Yamaha YZ250F
- Thread starter j bjork
- Start date
j bjork
100 kW
I have seen them before, but that was some time ago.
It seems to be mote info now, there was detailed info of a lot of features.
The 84V max voltage dosent sound that inspiring, but it seems like it is possible to use up to 92V "possibly with reduced output"
And it seems like it is not possible to use field weakening in that case, hopefully it will activate when the voltage go down in that case.
Different passwords for access to different settings sounds worrying, maybe not a problem when you buy a new controller?
But not much info about the output, it only says 340A continuous and 500A peak. Not if it is battery or phase amp, maybe both?
But it says 340 battery amps in one table, listed with the "nominal current 340A, peak current 500A" so I guess those are phase currents.
So it seems not enough for a single controller, would probably be nice as dual controllers. But I want higher voltage. A bit expensive, 830 euro for one. But 750 each for 2, so it is better. Maybe you have to pay extra for pre configuration, not sure if it is needed.
For dual controllers I am considering the new vesc based powervelocity, BESC G2, nucular 24fet, votol em150/200.
*PV would be best of them I think, 130V and MTPA (max torque per amp). So far only 400phaseA and 200batteryA, but will hopefully be better soon. $600 each I think, + import charges (about30%)
*BESC, also vesc based. I have to build it myself, but it will be cheaper (probably
) Should be possible to get MTPA and FW I hope..
100V and 400pA, battery amp the same?
Seems to take some computer skill to get the boards made, and set up the program etc. Would probably mean a lot of trouble for me :?
*Nuc, will hopefully get MTPA. I already have one, but would probably have to wait a long time for the second one.
90V, so a little low. 500pA 3-400bA
*Votol, cant really run in master/ slave mode. I think all the other can, at least it exists on vesc and nuc..
Cheaper than the others, except maybe BESC.
The newer models may be limited, the em150 I have on the ktm I get 540pA and around 350bA from.
90V, so also low.
I have 12s modules that would be nice to be able to use as they are:
Welded terminals, and even the cases are welded together.
If I should run 90V max, I would "have" to reconfigure to 22s.
With the besc I can keep them as they are, also with the higher voltage controllers of course. But with them I would like to reconfigure a third module and run 30s.. Not sure if I will be able to fit it in the available space.
For a single controller I have considered Votol em300, APT 96800, 961000 or sevcon size 6.
QS dont want to sell votol em300 because they brake..
They say they will fix the program for the APT 96800 and recommend that.
(se the APT 96600 thread for problems, I suppose they are the same)
120V max, 800pA 300bA(!)
Size and battery amp limit is not that inspiring, I dont know if it can be set higher possibly?
I have asked about 961000, but has been unable to get any answers. Either for specifications, or if they can sell it.
Sevcon, might be the best option? If I will be able to set it up..
It seems to be mote info now, there was detailed info of a lot of features.
The 84V max voltage dosent sound that inspiring, but it seems like it is possible to use up to 92V "possibly with reduced output"
And it seems like it is not possible to use field weakening in that case, hopefully it will activate when the voltage go down in that case.
Different passwords for access to different settings sounds worrying, maybe not a problem when you buy a new controller?
But not much info about the output, it only says 340A continuous and 500A peak. Not if it is battery or phase amp, maybe both?
But it says 340 battery amps in one table, listed with the "nominal current 340A, peak current 500A" so I guess those are phase currents.
So it seems not enough for a single controller, would probably be nice as dual controllers. But I want higher voltage. A bit expensive, 830 euro for one. But 750 each for 2, so it is better. Maybe you have to pay extra for pre configuration, not sure if it is needed.
For dual controllers I am considering the new vesc based powervelocity, BESC G2, nucular 24fet, votol em150/200.
*PV would be best of them I think, 130V and MTPA (max torque per amp). So far only 400phaseA and 200batteryA, but will hopefully be better soon. $600 each I think, + import charges (about30%)
*BESC, also vesc based. I have to build it myself, but it will be cheaper (probably
) Should be possible to get MTPA and FW I hope..100V and 400pA, battery amp the same?
Seems to take some computer skill to get the boards made, and set up the program etc. Would probably mean a lot of trouble for me :?
*Nuc, will hopefully get MTPA. I already have one, but would probably have to wait a long time for the second one.
90V, so a little low. 500pA 3-400bA
*Votol, cant really run in master/ slave mode. I think all the other can, at least it exists on vesc and nuc..
