Arttu Posted September 7, 2015 Share Posted September 7, 2015 Hi ArttuET crank so I guess that is small taper. Hi. That's what I was afraid of as I have heard earlier that some GSX-R flywheels fit on the small taper cranks. ET is that early GSX model with square headlight, right? Years '80-81 or something like that? I guess I will never learn those letter designations as they are less used around here Any way, large taper cranks appeared with "black engines" somewhere mid '82. Quote Link to comment
coombehouse Posted September 7, 2015 Share Posted September 7, 2015 As you say ET has the square headlight. I believe this & the katana motor & the EZ had 25mm dia with a 1:5 taper. The 83 on ESD with the half fairing & the 1150 motors had 29mm with a 1:7 taper. It is possible that the small taper could be machined to suit the bigger taper with a tapered reamer or maybe a very accurate machining centre. I will sketch it out tomorrow at work to see if there is enough material.Nick Quote Link to comment
Gammaboy Posted September 8, 2015 Share Posted September 8, 2015 (edited) This show size that Gsx gear has to be turned to. Does that Vernier say 39.99?Anyone remember off the top of their head the diameter of the small Katana flywheel?Oh, and what's the PCD on the 6 socket heads that bolt it to the sprag? Edited September 10, 2015 by Gammaboy more Quote Link to comment
Gammaboy Posted September 8, 2015 Share Posted September 8, 2015 Interesting to note that the later (2011ish on?) bikes did away with the button heads and went to a normal hex bolt. Quote Link to comment
Screwriverracing Posted September 8, 2015 Share Posted September 8, 2015 How about using the modded starter clutch then putting a outboard alternator on.there are some very small alternators with good output for reasonable money out there.Cheers SRR Quote Link to comment
coombehouse Posted September 8, 2015 Share Posted September 8, 2015 How about using the modded starter clutch then putting a outboard alternator on.there are some very small alternators with good output for reasonable money out there.Cheers SRRcan you point me in the direction of these small alternators. I have never managed to find any before other than Kubota stuff which were still quite large. Quote Link to comment
Gammaboy Posted September 10, 2015 Share Posted September 10, 2015 (edited) So, a quick rundown of dimensionsStandard ET rotorOD: 130mmID 105mmDepth (measured internally) 35mm.GSXR rotor:OD 118mmID 108mmDepth (measured internally) 27.5mmI suspect the backing plate on the GSXR rotor is thinner, not being rivitted together out of 2 pieces like the ET rotor...Katana/750 rotor (Rotors and stators are pretty easy - GN125 apparently!, cases to take the small stator are rare as hens)OD: 118mmID: 95mmDepth (internally) 35mm I wonder if the ET stator will work spaced inwards?All told, looks a lot easier than Arnouts epic of ungluing magnets, narrowing the housing, and machining things down to gain an extra 1/2"... Just ordered a 2011 750 rotor and sprag, will try it with a spaced GSX stator first.... Much easier than the 3XV TZR250 rotor i was contemplating (105mm OD, 92mm ID) Edited September 10, 2015 by Gammaboy Quote Link to comment
Gammaboy Posted September 10, 2015 Share Posted September 10, 2015 So, talking to a mate, he reckons the GSX starter gears are case hardened rather than through hardened, and we'll have to get the gear re-case-hardened/Nitrided to get the surface hardness back.@coombehouse Did it get easier to machine once you were in a mm or two? Quote Link to comment
Jonboy Posted September 10, 2015 Share Posted September 10, 2015 So, talking to a mate, he reckons the GSX starter gears are case hardened rather than through hardened, and we'll have to get the gear re-case-hardened/Nitrided to get the surface hardness back. Good point, also if you running a one way bearing then surely that would need to run on a ground surface as opposed to a turned finish? Quote Link to comment
Gammaboy Posted September 10, 2015 Share Posted September 10, 2015 It's no biggy really, an engine reconditioner who can grind cranks can do it and sort the nitriding, will investigate once mine shows up, have a spare starter gear to play with. Quote Link to comment
