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Discussion Starter #1 (Edited)
This project may take a while to gain momentum, but I hope to have it up and running by mid-spring.

I've got one of PlacerLode's counter shaft extenders, so I've been looking for a suitable XT/TTR engine donor.

Well, I found this little gem on Craig's List, only 8 miles away! :cool:

ttr225 - 1.jpg

ttr225 - 2.jpg

It's a 2004 TTR225... it's a little rough around the edges, but generally in good shape. I'm hoping to part out quite a bit of the stuff I don't need, to offset the cost of the build.

My basic plan is to use the TTR engine (obviously) with the TW left side case and shaft extension.

I also want to install my right side TW case, with all the kick-start hardware... that should work, right?

The stainless header is a bonus! I'm also going to try to use the TTR muffler... the cap and spark arrestor are gone, but the baffle has not been drilled. If I can fit this to my TW, and use my existing cap and spark arrestor, maybe I'll finally have a reasonably quiet running motorcycle!

I'll figure out how to mount the steel tube skid plate... and that handlebar mounted choke knob will find it's way to my TW as well!

I'll have to look closely at the carburetor. I like the pumper that I'm running now, but if the factory TTR carb is in good shape, I may give it a try first.

Anyhow, this weekend I'll get a closer look, and add some more photos. The tear-down should commence pretty soon.

This is going to be fun! :eek:ccasion14:
 

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there are something design things you wonder about, like why they would put a handlebar mounted choke on one bike... and down on the carb on another.

you will really appreciate the extra cc's and 6th speed. enjoy!
 

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Likely he will have to retain the TW 5-speed transmission in order to use the extended output shaft.

Charles.
?
isn't that the benefit of the extended shaft, that you can just drop the TTR/XT motor in and use as is, with the 6th speed?
 

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Discussion Starter #6
Yes, using Placerlode's extension on the stock TTR counter shaft, all I really need to swap over is the TW side case (and associated electrical parts) with the outboard counter shaft support bearing.
 

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Discussion Starter #7

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Has anyone actually done the swap and compared the power differences? Are there any power losses from the TW electrical verses the Ttr electrical?
 

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I rode some one's a bit on bottom of Schaefer Trail in Moab. Plus TW-Brian recently let me ride his 226 six speed with the new Duro2 ATV tire on suburban roads. Very nice but I didn't try to flog the borrowed bikes. They both seemed stronger at slow speeds. What really made a difference was riding IBXR's (?) one that also had about 35 lbs of weight removed. Like Lotus's Collin Chapman he really knows how to add lightness.
On mine I forgot to weigh the two different flywheels but both seemed about the same and easily confused. TW's smaller, yet heavier rear wheel should add additional flywheel effect decreasing acceleration but increasing stall resistance.
It would take our CDI guru to know if there is any ignition mapping differences between the bikes. Heads, timing and cam duration all seem the same.
 

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Discussion Starter #10
Has anyone actually done the swap and compared the power differences? Are there any power losses from the TW electrical verses the Ttr electrical?
I'm not expecting a huge power increase, but a 10%+ displacement increase should certainly be noticeable. I'm also looking forward to a lower 1st gear, and a higher top gear.

I'm stuck with my '87 charging system, for better or for worse.

On another note, I'm worried that I won't be able to install my kick starter, because the inside shaft mount might not be finish drilled. I won't know until I pull the right cover off. :dontknow:
 

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I'm not expecting a huge power increase, but a 10%+ displacement increase should certainly be noticeable. I'm also looking forward to a lower 1st gear, and a higher top gear.

I'm stuck with my '87 charging system, for better or for worse.

On another note, I'm worried that I won't be able to install my kick starter, because the inside shaft mount might not be finish drilled. I won't know until I pull the right cover off. :dontknow:
mine was not plug and play ready, so i had mine drilled and ground to take a seal. a machine shop should be able to get it done using the tw cover as the guide.
 

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Discussion Starter #13 (Edited)
mine was not plug and play ready, so i had mine drilled and ground to take a seal. a machine shop should be able to get it done using the tw cover as the guide.
I'm more worried about the hole for the back end of the shaft. VanillaGorilla had a problem with it here: https://www.tw200forum.com/forum/performance-customization/13890-warning-installing-kicker-ttr225-cases.html

It seems that XT and TW cases were all machined for the kick starter to fit (TWs still are), but TTR cases after 1999 generally were not... although evidently some TTR cases were taken off the XT assembly line, and have the machining done. :dontknow:

I'll let you know what I find when I pop the cover.

As for the outside case (clutch cover), I was planning to just use the one from my TW. You're right though, a machine shop could drill the hole and mill the seal seat pretty easily.
 

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R.E. using TW clutch cover on a TTR/XT six disc clutch: [h=3]TW225 Countershaft Extension for XT - TTR etc 6 speed Big Bore Conversions[/h]See post #135 in the Classified's Countershaft Extension thread where TW-Brian shows in detail how to gain clearance for the TW's thinner clutch cover.
Think it entailed a bit of grinding, nibbling, chewing & maybe a Jenny Craig Diet but to paraphrase our former administration "If you like your clutch cover you can keep your clutch cover". The precision required seems less than what is required to bore and install a leak free kick shaft seal in a basic TTR clutch cover. The TTR's oil fill fitting certainly is further outboard possibly making pouring oil in easier, a minor point
 

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Discussion Starter #16
R.E. using TW clutch cover on a TTR/XT six disc clutch: [h=3]TW225 Countershaft Extension for XT - TTR etc 6 speed Big Bore Conversions[/h]See post #135 in the Classified's Countershaft Extension thread where TW-Brian shows in detail how to gain clearance for the TW's thinner clutch cover.
Think it entailed a bit of grinding, nibbling, chewing & maybe a Jenny Craig Diet but to paraphrase our former administration "If you like your clutch cover you can keep your clutch cover". The precision required seems less than what is required to bore and install a leak free kick shaft seal in a basic TTR clutch cover. The TTR's oil fill fitting certainly is further outboard possibly making pouring oil in easier, a minor point
Ahaa, I do remember reading about that, now. :thumbsup:

Once I get the motor on my bench, I'll pull the right side cover, and see if the interior hole is finish drilled. If it's not, I'll put the side cover back on with a new gasket, and forget about the kick-starter. If it is, then I'll have the side cover drilled and machined for a seal.

I'll leave the TW side cover with the TW engine. :p

Thanks, guys!
 

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Get two gaskets then.:p The clutch cover gaskets on TWs at least seem rather difficult to re-use or remove.
 
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