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Discussion Starter #42
Okay, here's an odd observation... my TTR225 case has a 76mm bore for the cylinder skirt, but my XT225 case has a 78.5mm bore!

What's going on here? :dontknow:
So, it looks like Vagabond ran in to this same problem back in 2013: https://www.tw200forum.com/forum/performance-customization/7810-tw230-engine-notes-xt225-ttr230.html

Apparently, 2001-2007 XTs used a "Nikasil" plated aluminum cylinder, rather than a steel sleeved cylinder, and that required a larger case mouth.

He used a TTR sleeved cylinder (as I am doing), but he was able to use a larger section o-ring to fill the gap.

I suppose that's what I'll do, too! :thumbsup:
 

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Discussion Starter #43
Your XT case is probably from a later year that used Nikasil cylinder jug - they had a larger skirt.
It looks like we were typing at the same time!

Man, there sure are a lot of variations of these engines that should be identical!
 

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All the same???? That's crazy talk! Seriously, I think these minor differences are in our favour - they give us a lot of options to build/customize as we want. You definitely have the oportunity to go to a 74mm sleeved bore if you want.
 

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Discussion Starter #45 (Edited)
Well, Fred said it... JMS said it... and then my wife said it... :couple_inlove: I love my wife!

74mm rabbit hole, here I come! :eek:ccasion14:
 

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Discussion Starter #46
All the same???? That's crazy talk...!
I just figured out my XT engine uses a different timing chain and sprocket, too. How Special! :rolleyes:

I ordered a bunch of parts today for the 250 build. In another week or so, I should be moving forward again.

I'll keep you posted! :eek:ccasion14:
 

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Steve, you have enough momentum going on the original TTR donor motor that perhaps someone wants to chase you partway down the rabbit hole, pick up your cast off pieces and make themselves a 6 speed TW by one of several routes....just install TTR gears with appropriate shaft mod in TW core...or get your XT or TTR cast offs plus a PlacerLoad adapter and complete you original plan, no kicker but a better clutch, more power and 6 gears. Other than your "Special" second donor motor most of these ~2000 model year TWs, XTs & TTRs seem to have a lot of mix-n-match potential. Lizrdbrth went into some detail on the specific differences...miss that guy's encyclopedic knowledge and hands on experience.

Take the proceeds and buy more Av gas or take family out to dinner. Or just maybe invest more in your build so you may finally be faster than your wife riding LittleTommy's super quick, super clean '87 TW200
 

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Discussion Starter #48
Steve, you have enough momentum going on the original TTR donor motor that perhaps someone wants to chase you partway down the rabbit hole....
I was thinking that too, but I also might build it up and keep it.

When I get the "XTW250" finished, I'll still have the TTR lower end, with the right side (clutch) cover, a good cylinder (excellent, really), and a Wiseco 71mm 10.25 CR piston kit (the cylinder needs to be bored out to use this piston).

I just need to buy another XT/TTR clutch, and one more countershaft extension, and I'll essentially have a TTRW230HP "kit," that could be swapped in one day.

It's funny how these little projects can take on lives of their own!
 

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I was thinking that too, but I also might build it up and keep it.

When I get the "XTW250" finished, I'll still have the TTR lower end, with the right side (clutch) cover, a good cylinder (excellent, really), and a Wiseco 71mm 10.25 CR piston kit (the cylinder needs to be bored out to use this piston).

I just need to buy another XT/TTR clutch, and one more countershaft extension, and I'll essentially have a TTRW230HP "kit," that could be swapped in one day.

It's funny how these little projects can take on lives of their own!
I'd like to do what you're doing at some point, if I can ever find a good deal on the parts.

Funny you mention a XTW250. Maybe you already know but there was a concept bike with that designation, also called Ryoku. You'd think they had been reading the forum to get their ideas. It even had a cooling fan.
image-77300d10-640x400.jpg
 

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and as if to show the heritage... they even used the same crappy, death wing front tire!

 

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Discussion Starter #51
Funny you mention a XTW250. Maybe you already know but there was a concept bike with that designation, also called Ryoku. You'd think they had been reading the forum to get their ideas. It even had a cooling fan.
View attachment 190664
Dang, that's pretty slick!

Frankly, if they don't have R&D "spies" following forums like this one, then they're missing out! The actual users of a product will fine-tune it for free, ;)
 

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Discussion Starter #52
and as if to show the heritage... they even used the same crappy, death wing front tire!
They must have signed a 50 year contract for those damned tires! ;)

That bike has some fluff, but also has some cool features... this weekend, I may take a closer look at the idea of turning an old shovel in to a skid plate! :eek:ccasion14:
 

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Discussion Starter #53
In other news... I added a ball-bearing on the fat end of my camshaft. I had it all opened up anyway... and this is quite possibly the simplest mod you can do to a TW engine!

cam bearing - 1.jpg
 

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In other news... I added a ball-bearing on the fat end of my camshaft. I had it all opened up anyway... and this is quite possibly the simplest mod you can do to a TW engine!

View attachment 190666
I questioned whether this was an upgrade or not since my original bearing at about 30,000 miles had no wear at all. Personally I think that at least on my bike the oil layer must be perfect lubricating with very little friction at all. Does adding more moving parts cause less wear in this case? That was what crossed my mind.
 

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Discussion Starter #56
I questioned whether this was an upgrade or not since my original bearing at about 30,000 miles had no wear at all. Personally I think that at least on my bike the oil layer must be perfect lubricating with very little friction at all.
Well, maybe it helps that CJ7Pilot is in the ball-bearing business.;)
I think the bushing (plain bearing) is fine, as long as you have oil pressure.

I was intrigued by the ball bearing idea, and I had one, so I dropped it in.

However, now there is no direct lubrication to the bearing, as it covers up the oil passage that fed the plain bearing. This should result in slightly higher oil pressure to the plain bearing on the other end, and on the cam lobes... and I'm hoping there will be enough "splash" lubrication to keep the ball bearing happy. :dontknow:

It was something to do. :p
 

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Discussion Starter #58
So, the thing about build threads, is that they tend to be really busy at first... while we're tearing down our projects, and deciding how to put them back together.

Then there's a lull, as we're waiting for parts to arrive, and machine work to be done....

With this thread, it's actually staggered, because I got hung up on the kick starter, and now I'm building two engines! :rolleyes:

So, parts are in for the first engine. I wish I had just done this for myself, and been happy with it! But... that's not how it worked out.

This engine is destined for a friend's bike, which is being rebuilt using a frame from Placerlode, due to arrive sometime this month.

It's based on a TTR225, bored to 71mm (229cc), with a Wiseco 10.5:1 piston... this is going to be a good runner!

Stay tuned.... ;)

engine - 1.jpg
 

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Discussion Starter #60
Steve's 249cc TW/XT225 6-Speed

I haven't updated this thread in a while, but here's what's going on:

I sold the 229cc TTR225 engine to a fellow forum member, who is finishing it up now. I'm hoping he'll review it when he gets it installed.

The 249cc XT225 engine is next in line for re-assembly. This is an insanely expensive project, mostly because I bought most of the parts individually, instead of starting with a complete engine. When all is said and done, I'll have about $2,000 tied up in it... but I think it could be done for about half that with some careful shopping around.

I never did split the case, but I examined the lower end pretty carefully, and I'm confident it is in good condition.

I added the kick-starter guts out of a TW parts engine:

Right Side - 1.jpg

New Barnett clutch parts:

Right Side - 2.jpg

Clutch adjusted and gasket set on:

Right Side - 4.jpg

Right side all buttoned up... now we can move on to the fun stuff:

Right Side - 5.jpg
 
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