coombehouse Posted September 10, 2015 Share Posted September 10, 2015 Don't think the Gsx gear is case hardenedhardened. It was difficult to machine from start to finish with glowing red swarf.I doubt it is nitrided as this is applicable obly to certain types of steel. I would guess it is induction hardened maybe as the inside bore is hard too for the needle bearings. I will try it as is & if it is a problem i will consider the options, perhaps hard chroming?Regarding the surface finish grinding would be nice but I don't have a grinder. You can get a suitable finish by turning if you are careful. I will have mine finished in a day or so & I have done a few drawings too. Thinking maybe we ought to start a new thread to make it easier to find in the future. What so you reckon?Nick Quote Link to comment
coombehouse Posted September 10, 2015 Share Posted September 10, 2015 So, a quick rundown of dimensionsStandard ET rotorOD: 130mmID 105mmDepth (measured internally) 35mm.GSXR rotor:OD 118mmID 108mmDepth (measured internally) 27.5mmI suspect the backing plate on the GSXR rotor is thinner, not being rivitted together out of 2 pieces like the ET rotor...Katana/750 rotor (Rotors and stators are pretty easy - GN125 apparently!, cases to take the small stator are rare as hens)OD: 118mmID: 95mmDepth (internally) 35mm I wonder if the ET stator will work spaced inwards?All told, looks a lot easier than Arnouts epic of ungluing magnets, narrowing the housing, and machining things down to gain an extra 1/2"... Just ordered a 2011 750 rotor and sprag, will try it with a spaced GSX stator first.... Much easier than the 3XV TZR250 rotor i was contemplating (105mm OD, 92mm ID)where did you get the rotor from. I struggled to find one though i was conscious of the price. Regarding the stator I paid less than £30 for a new one. The Gsx stator is quite a bit thicker too which will mean it is no covered by the flywheel. Quote Link to comment
Gammaboy Posted September 10, 2015 Share Posted September 10, 2015 where did you get the rotor from. I struggled to find one though i was conscious of the price. Regarding the stator I paid less than £30 for a new one. The Gsx stator is quite a bit thicker too which will mean it is no covered by the flywheel.US Eblag - but because the Aussie dollar is bombing, it's costing me ~$180 AUD shipped... it's rotor, sprag and starter gear, so have the whole lot to play with, and being a 2011, it's got the later hex bolts (saw a 07 with mullered socket heads for double the price - muppets).I can get the same stator out of China shipped for just under $100AUD - but will see how the GSX unit goes first. Good to hear it's through hardened - and I was thinking about the sprag itself - the gear is running on the needles of the stock setup, and the starter rollers are out of contact care of centrifugal force - i imagine the GSXR sprag rollers pull up under centrifugal force too.Nitriding gives plenty of surface hardness and can be applied to pretty much any steel - it's likely to cause less distortion than case or through hardening which is why I mentioned it - the stock gear isn't nitrided because its not black. Quote Link to comment
coombehouse Posted September 10, 2015 Share Posted September 10, 2015 I don't have much experience of nitriding, all I can remember back in the day was that on A series Mini engines only high spec cranks could be nitrided. Maybe the normal cranks were just some sort of cast crap. I have done the drawings & will put them up before the weekend. What do you think about starting a new thread with all the information that is relevant posted at the beginning. We have after all highjacked someone else's post?Also you will need to make a replacement spacer from phosphor bronze to replace the thrust washer that sits against the crank behind the Gsx main starter gear. I have drawn this too.Nick Quote Link to comment
Gammaboy Posted September 10, 2015 Share Posted September 10, 2015 (edited) Yeah, you can't nitride cast iron, which is what stock A-series cranks are... Been messing with steel cranked motors for long enough that I'd forgotten that!Phosphor bronze spacer - I assume it's thicker than the stock unit?We have hijacked the thread a little, however, the answer to the OPs question does lie in here - small diameter Katana flywheel is the same as GN125... Edited September 10, 2015 by Gammaboy Quote Link to comment
