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My TM250 setup

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Wanted to share some info about my TM250mx setup

I race the bike in Harescrambles,so I had to get it more enduro.HA setup to my personal liking.

First-I modified the tank to 3 gallons. Stock was 2.5 gallons or abit over,but I needed more fuel for 2-3 hour events.I cn now make quicker and less pit stops.

The bike fits me great.I am 6 ft tall and 200lbs. The stock springs wer good in front,but I ended up going to a 5.4 for the rear.I think the stock was 5.0 or 5.2

I had shaved the seat and contoured it to my liking and added an N-style gripper cover.

I found 225cc in the outer chamber and properly bleeding the inner cartridge critical for a good ride. The forks are really great-you can adjust sag/preload via a circlip on the inner cartridge. I am in the 4th clip position

I run 120mm of sag.I also made a small linkage modification. It didn't make a huge difference,but complimented my suspension setup and way I ride.

I run air chambers on the front forks.It is an easy way to adjust the fork oil/air volume in the outer chamber and gives more plush in initial stroke.

I run a 2 ring piston and a boyesen Rad Valve. I also changed the port timing,ignition timing and the powervalve opening setting to my liking via the PV mechanism internally.I made some crude modifications to experiment in opening the PV at different RPM.Stock opens at 6200-6400 RPM. My mod made the PV open at 5700-5800 RPM. I finished by making a bunch of different pipes and tried to have a mid-top oriented pipe and a bottomm/torque pipe. Lastly-jetting..I started out rich. THe stock needle works very well,but with my mods,everything was way too rich. I am currently at the 2nd clip from top NOZE needle,45 pilot and 176 main.

The bike was great stock,but I love to customize and tune. These mods made the bike work perfect for me. Just wanted to share my setup and options that are out there. Oh-I also went to 13-48 gearing. The changes I made,I am able to pull taller gearing which is great for the fast sections

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here is seat

TMmodpics015.jpg

linkage mod

TMmodpics018.jpg

tank mod and sub tanks for forks

TMmodpics011.jpg

This bike revs to 9,543 RPM stock in map 1 igniton setting. HP stock was 49.7 peak.IN stock form it is a rocket,but I wanted a bit more snap and bring the "snap" on sooner. The HP peak is less ( 47.2) with my mods,but I broadened and shifted the powerband more towards the bottom and added more torque. The mods gave a stonger bottom-mid hit..I love this bike

Its a great jumper and turns excellent

ridingpics013.jpg

low rider haha

ridingpics012.jpg

Edited by ac717
pics

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My setup gives me a good MX ride,yet can take rocky,rooted,log hits good. Its hard to get the best of both,but after alot of testing-I feel that I have it dialed

ridingpics006.jpg

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Why dont you try the JRF Torque Control. Makes changing the power valve timing a lot easier than what you have done

http://www.crossaction.com.au/Pages/jrf_review_adb.html

It was developed in Oz by the TM importer & getting rave reviews.

Regards

Pete

Because that governs how hard it engages/slows it down. I wanted it to do the exact opposite-open faster/sooner/harder!

I do think the JRF Torque Control is a brilliant idea,but what I really want to make,other than having to take the side case off...Is to be able to adjust the PV to open from say 5,000 and adjust up to 7,000 Combined with the jrf-it would be a nice,adjustable powerband. Provini also makes them. Provini has torque controls for just about every 2 stroke out there

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LOL is it safe to talk about TM's. My son's bike needs some suspension work and he may be calling you. TM's are sweet bikes! Now they need to make me a 200 woods bike as you are correct the 250 is a pure race rocket and to much for this old man.

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LOL is it safe to talk about TM's. My son's bike needs some suspension work and he may be calling you. TM's are sweet bikes! Now they need to make me a 200 woods bike as you are correct the 250 is a pure race rocket and to much for this old man.

