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DIY dyno. ish...


Mr Fro
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Seeing as I've not put much effort in to finding a proper dyno company near me, I thought I'd "think outside the box" :roll: and have a bash at an alternative. Seeing as a dyno basically gives a graph of HP vs RPM, I figured why not just do a speed vs time plot - should be a reasonable indication of any horrendous flat spots, right?


My horrendous flat spot: :-)

http://i760.photobucket.com/albums/xx246/Mr_Fro/2013-08-19_21-31-17_1.jpg


This was my first attempt using a telemetry logging app on my phone which was in my pocket with my lard hindering the GPS signal. I gave it the beans in 2nd from a slow rolling start and am not yet convinced this is accurate - I'll have to give it a few more goes with my phone on the tank or something.


Has anyone else given this sort of thing a try before?


Cheers,

Fro

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so you didnt even bother to call the companies that were reccomended to you when you first asked about Dyno'ing your bike? hmm. :roll:


and to answer your question, if you have years of experience of tuning bikes then you'll be able to have a fairly decent attempt at tuning using a "butt dyno", if not, you'll be needing a proper dyno to show you your AFR/power curve through the rev range and then you will be able to see exactly where the AFR needs tweaking to provide the correct fuelling to improve power and eliminate flat spots etc.

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so you didnt even bother to call the companies that were reccomended to you when you first asked about Dyno'ing your bike? hmm. :roll:


and to answer your question, if you have years of experience of tuning bikes then you'll be able to have a fairly decent attempt at tuning using a "butt dyno", if not, you'll be needing a proper dyno to show you your AFR/power curve through the rev range and then you will be able to see exactly where the AFR needs tweaking to provide the correct fuelling to improve power and eliminate flat spots etc.

 

I had a chat with the guy at Xbikes in Wisbech but that's about it - I'm hectic at work at the mo and am in the lab from 8-6 every day without a phone so haven't had much of a chance to ring around.


To be fair, the arse-cheek system is my preferred method and I've never used a dyno - I was just interested in trying something out to gain some data and thought I'd share my experiment. I was poking fun at myself a bit with the thread as there's a sampling error in the graph ~11 seconds 0-60 would be reasonable in a Volvo estate but not so good on a bike after all. :-)

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lol. id be dissapointed in athing that 11 seconds to hit 60.


using a Butt Dyno is ok for seeing if things like gear ratio changes have made a difference etc or to see if a bike feels like its running properly. but to obtain usable and accurate "data" you need something a tad more advanced. :)

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Precisely. Seeing as this one is destined for the track, I want to get it chugging along as well as is practical considering that it's reasonably standard.


I'll do a few more runs and see if I get anything better - it'll be interesting to see how far off it is from the real deal anyway... :-)

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i remember the hours i spent on my fz750. it had spent a lot of time beuing raced on the track before i bought it for the road. it wouldnt run properly below 4k and was rough unless being thrashed. although i did love the flames and the way it popped and banged on the over run :twisted:


i messed around with different jets/air filters and the full lazer exhaust system. i could never get it running as i wanted it to despite wasting hours and hours fettling, re jetting and riding up and down the road.


it took a garage less than an hour to sort the carbs/fuelling out and get it running properly. twas then that i learned the limitations of road tests and Butt dynos.



i learned a load more when i had my R1 tuned at Track Electronics in norwich earlier this year. just a slight tweak to AFRs can make a huge improvement to the smootheness of the power delivery and throtttle response.

without the ability to see this data in realtime all you have is guesswork and run the risk of getting it seriously wrong and potentially destroying a piston or two if you end up too lean. :shock:

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I know what you mean - mine was also soley for track and ran like a slag low down. I changed the jets out (amongst other things) and now it's back on the road and running alright - I need to pull the plugs soon to see how it's getting along come to think of it.


Thanks for pointing me in Phil's direction by the way. I finally got a few minutes to give him a call and his AF meter is up the swanny! :-)

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