coombehouse Posted September 11, 2015 Share Posted September 11, 2015 (edited) I have attached a PDF file of thethe schematic I have done of how all this goes together. Bear in mind that it is a representation of the assembly. The measurements are correct but the outside shape of the cover is not a true drawing, its just there to make it easier to understand. This sketch is correct for Gsx et models with small taper crank & large flywheel. For Katana models with smaller flywheel the 38,05mm recess in the spacer will be 35,05mm dia as the stator mount in the cover is 35mm. The hole pcd is probably smaller too so you may need to use 6 bolts, 3 of which will have to be countersunk to mount the spacer & 3 offset to mount the stator. Hope this makes sense. Kat gsxr rotor.pdf Edited September 11, 2015 by coombehouse Added text Quote Link to comment
coombehouse Posted September 11, 2015 Share Posted September 11, 2015 (edited) The same drawing as a .jpgFor the 29mm large taper motors there is enough material on the Gsxr flywheel to remachine it. How to do it is another question though. A 29mm 1:7 taper reamer would be perfect but expensive. Don't think it could be turned in a lathe accurately enough but maybe internal grinding would work. Maybe someone will suggest something if anyone fancies trying. Failing that you could always regrind the crank but that is a bit drastic. Will post some more info tomorrow.Nick Edited September 12, 2015 by coombehouse Quote Link to comment
coombehouse Posted September 12, 2015 Share Posted September 12, 2015 All the necessary bits ready to fit.Gsx starter gear diameter machined to 39.60mm diameter, spacer for stator & bronze thrust washer. Quote Link to comment
Duckndive Posted September 13, 2015 Share Posted September 13, 2015 All the necessary bits ready to fit.Gsx starter gear diameter machined to 39.60mm diameter, spacer for stator & bronze thrust washer. All Good stuff but what is the PCD of the 6 bolts in the GSXR starter clutch / rotor ? Quote Link to comment
Jonboy Posted September 15, 2015 Share Posted September 15, 2015 liking what your doing, just a thought, what is the likely effect of having a lighter flywheel assembly? will there be less inertial force on the crank as it spins up perhaps allowing it to rev a little quicker? and if that is the case will there be a reduction in torque ( probably negligible ) due to less rotating mass?All of these things may be irrelevant if the end result gives a more robust and more powerful ac alternator. Jonboy Quote Link to comment
coombehouse Posted September 16, 2015 Share Posted September 16, 2015 All Good stuff but what is the PCD of the 6 bolts in the GSXR starter clutch / rotor ? PCD of bolts in starter clutch is 72mm 1 Quote Link to comment
coombehouse Posted September 16, 2015 Share Posted September 16, 2015 liking what your doing, just a thought, what is the likely effect of having a lighter flywheel assembly? will there be less inertial force on the crank as it spins up perhaps allowing it to rev a little quicker? and if that is the case will there be a reduction in torque ( probably negligible ) due to less rotating mass?All of these things may be irrelevant if the end result gives a more robust and more powerful ac alternator. JonboyMy initial objective was to get a more reliable starter clutch. The bonus is the lighter flywheel & hopefully the improved electrical output. The weight difference should hopefully make the revs rise quicker & give the small taper crank an easier time as they are prone to breaking. It may affect the torque but that is something I have plenty of.Weight of Gsx large rotor assembly = 2.6kgWeight of Gsxr rotor ready to fit to Gsx = 1.2kg.Weights are approximate as I only have a kitchen scale but a 50% reduction in this area is pretty big. 3 Quote Link to comment
Gammaboy Posted September 16, 2015 Share Posted September 16, 2015 That's an excellent improvement! 1 Quote Link to comment
Screwriverracing Posted September 17, 2015 Share Posted September 17, 2015 When are you going into manufacturing them, could probably sell quite a few.lovely work.cheers SRR Quote Link to comment
Gammaboy Posted September 23, 2015 Share Posted September 23, 2015 Just got my Rotor out of the US - will see how things go - need to buy some more rigid tooling for the lathe. Quote Link to comment
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