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denisesewa

Super Mini Sized Trials Bike Build

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Nicely done.  I am fiddling with a build using a Suzuki TC100 as the base bike. Did you lengthen the swing arm? Looking forward to more reports.

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Nicely done.  I am fiddling with a build using a Suzuki TC100 as the base bike. Did you lengthen the swing arm? Looking forward to more reports.

 

 the swingarm is a stock gas gas swingarm , I plan on shortening it 1 inch since its designed for an 18 inch wheel and I am using a 17 inch wheel.

 The spokes showed up today so I laced up the 17 inch rim and mounted the tire, tomorrow I'll get the front wheel, brake and tire finished up.

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Personally I would lace in a 21" front & 18" rear as that is what the bike was designed around originally & the tyres are much better.

The tyres fitted to the small wheel bikes don't grip very well, they're more like hard plastic than the flexible rubber of the full sized bikes 

 

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Personally I would lace in a 21" front and 18" rear as that is what the bike was designed around originally and the tyres are much better.

The tyres fitted to the small wheel bikes don't grip very well, they're more like hard plastic than the flexible rubber of the full sized bikes 

 These Vee-rubber tires ( same tires that come on the Gas Gas 80 ) actually seem decent, pretty soft unlike some of the "trials pattern" hard rubber tires you mention, I'm sure they are not as good as the Name brand trials tires but they will do for my purposes.

 

Been working on shaping the rear fender from pink insulation foam , layed up the glass and now have a mold , I did cut up the subframe ( it was bent anyway) and shaped the fender for a bit more modern look.

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I've spent the past week or so working on fabricating the carbon fiber parts, the construction is finished ( except for the airbox and side plates which I'm still working on) , the final finish of all the parts will come after the rest of the bike is done , I also cut up and redesigned the exhaust and added a shortened FMF silencer from a KTM ( sounds great!, nice and quiet too ). Got the hydraulic clutch sorted out and it works awesome, easy one finger and predictable actuation .  found a piece of really tough aluminum for the skid plate compliments of the scrap pile at a decommissioned military base, not sure what the alloy is but it was hell to bend it into shape , took 2 people, 2 trucks and a railroad tie to get it done. 

 So today I strapped a lawn mower fuel tank to the handlebars ( going to wait till the carbon tank is completely cured) and fired it up for the first time, rode it around the yard a bit but since nothing is completely welded on the frame I just poked around slowly, the motor feels really good with the bigbore kit , I opted for a mikuni VM 24 for the carb and throttle response is excellent ( unlike the stock TTR) I think I'll need to gear it down some more, presently running 12-54 and can go to 12-60 but thats about the max unless I get a custom rear sprocket. geometry feels good ,   Still a hell of lot to work out and fabricate but I'm pretty stoked :)

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Looking very good, I love the skid plate that is brilliant!

What did you use for the carbon parts? Pre-preg, wet lay-up, RIM and what resin? Are you planning on lining it with an ethanol proof coating? 

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Looking very good, I love the skid plate that is brilliant!

What did you use for the carbon parts? Pre-preg, wet lay-up, RIM and what resin? Are you planning on lining it with an ethanol proof coating? 

 

 I have alot of various types of carbon cloth left over from building Kiteboard hydrofoils and did hand layup for these parts since vacuum bagging these shapes would be complicated ( RIM would be even more complicated and I've not studied the process). the Epoxy resin I use is from "US Composites" and has served me well, it is also alot cheaper than "Resin Research" which would be my preferred epoxy otherwise, the only down side to US comp's epoxy is that it does not have UV inhibitors in it so will require painting, thats OK with me since natural carbon would really heat the fuel in the sun. Once its Post cured it should be resistant to ethanol but I am going to use " Red Kote" tank liner to be on the safe side, I've had good luck with that product in the past and have some on hand.

 Yesterday I finished the airbox construction , have to add a couple mounting lugs then it will be ready for sanding and finish.

