Motorised Bicycle Tacho - Super Simple & low cost
- Thread starter Fabian
- Start date
Warner
Member
Warner
Member
Yeah...if they were that expensive here, I just wouldn't have one personally. But your plans are great for your situation. I am more interested in the hour meter than max and average rpm's. I like those features on my heart rate monitor, but I don't know what use they would be to me with an engine. I really just want to know what rpm I'm cruising at and how many hours I have on my engine.
Warner
Fabian
Well-Known Member
Hi Warner
Those solutions are good, but still twice the price of a bicycle speedo and they do exactly the same job.
Cutting two wires in half and joining in an extra 1 meter of wire length isn't exactly hard or time consuming.
If the bicycle speedo came with a wire that had an extra 500 or 600mm to it's length, all you would have to do is mount the sensor pickup and magnet and input a figure of 1162mm and the job would be done - easy peasy, super simple bicycle tacho.
Fabian
Those solutions are good, but still twice the price of a bicycle speedo and they do exactly the same job.
Cutting two wires in half and joining in an extra 1 meter of wire length isn't exactly hard or time consuming.
If the bicycle speedo came with a wire that had an extra 500 or 600mm to it's length, all you would have to do is mount the sensor pickup and magnet and input a figure of 1162mm and the job would be done - easy peasy, super simple bicycle tacho.
Fabian
Warner
Member
Fabian, I like your idea and LOVE your creativity. But for me, it was so much easier to buy a finished product for $35 that also gives me an hour meter. One other (minor) flaw in your design is that it doesn't allow for any clutch slippage as it's measuring rpm's based on the jackshaft revolutions and assuming the clutch is fully engaged and not slipping (which is SHOULD be, but may not necessarily be). Again, Kudos for the enginuity....
Warner
Fabian
Well-Known Member
Hi Warner
Yes, i must give you credit for raising that point: ""quote"" One other (minor) flaw in your design is that it doesn't allow for any clutch slippage as it's measuring rpm's based on the jackshaft revolutions and assuming the clutch is fully engaged and not slipping (which is SHOULD be, but may not necessarily be).
This is a very valid point - i accept it completely and technicially it is a flawed system based on that observation.
I would think that anything over 20 or so rpm slippage would burn out the clutch in fairly quick order though.
Good point - and point taken
Fabian
Yes, i must give you credit for raising that point: ""quote"" One other (minor) flaw in your design is that it doesn't allow for any clutch slippage as it's measuring rpm's based on the jackshaft revolutions and assuming the clutch is fully engaged and not slipping (which is SHOULD be, but may not necessarily be).
This is a very valid point - i accept it completely and technicially it is a flawed system based on that observation.
I would think that anything over 20 or so rpm slippage would burn out the clutch in fairly quick order though.
Good point - and point taken
Fabian
Last edited:
Warner
Member
It IS a minor flaw....these clutches fully engage pretty quickly.....and like you said, if it's slipping much at all, that problem will remedy itself rather quickly...Hehehe...
Warner
Victor Vance
Member
I have read you first post and now planning to do something similar. But i dont have a shift kit. What if the magnet was attached to the main drive cog thats on the crank? Fitting the magent most likely wont be a problem, but the magnet will most likely be out of reach for the sensor. If it was to work, it would be accurate and no slipping clutch would effect it. I think its possible.
customcruiser
Member
- Local time
- 1:42 AM
- Joined
- May 28, 2009
- Messages
- 79
i know tell me about the laws over here just the other day riding with victor he was running his bike in doin no more then 25kmh or something on the footpath wearing a helmet being a good boy meanwhile i was doing burnouts in the medien strip then he was up the road (i had no helmet) then out of nowhere i came flyin up the left lane cut over 2 lanes of traffic and cut a cop off...a detective sorry...i didnt get a fine or anything not even a "walk the bike please" well i did but he said "u should think of ur health its not my brains that will be scattered over the roads i just have to tell ur family at least walk the bike till we are out of sight"......in my and victors oppinions it depends on the cop.
Fabian
Well-Known Member
Hi Victor Vance
Your idea is a workable solution - only thing is the sensor and magnet would get covered in the filth and grease that's constantly being made in that area - almost seems like the crankshaft seal was deliberatly made to leak a bit of oil as my chain is always covered in a lovely wet coating of 2-stroke oil (perfect for me) especially as i run my motor on 98 octane and 20:1 oil/fuel ratio.
I've put over 100 kilometers of distance on the bicycle speedo and it works beautifully; it's in a location where everything is accessable to make easy visual inspection and to be honest, the issue of clutch slip is irrelevant.
Say your clutch is working perfectly and say it slips at less than 1 rpm per minute (any more than that and it wouldn't take too long before it burns out) would that figure really cause you so much trouble that your sleeping hours would be filled by the gnashing sound of you grinding your teeth worrying about an error figure of 1 or even 2 rpm per minute.
Don't even waste your time thinking about any rpm error on a clutch that's working properly.
If your clutch isn't working properly, you'll soon know that something needs to be adjusted.
Cheers Fabian
Your idea is a workable solution - only thing is the sensor and magnet would get covered in the filth and grease that's constantly being made in that area - almost seems like the crankshaft seal was deliberatly made to leak a bit of oil as my chain is always covered in a lovely wet coating of 2-stroke oil (perfect for me) especially as i run my motor on 98 octane and 20:1 oil/fuel ratio.
I've put over 100 kilometers of distance on the bicycle speedo and it works beautifully; it's in a location where everything is accessable to make easy visual inspection and to be honest, the issue of clutch slip is irrelevant.
Say your clutch is working perfectly and say it slips at less than 1 rpm per minute (any more than that and it wouldn't take too long before it burns out) would that figure really cause you so much trouble that your sleeping hours would be filled by the gnashing sound of you grinding your teeth worrying about an error figure of 1 or even 2 rpm per minute.
Don't even waste your time thinking about any rpm error on a clutch that's working properly.
If your clutch isn't working properly, you'll soon know that something needs to be adjusted.
Cheers Fabian
Last edited:
