I think I have got the cooling under control as the temps on the hoses stay between 160-180 via my temp gun. The heatsoaked thermostat housing is at about 202 or so. I did wire up my electric fan to the sending unit atop the head. The fan did kick on and stays on until about 160 F. As others have mentioned I think this atop the head is a varying resistance temp gauge sending unit, not an ON/OFF fan switch thus the fan flickering as it drops down to 160F. I will need to get one and thread it into the hole in the thermostat housing currently blocked off. When I have wired the temp sending unit to my Chinese digital cluster I do not seem to get any consistent readings. I am unsure the ohm resistance values this gauge needs for Hi to Low output readings.
I did ride the beast to the local scrapyard where I found the 2 complete Carrier APU Z482 units. My second unit is shown in the photo below. Who on earth takes these awesome fully functional Kubotas to a scrapyard?!?
My TIG welded chrome exhaust, motor mounts, a lot of the materials are sourced from this scrapyard. I am so grateful to have them in my neighborhood just blocks from my home. The guys there really got a kick out of seeing the bike up close and listening to the motor. While there I found from a collection of dinosaur lathes and heavy equipment a louvered panel to attach atop my expanded metal radiator cover. I will trim the mounts closer to get the shroud really close to the cooling fins then switch the polarity to draw the air through being introduced by the louvered panel on the opposite side.
While the motor is mounted solid to the frame with 3 bolts, the rear is on 2 rubber mounts from the APU. These (along with the vertical 1x3/16" tube and 1/4" angle extensions welded to the front mounting plate) apparently are flexing a bit and when the bike is on the center stand at full throttle with the knobby tire spinning furiously. The guys noticed the center to center distance of the drive/primary and driven/secondary clutches coming together 1/8"-1/4". This surely is contributing to my less than ideal engagement and top speed. I may replace the rear upper bushes with plastic or aluminum. I may instead utilize a section of the thick aluminum diamond plate from the APU and use it as a lower bash guard which will also prevent the motor from rotating about the front upper axis.
The 10T front sprocket is doing much better than my 17T at acceleration and higher top speed. After I calibrate my speedometer to a GPS I will try a 14T and 12T if necessary.
Yesterday I got at the local swap meet 2-40mm ammo cans to use for saddle bags. Time to bend up some 1/2" EMT and powdercoat the racks (and all the fabricated parts) in my oven! Good times indeed...
