Full Tilt TM Racing Two Stroke Build(s) Update: Dirt Magazine "Two Stroke Tuesday"

blackdiamond
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blackdiamond
Edited Date/Time 5/7/2022 10:52pm
After a lot deliberation, research and thinking I finally decided on what I wanted to do for my next two stroke build. I decided on a couple of TM's because I feel they have the most advanced two stroke engines in the world right now. They dominate the kart racing circuit and have won a lot of world championships over the last 10 years.

I decided to buy a 250 and a 144 and build both of them at the same time. One of the main reasons I decided to buy both bikes now is because I have heard rumors that TM Racing is going to EFI on all of the two strokes in 2019 and I really prefer the carbureted version. If 2018 was going to be the last year of the carbureted bikes, I definitely wanted to grab one of each size while I still could.

After going over these bikes with a fine tooth comb and trying to figure out what I want to change and modify, I have a newfound appreciation for the attention to detail that TM puts into their machines. The design, craftsmanship and attention to detail of these bikes is second to none and simply amazing.

Below are a few of the preliminary pics and a few of the details that make the TM Racing machines special.







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blackdiamond
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blackdiamond 3/30/2018 2:09am
3/30/2018 2:09am Edited Date/Time 3/30/2018 12:14pm
Some pics of the frame welds:







Squidward
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Squidward 3/30/2018 2:09am
3/30/2018 2:09am
This is gonna be epic. I've been waiting to see someone throw together a good TM build. Definitely following this, I gotta ask though. What makes you think the EFI is going to be bad? I personally prefer carbs because I at least have a bit of knowledge on how to tune them, rebuild them, etc. EFI scares me because I just picture more electronics, sensors, and stupid little issues taking forever to find and fix. However, I could see EFI making a huge power increase, fuel economy, and whatnot. Either way, those are some killer bikes you picked up! Wish I had money, first thing i'd score is a new TM125. Good luck with the build man!
Aggie15
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Aggie15 3/30/2018 6:22am
3/30/2018 6:22am
Looking forward to this! I just picked up a 2015 TM 125 that I've got torn down to the frame right now, started a build thread about a week ago. These things are really sweet. I'm working on finding crossovers for all the bearings, if I can verify them I'll be sure to share it.

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FWYT
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FWYT 3/30/2018 7:38am
3/30/2018 7:38am
Sweet!!!
blackdiamond
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blackdiamond 3/30/2018 10:19am
3/30/2018 10:19am
Squidward wrote:
This is gonna be epic. I've been waiting to see someone throw together a good TM build. Definitely following this, I gotta ask though. What makes...
This is gonna be epic. I've been waiting to see someone throw together a good TM build. Definitely following this, I gotta ask though. What makes you think the EFI is going to be bad? I personally prefer carbs because I at least have a bit of knowledge on how to tune them, rebuild them, etc. EFI scares me because I just picture more electronics, sensors, and stupid little issues taking forever to find and fix. However, I could see EFI making a huge power increase, fuel economy, and whatnot. Either way, those are some killer bikes you picked up! Wish I had money, first thing i'd score is a new TM125. Good luck with the build man!
The best part about two strokes is the simplicity and light weight and EFI will definitely complicate things and add about 5 pounds in the process. In addition to that, I am sure it will push the MSRP up quite a bit as well.
mattyhamz2
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mattyhamz2 3/30/2018 10:38am
3/30/2018 10:38am
Definitely watching this one! Something about the TM's that catches my eye
H4L
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H4L 3/30/2018 11:08am
3/30/2018 11:08am Edited Date/Time 3/30/2018 11:12am
Been at this for about 4 decades & found the case reed engine to make the most power & also a broader range with a good tune. Just curious as to what makes the TM engine design superior ?
blackdiamond
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blackdiamond 3/30/2018 12:06pm
3/30/2018 12:06pm Edited Date/Time 3/30/2018 6:32pm
H4L wrote:
Been at this for about 4 decades & found the case reed engine to make the most power & also a broader range with a good...
Been at this for about 4 decades & found the case reed engine to make the most power & also a broader range with a good tune. Just curious as to what makes the TM engine design superior ?
Just a lot of details like the main bearing design, the way the intake tract is angled towards the carb, etc. The 125's and 144's also have water cooled crankcases as well.