Cheaper than the others, except maybe BESC.
The newer models may be limited, the em150 I have on the ktm I get 540pA and around 350bA from.
90V, so also low.
I have 12s modules that would be nice to be able to use as they are:
Welded terminals, and even the cases are welded together.
If I should run 90V max, I would "have" to reconfigure to 22s.
With the besc I can keep them as they are, also with the higher voltage controllers of course. But with them I would like to reconfigure a third module and run 30s.. Not sure if I will be able to fit it in the available space.
For a single controller I have considered Votol em300, APT 96800, 961000 or sevcon size 6.
QS dont want to sell votol em300 because they brake..
They say they will fix the program for the APT 96800 and recommend that.
(se the APT 96600 thread for problems, I suppose they are the same)
120V max, 800pA 300bA(!)
Size and battery amp limit is not that inspiring, I dont know if it can be set higher possibly?
I have asked about 961000, but has been unable to get any answers. Either for specifications, or if they can sell it.
Sevcon, might be the best option? If I will be able to set it up..
It's 500A peak in battery current, 36kW (72*500), and 360A continious (24.5kW).
I've worked a bit with one supplier here in Sweden who sell these to the Cake bikes, and they are very happy with them.
I have no idea what the relation between phase amps and battery amps are, all I know is that battery amps * voltage = W
And more W = more fun!
I've worked a bit with one supplier here in Sweden who sell these to the Cake bikes, and they are very happy with them.
I have no idea what the relation between phase amps and battery amps are, all I know is that battery amps * voltage = W
And more W = more fun!
j bjork
100 kW
I hope this works, here you can see what difference higher phase amps make:
https://ebikes.ca/tools/simulator.html?motor=MX4503&batt=cust_100_0.01_8&cont=cust_200_200_0.03_V&cont_b=cust_200_400_0.03_V&motor_b=MX4503&batt_b=cust_100_0.01_8&bopen=true
Basically you get more torque up to where the battery amp limits.
https://ebikes.ca/tools/simulator.html?motor=MX4503&batt=cust_100_0.01_8&cont=cust_200_200_0.03_V&cont_b=cust_200_400_0.03_V&motor_b=MX4503&batt_b=cust_100_0.01_8&bopen=true
Basically you get more torque up to where the battery amp limits.
j bjork
100 kW
In the absence of a motor, that pretty much dictates where everything else goes I am pretty stuck.
I got tired of trying to read up on controllers and had to do something else..
I set up some kind of test station for my batteries:
I used a 12v electric heater element as a load, and one multimeter to measure A and one for V on the cells.
I tested 2 leftover golf gte cells from the ktm build. One cell had 3,706V, the other 3,704V. On the pair I got 7,39V (I know it dosent add up perfectly) With 42A load, it dropped to 7,26V. So a drop of 0,13V/42A= 0,003 for the pair, 0,0015ohm or 1,5m ohm each.
Then I tested the older type of passat gte cells:
The cells measure 3,713/3,715V and 7,41V for the pair. Under 42A load they drop to 7,28V, so the same 0,13V as the golf, and the same 1,5m ohm
On to the newer passat gte cells:
Those measure 3,758/3,760V or 7,50V for the pair. Drops to 7,40V at 42A load, so a little under 0,0024/2=0,12.
So slightly under 1,2m ohm.
The conclusion is that I need a more accurate way of measuring, and more load would be good too.
But the results sure looks to be in favor of the newer passat cells.
Possibly just because they are newer, maybe 1 year old while the older passat and the golf cells are about 5 years.
And the capacity sure are in their favor too, I think they are 37Ah, older passat about 27Ah and golf 25Ah.
They are a little heavier though, a 12s mudule are about 12kg. The older module are about 11kg. But that is a small penalty for 10Ah more.
A downside is that I only have one of those modules
I got tired of trying to read up on controllers and had to do something else..
I set up some kind of test station for my batteries:
I used a 12v electric heater element as a load, and one multimeter to measure A and one for V on the cells.
I tested 2 leftover golf gte cells from the ktm build. One cell had 3,706V, the other 3,704V. On the pair I got 7,39V (I know it dosent add up perfectly) With 42A load, it dropped to 7,26V. So a drop of 0,13V/42A= 0,003 for the pair, 0,0015ohm or 1,5m ohm each.