The TM motors are actually very easy to tune/change the feel of the powerband. In past,they had a very strong hit.. The motors now, have a very friendly powerband-they can be ridden below the PV opening point with very little punch or revved above 6200 RPM,where they pull and rev like crazy. The 144 can be made to be very bottom end oriented,just like my mods to the 250..kinda like you did to the husky Cr. The thing about any bike is-you gotta find what fits you,then alter and fine tune from there. I am a 2 stroke guy. Everyone except for yami and the "exotics" have given up on 2 strokes. The advancements TM,KTM,husky and GG are making on these bikes-makes them all very versatile.With simple mods you can have a top-end screamer or a torque monster that will chug along all day. All the changes I made to the bike are able to be changed. The only permanent thing I did was minor porting...which was just cleaning up the exhaust casting and I polish the powervalve. The intake is already polished from the factory. Polishing any moving flowing component "typically" adds in a performance gain and better life of components. I polish anything in the motor and suspension that is a friction point. A smooth even surface lubricates and function better IMO. I has a 200xc and recently rode a tm144 and the ktm 150xc. I owned a ktm 200xc and I know the potential of both bikes. Honestly,I feel the 144 displacement has better power characteristics than a 200. 144 is more responsive and you can use the rev ceiling better to its potential. To me a small bore is all about response and revability,yet able to pull out of a lug. In stock form TM has more of an uper revving motor,but the terrain most ride-this is suitable. For us on the east coast or tight woods-we will have to make mods to most any bike to get the power we like. I haven't ever owned or ridden a bike that I felt was "perfect" stock. Each motor/suspension and geometry needs to be tuned to the pilot. Only bike I have never gotten along with is four strokes...not sure why-but I cannot ride them:banghead: Glad I can still ride/get a 2 stroke:thumbsup:

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Great write up. I too have a 2010 tm 300 with a good bit of mods. A good bit has been done by the factory as well as tm electractions team mechanic. The head has been shaved and a .93mm base gasket, it has a lighter genny/flywheel. slight porting and machine work done to bottom of barrel. suspension has been re valved and i think 4 shims removed and some passages drilled (top secret that the suspension man will not give out) but works amazing. Rear shock has also been modded but un sure what was done. I'm still running stock vertex pistons but the 2 oil holes have been countersunk to increase oil flow. I too have went to a smaller rear sprocket(50 tooth). What pipe have you fitted, i know a friend of mine has a 2008 tm250en and has a fmf gnarlly from a 2005+ YZ250. It fits great just had to mod the bottom fwd mount

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Great write up. I too have a 2010 tm 300 with a good bit of mods. A good bit has been done by the factory as well as tm electractions team mechanic. The head has been shaved and a .93mm base gasket, it has a lighter genny/flywheel. slight porting and machine work done to bottom of barrel. suspension has been re valved and i think 4 shims removed and some passages drilled (top secret that the suspension man will not give out) but works amazing. Rear shock has also been modded but un sure what was done. I'm still running stock vertex pistons but the 2 oil holes have been countersunk to increase oil flow. I too have went to a smaller rear sprocket(50 tooth). What pipe have you fitted, i know a friend of mine has a 2008 tm250en and has a fmf gnarlly from a 2005+ YZ250. It fits great just had to mod the bottom fwd mount

Nice work!I have talked alot with some of the electraction team-alot of smart guys that love TM's and know them well.I have shared some of my setup and they have shared theres with me. Drilling out the oil holes on the piston a little bigger is a good idea-especially on the 300. The 250 seems to be easier on pistons than the 300. My pipe I make myself. I saw guys use pipes from other bikes like the YZ and the CR pipe,but it gives up too much in one spot or another-probably because they are tuned more towards whatever bike's engine design is. The first pipes I built-I used sections of different pipes and the stocker to get the design I wanted and to test ride them and run on the dyno. The pipe that I have on my bike is a cone-pipe.It is similar to the build that dyno port uses on building pipes. Every small section isn't exactly coned-I form a section and bend it out on an english wheel,hammer and a mandrel to spread-then tig weld everything.Took me 6 hours to make a pipe. I made 2 of the cone pipes and have smashed all the other pipes I made while riding:smirk:.The pipe in the pics is one of the first ones I made out of other pipes,when I was testing. The stocker is pretty darn good all around,but dents easily.It sounds pretty cool though,with the thin wall. Some say the thinner wall makes better power too,but for offroad-we all know a thin pipe doesn't last long.I did hear HGS will be makng a heavier walled pipe available. I have no plans to get into the "pipe business".It's just another thing I like to tinker with. Sometimes I make things that work better than stock..other times stock is best. In all honesty though-I really wouldn't have had to do any mods-the bike is damn good stock. I was turning 4-5 second faster lap times on my track compared to my old race bike.That says alot,since my old bike I knew and the TM I had just got.I cannot resist though...If I had a Ferrari-I'd have to modify it:lol::thumbsup:

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I haven't heard of anything they offer but a call to a dealer would answer or help for sure. I do think manufactors should have something in place. I know it's helped Husky and one of the guy's that works for me has jumped on the Kawasaki deals they have had going. LOL a raining day and he's signing on a new Kaw.

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Most people can get better financing through local banks. Even a credit card with 0% for payments would be better than dealer financing...Dealer financing is a ploy to shift cost-simple as that. It does make for an easier purchase-which is why people are attracted to it. Anyways..been doing some more testing.Tried a 36mm PWK.Stock is a 38mm PWK AS. It made a bit more response and alot more bottom than the 38mm stock carb. I think a divider-like RB designs does would be good for this bike. I am going to try the 36mm carb in the race this weekend. The carb swap is not an easy job-it takes some more serious changes,due to the 36mm carb being shorter.I also brought the reed valve out 3mm,so this may have attributed to the power change also. This bike responds very well to changes. I like that-it makes things more fun! I spent most of this past week rebuilding jumps on my track and tinkering with the tm250. I took the bike down the road.72 mph was the top speed according to GPS in 5th gear with the current setup and 13/48 gearing with stock MX transmission. I was worried about losing top-end and top speed with my mods to more torque,but 72mph is plenty while still able to pull the wheel up in 4th gear and have instant throttle response. I hope to get it on a dyno with the current setup. Dyno's usually favor the 38mm,but the seat dyno says different. I like the fact that the bike makes nice peak HP. Motors made like that are typically easy to shift the power to wherever you want it. By now-I have found that I can make it a top-end screamer or make it a tractor,while still keeping the stock attributes I like. I must admit-at first I loved the chassis,liked the suspension and thought the motor was OK. After studying and testing this bike like a mad man-I love the entire bike. Since there isn't many aroud-it takes forums like this-guys share info and then it makes it easy to get a setup you may like. I hope my setup/testing helps some others out. Wish me luck this weekend at the National Harescramble in NJ..If you see a TM250mx with #717-say hello. If your racing....please mover over...LOL

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any idea what the minimum thickness of the clutch friction plates and steel plates should be, i can't find them anywhere in the manual

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Doc-sent you a PM. I am not sure what the wear limit is.

OK..been doing some more testing. my latest setup is pretty damn good.I got the flu and didn't race this past weekend. I could barely breathe and coughing so 3 hour race was not doable. So-here is what I came up with..

CDI- swapped stock CDI for a KTM 250sx..BINGO! Great bottom with huge midrange.

Pipe and silencer-fixed up a cr250 style pipe I had made and bolted on the pro circuit TM spark arrestor-this smoothed out the mid-top and shifted everything down a little.

36mm carb-this is my favorite. For woods the 36mm is just more responsive in the tight. I am going to machine the carb for an insert and install a divider on the 38mm and try the 38 again. The 38 should give what I am looking for,but for some reason-it isn't at the moment.

Gearing 13/48

2 ring piston

Powervalve mod to open at 6200 RPM

Boyesen Rad Valve

1 degree advanced timing from stock setting.

.2mm base gasket

I may reshape the head a little. At sea level my compression is really high- 228psi. The comp ratio is very high stock on the TM and the twin ring piston may be attributing to a higher CR from stock.also,the thinner base gasket. So I may reshape the bowl to get the CR lower.I feel this will give better bottom and attribute to the powerband I am after. As it is right now-it feels alot like a KTM 300xc. I love the KTM motors and alot of my mods were to get the power I was more familiar with from my old ktm. I would still be on a KTM for the engine-but the TM chassis and suspension are that much better than the KTM. Motors are easy to change,but a chassis issue always seems to be a larger hurdle.The TM also feels much lighter. I like perimeter frames and Tm has the gas hung low in the frame.It is a very responsive and agile chassis compared to other bikes I have raced.

