My 101 Scout Cannonball Build

[kitabel]

Best of luck with this!
W/r/t pitting in bushing ID: IMHO (just me!) unless the pitting is wide enough to actually make a leakage path to either end (viz., are the pits connected?), the rotating journal will still develop oil pressure by the hydrodynamic wedge effect. I would leave the bushing alone unless this can be done devoid of any error (too loose, too tight, misaligned). I have seen cases and inserts cracked by inserting a "new" bushing that was a RCH too large.
I haven't worked on a 101 for 40 years, so much of this is generic to flatheads for me.
I would be conservative on valve seat width, .125" rather than .060" especially for the exhaust - wide will run the valve head cooler and eat more dirt without losing seal (even though it will flow slightly less).
The exhaust valve must present to the chamber instantly it cracks open: with the valve open .001" there should be a clear path from the seat to the open chamber without any masking/shrouding. Check with a flashlight. Easy to do, just blend the upper head gasket surface into the seat OD (final highest angle cut) all around (but the 180 degrees facing the bore most important). This greatly affects seat and cylinder temperature.
A bronze guide insert will run dry without damage vs. an iron guide.
If you have the room, a lash cap will save the valve stem tip from pounding a dent in the tappet.
I have a gut feeling that a squirt of something (aerosol?) inside the valve cover on occasion will keep the spring cooler and extend stem life, but haven't tried it. Even a small hole will push out oil vapor when the engine is hot, so if you make a hole figure out how to cover it when you don't need it.
I know very little about the breather disc except that continuous high speed use needs slightly different than traffic?
I would cover as much of the drive chain as possible top & bottom, but leave a hole to spray it daily (rotate the wheel to get the whole chain).
They used to drill holes in the skirt half-way down the skirt for oil to reach the wall but stay small (1/4"?) and radius the hole inside & out. Not close to skirt bottom, or directly on the thrust line! I've seen skirts cut with a hacksaw in a shallow "X" across the thrust for oil retention, but results?
Paint: sandblast cylinders and heads, lightest possible coat of flat black for lowest temperature.
Crude trick for 1/4 added hp: remove some teeth from rear sprocket; 48 remove 12, 16, or 24, 1/3 if divisible by 3, etc. On some counts the math doesn't work, should keep the sprocket balanced.

Whew!

[d_lasher]

>> Mike
Thanks, I too learned a lot from the previous threads and have read them frontwards and backwards. I'll try to get pic's up as often as I can.

So I got almost all of the engine and transmission apart, all the gears look good, none of the bushings are even close to spec and all of the bearings and races have some or a lot of rust pitting. I can replace all of the bearings in the engine and transmission pretty easily but I'm worried about the drive race and pinion race. They both have some pitting, but not horrible.

So my question is will I be able to replace these races without making things worse. Are there any 'got-yous' I should know before I replace the drive or pinion races in the crankcase? Also the trust washer under the pinion race is lose. Is that normal? Is it just the pinion shaft that keeps it lined up?

Thanks for any help.
Dana

[ihrescue]

Dana -

As the Moderator of AMCA Forum I like to promote the heck out of member bike builds and I am glad you have already start your build thread for the 2020 Cannonball. If I can do anything from the forum perspective please give me a holler. s we have seen in other Cannonball build threads people follow right up through to the end of the race. I always learn a great deal especially about problem solving and the big one - logistics. Goodluck.

Mike Love

[d_lasher]

Well the hydraulic thing worked, I got all three blind bushing out in less then 10 minutes!

I sealed up the oil hole and groove with just a tiny bit of epoxy and let it cook in the oven at 225 for awhile. Then filled the bushing with grease and gave it a good 'tap', not a whack. It was pretty damn cool, the thing just popped right out. One quick safety tip, I turned down a piece of junk steel rod to fit the bushing but I only did about an inch and the bushing gets stuck on it about half way out. You'll need a good two inches to get it cleanly with one quick tap.
IMG_1105.jpg

[d_lasher]

>> Congratulations on getting into the Cannonball, its a hoot! Better start spending now....

Thanks, The spending has already started and I've been practicing by burning $100.00 bills every morning.

I tried the hydraulic way this weekend and like an idiot completely forgot about the oil hole and got an eye full of grease with the first hit. I might try filling the bushing groove and hole with epoxy and try it again this coming weekend.

And, thanks for the oil pump trick to test the gears binding, that's a good idea.

Thanks,
Dana

[gharper]

Congratulations on getting into the Cannonball, its a hoot! Better start spending now....

I just completed a timing gear rebuild on my 24 Big Chief, post Cannonball 2018. It was always noisy and by the end of the cannonball, it was much worse!

Three ways to get the bushing out: Plug the small oil hole, tightly, then fill the hole with heavy grease and use a steel shaft that fits the hole as snug as possible without binding. Drive it in briskly, sometimes the hydraulic pressure will push the bushing out. May also need to plug the oil slot.

Second way is to use a bushing puller made for blind holes. Here is one on ebay: https://www.ebay.com/itm/16PC-SET-BL....c100005.m1851

I had to do some modification to get mine to fit as there is very little room behind the bushing to grab onto.

Third way is to tap the hole and use a bolt and socket or such to pull it out.

I also made new shafts for the idler gears as the originals were worn very badly, some of the bushings had over .014" clearance between the worn shaft and bushing. The shaft should be .623" and using a .625" reamer, that gives .002" clearance. I carefully fitted each bushing then assembled the gear train with no cam followers. There was some slight drag in places so I put 500 grit lapping compound in all the holes and turned the entire train using the oil pump drive worm and lapped in the bushings. It now turns easily all the way through.

Good luck!
Gene

[d_lasher]

Good news, I got picked to run in the 2020 cannonball on my 29 Scout 101! Bad news, I've got to get my pile of parts ready to drive across the USA in 76 weekends. I've restored a few cars but this is my first motorcycle, my first flat-head, and my first air cooled 2 cylinder so I might need some help. I'm trying to do as much of the work myself, building the bike instead of just bolting parts together.

So right away I have a question, All of the bushings on the bike are long since shot and I'm stuck trying to push out the cam intermediate gear blind bushings. Is there a secret to getting these bushings out?

Thanks for any help,