Motorized Bike Altitude World Record Holder????

[Skyliner70cc]

I'm claiming the title of unofficial world record holder of riding a motorized bike at highest elevation above sea-level.

I conquered Cotton Wood Pass today starting from Buena Vista, Colorado up to the Continental Divide at 12,126 feet . Any doubters can join me on my next ride and I'll even provide a bike for you to borrow.

Equipment used:

Schwinn Searcher Comfort Bike: 100% stock except for tire tubes which have 5x thickness slime tubes. Tires are from Walmart.

ThatsDax HT Engine with over 200 hours of use on it, purchased new in 2008. It gets a pair of new rings each year but I haven't done that yet this summer.
+ Speed NT carb, 65mm jet (run 70mm at home)
++ e-clip on needle valve on top most setting
+ Added BGF sland head when new
+ Run on castor oil blend since day one. Ran 32:1 mixture of 50% Sig AA castor oil blended with Supertech TCWIII 2 stroke oil. Engine saw cylinder head temps up to 450 deg F on occasion with temps over 350 deg F the entire time.
+ Additional engine modifications: Improved head studs that I JB welded into the block. Nothing else done to this engine.
+ NGK B7HS Spark Plug (runs cooler than usual B6HS I use)

Exhaust
+ Sick Bike parts expansion chamber with added muffler. I removed muffler about 1.5 miles from summit to help keep motor "on the pipe".

Powertrain:
+ SBP shifter kit with 9 tooth drive gear chained to a 48 tooth freewheel chain ring.
+ BGF Centrifugal Clutch
+ Mega range 7 speed cassette
+ Shimano tourney derailleur

Fuel: 2 fuel tanks, one in front and a rack mounted tank. Rear tank had special blend of fuel containing more than usual 10% ethanol and a little more oil than what I normally use. The extra ethanol used to account for richer mixture at high altitudes but really wasn't needed. Stock fuel cost me about 3mph in top speed which is not worth the hassle of using 2 different fuel blends.

A special thanks to my wife Toni for putting up with me and allowing me to do this on my last day of vacation.

 

[jrowse]

You rule ! i wonder what other motorizrd bike record are still waiting to happen

 

[Fabian]

I would love to join you on the Cotton Wood Pass, towing my 6 trailers, loaded up with supplies, spares and the local mail run. The bike is capable of hauling (up a 10% incline) around 400 lbs in cargo, using low range 1st gear.

Shame we don't have those kind of hill climbs in Australia.

 

[Skyliner70cc]

I would love to join you on the Cotton Wood Pass, towing my 6 trailers, loaded up with supplies, spares and the local mail run. The bike is capable of hauling (up a 10% incline) around 400 lbs in cargo, using low range 1st gear.

Shame we don't have those kind of hill climbs in Australia.

10% is the max grade of the pass. Even with your gearing, I wonder if it'd pull 400 lbs in cargo up the pass given the 3% loss in HP (assuming ideal air/fuel mixture which isn't possible without fuel injection) for every 1,000 foot gain in elevation.


BTW, I trailered two bikes with me in case one broke down. At last minute I chose the well used Dax instead of the PK80 with mild porting, RSE reed valve intake, manic mechanic 1st generation high compression head, RT carb, and a couple of other goodies. The Dax with fewer goodies pulled a little better and its NT carb allowed me to raise e-clip to lean mixture a bit more. The PK80 bike drive chain stretches after 5 minutes of riding and I've now had to tighten it 6 times in the past 2 weeks since I finished the build; this is getting old. '

I'm glad the bike I chose to ride didn't break down. My wife got carried away hiking on a trail she found on the pass and we didn't catch up with each other for a couple of hours allowing me to ride more.

 

[Skyliner70cc]

NEXT GOAL: 14,130 feet via Mount Evans Scenic Byway. I'm going to have to drop down to a 60mm jet or mess with blending ethanol with gasoline again so mixture doesn't richen too much up on this ride. I'm going to try doing Mt. Evans this summer but if not, definitely next year.

If I have time, I'll see if I can add an extra sprocket w/ front derailleur to get more gearing options but what I have seems to work (thanks Fabian for tips)

BTW, I have biked at 14,110 elevation but that doesn't count since it wasn't a motorized bike. It was a guided bike tour starting at Pikes Peak Summit going downhill for about 13.8 miles. It was ok but riding the brakes the entire time got old after a couple of miles.

 

[Fabian]

All of your jetting vs altitude problems will be solved when Rock Solid engines releases their new generation Walbro (twin needle) carburettor, so you can adjust your air/fuel mixture on the fly.

Although there is nothing wrong with the NT Carburettor it's a waste of time when compared to the quick and easy mixture adjustment of a Walbro.

Having said that, the Walbro is the best stop gap measure until Rock Solid Engines releases their fuel injection kit for these engines.
For me it can't come quickly enough; i don't care how much money i have to pay to get the kit in my hands - fuel injection isn't a novel option - it's an absolute necessity...

 

[sp454e]

a long distances for the record

 

[Skyliner70cc]

All of your jetting vs altitude problems will be solved when Rock Solid engines releases their new generation Walbro (twin needle) carburettor, so you can adjust your air/fuel mixture on the fly.

Although there is nothing wrong with the NT Carburettor it's a waste of time when compared to the quick and easy mixture adjustment of a Walbro.

Having said that, the Walbro is the best stop gap measure until Rock Solid Engines releases their fuel injection kit for these engines.
For me it can't come quickly enough; i don't care how much money i have to pay to get the kit in my hands - fuel injection isn't a novel option - it's an absolute necessity...

Please please please please RSE get this to market ASAP. No more jetting, e-clips, tapering needle valves to get good transition, etc..etc...etc.. Even my cheap Walmart POS 2 stroke weedtrimmer has a high speed and low speed mixture screw (granted they were capped due to EPA regs but a little dremel work fixed that problem).

Because most of my riding is uphill, I envision welding a metal servo arm to the high speed mixture screw and either mechaniaclly or electronically (micro servo) adjusting mixture on the fly from a handlebar activated control. An inpensive EGT probe would be nice. I did use an RC CHT guage made by Venom. It did well and I feel is more accurate than a laser heat gun.

 

[jrowse]

a long distances for the record

or maybe hypermileing ? i was wondering what kind of mpg i might get at a lazy crawl using little throttle.... 200 mpg maybe ?

 

[Skyliner70cc]

You can get infinite gas mileage if you only pedal. I did also 2200 miles with my motorized bike, granted it was on a bikerack the entire time.