Thumper Club Forum
Technical => Project Progress => Topic started by: JOOLZ on September 16, 2015, 11:16:59 AM
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I finally managed to get hold of one of those small superchargers, the Aisin AMR500, off of a 650cc Japanese micro car, this will be my winter project.
I will have to make up a side plate with an oil seal for the crankshaft, the engine pulley and a mounting plate and covers and also work out what carb I will use and how to modify the jetting for use with the supercharger.
I have the original XBR cdi with 20' advance so that should be fine, but I will have to machine the piston crown to lower the compression.
This winter should be busy, Im hoping for a few more fine days for riding between then and now though
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Make sure the oil feed is a good one.
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hi joolz busy winter ahead eh, you could probably use extra base gaskets to lower the compression tommy
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Hi Tommy I thought about base gaskets, but it would be very thick to get it from 10.75:1 down to 8:1
The supercharger has its own on board oil supply just needs topping up every now and then
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Looking forward to seeing this one.
Tommy, regarding adding base gaskets, how would this affect camchain tension and valve timing?
Joolz, are you planning on putting the blower upstream or downstream of the carb? What carb are you going for?
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You could probably get someone to laser cut a thick base shim using the gasket as a pattern. Just adding gaskets will only make a minimal difference.
By my calculations* a 1mm shim would increase the c/c volume by around 6.6cc. A c/r of 10.75:1 on 498 cc indicates a c/c volume of around 50cc. To get 8:1 you need a c/c volume of 70 cc-ish so a shim of 2 mm +.
*which of course could be wildly off..........
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The capacity of the engine is 601cc I think it will need a 4mm spacer to reduce compression, the carb will be fitted before the supercharger so that mixture is going through it, more efficient that way, but the plenum will have to be fitted with a spring loaded blast plate to relieve any backfire.
I will have to slot the sprocket further as the cam timing will be way out
Carb options are stick with the Amal I have now and modify it to cope they have the parts available so easy to do but the carb would be a bit undersized
Switch over to an SU 1 3/4inch they have been used many times with superchargers, a mikuni carb off a Harley could get a 44 or even a 48, or a real oddball idea is a 50mm Lectron but that would be very tricky with the jetting, and I cant think of anyone else who has tried the Lectron with a supercharger
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I rebuilt and painted the supercharger to match the bike :) The XBR comes off the road at the end of the month then the serious work gets going
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Best of luck joolz with the "new" project I will defo be reading this thread with a keen interest. Like I say good luck. Cheers Michael
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Yep, me too :)
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Best of luck joolz with the "new" project I will defo be reading this thread with a keen interest. Like I say good luck. Cheers Michael
+1
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I have made start on the project now, found a space to put the supercharger, but its an extremely tight fit, nothing lines up properly so lots of headaches on driving the thing, I think my brain will explode with all the variables involved, but I am getting there slowly
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Keep at it joolz, I,m sure you,ll get there in the end. Plus the end result should be brilliant. Please keep us posted on any developments. Cheers. Michael
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You thinking of putting an outrigger bearing at the crankshaft end? To help take the over hung load of the belt? I assume you're using a belt?
You keeping the starter motor? Where's the blower going? Or you keeping it a secret till it's finished? ;)
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The supercharger has to sit on top of the oil tank, I got rid of he starter motor a few years ago so that is not an issue. I wont be having an outrigger bearing on the end of the crank, I am trying to see if I can fit a pulley to the back of the alternator rotor, that means removing the flywheel from the back of it to give me clearance, if I cant I may remove the crank end alternator altogether and fit a small alternator behind the cylinder.
I cant get a straight run from the crankshaft to the supercharger as the frame is in the way so I might have to make a second pulley to move the the drive further inboard through 2 shorter belts.
Its all very easy and straight forward in my head, its just the implementation thats the problem, and it has to be done with what I can make at home and what is easily and cheaply obtained off the shelf and adapted
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Thank goodness somebody knows what they're doing :o
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The supercharger has to sit on top of the oil tank, I got rid of he starter motor a few years ago so that is not an issue. I wont be having an outrigger bearing on the end of the crank, I am trying to see if I can fit a pulley to the back of the alternator rotor, that means removing the flywheel from the back of it to give me clearance, if I cant I may remove the crank end alternator altogether and fit a small alternator behind the cylinder.
I cant get a straight run from the crankshaft to the supercharger as the frame is in the way so I might have to make a second pulley to move the the drive further inboard through 2 shorter belts.
