Hi , I have an idea to replace the primary gears with straight cut gears like the rs . What are the pro's vs cons ? Has anyone tried this yet ?Is it worth a second a lap ?
Is it worth a measureable amount at all is probably a better question.
A second a lap is a lot to find from power alone, I reckon you'd need an extra 3 or 4 bhp. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
Better to have a slow bike, and ride it fast......than have a fast bike and ride it slow !!! _________________ Proud Father of , 05 ktm 400exc supermoto 2018 honda crf rx supermoto
Lesviffer750 wrote:Better to have a slow bike, and ride it fast......than have a fast bike and ride it slow !!!
Depends which results in the best laptimes
Who do you remember from the 2007 MotoGP?
Casey Stoner laying the field to waste on a red missile?
or Marco Melandri repeatedly podiuming one of the slowest bikes out there? _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
fontyyy wrote:Who do you remember from the 2007 MotoGP?
I don't remember ANYTHING as i've successfully erased all memory of that year's Gippo racing from my brain!
Straight cut primary gears would be the sort of difficult mod you'd make in the search for ULTIMATE POWER. So as part of a comprehensive tune including modification of everything that might yield a few more horse power - like using single ring pistons and altering the insides of the crankcases, running higher compression and getting some of those bigger carbs etc, then i guess it'd be another worthwhile job on the list.
But then, if you're going to these lengths it maybe alot cheaper and less heart breaking to buy an RS engine and put that in your frame (or better yet, try to find a complete RS to run instead). Though if you're actually racing the NSR then this would likely make it illegal for the class you normally run it in.
However, if a big part of your motorcycling hobby is playing with the engine to see what changes make what difference regardless of whether its a cost effective way of getting better lap times, then that's what you're going to do and i'd be very interested in hearing about the results when you try it.
As for the worth of straight cut primary gears in terms of laptimes - i agree with the others that its unlikely to give a measurable improvement on the track - though you could maybe see it on a dyno graph if you zoomed right in on the 'before and after' power curves.
Quick shifters apparently can give you a measurable laptime improvement because of the time and momentum normally lost on clutchless upshifts that require you to momentarily back off the throttle. I read that they can gain you "up to 8 feet per gear change". I'm just wary of them because they introduce another potential electrical fault. _________________ After years of moaning about immigrants now i am one...
However, if a big part of your motorcycling hobby is playing with the engine to see what changes make what difference regardless of whether its a cost effective way of getting better lap times, then that's what you're going to do and i'd be very interested in hearing about the results when you try it.
Hi Hermit ,
I enjoy working on the bike . Our bikes have been put into another class so the rules are now open to a degree . At some tracks we race with anything up 1990 .
We don,t find rs 250's here . I should have bought one with all the money i have spent on the nsr !
I am very keen to do this mod and will post my results when i have finished .
I don't understand why straight cut gears will produce more power. Please enlighten me... _________________ MC21SP Plaything
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Hi Dave
I believe the theory is that helical cut gears driving or being driven produce a negligible amount of sideways force or thrust. This force will load the bearings and a teeny weeny little bit of power will be sacrificed for the sake of a smooth and quiet meshing of gears. Straight cut gears do not produce any thrust.
And the downside of them is...? _________________ MC21SP Plaything
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Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
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, otherwise, I would think not.
I have a need 
