Honda MT50/H100 project

[Fladdem]

I posted this in offroad and supermoto then thought that here was probably a better place for advice on this sort of thing.
Hello all, I'm currently ruining a Honda MT50, I have the engine, exhaust, carb, air filter but I still need the CDI for the H100 engine. I also have upgraded shocks on the back and a jack-up kit, I also have some MTX125 forks and drum braked wheel to go on the front. I'll be giving it a new paint job as well eventually. I would like to get a h100 wheel for the back too, as it is 18 inch rim compared to the 50's 16 inch, it will fit as the MB50 shares the same swinging arm which has an 18 inch rim. My question is just wondering what the H100 spindle diameter is? I was just wondering if the spindle will fit in the swinging arm without any hassle. Another problem is the MT5 expansion chamber is rusted to the engine and the exhaust studs are rusted up, its just a block of rust down there, I need to remove the exhaust before I can drop the engine out and I want to keep it undamaged as I want to keep all the original parts with the bike if I need to go back for some reason, How will I get the exhaust off? Another thing is; the back-end will be three inches taller than standard with the new wheel as well as the suspension but the forks are 6 inches longer so the front end will be 7 inches taller with the wheel as well, I am aware this will make turning awful, will dropping as much fork through the yokes as possible help to counter-act this a bit?
Any advice on any of these things will be much appreciated,
Adam
P.S. This has been planned for two years, I know it would have been easier and cheaper to have bought an MTX80, same size and the same power as mine will be when it’s done, but I want to do this, so please no “Buy another bike” like I always get when asking for help.
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Current:1991 Honda MT50 (Soon to be a H100/MTX/MT5 hybrid), 1976 Honda Cub C70, 2005 Honda Varadero 125, 1993 Yamaha TTR250 Open Enduro , 2010 Road Legal Stomp YX140, 1994 Honda CRM 250 MK III, 1999 Cagiva Mito 125, 1992 Honda CB400 Super Four, Stomp T4 230, 1984 Honda H100s, 2009 Sym XS125K
Past:2003 Aprilia RS125, 1982 Kawasaki GPZ550(FREE BIKE!)
I'm having more fun than a well-oiled midget.

[hmmmnz]

shouldnt make too much difference to the handling, it'll be different to the h100 but you'll get that when you ride any dirt oriented bike

as for the spindle size wemoto says the rear bearings are 12x37x12mm
so a 12mm spindle and also the mb/mt50 has the same size bearing so that should pose you no problems,

exhaust, i might be easiest just to buy a nut cracker and break the nut off the post so you can slide the exhaust off, rather than risk breaking the post it self,
once the exhaust is off you can make an informed decision on whether to replace the posts, or just clean up the thread of the original posts

make sure you do a build thread in the show and tell section
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the humans are dead
I kick arse for the lord
Wiring Diagrams BIDNIP it bitches

[truslack]

H100A had a 12mm spindle, H100 SD/SJ2 has a 14mm spindle (although parts websites will quote SD/SJ rear wheel bearings as taking a 12mm spindle- they are wrong)

You'd probably be best with an SJ wheel (or CG125 - it's the same part) and either using different bearings, or drilling out the swing arm - H100A sprocket carriers are a right pain in the arse.
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Current: Suzuki RG 125 Gamma, Honda H100, Triumph Tiger 800XC, Suzuki SV650 (minitwin)

[Fladdem]

Thanks for getting back to me. Are you saying that I could probably use an SJ wheel with a 12mm spindle so long as the bearings fit around? I suppose I could just get a wheel, try it and if it doesn't work sell it on again or have a play on the swing arm.
With the exhaust studs I have new ones anyway, so I just need to get the old studs out then swap engines round which is puzzling me, when I get a chance I'll take some pictures of the studs to show you. I'm in no rush to do the build, I was thinking of just putting the engine in first before playing about with wheels and suspension and bodywork and what not.

I'm still planning but once I'm ready to go, with all the bits, probably in the summer, I'll start up a build thread.
____________________
Current:1991 Honda MT50 (Soon to be a H100/MTX/MT5 hybrid), 1976 Honda Cub C70, 2005 Honda Varadero 125, 1993 Yamaha TTR250 Open Enduro , 2010 Road Legal Stomp YX140, 1994 Honda CRM 250 MK III, 1999 Cagiva Mito 125, 1992 Honda CB400 Super Four, Stomp T4 230, 1984 Honda H100s, 2009 Sym XS125K
Past:2003 Aprilia RS125, 1982 Kawasaki GPZ550(FREE BIKE!)
I'm having more fun than a well-oiled midget.

[truslack]

SJ wheel,wheel bearings from an H100a, spindle from the MT50 should all work, spacers I'm not sure on - I'm making a set of H100A spacers on the lathe this week sometime for one of mine.


can you tell me the width of the MT50 swingarm at the spindle end? Saves me measuring one tomorrow to check what spacers you'll need.
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Current: Suzuki RG 125 Gamma, Honda H100, Triumph Tiger 800XC, Suzuki SV650 (minitwin)

[Fladdem]

I make it 200mm, but it's not very accurate as the wheel is still on, I'm not gonna start taking it apart tonight.

I reckon that seems like a good idea, I'll begin the hunt for parts right away.
____________________
Current:1991 Honda MT50 (Soon to be a H100/MTX/MT5 hybrid), 1976 Honda Cub C70, 2005 Honda Varadero 125, 1993 Yamaha TTR250 Open Enduro , 2010 Road Legal Stomp YX140, 1994 Honda CRM 250 MK III, 1999 Cagiva Mito 125, 1992 Honda CB400 Super Four, Stomp T4 230, 1984 Honda H100s, 2009 Sym XS125K
Past:2003 Aprilia RS125, 1982 Kawasaki GPZ550(FREE BIKE!)
I'm having more fun than a well-oiled midget.

[truslack]

Not the best condition, but here's an SJ wheel for sale https://www.ebay.co.uk/itm/1990-Honda-H100-S-J-Rear-Wheels-/170979152955?pt=UK_Motorcycle_Parts_13&hash=item27cf26d43b

I'll check bearing sizes later on if I get chance.
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Current: Suzuki RG 125 Gamma, Honda H100, Triumph Tiger 800XC, Suzuki SV650 (minitwin)

[Fladdem]

I've been eyeing up that wheel for a while now, when I first decided to get a bigger wheel on the back of the slow-ped.
I would have used an MB5 wheel but it isn't spoked like the h100 wheel.
Thanks.
____________________
Current:1991 Honda MT50 (Soon to be a H100/MTX/MT5 hybrid), 1976 Honda Cub C70, 2005 Honda Varadero 125, 1993 Yamaha TTR250 Open Enduro , 2010 Road Legal Stomp YX140, 1994 Honda CRM 250 MK III, 1999 Cagiva Mito 125, 1992 Honda CB400 Super Four, Stomp T4 230, 1984 Honda H100s, 2009 Sym XS125K
Past:2003 Aprilia RS125, 1982 Kawasaki GPZ550(FREE BIKE!)
I'm having more fun than a well-oiled midget.