'81 CM400T Street tracker "Comstar Love"

flyswat2006

Been Around the Block
After selling my successful CB200 cafe racer and pawning off my CX500 resto, I have started a new endeavour. I've finally come to realize that a 400cc bike makes most sense for me. Here in BC, 400cc is the largest displacement in the cheapest insurance bracket. I'm going with Street Tracker / Scrambler purely for comfort. I picked up this beauty for $700. She needs a top end - else everything is mint. Almost to mint to chop...

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Plans as follows:

Engine:
- Top end rebuid
- DCC VM32's
- pods
- modern GM coil
- Iridium plugs

Exhaut:
- Ditch H-box
- dual shorty reverse cones

Suspension:
- 2000 Yamaha R1 fork
- RFY rear shocks

Brakes:
- 2000 Yamaha R1 leftside rotor, caliper, lever

Frame:
- chop rear frame and replace with hoop (w/ lip)

Seat:
- flat pad w/ lip dark brown

Headlight:
- 4" bottom mount off-centered
- aluminum raceplate
- HID

Electronics:
- Relocate under seat and behind race plate
- 4 cell A123 Lithium bat
- LED blinkers

Paint:
- since the tank is near mint, probably going to just clear coat
- frame, wheels, etc will be black

Wheels:
- front is original comstar 18"
- rear replace 16" with semi matching 18" comstar

Tires:
- Shinko 705 4.10 x18 w/ tubes
 
I did the top end rebuild a couple months ago. No surprizes other than it looked like no maintenance (other than oil changes) have been done for years.

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Paint turned out good. I sanded the head fins and some of the lines on the crank case. I painted the valve cover with transparent green because at the time I was planning on a Green/Black tank. So it will most likely be redone.

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Got my R1 fork and brakes for $400. By the time the swap was completed it was up to $600. For the head set all I needed to do was reuse the original bottom one and replace to top one from Allballsracing. To adapt the Comstar wheel to the R1 22mm axle I had to source some 42x22x12mm bearings. Fortunately I found some from a unicycle shop in Calgary. Next I got a machine shop to make me some axle spacers.

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Next I had to tackle adapting the R1 brake rotor. It's centre boar was huge so I had to reduce that first. Got this 8"x8" 3/16" plate from a local fab shop, made my marking and started cutting. Thirty minutes and six blades latter I had my outside diameter done. Then I spent an hour doing "precision" drill and tapping. Next was the centre boar which I had planned to do with a whole saw. That failed. So I took it back to the fab shop and asked them to do it. They laughed and said they could have done the whole thing for me on the water jet for $25. They ended up just cutting the whole with a plasma cutter for free.

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Then it was back to the machine shop for the last spacer. Done.

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I'm on the rear frame. Got my hands on some 1" tube so now I just needed to fine someone to bend me a hoop. That did not go well. There was only one guy in town with the right bender and he was NOT cool. So I had to get a muffler shop to bend it. They were cool but bend was not. It was too tight so I had to chop it and add a spacer.

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Measure measure chop chop

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I found some old 7/8" handle bars that slid perfectly into the ends of the hoop. Drilled some 7/8" holes into the frame..... tac.....tac

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That is as far as I've gotten. More to follow....

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I need to move 3 hours south... All the cool people are there.

Bike is looking great so far!
 
I don't think I've seen anybody try to add a rear hoop like that to one of these frames. I like where this is going.
 
I've been ill so progress has been slow.

Here is a closer look at how the hoop got attached to the frame.
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Picked up this tube notcher. Definitely worth it.
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Lower arms tacked.
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After plenty of massaging we managed to fit some DCC frame slugs.
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Continuing on building the rear shock mounts out of 3/16" flat bar.
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More hole saw action to fit the DCC shock eyelet mounts.
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Mounts tacked into place.
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Everybody's favourite Chinese shocks getting mocked up.
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Are those Chinese Ebay shocks actually anything decent or do people just knock them cause they are cheap ebay ones? Obviously, they aren't gonna perform like more expensive ones, but was just wondering.
 
D4N63R said:
there is a thread dedicated to RFY shocks in the suspension section

Found these two articles about them:

http://chrislivengood.net/wp/?p=824

http://chrislivengood.net/wp/?p=1304
 
iGreek said:
Are those Chinese Ebay shocks actually anything decent or do people just knock them cause they are cheap ebay ones? Obviously, they aren't gonna perform like more expensive ones, but was just wondering.

Ya they are decent. I used them on my last build. Cheap, look good, and still perform much better than OEM.
 
Cool build! Look forward to seeing those Shinko's on this bike. Installing them on the XS850 I'm building this weekend.
 
Looks good! Are you measuring the whole subframe for straightness now and then? It looks like you don't ;)
You can make a poor mans jig with a piece of rope.

Tie a long rope onto the shockmount hole. pull the rope over to the front of the bike (over the steerertube) and back to the other shock hole. Now you can measure the distance between rope and various parts on the frame on both sides.
 
Subscribing to this one for sure!

That transparent green on the aluminum is a tough look to get right. But it could be a killer combo with the gold front end if done right
 
Bert Jan said:
Looks good! Are you measuring the whole subframe for straightness now and then? It looks like you don't ;)
You can make a poor mans jig with a piece of rope.

Tie a long rope onto the shockmount hole. pull the rope over to the front of the bike (over the steerertube) and back to the other shock hole. Now you can measure the distance between rope and various parts on the frame on both sides.

Straightness? Naw, I'm just winging it!

No, but seriously I've been going back and forth with similar measuring methods. Last thing I want is a crooked ass frame....
 
treitz said:
Cool build! Look forward to seeing those Shinko's on this bike. Installing them on the XS850 I'm building this weekend.
Ya, me too. These two have been staring at me from the corner of my garage for a while. I should get them mounted....

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