Check out how the intake looks in this pic and the angle of the reed cage:



H4L
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H4L 3/30/2018 4:03pm
3/30/2018 4:03pm Edited Date/Time 3/30/2018 4:09pm
blackdiamond wrote:
Just a lot of details like the main bearing design, the way the intake tract is angled towards the carb, etc. The 125's and 144's also...
Just a lot of details like the main bearing design, the way the intake tract is angled towards the carb, etc. The 125's and 144's also have water cooled crankcases as well.

Check out how the intake looks in this pic and the angle of the reed cage:



Interesting. Have heard Ian Williams is a race kart guru & gets good power out of the CR case reed engines as well. Didn't know the TM 2 stroke engine was that advanced. What is the TM 250 rated HP in stock trim ?
Looking forward to your build.
blackdiamond
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blackdiamond 3/30/2018 4:24pm
3/30/2018 4:24pm
H4L wrote:
Interesting. Have heard Ian Williams is a race kart guru & gets good power out of the CR case reed engines as well. Didn't know the...
Interesting. Have heard Ian Williams is a race kart guru & gets good power out of the CR case reed engines as well. Didn't know the TM 2 stroke engine was that advanced. What is the TM 250 rated HP in stock trim ?
Looking forward to your build.
I am not sure, we have not had it on the dyno yet. I would guess 46-47? Maybe 48?

They have to be fairly strong, I have watched them pull a LOT of holeshots at Glen Helen and that doesn't happen without HP at that track.
crc245
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crc245 3/30/2018 10:02pm
3/30/2018 10:02pm
In! Thanks blackdiamond for coming back with more drool-worthy builds
blackdiamond
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blackdiamond 3/31/2018 1:01am
3/31/2018 1:01am
So over the course of the last few days (and late nights) I have torn these two bikes almost completely apart (except for the engines) looking for things I can do to improve on them. I can honestly say that improving these bikes is not going to be easy outside of some small details, basic suspension work and some engine work on the 144. The thought TM puts into the pieces and parts of these bikes is impressive. In the next few posts I will highlight a few of the trick details that caught my eye.



blackdiamond
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blackdiamond 3/31/2018 1:08am
3/31/2018 1:08am
The axles have externally butted wall thickness between the bearings to save weight. The axle blocks are billet and the nut is billet aluminum as well. Pretty trick for a stock OEM part.







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blackdiamond
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blackdiamond 3/31/2018 1:12am
3/31/2018 1:12am
The radiators come with braces from the factory which is a nice touch. I am not at all happy with the position of the filler neck however, and I will deal with that later in the build.



blackdiamond
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blackdiamond 3/31/2018 1:22am
3/31/2018 1:22am Edited Date/Time 4/1/2018 12:08am
TM seems to go to great lengths to try to save weight and it shows.

This is the area behind the footpeg bracket. It is CNC machined to remove all of the excess material.



The footpeg brackets are really light as well.



blackdiamond
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blackdiamond 3/31/2018 1:24am
3/31/2018 1:24am
Same deal with the seat. This thing is sweet and it is almost as light as some of the exotic seat foams on the market.



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.kyle
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.kyle 3/31/2018 1:42am
3/31/2018 1:42am
Very cool build. Can't wait to see the finished product. I've been somewhat obsessed by TM since seeing a 2003 one years ago. Would still happily buy a TM even though I don't ride any more. Haha.

One thing you could try and find - a hub that doesn't use half of the worlds supply of sprocket bolts like the stiocker - i.e a 6 bolt hub instead. Should be able to save some weight with that.

Any chance of a picture to show how the fuel tank allows the ram air system to work?
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sende 3/31/2018 3:44am
3/31/2018 3:44am
I'm so looking forward to this.
H4L
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H4L 3/31/2018 8:09am
3/31/2018 8:09am
blackdiamond wrote:
I am not sure, we have not had it on the dyno yet. I would guess 46-47? Maybe 48? They have to be fairly strong, I...
I am not sure, we have not had it on the dyno yet. I would guess 46-47? Maybe 48?

