that the Bates 5 3/4'' old school headlight I bought from a German web shop, looks perfect in its new home between the [still prototype] fork legs of my tracker. Next week it will be adorned by a mesh grille taken from Triumph's accessory program.

And if you think you've already seen that particular combo (black Bates light /Triumph Scrambler mesh) on a street tracker somewhere, you've probably visited the fabulous website of the bike brand with the most pretentious name in biking history: Deux Ex Machina. Their super cool "Mono" has exactly the same combo. In fact, I sent them an email about where that cool mesh came from, and they were kind enough to send me in the right direction.

Originally, I had planned on using a front number plate with a small projector light poking through one of the digits, but since Richard Pollock of Mule Motorcycles thinks number plates on street trackers look "goofy" [see sideburn #3], I went with this setup instead:o)

Friday, 21 August 2009


Me and my big mouth. I should have used one of those gearing calculators after all (see last post). Instead of lowering the sprocket ratio by 15% I should have increased it by 15%. In other words: I need a larger rear sprocket than standard for my now larger wheel (too make it spin slower). Not a smaller one (which makes it spin faster). In fact, I need a 52 tooth rear sprocket (if I use my 16 tooth front). Learning by screwing up. Now, where did I put that phone number to Talon again?

BTW: does anyone need a 42 tooth rear sprocket for a PM-wheel. Never used...

Tuesday, 18 August 2009


In its original state, my Husqvarna SMR ran a 48/17 sprocket combo. But that was with the dinky little 17 inchers. Now, with the huge 19-inchers, and the swollen Maxxis flat track tires, we need a different gearing altogether. There is no shortage of "gear calculators" to be found on the web and some are really OTT (here's one), but some simple maths is actually enough.

Here goes: The stock sprocket ratio is
48/17=2,83. The standard tire (150/60-17) had a circumference of about 1,92 meters.The new tire has a circumference of about 2,20 meters, i e about 15% bigger. That means we need to lower the sprocket ratio by the same amount (15%) to get the same "total gearing". 2,83/1,15 comes out to about: 2,46, which is our target ratio. I wanted to keep the front sprocket with 17 teeth and only change the rear sprocket. So I chose a 42 tooth rear sprocket, giving a sprocket ratio of 2,47 which is pretty close to what I need. I've always thought that the original gearing was a little long and I have a 16 tooth front sprocket in reserve should the gearing turn out to be on the long side.

BTW: does anyone know of a company that sells stainless Allen bolts with "countersunk" heads in 7/16''? The ugly hex bolts I'm using now have to go. I've been googling furiously, but to no avail.

Thursday, 13 August 2009

The missing link.

My 570 Husqvarna engine has two exhaust ports and two 32 mm stainless exhaust headers. These two headers continue separately all the way back to the muffler (image here), which limits the choice of aftermarket mufflers to a a few specially made for the SMR/TE570. All of these have the same problem as the standard muffler: they are very long and looks terrible on a flat tracker. So, in order to run a smaller and better looking muffler I needed to somehow link the two header pipes into one larger pipe. And as it happens, the more recent Husqvarnas share the 32 mm headers, but use a 2-into-1, Y-shaped connector pipe followed by a larger diameter link pipe back to the muffler. For some reason, this 2-into-1 pipe is not availble as a spare part from the dealers – You have to buy the whole system... But as usual, Ebay came to the rescue, and I was able to find this stainless little time saver (It saved me the work of trying to find suitable stainless tubes, bending and welding them). The part number is A0868. Next up: trying to decide what type of Super Trapp muffler to order...

Monday, 10 August 2009

Rear light.

Another piece of the puzzle falls into place. I've been looking for a rear light on ebay for for some time, but not been able to find a suitable one. They were either too large – most jap/standard bikes use huge rear lights – or just too flimsy/ugly. I've also visited my local breakers yard looking for something that might fit, but to no avail. However, a trip to a nearby place catering to cruiser/chopper types (let's keep that one under wraps shall we), solved my problem. I would have prefered a red lens since I think clear lenses are bit chav, but none was available. So this one had to do. At least it looks well made, and I think the rounded shape snuggles up quite well under the seat unit. I know from experience that the vibey Husky engine kills off lightbulbs at a frightful rate, so I've put some extra rubber bushings between the lamp housing and the "carrier" to protect the diods. The "carrier" (professional builders look away now) started life as a bracket inside a PC, but an hour or so of cutting and drilling later, it now serves a bigger purpose in life. Isn't recycling great?:-)