Landracing Forum
Loring Timing Association (Maine) => Loring (AFB) land speed venue => Topic started by: Truckedup on April 04, 2017, 09:12:19 AM
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I built the dual engine Triumph you see in the photo....It will be coming to Loring in July.....The engines are linked by #428 duplex roller chain (like a Harley primary chain) ...the chains and clutch are enclosed by the sheet metal cover to comply with the rule to prevent rider entanglement with open primary drives...My rider fabricated the cover from 16 gauge steel ,.062 inch.It's securely mount with eight 1/4 and 5/16 bolts It's open on the bottom because I feel it better for a potential broken chain to exit easily rather than jam and possibly lock the rear wheel....
Is this cover adequate for the rules ? Thanks
(https://c1.staticflickr.com/3/2913/33029698192_d636939808_c.jpg)
This is what's under the cover....Been tested on the rural back roads :evil: and next week the bike goes on the chassis dyno for tuning and durability tests.
(https://c2.staticflickr.com/4/3939/33794778956_db815f29bf_c.jpg)
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That should be fine. I see no issues with it.
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As a triumph owner myself I must say that is SOOOOOOOO nice cant wait to see that bike run!
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Thanks, The double engine bike goes on the dyno May 4th.....If it doesn't blow up you will see it at Loring in July... My 650 MPG Triumph held the record at Loring for a year at 128.2 MPH, but the dreaded BSA took the record back.... However it's likely I won't be there ,just my rider and the bikes...
The 650 MPG bike had a few changes and now looks like this....
(http://i.imgur.com/8ppeSDQl.jpg)
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Six Hundred and fifty miles per gallon is significant!
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Six Hundred and fifty miles per gallon is significant!
650cc modified production pushrod gas :-D
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How do you have the engines phased: alike, or #1 TDC ignition = #2 TDC overlap?
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...and did you get to the Dyno?
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How do you have the engines phased: alike, or #1 TDC ignition = #2 TDC overlap?
Left front cylinder fires degrees before the left rear cylinder...So it's like a big 360 degree twin so to speak...it's actually fairly smooth running, not radically tuned and idles like a stock Triumph at 900 rpm
On the dyno it made 93 HP @ 6000 rpm...and 95 HP at 7200 rpm....85 ft lbs torque@ 5400 rpm.....As suggested by Panic above, the exhaust pipes are too long causing the power curve to flatten out but the engines are still willing to rev freely to 7500 rpm.. I shortened them 4 inches, see how it goes at the track...50 RWHP is a decent number for a modified Triumph 650 engine with a more or less stock head with a careful valve job
The many runs on the dyno also tested the primary drive for durability...No problems
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Just playing with Pipemax. On the two engine bike are there 4 individual pipes or collected into 1 with a megaphone as on your single? Quickie Pipemax says 31-34" primary so Panic's cut 4" off suggestion is on the money for primary. If they are collected it looks like the pipe length on the front engine would be much longer than on the rear.