Then I tested the older type of passat gte cells:
The cells measure 3,713/3,715V and 7,41V for the pair. Under 42A load they drop to 7,28V, so the same 0,13V as the golf, and the same 1,5m ohm
On to the newer passat gte cells:
Those measure 3,758/3,760V or 7,50V for the pair. Drops to 7,40V at 42A load, so a little under 0,0024/2=0,12.
So slightly under 1,2m ohm.
The conclusion is that I need a more accurate way of measuring, and more load would be good too.
But the results sure looks to be in favor of the newer passat cells.
Possibly just because they are newer, maybe 1 year old while the older passat and the golf cells are about 5 years.
And the capacity sure are in their favor too, I think they are 37Ah, older passat about 27Ah and golf 25Ah.
They are a little heavier though, a 12s mudule are about 12kg. The older module are about 11kg. But that is a small penalty for 10Ah more.
A downside is that I only have one of those modules
Very cool test, though 5C and 10C loads would be amazing.
I have nearly everything designed and thought of except for the batteries with my build. Too many things to consider and choose on, capacity, voltage drop under load, energy per mass & size.
My short list is down to Gen 4 Nissan Leaf cells, everything else is old technology which either is heavier or larger for the same energy potential & capacity though these new VW cells look tempting if there is anyway to reconfigure them.
12s 37AH at 12Kg isn't bad, especially since these were made for a hybrid so designed for high c values.
Apparently the Passat GTE has a 13kWh battery and can produce 160kW at the electric motor alone so there is more than 10c alone.
Do you have dimensions for them? If I could fit 4 of them for 24s 74AH that would be amazing.
I have nearly everything designed and thought of except for the batteries with my build. Too many things to consider and choose on, capacity, voltage drop under load, energy per mass & size.
My short list is down to Gen 4 Nissan Leaf cells, everything else is old technology which either is heavier or larger for the same energy potential & capacity though these new VW cells look tempting if there is anyway to reconfigure them.
12s 37AH at 12Kg isn't bad, especially since these were made for a hybrid so designed for high c values.
Apparently the Passat GTE has a 13kWh battery and can produce 160kW at the electric motor alone so there is more than 10c alone.
Do you have dimensions for them? If I could fit 4 of them for 24s 74AH that would be amazing.
j bjork
100 kW
The modules are about 355x150x110mm.
I would say it is difficult but not impossible to reconfigure them.
The terminals are welded, but I think there are enough material to cut the bus bars in the middle and drill holes for a screw connection. It looks like the bus bars are aluminum, but I am not sure.
The cages are also welded together, so it will be interesting to cut them open..
At first I wanted to be able to use 24s, to not have to mess with it. But it seems like I will be able to fit 30s..
But then there are the problem that I dont have 3 modules of any of them
Sure 10c load test would be good, but I think I would have to do it on the whole 12s module in that case.
The only place to get a good enough connection would be the end terminals where they are connected.
I dont think I have anything to use as a load for that.
I was thinking more like see if I can find one more of those heater elements, to get about 80A load.
And measure with an oscilloscope to get more exact readings.
I would say it is difficult but not impossible to reconfigure them.
The terminals are welded, but I think there are enough material to cut the bus bars in the middle and drill holes for a screw connection. It looks like the bus bars are aluminum, but I am not sure.
The cages are also welded together, so it will be interesting to cut them open..
At first I wanted to be able to use 24s, to not have to mess with it. But it seems like I will be able to fit 30s..
But then there are the problem that I dont have 3 modules of any of them
Sure 10c load test would be good, but I think I would have to do it on the whole 12s module in that case.
The only place to get a good enough connection would be the end terminals where they are connected.
I dont think I have anything to use as a load for that.
I was thinking more like see if I can find one more of those heater elements, to get about 80A load.
And measure with an oscilloscope to get more exact readings.
Oh wow, they're very large and don't seem to have that great of an energy capacity per volume but may have a really high power per volume & weight
If my maths is correct 1600Wh / 5.86L = 273Wh/L
and 1600Wh / 12Kg = 133Wh/Kg
I can barely fit 3 of them, 4 seems impossible so I may need to rule these out
A Leaf Gen 4 Module is about 1600Wh / 4.66L = 343Wh/L
and 1600Wh / 8.7Kg = 184Wh/Kg
while their raw cells are 460Wh/L and 224Wh/Kg
I'm also tempted by Turnigy High Capacity LiPo as this would be a "performance" vehicle and not a daily driver. 4s 20Ah and apparently 12C capable.
