TW200 engine fit a TT-R125 frame?

Any one know if a TW200 engine would fit into a TT-R125 frame?

Thanx,

HB

I don't know for sure, but I doubt it. My buddy has a tw200 and the engine looks a lot more massive than the 125.

If I was going to do something like that, I'd try to put a 2-smoke engine in there.

Possibly, the TW200 is an overgrown 125, just like the 225 is. You're probably better off going with the proven big-bore kits though.

Thanx for your input guys ('Smacaroni' & 'DDACT').

Here's the deal, I'm getting out gunned by the others in 126-200 cc class. I KNOW that some of it (ok, lots of it) is rider ability (theirs over mine, and I'm man enough to admit that - LOL). But, I also know that some of it is simle engine grunt. I've thought about a BBR 150 kit . . . but to be completely honest, I didn't even know about the Yamaha 200 four stroke engines until just he other day. So, I was simply trying to figure out what would be the better R.O.I. . . . the 150 big bore, or attempting to fold a 200 into the frame. <G>

Thanx again guys,

HB

P.S. - it's a four-stroke division, so, can't do a 2-smoke conversion or bike swap.

P.P.S. - I guess the other thing I should be looking into as well would be gearing. I'm still on the stock front and rear of this little TT-R 125. <G>

Edited by Haybails

I would try a XT200 motor before a button start TW200. The XT is essentially the same as the TW with a narrower back half to the case. You have to remember, the TW rear wheel is a 180-80/14, which calculates to 7.1 inches wide. The XT was more of a traditional enduro, with a 18 inch rear wheel.

Having ridden one lightly modified with a stock chassis, I can say that they're actually on a par or more powerful than a XR200 or DR200 (in stock form anyways). With nothing more than a larger carb off a XR and a opened exhaust, it torqued my 180lb arse around without a problem.

The head is the same as on the current TW200, so there's a few cams available, mostly under the YTM225 or YFM225. I've heard that you can slip a TTR230 top end on, but you're stuck under 200ccs without cheating, which is only cheating if you get caught :smirk:

Thanx for the thoughts '500XC'!

Do you know, would an XT200 motor bolt straight into a TT-R125 frame?

HB

Well in that case (knowing the why is helpful), I would sell your TT-R, buy a DR-Z125, slap the KX100 suspension on it and stuff a DR200 motor in there. Lighter, meaner, unfortunately probably not cheaper (and I'm cheap!).

Personally, I'd work on your skill, this will have a much bigger impact on your times than any motor change on any bike. I wish I had a copy of it, but somewhere out there is a "Ryan Hughes vs RMZ450" (or similar) article from 2006? where he spanks a 450 C Vet (again, not sure) on bikes as small as a DR-Z125. From what I heard, it was embarrassing.

If anyone has a copy, I'll pay for it, or photocopies/scans of it, shipped to me. I'd love to read it.

Personally, I'd work on your skill, this will have a much bigger impact on your times than any motor change on any bike.

I understand exactly what you're saying - and (as alluded to in one of my earlier posts in this thread) I completely agree. I realize that improved skill will help me the most . . . And, therefore, I am working on that end of the equation whenever I can (promise). <G>

....stuff a DR200 motor in there....

Think the DR200 motor would fit in the TT-R125 frame? <G>

HB

Hmm... good question. I'd have to have one side-by-side a TT-R125 and a DR200 to say for sure. I don't see why not with the exception that the motor will be taller and if the tank on the 125 is like the 225, I suspect not.

You also would need to do a Yamaha front end swap instead of a KX, but you could ditch the battery.

I realize this is a TT-R forum, but I think the DR-Z is a better platform, certainly if you wish to modify it. Obviously there are ones even better than the DR-Z, but not in the budget mainstream youth sized 4T. (no motocross high-strung 4T, YZ-F, CR-F, etc.)

Here comes the flames.

Hmm... good question. I'd have to have one side-by-side a TT-R125 and a DR200 to say for sure. I don't see why not with the exception that the motor will be taller and if the tank on the 125 is like the 225, I suspect not.

You also would need to do a Yamaha front end swap instead of a KX, but you could ditch the battery.

I realize this is a TT-R forum, but I think the DR-Z is a better platform, certainly if you wish to modify it. Obviously there are ones even better than the DR-Z, but not in the budget mainstream youth sized 4T. (no motocross high-strung 4T, YZ-F, CR-F, etc.)

Here comes the flames.

I doubt the DR 200 motor would fit. The TTR frame is pretty tight around the motor.

What are the rules for the class? Let us build you a nice cheater bike:p or one that "fits" the rules:smirk:

We race as a family. Myself along with my young son and my younger daughter . . . so, cheating, is out of the question. Even if I were alone, I wouldn't want to start wandering down that slippery slope anyway.

