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Scorpa Sy250f As A Trail Bike


grinch
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Hi all,

First post, looking for some detailed info. First, some background. I'm a metal fabricator and have built several custom cycles for my wife for Off Road/ Enduro/ Hare Scramble use. She's 5'2" tall and very skilled but she has trouble touching the ground in some of our extremely technical terrain, especially when the turns are VERY sharp combined with slow speeds.

So, my newest brainchild is to (finally) start with a good trials bike, such as a SY250F and make it trail worthy. My plan is to morph a subframe and seat from a KTM or other brand and make the bike look and feel more like a Medium bike rather than a mini or standard sized bike. Again, the fabrication is not an issue and I may even have to build a gas tank and yes, I've done everything know to man to lower her KTM 125 SX. Without literally building a new frame from scratch (something I've considered) the nike now sits with only 10" of clearance and almost no suspension left.

Now, on to the technical questions- SY250 - too hard to kick start for a 120 pound women in difficult terrain?

SY250 - transmission rebuilt for offroad applications?

SY250F - same motor as WR250 with electric start and standard transmission?

SY125F - is this just a TTR motor?

I really want to thank everyone in advance.

-tom

Whoracing.com

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Could she not simply use a TTR125 big wheel, with electric start they are an ideal smaller persons trail bike?

With the right gearing they will do 70mph on the road and the little Yamaha engine plods really well in the tight stuff.

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So, my newest brainchild is to (finally) start with a good trials bike, such as a SY250F and make it trail worthy. My plan is to morph a subframe and seat from a KTM or other brand and make the bike look and feel more like a Medium bike rather than a mini or standard sized bike.

scorpa have already made one, its called the T ride. check the link

http://www.scorpa.fr/fiche_moto.php?moto_id=12

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Been there... New England eats TTR's up in a few weeks and they weigh a ton. So, I bought a new YZ85 and put the TTR motor in it. It's pretty gutless.

P1010005.jpg

So, I bought a BBR Bigwheel and put a CRF250 motor in it,

P1010215.jpg

P1010219.jpg

Realizing small wheels aren't well suited for upper level New England racing and riding, I starting working on a 2008 KTM125SX. The best yet, super light, etc but it had to be lowered so much there's no ground clearance or suspension travel left and the wheelbase makes narrow trails and slow speed turns impossible.

P2080037.jpg

Manipulating a trials bike into a trail bike will be the easiest fab job yet.

-tom

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The T-ride is EXACTLY the right size for what I want; 34" seat, 13"+ ground cearance, 55" wheelbase... When you get them over there, let me know and I'll book my flight!!! It'll save me a lot of effort...

Now, back to the motor questions!!!

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Here's a picture of the three 250 Yamaha engines side by side.

Scorpa-YamahaEngines.jpg

Here's a close up of a SY125 engine, it's a carbon copy on the outside of the TTR125 but without the starter motor.

100_0694.jpg

There are big bore versions, but I don't know if that would make a huge difference for the type of going you are thinking of.

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Thank you for taking the time to get those pics. I'd have to say without closer inspection the WR250 is the source of the SY250F motor. Might be easy to do the swap. As far as the 125 goes, the 200 would be a waste since I would be building an electric start vesion anyway and I'd source the BBR parts to make it happen.

Man, I have a lot of research to do...

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I looked at fitting a starter motor to a SY125 trials bike for my other half, but mounting the battery and the cost of the parts made it an expensive exercise. She only wanted a trail bike, so the TTR is pefect now that it's road registered.

I would say that the WR is definately the basis for the SY250F and the T ride motors. I was really hoping the original delivery date of July this year was going to happen. I think the T ride will be a brilliant Long DIstance Trials bike nad LDT's are becoming much more popular now.

I rode a Gas Gas Pamepra in LDT's for a few years and they are fabulous for those kind of events, but I should think they wouldn't last long if used for enduros.

Let us know how you get on and good luck.