296Wh / 0.89L = 332Wh/L
296Wh / 1.8Kg = 164Wh/Kg
I guess price is a big factor as well.
A complete 2019 GTE pack is about £2k, so £500 for 24s 37Ah or £1000 for 24s 74Ah
Leaf Gen 4 2018 modules are about £200 each, so £700 for 28s 56Ah
Turnigy High Cap 4s 20Ah are £100 each, so £1200 for 24s 40Ah or £2100 for 28s 60Ah which actually fits in the space I have
All in all the 37Ah GTE modules seem to be the best choice when you factor in potential power output and cost, VW guarantees them for 12C while Nissan has only pushed their modules to 6C in their own vehicle.
I'm going to measure again and see if there is anyway at all to fit 4 of them.
Also going to research other vehicles that have battery packs designed to handle 10c+ or might buy 1 Gen 4 module and try to load test it, though Nissan uses it at only 6c it may be capable of more
If my maths is correct 1600Wh / 5.86L = 273Wh/L
and 1600Wh / 12Kg = 133Wh/Kg
I can barely fit 3 of them, 4 seems impossible so I may need to rule these out
A Leaf Gen 4 Module is about 1600Wh / 4.66L = 343Wh/L
and 1600Wh / 8.7Kg = 184Wh/Kg
while their raw cells are 460Wh/L and 224Wh/Kg
I'm also tempted by Turnigy High Capacity LiPo as this would be a "performance" vehicle and not a daily driver. 4s 20Ah and apparently 12C capable.
296Wh / 0.89L = 332Wh/L
296Wh / 1.8Kg = 164Wh/Kg
I guess price is a big factor as well.
A complete 2019 GTE pack is about £2k, so £500 for 24s 37Ah or £1000 for 24s 74Ah
Leaf Gen 4 2018 modules are about £200 each, so £700 for 28s 56Ah
Turnigy High Cap 4s 20Ah are £100 each, so £1200 for 24s 40Ah or £2100 for 28s 60Ah which actually fits in the space I have
All in all the 37Ah GTE modules seem to be the best choice when you factor in potential power output and cost, VW guarantees them for 12C while Nissan has only pushed their modules to 6C in their own vehicle.
I'm going to measure again and see if there is anyway at all to fit 4 of them.
Also going to research other vehicles that have battery packs designed to handle 10c+ or might buy 1 Gen 4 module and try to load test it, though Nissan uses it at only 6c it may be capable of more
j bjork
100 kW
The golf cells are about 27x149x92mm, I think the passat cells are the same size.
But the 92mm height is without connections so you will have to add at least 10mm.
When calculating volume I think those measurements are more accurate.
The leaf cells are so damn wide, I think I would only fit 2 of those modules.
Make sure that 2019 battery is the newer model. I am not sure but it seems like they came on 2020 years model, but probably in the later part of 2019. That prize sounds interesting, I have only seen at least double that here.(but there are not many of them) The older model seems like I can get for a little less than that, but there are a lot more of them.
I wonder what internal resistance there are in those lower c-rate lipos? I have looked a little at high c-rate lipos, but they are about
100 euro for 6s 5Ah. It gets expensive fast, 40 packs for 30s 40Ah about 4000 euro. 2 of those so I can change
But the 92mm height is without connections so you will have to add at least 10mm.
When calculating volume I think those measurements are more accurate.
The leaf cells are so damn wide, I think I would only fit 2 of those modules.
Make sure that 2019 battery is the newer model. I am not sure but it seems like they came on 2020 years model, but probably in the later part of 2019. That prize sounds interesting, I have only seen at least double that here.(but there are not many of them) The older model seems like I can get for a little less than that, but there are a lot more of them.
I wonder what internal resistance there are in those lower c-rate lipos? I have looked a little at high c-rate lipos, but they are about
100 euro for 6s 5Ah. It gets expensive fast, 40 packs for 30s 40Ah about 4000 euro. 2 of those so I can change
Yea, I tried to use overall module dimensions when calculating the energy per weight and size, others try to use the raw cells which will serve only inflated unrealistic numbers.
I'm gonna try to find the part number for the packs with the 37Ah cells as the car breakers tend to be unhelpful with this information.
