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Twice the problems

2K views 7 replies 6 participants last post by  tjkoko 
#1 ·
I've been building this from a pile of mismatched parts for about 7 months. It's close to finish so I pushed it outside for a few photos.I'm waiting for the igntion to arrive and still need to make the seat and a few small details..
It's made for land speed racing....basics are 56 650 engines with late 60's unit upper ends , MAP steel rods, forged 10.5 pistons, nitrided cranks, Web cams and a lot other stuff..5 speed Harley transmission and clutch...The Harley electric starter is retained and does turn over both engines. 90's Suzuki forks and wheels..I had the basic frame made to my needs and the clip ons are custom made...but everything else was hand made in my garage shop...The speed records for the naked frame push rod gasoline 1350 cc class is 152-172 MPH depending on the track..I expect the bike to be competitive in this Harley dominated class..



 
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#5 ·
Wow...
There were a number of twin engined bikes raced at Santa Pod in England back in the day. They seemed to destroy the chain (or belt) that coupled the two engines together at fairly frequent intervals. I gather getting the firing relationship between the two engines is pretty critical in maintaining drive integrity. Good luck with the record attempt. Keep us posted!
 
#6 ·
There very little reliable info available on double Triumphs....The ""Parasite" from the early 50's , Sonny Routts drag bikes fired a front and rear cylinder at the same time. this is also what Bob Leppan used on his LSR bikes from what I can figure out.They all seem to suggest a slight lead on the front engine.. So to follow them, I have the left front firing 5 degrees before the left rear....
The primary chain using a counter shaft was a design used by The Martinez/ McAvoy double Triumph in 1970... It was the second naked frame bike in LSR history to exceed 200 MPH using 750 Triumphs on nitromethane..
The primary chains get hot due to a lack proper lubrication..Larger chains 5/8 pitch chains get hotter quicker than the 3/8 chain on mine....
John Healy cautioned me about using triple strand chains where there is flexing...My bike's chassis is well triangulated but I will use caution on the initial trials...
 
#7 · (Edited)
I got two Pazon Smart Fire Magneto conversions in the mail today. Install them and the engines are ready fire up....But... I don't have magneto gears....But I do have two gears with 44 teeth, probably from a Triumph or BSA single.....Punched out the rivets, toss aside the gear and just using the steel hub...It's gets pressed into Triumph cam gears with the center bored out and a counter bore for lateral alignment. Then I TIG welded the two pieces....This is complicated by the hard gears, dull and limited tooling for my vintage lathe...And my untrained machining skills..But I managed to get it spinning true and TIG weld the two pieces ... Tomorrow I'll make another one and the thing might be running early next week...I have oil, about a gallon left of leaded 108 octane race gas...
My wife helped me weigh the bike one end at a time on the bathroom scale..220 front, 230 rear... The bike is all steel and has a heavy Harley 5 speed...
 
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