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Thank you for taking the time to get those pics. I'd have to say without closer inspection the WR250 is the source of the SY250F motor. Might be easy to do the swap. As far as the 125 goes, the 200 would be a waste since I would be building an electric start vesion anyway and I'd source the BBR parts to make it happen.

Man, I have a lot of research to do...

I've never ridden an SY250f or a WR250, however, the gearing is probably going to be a major problem. Traditional trials gearing puts the first 3 gears close togather and 1st gear is pretty low, 4th gear is a large leap from 3rd and 5th is like a normal wide ratio from 4th. The cam profiles are way different, the Sy is going to have little or no overlap for max low end. The carb is also completely different one of the main differences is that a trials motor uses a small throat bore to keep air flow velocity high at low rpm. A WR/YZ motor is a screamer with a rev limit at around 13K an SY is probably going to give out about halfway there due to cam profile and carb flow limits. You might be better off buying 2 bikes and swapping motors. Like I said before I really don't know the specifics of either machine just generalities. Of course you may have known all this already.

Neil

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I appreciate all of the input and don't assume I know anything!! One scenario that is coming to mind as realistic is simply buying a nice, clean and popular 2t trials bike (so that the spare parts have good value) and swap in a KTM 125 or 200 motor, carb, seat, subframe, etc. Since I have both bikes currently and the KTM's wouldn't actually suffer any fabrication damage (cutting, welding, etc) it would be a fairly easy experiment. If it works, I'd have a nice 2t trials motor and rear section for sale, both of which should be fairly easy to sell for a fair price.

Keep 'em coming, I love the info.

-tom

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I appreciate all of the input and don't assume I know anything!! One scenario that is coming to mind as realistic is simply buying a nice, clean and popular 2t trials bike (so that the spare parts have good value) and swap in a KTM 125 or 200 motor, carb, seat, subframe, etc. Since I have both bikes currently and the KTM's wouldn't actually suffer any fabrication damage (cutting, welding, etc) it would be a fairly easy experiment. If it works, I'd have a nice 2t trials motor and rear section for sale, both of which should be fairly easy to sell for a fair price.

Keep 'em coming, I love the info.

-tom

I would not go to any of that effort, until you tried a Scorpa SY175F. Yest it is the TTR 125 engine, but punched to 143cc. Not a fire breathing monster, but far from gutless. All the characteristics of a trials bike, but you can add the seat kit, which is still close enough to the ground for her. If you wanted to go all out, the new SY200F is punched to 163cc, but they are new for this year, and you probably wouldn't find a used one. The engine already has all the mounts for an electric start, if you find she can't kick it over. But, I can't imagine she would have a problem, since the kickstart level is longer than a normal trials bike, and it is low enough to the ground that she could get some leverage.

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I would not go to any of that effort, until you tried a Scorpa SY175F. Yest it is the TTR 125 engine, but punched to 143cc. Not a fire breathing monster, but far from gutless. All the characteristics of a trials bike, but you can add the seat kit, which is still close enough to the ground for her. If you wanted to go all out, the new SY200F is punched to 163cc, but they are new for this year, and you probably wouldn't find a used one. The engine already has all the mounts for an electric start, if you find she can't kick it over. But, I can't imagine she would have a problem, since the kickstart level is longer than a normal trials bike, and it is low enough to the ground that she could get some leverage.

That's some REALLY good input. I know the TTR motor can be a 16 hp 'mini monster' with BBR goodies and I had not considered that the estart mounts are already there. Believe me, it's not that she can't kick the bike, it's more that some of the situations we get into there are times you just can't find a spot to touch long enough to get a good kick in. This combined with the time consumed during a race/ride in one of these situations getting to a spot to get it going is not good. Now, building a bike that she can touch as well as us on our full sized bikes is a different story altogether.

It's difficult to describe the frustration unless you've ridden with someone who isn't tall enough to make the bike what ot was designed to do.

Thanks again,

-tom

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