£2000 isn't cheap by UK standards, all EV/Hybrid used packs carry about the same price per kWh which is roughly 100-150gbp per kWh depending on age and technology/chemistry.
Gen 4 Leaf is about £200-250 per module, so also follows the same rough price
£2000 for 13kWh is actually inline with other manufacturers (£154/kWh) such as BMW, Volvo, Nissan etc though seem to be used at the highest C
I'm gonna try to find the part number for the packs with the 37Ah cells as the car breakers tend to be unhelpful with this information.
£2000 isn't cheap by UK standards, all EV/Hybrid used packs carry about the same price per kWh which is roughly 100-150gbp per kWh depending on age and technology/chemistry.
Gen 4 Leaf is about £200-250 per module, so also follows the same rough price
£2000 for 13kWh is actually inline with other manufacturers (£154/kWh) such as BMW, Volvo, Nissan etc though seem to be used at the highest C
Just found this, deep testing of the Gen 4 Nissan Leaf cells.
https://ssj3gohan.tweakblogs.net/blog/18181/how-to-manage-a-battery
Interesting article with a lot of information which has only created more questions and things to think about than before, but it seems they also recommend the VW GTE cells.
https://ssj3gohan.tweakblogs.net/blog/18181/how-to-manage-a-battery
Interesting article with a lot of information which has only created more questions and things to think about than before, but it seems they also recommend the VW GTE cells.
larsb
1 MW
Read on facebook that apt96600 max batt A at 120V is around 160A, it’s derated from 250A at higher voltage. You better check this with QS for the APT96800 if you’re planning to go this route..
j bjork
100 kW
c70r, thanks for the link, it was interesting :thumb:
But I didnt see anything about vw in there?
(I mean you said the seem to recommend GTE cells)
larsb, Thanks. They hasent said anything about that, I will ask if I go that way.
At the moment I am mostly considering 2x votol em200 96V or 2x PV vesc based controller.
But I didnt see anything about vw in there?
(I mean you said the seem to recommend GTE cells)
larsb, Thanks. They hasent said anything about that, I will ask if I go that way.
At the moment I am mostly considering 2x votol em200 96V or 2x PV vesc based controller.
j bjork
100 kW
Finally some progress, I got a motor
Eh, not really.. But I have a model of a motor :lol:
Haggan90 made quick progress when I gave him the go.
Thanks a lot :thumb:
I was trying to get it done locally first, and wasted a lot of time.
Someone has a friend that can probably do it, it turns out they cant.
Someone else has a work colleague that turns out cant do it either and so on :?
In the end it was just weeks of wasted time.
Hmm, it is kind of big..
Eh, not really.. But I have a model of a motor :lol:
Haggan90 made quick progress when I gave him the go.
Thanks a lot :thumb:
I was trying to get it done locally first, and wasted a lot of time.
Someone has a friend that can probably do it, it turns out they cant.
Someone else has a work colleague that turns out cant do it either and so on :?
In the end it was just weeks of wasted time.
Hmm, it is kind of big..
SlowCo
1 MW
j bjork said:Finally some progress, I got a motor
Hmm, it is kind of big..
:lol:
But the real one will have lots of power 8)
j bjork
100 kW
c70r said:
Where did you see that? They havent said anything to me.
j bjork
100 kW
Haggan90 said:It's nice to get some use out of that big printer
I just loved the color of the middle section, black with sparkles of gold lol.
Yes, it looks really cool
It dosent really show in the picture though.
There are some gold sparkle in the blue sections too.
I'm back to "ordinary mans CAD"
A first model of how it could look.
It is so annoying though, I ordered some sprockets a long time ago that I still havent got.
I didnt think too much about that they came from England..
Somehow I got the idea that there was a free trading deal after brexit, but that is not the case apparently
The biggest sprocket I have now is 13T, but the plan is to use 17 or at least 16T.
So all I can do is calculate sizes, compare to sprockets I have and guess how much room I need.
A later model that probably looks more like the finished part.
I have been considering using a tensioner or not, and I think I will try to avoid it.
I worry that it will break when using hard regen on uneven surfaces and things like that.
Instead I will make the motor movable about 20mm back and forth.
The plan is a 30mm thick plate that is milled out where the chain and sprockets are.
You can see the lines on the model how it should look.