Its all very easy and straight forward in my head, its just the implementation thats the problem, and it has to be done with what I can make at home and what is easily and cheaply obtained off the shelf and adapted
I see the dilemma! A nice, juicy problem. I'm sure you'll overcome it and I look forward to seeing the result.
Edit: if you could just sneak a narrow as possible belt past the frame rail, would you be able to get your lower leg into position? Larger pulleys=narrower belts (and lower overhung loads). Would moving the pegs back to a more rear set style help? Larger pulleys=higher belt speed! A dilemma.
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....... I may remove the crank end alternator altogether and fit a small alternator behind the cylinder.
I cant get a straight run from the crankshaft to the supercharger as the frame is in the way so I might have to make a second pulley to move the the drive further inboard through 2 shorter belts.
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Using the alternator as the mounting for the intermediate pulley? Could work, with a stub shaft and outrigger maybe.
Although this setup increases side load onto the crank, as the first belt has to handle the torque of the alternator and blower combined.
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Really enjoying this thread, it,s good to see someone having a go at something different. (Yes I know supercharging is,nt a new concept but you all know what I mean) me n big bro have talked about supercharging something for quite a while now but still have,nt "got round to it" maybe joolz,s project might just give us the kick up the a....e we need, got a gs500 on the bench at the moment maybe that,d be a good starting point??? You up for the challenge Andy ??
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Really enjoying this thread, it,s good to see someone having a go at something different.
......got a gs500 on the bench at the moment maybe that,d be a good starting point??? You up for the challenge Andy ??
Are you mad! Think of the hassle mounting it, coming up with a decent drive arrangement, to say nothing of fuelling it properly. Given our lack of experience with supercharging (zero!) we'd have to be wrong in our heads to attempt it.
Count me in! ;D
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Could you lock the starter clutch and then run a shaft out in place of the starter and then take a belt up to the supercharger from there?
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I thought about running from the starter clutch but realized the shaft would spin far too quickly and there would be problems gearing it back down again
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Joolz, you keep on thinking outside the box mate. I've just logged on in what seems ages and looked for an interesting post and you've certainty hit the mark. A thought came to mind but I wasn't sure wether to voice it and show my ignorance. Do you think it would be possible to make a bracket to fit the starter motor hole and incorporate a shaft and bearings,seal to drive it off the starter gear, with the other end with a serpentine belt to drive the blower?
Providing the blower is mounted separately with a sprung tensioner, It wont need to much horses to drive it and the response would have minimal delay. Bit of machining involved but I had thought of how it could be done and gave up...
Stu
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About to cut out the oil seal bearing carrier
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That looks just like the plate I had on my racer with the Piranha ignition.
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Sounds interesting have you got a pic of the piranha set up
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Almost finished this part
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It all seems to fit ok, now I have to work out how to take a supercharger drive off of it or do I relocate the alternator
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Looking forwards to the next stage.
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A little bit more progress with the supercharger, XR cover fitted to the XBR engine, crank pulley positioned, and the top mounts done, This part of the project has been the most complicated so Im doing it in 2 parts, this year Im making and measuring things, next year will be engine modifications and fitting it
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Couple more pics
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"Blimey Charlie!" Great to see some proper engineering going on, instead of my usual bodges and lash ups :-\
Would love to get a proper look at the bike in the flesh sometime.
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Afternoon Joolz.....was just wondering how the supercharge build was going?? Been following it with a lot of interest (as I'm sure a lot have) you any closer to getting it out on the road yet??
Cheers..Michael
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Hi, I ran out of time and money this year its a huge job, I got the supercharger fitted and worked out how to drive it, made various brackets and an outrigger bearing fitted in an xr alternator case. I want to get the crank extension made this summer and the 3 pulleys that I need. I then have to make a new flywheel and find a small external alternator. next winter it will be simply a case of bolting on the crankshaft extension fitting the flywheel fitting the pulleys and lowering the compression and changing the cam
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Ah...so still a way to go but sounds like you've got all the bases pretty much covered, get out and enjoy a ride in the sun while it's here I say. Best o luck with the rest of the build during the autumn/winter months and defo keep us all posted...cheers...Michael
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Looking forward to the summer rides, bikes looking clean and shiney and we have plenty of places to visit. Hope everyone has a great summer
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Looking forward to the summer rides, bikes looking clean and shiney and we have plenty of places to visit. Hope everyone has a great summer
Will you be coming up to the Thumper Club Annual rally at Llanfairfechan so we can all have a look see?
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I would love to come up, unfortunatly Suzanne has a serious illness and cant travel far from home so we only do local events
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Started work on the flywheel