Project: "HonkyKong" 1979 KZ750 B Twin (brat-tracker-thingy)

blipside said:
Interesting to use copper pipes. Have you heard of any problems with it? Are the inner & outer diameters the same? I haven't taken my carbs off yet to see.
I haven't been made aware of anything to be concerned about due to the use of copper. This is pretty heavy guage stuff, and I plan to support the weight of the carb somehow also. The intake ports measure just about exaclty 1-1/2" in diameter, so the standard size pipe should work well. I could just stuff these into the stock rubber boots, but I'm going to try to make some flanges to replace them.
 
Minor updates. I installed some 11" shocks (aftermarket Harley Sportster, Dyna, FXR, type). These things are crazy stiff, so I'll need to back off on the preload. I like the stance, and that the swignarm and lower frame rails both sita bout parallel with the earth, but don't like what the lower rear has done to the look of the muffler angle, which used to be closer to parallel with the ground. I don't have a ton of room to angle them back up, as the fit near the frame and oil pan is very tight.

The pipe 'sag' doesn't actually look this bad in person, but I was trying to get the viewing angle that would make it as obvious as possible.

To get these to fit, I swapped the rubber and steel bushings from the stock shock over to these. Also, the lower eyelet cylinder needed to be ground down to fit the female swingarm mount. No big deal, but it took a few minutes to get it all to fit right.

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Comparative photo with stock shock length:

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Very short travel shocks. Probably only about 1.5" of functional travel, but who cares. I'm not building a touring bike here.

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All of the tight sports should still clear, even if these things bottom out.

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NEXT UP: I plan to 'properly' lower these forks via internal spacers, and increase the spring preload while I'm at it, because the front end is WAY too soft. I was going to use this method:

http://www.xs650chopper.com/2009/06/mulligan-machine-lower-your-xs650-forks-low-buck-garage-tech/

Any concerns with this? I'll cut maybe 1/2 less from the springs than the amount of spacer added to help stiffen it up. Has anyone out there done this to a KZ750 twin? They look to have all the same guts as the XS650 model shown in that link.
 
Loving the stance bro! I barely noticed the problem you mentioned with the exhaust, you can probably get away with it....but like you mentioned you were gonna lower the front forks? that may help correct it visually?
 
I think the horizontal pipes looks better. Why are you swapping the shocks if the new ones are too short and too stiff?
 
Pablo83 said:
I think the horizontal pipes looks better. Why are you swapping the shocks if the new ones are too short and too stiff?
As stated, the exhaust angle in that photo is exaggerated. I can probably raise them back up a few degrees by adjusting my rear hanger under the frame and get them back to near-horizontal again. Why do the shock swap? I wanted a low, fat-ish bike and that's not likely to happen with the stock length shocks. I'm also a heavier rider rider, so stiff springs are ok, and I'll be attempting a near equal increase in fork stiffness soon.

Here is the exact same image, rotated 1.5 degrees, to place the bottoms of the tires in the same plane. This is a better representation of what it actually looks like.

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Bikes looking great! I do however recommend a mod to your taillight/license plate bracket. I give it about 20 minutes of normal road use before it snaps off at the bolts under the tail. I would add another plate below that connects all 4 bolts together. This will strengthen it quite a bit more than it already is. Now its just a diving board.
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tobiism said:
Bikes looking great! I do however recommend a mod to your taillight/license plate bracket. I give it about 20 minutes of normal road use before it snaps off at the bolts under the tail. I would add another plate below that connects all 4 bolts together. This will strengthen it quite a bit more than it already is. Now its just a diving board.
I was considering doing something similar to 'box' that section, both for rigidity and also to help hide the rear of the tail lamp's socket. These parts weigh almost nothing. That tail light is tiny. Rebuilding this assembly out of steel rather than aluminum may be a good idea too.
 
I say stick with aluminum and box it in. A steel bracket would be just as likely to break if built in the same manner unless it was gusseted/boxed in. Even though those parts don't weigh very much, if you put them at the end of a lever and get them vibrating at a good rate its fatigue city.
 
Trackers are supposed to be thrown around with little care towards dragging the ground. I say lift the rear if anything and get some more ground clearance.
 
I'm going to be working on my wiring this weekend. Does anyone know what kind of current the starter switch needs to handle? It's not much, since it just closes the solenoid, and the starter motor current flows through it, not the button, correct?

I have some like this, for the starter and/or horn, but am considering a more flush-mount chrome unit, for a more subtle look.

21hCKWlIHCL._SL500_AA300_.jpg


vs. ...............

31-uNHvj8KL._SL500_AA300_.jpg
 
I have one of the chrome ones for my starter button on my little cb350. They have a nice feel when you press them. A positive but smooth click.
 
hallin222 said:
I'm going to be working on my wiring this weekend. Does anyone know what kind of current the starter switch needs to handle? It's not much, since it just closes the solenoid, and the starter motor current flows through it, not the button, correct?

I have some like this, for the starter and/or horn, but am considering a more flush-mount chrome unit, for a more subtle look.

21hCKWlIHCL._SL500_AA300_.jpg


vs. ...............

31-uNHvj8KL._SL500_AA300_.jpg

The starter button only operates the solenoid so it's only a couple amps. The one in the top picture looks like the kind available at RadioShack. I tried using a couple of those and they broke pretty quickly. The bottom on looks solid.

I like these:

http://www.highwaydirtbikes.com/HDB_Shop/index.php?app=ccp0&ns=prodshow&ref=pb_mom_b

They are very durable and come with a screw on black rubber boot.
 
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