I plan to make the area a little bigger, so the chain will have some more room to move.
j bjork said:
Saw it in a Facebook group but can't find the post anymore, maybe they were mistaken.
By the way, have you ever tried separating the cells? I found some eGolf packs that have the 37Ah cells but their modules are either 4s3p or 2s3p so no use if the cells can't be separated.
Also the article recommended the GTE pack not individual cells somewhere in the comments because of the fact VW apparently temperature controls them while Nissan doesn't.
Can you IR test the cells at 25c temp+ or what temp was your previous test.
j bjork
100 kW
I havent separated these cells, but I did it on the golf gte modules I have on the ktm.
I think it will be easier to make a connection between the cells on these ones.
The bus bars are bigger, so I think it will work to cut them in the middle and drill holes in the parts that is left on the cell.
Then just screw on connections between cells or what you want to connect.
The cages are welded together though, so you will have to cut it very close to a cell.
I think that can be a little interesting :wink:
I am not sure how the e golf modules are built, but probably similar.
I guess it is rather new too, if it has the 37Ah cells?
My ir test was at about 19c, 18-20c
I think it will be easier to make a connection between the cells on these ones.
The bus bars are bigger, so I think it will work to cut them in the middle and drill holes in the parts that is left on the cell.
Then just screw on connections between cells or what you want to connect.
The cages are welded together though, so you will have to cut it very close to a cell.
I think that can be a little interesting :wink:
I am not sure how the e golf modules are built, but probably similar.
I guess it is rather new too, if it has the 37Ah cells?
My ir test was at about 19c, 18-20c
j bjork
100 kW
I realized that the cardboard wasent enough for my models. This will be a tight fit, so I have to get it very close to actual mounting positions.
I started working with 6mm wooden fiber board instead:
It is as I said, a tight fit:
I wonder how much room for movement that is needed for the chain on the backside of the sprocket?
It is pretty tight here too:
This is with 10/17 tooth primary gears, and 36 link chain.
With the same chain and 11/17 primary it will be about 3mm tighter.
I can go with a 38 link chain, but then it will be pretty tight in front of the motor..
But it also seems like the sprocket is about 3mm more to the front than it should be, so maybe it will be better than it looks at the moment :?
I started working with 6mm wooden fiber board instead:
It is as I said, a tight fit:
I wonder how much room for movement that is needed for the chain on the backside of the sprocket?
It is pretty tight here too:
This is with 10/17 tooth primary gears, and 36 link chain.
With the same chain and 11/17 primary it will be about 3mm tighter.
I can go with a 38 link chain, but then it will be pretty tight in front of the motor..
But it also seems like the sprocket is about 3mm more to the front than it should be, so maybe it will be better than it looks at the moment :?
Elektrosherpa
1 kW
- Joined
- Feb 7, 2021
- Messages
- 386
j bjork said:
I wonder how much room for movement that is needed for the chain on the backside of the sprocket?
From my experience of 45 years with motorbikes, I would say: this is TOO TIGHT.
In any case I would add a chain tensioner of whatever kind (something with a spring or an oil dampener) in this primary chain drive,
since a chain is permanently changing its length, due to wear, and forces transmitted.
And I think, a possibility for moving one of those two axles would be required, for adaption of the chain tension
(as it is usually realized in motorbikes' rear swing arm axle mounts).
thoroughbred
100 W
very nice work! You can get 1/2 links for the chain. I think this roller tensioner idea is interesting:
https://www.renold.com/products/accessories/roll-ring/
did you get good news about the motor being built and any progress on the controller/s?
https://www.renold.com/products/accessories/roll-ring/
did you get good news about the motor being built and any progress on the controller/s?
Great work with the wood fibre.
Glad you tried the single primary reduction and liked it, have you been able to maintain the original driven side sprocket position with the 17T sprocket on the reduction side or has it had to shift a little forward.
Also do you have a shaft yet for the reduction? I was going to use Honda sprockets from my bike but they have a weird 17 Tooth spine which I can't find any axle/shaft for off the shelf, would cost about £200 to make a custom one.
Glad you tried the single primary reduction and liked it, have you been able to maintain the original driven side sprocket position with the 17T sprocket on the reduction side or has it had to shift a little forward.
Also do you have a shaft yet for the reduction? I was going to use Honda sprockets from my bike but they have a weird 17 Tooth spine which I can't find any axle/shaft for off the shelf, would cost about £200 to make a custom one.
