TRIUMPH T20 CUB - MODIFIED

[Old Scrambler]

Its a single tank just under 2-gal. and is all aluminum.........the 1.6 qt. oil tank was made from a condensor bottle salvaged from a car.  Here is a pic of the underside............

[Koncretekid]

Great looking bike,
2 gallons should be plenty.  I made two or three runs at Loring, went back to the gas truck, and we couldn't put in 1/2 gallon.  I really like your pile of spare parts on the floor.  No doubt enough parts to build another bike.  Bring your buddy Dave along - - I want to see if he can lift my bike!

Will see you at BUB.

Tom

[Old Scrambler]

We had a great time on the salt!  The bike ran very well and we apparently have moved the 250cc M-PG record up to about 82.6 mph. Speed Team Doo had not yet run when we left for home. Look to Facebook for the Salt Team Advanced Landspeed for many pics and comments. I just arrived at home so I have a lot of things to do. Everyone from my team was very impressed with the great people they met on the salt........that includes YOU!

[Koncretekid]

Dennis,
It was great to meet you and your mechanic, Dave.  Congratulations on your record runs, the bike couldn't have looked any better!
Tom

[wobblywalrus]

Congratulations.  It was nice to meet you and see the Tiger Cub.  It is a professional looking little bike.  Welcome to the fraternity of Triumph racers.

[Bruin]

Dennis - Tucker here.  Congrats on the new record.  You did really great!  I know how good it feels to set a record.  I had bike issues but did manage to make 2 1/2 runs on the last morning.  Once we figured out the bike, it ran really well.  You've set the goal for next year.  Hope you're back in 2012 for a little friendly competition. 

[Old Scrambler]

Thanks Tucker.  Yes, it feels good but has not totally set in.............maybe I'm getting old???  The Cub really ran better than my builder, Dave Murre, expected. We only have 201.44cc so a little building may be in order.

[wobblywalrus]

Dennis, in a previous post on another build you mentioned how smooth your engine is with a small flywheel.  There might be another benefit - a reduction in non-aero losses.  Vibration is the frequent acceleration of a mass for a very short distance.  It takes energy to do this and the engine supplies it.  The mass cannot be accelerated if it is restrained so it does not move.  This means the force creating the vibration does not need to be eliminated if the parts subject to vibration can be braced so they are stationary.  The best solution is to balance everything so the vibration causing forces are not present.  Your little flywheel might be doing the latter.

This was told to me many years ago and it seems to make sense.  I am not a physicist -  so I could be wrong.   

[wobblywalrus]

Dennis, you will like the book on drafting you ordered from based on info in Sumo's build diary.  A peculiarity of a technical education when I had mine was the hard work of engineering, such as dimensioning, fits, tolerances, limits, etc. were taught in drafting classes.  The material in the back of the book about detail and assembly drawings are a must read part.  Especially useful are the sections about tolerance distribution and accumulation.  We do not manufacture the things we use on our bikes.  We do draw stuff up for others to make.  The techniques in this book are taught to both machinists and engineers.  It is a common language.

[Old Scrambler]

The closest I ever got to being an engineer was when I ran out of parts in my older brother's Erector Set before I was ten years old.  When I was about 13 I de-coked (didn't know the term then) our Lawson motor. Then my mother sent me off to a private school to become a teacher or a minister........(was in sales & marketing; then became a commercial appraiser)......so engineering books were not available.  I have always loved the simple motion of a lever. Then I fell deeper in love with levers coupled to springs! So now I am planning my retirement life to get back to doing things I enjoy. When I finish reading the book I will give it to Dave Murre, my very reliable engine builder.  He already knows this stuff but I figure if he has a book on his shelf then others will place more trust in him.

[Old Scrambler]

So its been a long time since my last post in this thread............something to do with a new computer that has new rules about posting pics. Anyhow..........WE HAD A FANTASTIC TIME AT BUB 2013.

We brought the same basic Triumph Cub chassis but with a new motor and added partial streamlining. The new motor was measured at 236cc but we calculated it to be 243cc.  We had a tech problem with the extended swingarm..........apparently the AMA does not accept a magazine article as a reliable reference regarding the standard wheelbase of a Triumph Mountain Cub.............so we had the swingarm marked according to the standard Cub wheelbase which only left a half-inch of adjustment. Thank goodness for half-links

We were competing in 250cc MPS-PG. After several practice-course runs with plug-chops on Sunday, we had our 1st and best run early Monday at a top speed of 89.339 mph.  The average should be about 88.74 mph for a substantial increase to the AMA record. We had plans of removing the fairing and running to up our existing M-PG record of 82.5 mph but decided to leave that for next year.

My trusted builder, Dave Murre, headed up my pit crew along with two new members who very possibly will be back with bikes of their own Tom (new record and fastest B50 in the world), Bo & Gretchen, Tom Mellor (now in the 200 club) & Crew, some crazy guys with fake steel valve-stems and 12v meters that register 1.3v apart from each other Peter with the red hair, the blind riders group, Speed Team Doo, and many others stopped to say hello.

As I gather my pics, I'll try to post a few...........especially the dimples on the intake valve stem.

[Cereal KLR]

Hey that was us with the fake steel valve stems, and multimeters that were voltage adverse 

It was great pitting next to you and talking Cubs with Dave. Congrats on the record!

[Old Scrambler]

Cereal.............We will be back next year. I'll bring my own multi-meter

You guys were a great resource.............and so where several others.........helmets, jets, half-links, and twice someone took down our canopy while we were in line for a run to save it from the wind. I hope to be that helpful someday

[Cereal KLR]

Glad you will return next tear, will see you there. We grabbed your canopy just as it was going over the truck at one point, the folks to our left did the same for us too. Who ever invents a secure 60 mph ezup will be rich.

[wobblywalrus]

Dennis, your record is on the list.  Now you can wait for that special flat envelope to come in the mail.