|April 2000 Bike Feature||www.virtualindian.org|
||Home / Features / 1928 Racer|
you are looking at 3 1/2 years of my life. The motor is a 1928 Chief, it
had a real nice mouse nest inside it to start with. The frame is a modified
101 Scout, the fork is early Scout, the tank is a 1928 Prince and everything
else was fabricated. Turned out better than I thought it would and it runs
well. Weighs in at 253 lbs and handles very nicely. I have had it to the
last three Davenport races, not counting the rained out year it has been
in the money every year. Went back through the motor and lightened up the
valve timing chest and modified the carburetor considerably. The carb still
looks like it has a choke from the outside but is has been eliminated and
the throat is bored at a 3 degree angle. It is a Schebler carb and the
body was not true so had to hone it round again and made my own venturi
that is a tad over 1 1/8 with my own emulsion tube that looks something
like they had in the MR 4 Linkerts. The power jet needle plug has a hole
drilled in it like some of the fixed jet carbs, it all works real well.
The motor is all Indian with the exception of the cams which are Ollie's.
At Davenport you can feel the rear wheel spinning about a third of the
way up the straight aways. It is fun. It's all the way a 1928 would have
been built down to the seat hardware, I was going to try and mock the AMCA
judging program with it but decided it was not the thing to do.
On the dyno.
Had a good start on sorting the board tracker today. Found 2 problems so far, the drive side crankcase breather was hung up, and the oil pump was set to oil way to much. I had originally set the motor up with the oil rings on the pistons. The pump did not over oil then. When the oil rings where removed the machine started to overoil badly, to the point of fouling plugs. After checking around the ideal setting seems to be to have a small dribble of oil coming out of the rear exhaust tappet. The oil pump adjustment has been leaned out 5 turns so far and there is still a trickle of oil out the rear tappet, but no more oil out the exhaust pipes.
Temperatures have been rather impressive, the spark plugs seem to run at about 400 degrees F on an average run. I ran it real hard one time and got them all the way up to 600! I have an infrared temp gauge with laser sighting. The sparkplugs run hotter than everything else. Interestingly, the intake seems to live at about 135 degrees at the back of it. The exhaust ports rarely get near 350, however I did not check on the real hot run.Now for those who are curios, please understand that these figures are relative to the dyno in my backyard, I do not know how they relate in reality to horse power. I think I could take a bike down to the local dyno jet place and get some figures there and then try out mine.... The fastest mph figure I had was 72 mph, with a 28 1/2 tire diameter and 5.47 final gearing that = roughly 4600 rpm or 200 rpm over redline. I think I am geared a little short, will try going up a tooth on the motor sprocket which equals roughly 5 more m.p.h. at the end of the straight. It felt like it was running out of r.p.m. last time I had it on 1/2 mile, now I see why.
Horsepower on my scale, whatever it is, equaled a high of 61 at max rpm by ear and 45 mph land speed, at 40 mph 58, 35 mph 55, 30 mph 51. These figures are taken at full throttle and the dyno is adjusted to create more drag, in this instance 5 mph increments. Nice flat torque curve. The only problem I see after more fiddling is an increase in hp when the throttle is backed off at high rpm/ load. This to me would mean a rich on top condition or carb work ahead. At present I have a Schebler on it that has been heavily reworked, to make a long story short there is a hole drilled in the plug by the high speed needle jet and this may be where the dyno will come in handy finding the correct size for this hole.
Does any body know how I can hook a tach up to my magneto, I went to the m/c junk yard today and found an electronic tach. I believe it is a single fire tach, have tried running it several different ways with no luck, does it need some kind of impulse to trigger the tach other than attaching it where the magneto kill wire would go. I believe the unit I have is of Yamaha of some kind?...
I must say that the races this time went absolutley perfect. Had to go up one heat range on the plugs and tighten the rear chain. The machine performed perfect. Was able to lead from wire to wire on everything except about 3/4 of a lap. Won the main event by a lot after the 2nd place rider lowsided going in to turn 3 and 4. I was told that we where clocked at 80 mph in the heat race and I know that i was going quicker than that in the main. I got so relaxed in the main event that I was wondering where I could get the video tape that the guy in turn one and two was shooting, wondered if I had remembered to tie my left boot also and also finally figured out that it was pieces of rubber sticking up out of the ground from old tires that marked the inside of the turn ages ago. We checked the cylinder temprature as I came off the track and it showed 280 F on the rear and 300 on the front at the plug after the heat race, and 380 on both after the main event. The track was in the best shape it has ever been, no holes anywhere. I found that rather than looking over my shoulder I could use shadows from the lights to see where 2nd place, until he fell, then it was over for the HD guys. Man they where all sad, about 10 HD's, some real trick 2 cams with Titanium valves, roller bearing thrust washers and every other thing they could do and they got beat, real bad. INDIAN WINS AGAIN!
PS. I got 68 units at Davenport compared to 61 at home on the dyno, lower elevation. Also Indian won the handshift pro with Kelly George at the helm!
OK, some of you have seen the story of this great bike before in the