Saturday, January 31, 2015

Some updated pics

Sunday, January 25, 2015

Good News and Bad News

The joy of used parts.  You stare intently at pics online, or on ebay, read and re-read the seller's descriptions until you have them memorized, and then, hoping for the best, pull the trigger and an electronic financial transaction takes place.  You wait a few weeks, pick up your wares, and hope for the best.
I've done OK in the past with used engines.  Although this has turned out to be dud #2 (the first being a KTM 450 engine for another supermono project years ago).  My plan was always to rebuild this engine, as while it was complete and advertised as a runner, mounting up the engine as a empty case in the frame is a lot easier weight-wise.  And I wanted to inspect the lump in detail anyway.  TT/XT 600 engines are pretty simple to take apart, with the only issue being a universally stubborn rotor removal.  I set about the dissasembly, going as far as getting the rotor nut off (with heat and an impact gun), and then flipped the engine over to remove the clutch side components.
Here is where I saw the first problem.  The main gear running off the transmission is missing 2 teeth, with a third damaged.  Where did the broken pieces end up?  Oh well, I was stripping the engine down to its cases anyway, so no big deal, right?

Here is problem #2.  The case is cracked.  You can see the crack in the cover face, as well as one extending down into the bearing pocket.  There is also evidence of the outside of this part of the case being painted over, to hide all of this.
With my OCD tendencies when it comes to engines, this is now for parts only.  I've opened c claim to get back some of what I paid for (admittedly cheap, but still).  The search is on for another engine in the mean time.

This pic shows some good things.  The 900ss shock is in great shape, and with some spacers will mount onto my collected shock mounts.  The axle adjuster on the right was advertised at 20mm, but it is not -- likely 17mm.  Another job for the friendly machinist.

A real shot in the dark was the tail pod.  When the subframe is done (after the tank arrives and is fitted) the end result would have meant a subframe that no readily available seat would easily bolt to.  Again some gazing at ebay pics found a zx10R solo seat cowl might work.  I found the cheapest available on ebay and bought it.  Turns out it should work OK.  The metal latches can all be easily removed and replaced with brackets or fittings tailored to my needs.  I will have to fabricate my own seat pan and foam, but I've done it once before and learned from that experience.  I think I can come up with something again.

The holes may well be filled, and the metal cross brace will definitely be removed as a part of the subframe fab process.

Saturday, January 17, 2015

Wheel alignment

With the spacers back from the friendly machinist, I was able to centre the swingarm into the frame.  With that accomplished, it was time to align the rear wheel -- to centre it in the swingarm.
As the tire is crowned, and the swingarm asymmetric, it took some time and careful measuring to make sure things were lined up.
I am using a drz400 rear brake caliper and bracket, as according to research, it is quite close to being the right size.  In my application, however, it needs to be machined down somewhat.  So it was back to the machinist with some instructions and some measurements, based on my work with the micrometer and vernier calipers.

With the correct width determined for the brake side, I set about finding out the proper size of spacer for the drive side.  I usually start with my various spacers and gubbins I've collected over the years and see what fits.  Some initial observation shows that this spacer, from some unknown application is quite close.  Here is where we will start, anyway.  The KTM wheels turned out to be in very nice condition.  More to follow as parts come in and work is done.

Thursday, January 15, 2015

Jigging up the frame

As you can read about in an earlier post when I swapped in the zx9R swingarm into my 7R machine, I used the same sine laws to determine the proper swingarm angle for this composite mish-mash of chassis parts.

What we have is a Muz frame, R6 forks (from the earlier 1999-2002 version), and a swingarm from a RGV125.  This swingarm is steel, and the pivot tubes were previously milled to allow a 17mm swingarm pivot to be used.  As I previously planned to use a different engine with this frame, I ground off all the other engine mount tabs.... some of them might have worked with the xt600 engine, but who knows?  Considering I need to line up front and rear wheels, and then sprockets, I am not going to lose sleep over cutting off tabs too soon.
You can get a sense of how things will line up.  The swingarm shock mount will be welded to the curve in the "banana arm", and then a mount will have to be fabbed on the frame tube itself.  Offset far to the left, this design solution is becoming more common.  The ex650, Aprilia Mana and Shiver, and a few custom designs have come up with an offset cantilever swingarm design similar to this.

Next step is to stop by Cycleboys for some fabrication input, as well as go about centering the front and rear wheels (the supermoto spoked rims) in the forks and then the swingarm.  More pics to follow.

Wednesday, January 14, 2015