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Showing some great skills there ! Old government street signs ... Contractors overspending our tax dollars ... Decades ago I built a 2wd toyota pickup for desert use ,(long before "pre-runners" were cool :) ) And one evening out in the desert in the coachella valley we came across a big old Desert stop sign on a bent pole ...(6 foot octagon type ) and I thought HHMMMNNN.... skid plate ! It was 1/4 inch thick with 6061 painted in bands across the backside ... With the help of a large hydraulic sheet metal brake and some tall jackstands under a hoist ,  I ended up with a skid plate that went from the bottom leading edge of the frame back to the tailshaft and was bowed down on the sides a bit so the lower control arms just cleared it when topped out ...worked a treat !

Glenn

 

  (and I never did get all of the red & white STOP off the metal , but it was on the topside so you never saw it unless you looked under the hood past the engine :))

  OOPPS ! just re read this ! 1/8 thick not 1/4 !!!!

Edited by axulsuv
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The underplate needs to be strong enough, not only for hitting purposes, but its also a part of the frame preventing the frame bends (too much).

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The underplate needs to be strong enough, not only for hitting purposes, but its also a part of the frame preventing the frame bends (too much).

 

 I think its strong enough but I'll give some thought to adding " wings" to the sides to stiffen it even more. the TTR 125 frame is prone to bending for that same reason ( Plastic skid plate and no cradle).

 On another note, I picked up a set of 40mm Zokes from a 2006 TXT, should be much better than the Paoli USD forks and lighter too , back to machining spacers , adapters etc., also laced up an aluminum rim to replace the steel rim for the front. 

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The finish on the parts looks very good considering how complex some of them are. I’ve not really ventured into tanks too much as we seem to have a much more limited selection of sealants this side of the pond. 

If you can vacuum bag then you can do RIM. There are minor changes to the bagging process, a couple of extra bits are required and the resin is slightly different, thinner and longer pot life. Having said that personally for small volume parts I don't think it's worth bothering with it and it doesn't work so well with complex shapes. 

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Wow great build. Build yourself silicon molds for those other Tricky consumables.

--Biff

 Well, I have the fiberglass molds I made initially so I'm covered if I break the fenders , the rest are pretty much repairable.

 

 Been working on adapting the TXT forks which turned in to more of a job than expected since I machined the frame's steering bearing pockets to accept larger OD bearings for the Beta forks, ended up having to press out the stems and swap the Beta stem into the TXT lower clamps, also had to start over with all the bushing and spacers for the front axle but what a difference these forks are over the Paoli USD forks , super rigid, Plush with no stiction  and the length is perfect, besides the bike really looks better in my eye with these forks. Also made a new temporary fuel tank , might even come in handy for future trail rides as spare fuel.  I had the swingarm axle slots extended forward 1 inch to bring the wheelbase to 51", changed the gearing to 11-60 which made a good difference and feels about right  but after riding a bit today I think I'll put the heavier flywheel back on(18oz heavier than this lightened flywheel) .

Made a carbon front fender mount and alum fork brace , kinda strange looking as it is 2 tiered but I think I like it and the added stiffness with the brace is substantial, laced up the aluminum front rim and mounted the trials tire , reworked the rear brake pedal to achieve a longer stroke with the kicker along with a bunch of other minor detail stuff.

 So its looking and riding like a trials bike now, ( at least to me) and I am close to the point of tearing it down, finish the welding and working on cosmetic stuff, sand blasting , sanding and painting as well as finish work on all the carbon parts, still havnt decided on a paint scheme, winter weather will determine when all that gets done.

 Pretty pleased so far :)

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Edited by denisesewa
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BTW, a quick check on a bathroom scale shows the bike to weigh 161 lbs ( 73 kg ) with oil but no fuel , weight bias is 76 lbs front and 85lbs rear ,with a tank of fuel ( 1 gallon) bias should be closer to 50 - 50 , anyone know what the weight bias percentage should be? Not really much I can do about it but I'd like to know anyway.

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