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Intresting to see your mods on the TM.

I just bought a 2010 EN144. The first thing I did was to rebuild the fork by the Marzocchi manual. It said that you should use 7.5W oil in both the inner- and outer-chamber, the amount of oil in the outer legs should be 320 ml. The bike was unridable with this setting. I got the tip to use 5W oil for the inner-chamber insted and go down to 220 ml in the outer legs. It made a huge differense, for the better.

I also added a little more preload (one grove), because the original setting had no preload.

The Sachs shock beats me up, I´m only about 65 kg so mabye a softer spring is the way to go. Do you have Sachs shock, if so, have you done anything to the valveing?

I saw you had changed the ignition timing, how did you check it?

I feel my bike runs harder at MAP2 then MAP1, what I have heard it should be the oposit.

The pilot jet is changed from #42 to #40.

The Needle is the stock NJWE in the third grove.

Mainjet is changed from #180 to #188

I would like a needle that is a little richer from 1/2 to 2/3 throttle, can anyone recommend one?

//Kristian

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Awesome thread, guys! It's good to see fellow maniacs who can't leave well enough alone!

I really like the thinking on power delivery AC717, sounds like a pretty awesome setup. I race GNCC on a modded out 508 bb/stroker Yamaha WR450f four stroke, and since acquiring a few TM's I have been converted to the realm of no valves! I have seen the light [blue].

Depending on how sponsor deals go for next season, I am seriously considering racing my (dinosaur) 2001 TM 300en, as initial rides have proven it much less tiring to ride than my chunky dark blue bike. When I first got it as someone's parts bike, it was a complete basket case and required 2 years of crazy research and investigations to finish what someone else had started. Turns out I have a +8mm long rod and a cylinder spacer installed under a 73mm big bored cylinder and custom piston.

In my haste to assemble and ride this contraption, I miscalculated the squish measurement, leaving bad port timing and overly high compression. I knew the squish was too tight and the ports were too low, as it was kind of gutless and detonated when lugged. "Aaaahhh, I'll just run 110 octane in it until I get around to looking at it". After a few 8-hour trail trash sessions, it was far too late for my detonation scorched piston and cylinder.

Now I am left with the choice of buying one of 7 remaining custom pistons in the world and replating the cylinder......or finding some stock stuff for cheap that will fit. Anyone have any top ends? I was in contact with a really cool guy from Canada, but I may have waited too long and dropped the ball on that one.

As my riding skill has improved vastly, I don't really care about power delivery, but I enjoy the precision in turning and the stopping power of the TM chassis. I am ready to sacrifice a few drag races in exchange for something that's 45 pounds lighter than my WR508F. So I guess in a game of opinions, what do you guys think I should do?

I'm down with a 250 top end mated to my long rod setup, which will have an electric smooth power delivery with no discernible "hit", or with a 300 top end which I'm sure will have more "meat" in the middle of the power. I just want this bike to move again!

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Hi

ac717

I emailed Boysen about a rad valve to suit TM 250 and the reply I got was they had heard a 86-98 Honda Rad valve P/N RAD02B might fit, so it seems they don't make one specifically for the TM.

Also what year model KTM250SX cdi do you use for the improved bottom end??

Do you think the EXC one would be even better for bottom end at the expense of top end.

Any help appreciated.

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Hi

ac717

I emailed Boysen about a rad valve to suit TM 250 and the reply I got was they had heard a 86-98 Honda Rad valve P/N RAD02B might fit, so it seems they don't make one specifically for the TM.

Also what year model KTM250SX cdi do you use for the improved bottom end??

Do you think the EXC one would be even better for bottom end at the expense of top end.

Any help appreciated.

Call Boyesen and ask for Chris. He knows which Rad Valve fits. Any 07-12 KTM CDI will fit. Sorry to say,but I don't have TM's anymore. I hope some of my testing will help others. I am back on KTM's and messing around with a 2011 RMZ450. Never thought I would be on a 4 stroke again LOL. My wish list for TM's would be: different gear ratios,easier PV adjustment,pipe selection and build some flex into the chassis.

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