They have to be fairly strong, I have watched them pull a LOT of holeshots at Glen Helen and that doesn't happen without HP at that track.
Ok. That's within the same rated HP as the latest 3rd gen AF CR2.
yz133rider
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yz133rider 3/31/2018 9:20am
3/31/2018 9:20am
blackdiamond wrote:
I am not sure, we have not had it on the dyno yet. I would guess 46-47? Maybe 48? They have to be fairly strong, I...
I am not sure, we have not had it on the dyno yet. I would guess 46-47? Maybe 48?

They have to be fairly strong, I have watched them pull a LOT of holeshots at Glen Helen and that doesn't happen without HP at that track.
H4L wrote:
Ok. That's within the same rated HP as the latest 3rd gen AF CR2.
There are other bikes than an 05 Honda please give it a rest. Hondas Hondas hondas
H4L
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H4L 3/31/2018 9:26am
3/31/2018 9:26am
yz133rider wrote:
There are other bikes than an 05 Honda please give it a rest. Hondas Hondas hondas
Seriously... I'm sure you have personal likes with bikes, but I could care less & wouldn't call you on it.. If you don't like my posts it's a simple fix just bypass it & don't read it...
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Andy7 3/31/2018 9:50am
3/31/2018 9:50am
It is such a nice bike, and I´m pretty sure you will make it KILLER! Keep it up!
blackdiamond
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blackdiamond 3/31/2018 12:09pm
3/31/2018 12:09pm
H4L wrote:
Ok. That's within the same rated HP as the latest 3rd gen AF CR2.
In the real world a KTM is usually around 47 and a YZ is around 44 stock from what I have seen.
blackdiamond
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blackdiamond 3/31/2018 12:18pm
3/31/2018 12:18pm
.kyle wrote:
Very cool build. Can't wait to see the finished product. I've been somewhat obsessed by TM since seeing a 2003 one years ago. Would still happily...
Very cool build. Can't wait to see the finished product. I've been somewhat obsessed by TM since seeing a 2003 one years ago. Would still happily buy a TM even though I don't ride any more. Haha.

One thing you could try and find - a hub that doesn't use half of the worlds supply of sprocket bolts like the stiocker - i.e a 6 bolt hub instead. Should be able to save some weight with that.

Any chance of a picture to show how the fuel tank allows the ram air system to work?
I used to think the same thing but if you look at the rear hub closely it all starts to make sense. The sprocket bolts line up directly between the spoke crossings. That allows the bub to be thinner in that area. I was able to see one of the bare rear hubs off of a bike a few weeks ago and it was really light. The other thing I noticed is how wide the flange separation is. This allows for a stronger wheel because of the spoke triangulation.

You can see the bolt placement in this picture:



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.kyle
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.kyle 3/31/2018 1:10pm
3/31/2018 1:10pm
Interesting! Thanks for the wheel picture. I wonder what the weight is like compared to other brands of rear wheel.
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Motofinne 3/31/2018 2:20pm
3/31/2018 2:20pm Edited Date/Time 3/31/2018 2:22pm
Those bikes are beautiful. This will be a fantastic thread!

I don't know what the pricing is in US but TMs are actually cheaper than the KTM/Husqvarna and the Yamaha in Europe(at least in Finland) the 250 2-stroke starts at 8000€. The KTM is 8700€ and Yamaha 8600€. You would think that there would be lots of TMs at the tracks but unfortunately there aren't for some reason.
blackdiamond
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blackdiamond 3/31/2018 2:27pm
3/31/2018 2:27pm
.kyle wrote:
Interesting! Thanks for the wheel picture. I wonder what the weight is like compared to other brands of rear wheel.
I will have a weight on them sometime next week when I get the wheels broken down, I will post an update at that time.
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Jrewing 3/31/2018 2:39pm
3/31/2018 2:39pm
H4L wrote:
Been at this for about 4 decades & found the case reed engine to make the most power & also a broader range with a good...
Been at this for about 4 decades & found the case reed engine to make the most power & also a broader range with a good tune. Just curious as to what makes the TM engine design superior ?
blackdiamond wrote:
Just a lot of details like the main bearing design, the way the intake tract is angled towards the carb, etc. The 125's and 144's also...
Just a lot of details like the main bearing design, the way the intake tract is angled towards the carb, etc. The 125's and 144's also have water cooled crankcases as well.

Check out how the intake looks in this pic and the angle of the reed cage:



This build coincides with Nystmac laid up in hospital.. does this make him feel better or worse? I don't know.
Anyway subscribed!

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