Monday, January 23, 2017

Engine test 2

Was able to trouble shoot the belt idle issue and try 4500 rpm today. As it turns out everything is working smoothly, although it would be preferable to get the idle to sit at 1200rpm (or lower) so either the vacuum lines on the fuel pump are not creating enough fuel pressure, or the timing is off. My guess is the timing, which is an easy fix. Enjoy the video! - cw

Sunday, January 22, 2017

Status: Engine and Rear-Axle Test 1

Here is the back end all put together, tightened down, and basically ready to run. The TAV2 is rated at 6-8hp, but the engine is easily producing more than that. My throttle cable is limited in travel slightly, so I have to fine tune that, but it's a good thing since I have no RPM limiter. The mounting strategy seems to be robust, and the chain has a nice firm tension on both sides. There is a slight fuel leak at the carb - probably because I cleaned it yesterday and didn't put the cup back on 100% properly. Gotta take off and re-attach because the flywheel will cause enough spark to set that on fire.

The sound of this engine is alot like a Harley Davidson (with this header) and clearly the balance of the crank is off (stock crank). I want to get some info from Comet and GTC to find out if they have something more robust. I have a feeling that something isn't right, it should not be spinning the belt on idle. -cw

Saturday, January 14, 2017

Great success

I had a difficult time finding pipe that would sleeve over my 1.25 axle for correct wheel spacing. As it turns out the only thing suitable is something called  'Schedule 80' which comes in a 1.257 inside diameter. There are several methods to properly space your wheel hubs away from your chassis, I'm using this method because it's the most robust in my experience.

Here is my trusty cutoff saw. Usually at home at a construction site but perfectly cozy in my tiny workshop under the counter. It takes a patient steady hand to get through heavy pipe (like this one) without warping the disc from the heat. Be patient and take your time, and it will cleanly cut through.

After some cutting and filing, I cut a notch (using a cutoff wheel) for the keyway. One thing to note, I put the keyed hub (right side) opposite the drive sprocket (mounted on the left side of the axle) to allow the axle to twist. Im hoping a bit of axle twist will work in my favor. Without a cushion drive it's possible the hub bolts will shear off since they don't go all the way through. Frankly I'm curious to see what happens! My engine and chain setup let's the maximum torque of the engine and TAV2 spin the rear axle. Every last bit of damping may be neceasary.

Here is another view from underneath. Using this method keeps the wheels from drifting along the width of the axle and eliminates 2 additional locking collars.