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Post Info TOPIC: More recent supermoto conversion, not as easy as it would seem......


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More recent supermoto conversion, not as easy as it would seem......
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Having read Punkawalla's thread, I decided to do the conversion. We live about 1/2 mile down a bridle path which is pretty rough, and I am a retained firefighter, so sometimes I have to travel down the lane a little more rapidly than is healthy for normal 4 wheeled vehicles. So thought a trail bike would be ideal. Then, however, I need to ride 2 miles on a winding tarmac road to  get to the station, so a road bike would make more sense for that. supermoto seemed to be the way to go......

Punkawalla made it all sound easy, so I started looking for wheels.....

... managed to source some XT125X wheels from a well known site, and they had the correct axle sizes, so I thought all would be easy.

Rear was OK apart from the bearings/spacers being slightly different, although the hub looks exactly the same.

Rear 2.jpg

TTR rear spacer on the sprocket side is meant to fit into the bearing, but the XT one does not, so the bearing is 20 id not 22 id. To make matters worse the od of the bearing is different too, and the combination of XT od and TTR id is not made, Doh!

Only solution was to carefully cut off the portion of my brand new spacer that was supposed to fit into the bearing, and just but it up to the bearing instead. Did that,everything else was fine.

Front wheel has a different hub, like the XT600 Tenere

Front 2.jpg

Spacers for this seem to be what punkawalla made up in his thread, but I may have to re-visit them to make sure. Main problem is that Punkawalla said "If anything, the front one is just a fraction too wide, as there is very little clearance between the forks. You may have noticed I've had to lift the gaiters out of the way!"....for very little, read 1mm each side! Hence the spacer sizes are pretty critical!

The disk is bigger (298mm) so as PW said, I had to make an adaptor plate for the calliper and some spacers. As the disk is a floating disk once I fitted the calliper, I found that the floating hinge thingies fouled the back of the calliper bracket where the new mounting bolts (M10 x 1.25 fine thread allen headed) secure it, so they and the slightly raised section of the existing bracket had to be ground down.

Next I found that the nuts on the end of my new adaptor bolts fouled the disk bolts! First attempt was to cut down the nuts, but it leaves very little nut, so my next effort will be to grind down the adaptor plate where the nuts fit, so that the don't protrude quite as much. the plate is 5mm thick, so I think reducing it to 3mm will do the job. The plate is stainless, pretty strong, and should cope with the loadings fine.

General shot of the front wheel

front wheel showing caliper and adaptor plate.jpg

Close up of adaptor and calliper (yes, I probably need a longer brake pipe and a method of securing the pipe out of harms way)

front caliper adaptor plate up close.jpg

View from above the calliper/adaptor set up

front caliper adaptor and spacers trial fit from above.jpg

So, back out into the barn this afternoon to do some grinding/re-fitting etc....

Oh, and quick picture of the bike with the new wheels/tyres and YZ silencer temporarliy fitted to do a test run of engine before I start cutting/shutting to fit properly. Also Raid tank in place with standard seat. Do I cut and shut seat, or try an make something up? Raid seats are pretty rare....

test fit of tank seat and silencer.jpg

Not up to Brian's excellent clean workspace, but best I can do at present...



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Deepest Dorset



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Well, it's been a while since I was here (3 years ), and over the last few weeks I've been back working on the bike again. Some may have noticed my desperate posts ref brakes, but that's another story hmm

Anyway, I just couldn't live with the really close clearances around the caliper/bracket/disk/disk bolts, and as i build wheels for a local classic bike man, I decided to build some for me :) So, I managed to source a TTR front hub from the US, and for a really good price including the postage , so I stripped down the existing front WR wheel (not XT as I'd originally thought), and used the spokes to mock up the rim on my shiny TTR hub, then I measured up the length and gauge of spokes I needed and decided on nipple size. So I then ordered some 10g 190 spokes with 250 nipples from central wheel, which duly arrived in a couple of days. I went for galvanised with zinc plated nipples, as the rear spokes are obviously old galvanised so it wasn't worth going mad on stainless and chrome on brass nipples.

Started to build up the wheel that day, and hit my first problem. the nipples were a really loose fit on the spokes, so much so that you could pull them off the spokes after turning them on 3 or 4 twists, in fact one wouldn't grip the threads at  all! fortunately I had a stock of 10g 250 chrome on brass nipples from builds I had done, just enough to build it up which  i did :) Next problem came with tensioning/truining, as because one side of  the rim was designed for the much larger diameter of the WR hub on that side, so the direction the nipples exited the rim meant that the spokes were badly bent at the end of the nipple. So out came the file and drill, and I "relieved" the wholes somewhat, which resulted in a not perfect, but acceptable bend. So, the result:

TTR SM 2.jpg

And this is what it looks like with the tyre on fitted to the bike:

New front wheel almost ready to MOT 1.jpg

 



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Deepest Dorset



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Another picture from the other side:

New front wheel almost ready to MOT 2.jpg



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Deepest Dorset



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That bike is beautiful, miss mine so much after looking at this.

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Thanks Charles,

 

Sadly, after all the time and effort to get it to this stage, I have to sell it as I'm downsizing my fleet, and it's the one that gets used least crycry

Once it's MOTd, it will be advertised.  cry



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Deepest Dorset



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That bike looks nice!...ive never been a fan of supermoto- but this looks right

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beautiful bike!!


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2004 Yamaha TTR250



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Thanks J smile



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