Quite frankly, it's not like I'm in love with my TT-R 125. It's just that it's what I have sitting there (I ride my YZ250F in two or three other classes). My son's on a YZ85 and my daughter is on a TT-R90 . . . so, it's kind of neat to all be riding the same machinery as a family.

I know it sounds like a contradiction after just asking if I could fit a DR200 engine into the frame . . . but, at least it would still look like a Yamy. LOL!

I guess I could start looking, again, into the BBR 150 Big Bore kit and a bigger carb.

I've already got YZ forks on it, the BBR Frame cradle, a BBR exhaust, and the open air box mod. Just trying to wring a little more out of her. LOL!

HB

We race as a family. Myself along with my young son and my younger daughter . . . so, cheating, is out of the question. Even if I were alone, I wouldn't want to start wandering down that slippery slope anyway.

Quite frankly, it's not like I'm in love with my TT-R 125. It's just that it's what I have sitting there (I ride my YZ250F in two or three other classes). My son's on a YZ85 and my daughter is on a TT-R90 . . . so, it's kind of neat to all be riding the same machinery as a family.

I know it sounds like a contradiction after just asking if I could fit a DR200 engine into the frame . . . but, at least it would still look like a Yamy. LOL!

I guess I could start looking, again, into the BBR 150 Big Bore kit and a bigger carb.

I've already got YZ forks on it, the BBR Frame cradle, a BBR exhaust, and the open air box mod. Just trying to wring a little more out of her. LOL!

HB

I was just teasing you, I might advocate pushing the limits of the rules (Building a bracket car that runs 10.90s and detuning it to run 11.30s) but I actually refuse to outright cheat. That's why I asked the rules.

IMHO, it shouldn't be difficult to cram a XT200 motor in a TTR chassis, although you might have to sell off your BBR cradle if it's the new forged one.

I'd sooner try that than spending god knows what on a BBR framed creation

Thanx '500XC',

I knew that you were just teasing and/or joking around. No offense meant to you. We're all just goofing around for fun here.

I wonder how one would go about comparing the mounting similarities and/or differences between the 125 engine and the XT200 (or DR200) engine? Strictly from schematics? (as I don't want to buy an engine and THEN find out that it doesn't fit. <G>).

I'm not an engineer . . . but, I ain't a weed-eater either. But, at the same time, I don't want to get into any sort of chop/cut/rebuild of the frame. If it's a straight bolt to bolt swap, I'll move forward, if I need to do torching and bending and welding, I'll just focus my time/efforts/$$ elsewhere. <G>

Thanx, again, to all for jumping in on this thread. It's nice swapping thoughts and ideas like this.

HB

Well, the DR/SP200 into the DR-Z frame is 99% nuts and bolts, one piece of fabrication which can be done from steel stock using a drill, vice and hammer.

I'm nearly positive if it were to fit in your 125 frame (and the tank fits), it won't be that easy. I didn't mean to suggest in any way that this is a high-priority candidate into a Yamaha frame.

The best thing you can do is find someone who has the bike, park your bike next to it and eye ball it. If it looks like it won't fit, stop.

Then, get a measuring tape or a large divider (looks like a pencil compass) and measure the distance between important mounting points such as the swing arm bolt. You can probably adjust the front or top engine mount, but I wouldn't do both, esp. if you're not real keen on welding.

And from my experience, you really want to start with a running donor motor. I spent $350? putting a motor back together only to find that it had a transmission problem and was half useless.

You >>*MIGHT*<< be able to swap the 200 crank, jug, piston and timing chain onto the TT-R125 cases. This would require a good bit of research and splitting the cases. I'd look into that if you're comfortable with this process since it's likely easier to find a good XT200 crank, new Wiseco piston and you might even be able to bore your cylinder. You might get lucky and your research will show you that the crank isn't necessary (wishful thinking, but maybe).

I don't think that the XT200 crank will fit. It's only a 55.7 mm stroke anyways.

I'd look more into boring the cylinder and replacing the head, which seems to be only a 125 head. If we can find the pin to deck of the 125 piston, we could find you something that will fit and give decent displacement; IE a 68.5 mm piston with a stock stroke puts you right at the displacement limit.

You should also look into the pistons from the Riva 180 and 200 scooters too. Same wrist pin diameter, potential candidate. Wasn't there some discussion about using a 600 road bike piston in these guys not too long ago?

I've never had my hands in a 125, but the 225 head has lots of room for improvement. You may be able to see similar output gains as a larger bore if you clean up a poor flowing head.

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