THE358BANSH Posted November 23, 2011 Report Share Posted November 23, 2011 I recently ran across some information pertaining to some very successful, purpose built endurance style banshees in the past. The engines were stock stroke ported deals, meant for smooth transitions onto the pipe with decent low end. The quads were run with 18" rear tires. The first through fourth gear sets were OEM banshee with the ratios being 2.461, 1.812, 1.500, and 1.22. The last two gears were replaced with clusters from an RD350LC, with fifth being .962 and sixth being .888. The transmission ratios were ran with a 16/37 sprocket combination. Using those ratios and 9000 rpm on the engine side of things, we get the speed below for each gear. To the right of the max mph in each gear is the mph gained in each gear. 1 Gear MPH~29.5 29.5 2 Gear MPH~40.0 10.5 3 Gear MPH~48.4 8.4 4 Gear MPH~58.1 9.7 5 Gear MPH~75.5 17.4 6 Gear MPH~81.8 6.3 Using stock banshee trans ratios and the same engine rpm, we get the speed below for each gear. To the right of the max mph in each gear is the mph gained in each gear. 1 Gear MPH~29.5 29.5 2 Gear MPH~40.0 10.5 3 Gear MPH~48.4 8.4 4 Gear MPH~58.1 9.7 5 Gear MPH~69.5 11.4 6 Gear MPH~83.0 13.5 What do you think the reason was for the longer fifth gear? Maybe being able to just wring the motor out a bit more instead of a shift up only to have to shift down again? And second, what kind of snot do you think the motor was making to be able to pull 16/37 gearing? I think they might have been trying to kill some of the violence out of the engine when it was coming onto the pipe by putting more load on it. Discuss? Quote Link to comment Share on other sites More sharing options...
711jrp Posted November 23, 2011 Report Share Posted November 23, 2011 I think Cam might have gone a lone way to answering here. that awesome. and by the way my old 350cc "trail bike was geared at 15/38 with 22" tires. i liked it in the trails because of the way it spread the power out. the motor was designed to have such a broad powerband that it was actually fun in the trails. i didnt have to shift it all the damn time. a lil whack on the throttle and the nose was in the air. and yes it had a round carrier stock length swingarm. also had a +4 on it at one time. no custom 2 1/4 length bs for me. on the dyno yea it hit like 95mph or some shit. but it never got there even at the dunes. my fat ass and the total lack of overrev due to its inherint desin and intended power output made it nearly impossible to pull middle rpm in 6th gear.. even after i farted a LONG time from some stankleg burritos it wouldnt go any faster.. DAMN! Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted November 23, 2011 Report Share Posted November 23, 2011 Does the 5th gear ratio have anything to do with the other gear it meshes with in the transmission? Quote Link to comment Share on other sites More sharing options...
lms1977 Posted November 23, 2011 Report Share Posted November 23, 2011 a 16-37 with 18in tires is probably real close to stock Quote Link to comment Share on other sites More sharing options...
Trick2stroke Posted November 23, 2011 Report Share Posted November 23, 2011 My guess is just what you mentioned, it allowed them to stretch out fifth to the speeds they needed without having to lug that tall ass 6'th gear and shift back and forth. Quote Link to comment Share on other sites More sharing options...
Jereme6655 Posted November 24, 2011 Report Share Posted November 24, 2011 you said the bikes were built as endurance style machines. i bet they put that longer 5th in there for a multitude of reasons. I am sure they did it to help the bike get to 6th gear....we've all tried our hardest on every surface to get into 6th.....unless your on hard pack or road your not going to pull in 6th....maybe stay at the current speed but your not really gonna pull. Also while riding with my woman this summer i came across something that freaked me out. She is a new rider so her speed is severly limited by her skills....which are not high yet (admitably she is getting ALOT better). What i discovered is when i ride with her and im taking it slow and im having to lug my banshee and im not up on the pipe.....i burn more fuel. And when i say more fuel im not talking a matter of 4oz or something here......im saying i burn a fuck ton more fuel. so much that riding my regular pace i can make it to the next town over AND back......riding with her i made it to town and almost out of town before i ran out of fuel. So i bet it helps them keep it up on the pipe to get INTO 6th OR to help keep it up on the pipe so they can run more endurance...... i know...im sure ill get a flame or something by saying i burn so much more fuel when im luggin going slow......but oh well....i know its true...i was the one who sat on the trail...out of fuel. LOL Quote Link to comment Share on other sites More sharing options...
THE358BANSH Posted November 24, 2011 Author Report Share Posted November 24, 2011 you said the bikes were built as endurance style machines. i bet they put that longer 5th in there for a multitude of reasons. I am sure they did it to help the bike get to 6th gear....we've all tried our hardest on every surface to get into 6th.....unless your on hard pack or road your not going to pull in 6th....maybe stay at the current speed but your not really gonna pull. Also while riding with my woman this summer i came across something that freaked me out. She is a new rider so her speed is severly limited by her skills....which are not high yet (admitably she is getting ALOT better). What i discovered is when i ride with her and im taking it slow and im having to lug my banshee and im not up on the pipe.....i burn more fuel. And when i say more fuel im not talking a matter of 4oz or something here......im saying i burn a fuck ton more fuel. so much that riding my regular pace i can make it to the next town over AND back......riding with her i made it to town and almost out of town before i ran out of fuel. So i bet it helps them keep it up on the pipe to get INTO 6th OR to help keep it up on the pipe so they can run more endurance...... i know...im sure ill get a flame or something by saying i burn so much more fuel when im luggin going slow......but oh well....i know its true...i was the one who sat on the trail...out of fuel. LOL Actually that makes a ton more sense and I didn't even think about fuel consumption. Two strokes are horrible inefficient machines when they are not on the pipe. Some where in the neighborhood of burning an extra .2-.4 lb/hp per hour of fuel. That changes things quick when you only have about 20 pounds of fuel. BSFC is the best way to compare efficiency in any engine. Most four strokes are in the neighborhood of .6 lb/hp per hour and when they are getting beat go down to .37-.40 lb/hp per hour. Great thought! Quote Link to comment Share on other sites More sharing options...
LaegerEliminator Posted December 10, 2011 Report Share Posted December 10, 2011 This was on a Duncan PDV Banshee I'll bet.... Quote Link to comment Share on other sites More sharing options...
THE358BANSH Posted December 10, 2011 Author Report Share Posted December 10, 2011 This was on a Duncan PDV Banshee I'll bet.... You are correct Erik. I love absolutely everything about these machines(except for the fuel tanks), as they are the very best prepped and rideable examples of our machines. Quote Link to comment Share on other sites More sharing options...
LaegerEliminator Posted December 11, 2011 Report Share Posted December 11, 2011 You are correct Erik. I love absolutely everything about these machines(except for the fuel tanks), as they are the very best prepped and rideable examples of our machines. Sweet! I figured it had to be there's or a Dean Sundahl bike. I fully agree with you on the above. The Duncan crew IMO know what it takes to go top notch and they are willing to put in the effort to get there. They are passionate craftsmen at their trade. Quote Link to comment Share on other sites More sharing options...
vulvafan537240 Posted December 14, 2011 Report Share Posted December 14, 2011 This was on a Duncan PDV Banshee I'll bet.... whats a pdv? Quote Link to comment Share on other sites More sharing options...
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