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170lb TM-400??? Possible???

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Joined: 31 Dec 2008
Posts: 52

PostPosted: Sun Jan 17, 2010 4:25 pm    Post subject: 170lb TM-400??? Possible??? Reply with quote

170lb. Suzuki TM-400???? I was looking at the beautiful TM-400 pics at the top of the Swap Meet page here...``170 lb TM400 in the air at Glen Helen, Dan Berg``. As a long-time TM-400 enthusiast, owner and racer, I find it quite impressive that a 170lb. TM-400 can exist! In stock form, these bikes were TANKS! Suzuki claimed a dry weight of 235lbs. for the TM-400. To shave off 65lbs., down to 170 would be quite a feat...isn`t that even lighter than a 125 Elsinore? As another comparison, Joel Robert`s 1972 RH72 Suzuki 250cc weighed in at 168lbs. Suzuki ran ads, back then, that this bike cost *USD*15,000.00 to build (in 1972 dollars!). The sand-cast magnesium engine on Joel`s bike only weighed 35lbs.! Ever try to lift a TM-400 engine? I have...many times. They`re not light. Until the FIM imposed minimum weight restrictions, practically everything else on Roger and Joel`s works bikes were either chrome-moly, titanium, magnesium, or aluminum. Now, I`m not saying a 170lb. TM-400 isn`t possible, just highly unlikely, mainly due to cost and the high initial weight. I`ve got one, a purpose-built 74 ``L`` model, that I`ve won a couple of regional championships on. I lightened it up as much as reasonably possible with my limited resources, but I`m sure it`s still well over 200lbs. Anybody else have any thoughts on a 170lb. TM-400?
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Joined: 31 Dec 2008
Posts: 170

PostPosted: Sun Jan 17, 2010 6:24 pm    Post subject: Reply with quote


Having & owning RH & RN Suzuki`s years 66-74 i have never owned one that was close to being under 200lbs. Now the works works bikes a hand full were under 200lbs. but not many have survived because of the fragile mag works frames. US Suzuki in La Mirada had Joels 1972 RH72 on display for several years in 1975 i had the chance to buy the bike but opted to buy a new 1972 RH72 instead that they also had on display (stupid me). There are more so called works bikes now than Suzuki ever built.
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Joined: 31 Dec 2008
Posts: 29

PostPosted: Sun Jan 17, 2010 6:27 pm    Post subject: Reply with quote

I agree, it would be very tough to get in the 170lb range. So if you own the Suzuki in question, tell us how you did it.
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Doug Childress

Joined: 28 Dec 2004
Posts: 436

PostPosted: Sun Jan 17, 2010 6:47 pm    Post subject: Reply with quote

I really can't see 170 pounds usuing an actual TM400 motor. If I recall, that motor is somewhere between 75-80 pounds dry itself. Been a long time since I had one, but I remember shipping one years ago when UPS had the 75 pound weight limit and I had to take the top end off to ship it--too heavy when complete. Add wheels and tires at about 40 pounds (using the lightest tires, magnesium hubs, etc.), forks and triples around 12-15 pounds, shocks around 10-12 pounds, and so on. Even with a 20 pound frame (which would not last long with a TM400 motor), super light seat/tank at about 6 pounds and 5-6 pounds for a pipe you're getting close if not over. Still need a chain, sprockets, nuts and bolts, cables, etc. Perhaps 180-185. The bigger question is why make it so light? With the brutal power of a TM400 (not the gross power, which is really only in the low 30s but the nature of the beast), a little extra weight can help tame it. Imagine pogoing and bouncing off all the rough stuff with that beast (even with well setup suspension--the lack of mass compared to power is what I'm getting at). A few pounds actually can help smooth out the hits in some cases. I think this would be one of those cases. A 190-200 pound TM400? Cool. A featherweight monster waiting to pitch you into the dirt? Not so much fun. Just my humble opinion. As a side note, I do recall several years ago Dirt Bike or some other mag had an article where someone had built a 167 pound CR125. Used every trick and lightest piece known to man, and carbon fiber bodywork. I am pretty sure a stock modern-era CR125 starts out way lighter than a TM400.
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Joined: 31 Dec 2008
Posts: 705

PostPosted: Sun Jan 17, 2010 8:14 pm    Post subject: Reply with quote

there is another thread on this somewhere if you look/search. I was there the day at Glen Helen when this bike was raced. I remember when the TMs came out new (all of us wanted TM125s as upgrades over the AT-1s we had) and several freinds and local racers had TM250 & TM400- which we called leg-breakers and Widow-makers because of the evil handling and light switch powerband. I can tell you this particular bike handled like no other. Deadly fast and stable with no hop on straights and woop sections and could easily carve under any bike on the track in turns with no instability visible- it just tracked like it was on rails. I also looked at it up close in the pits as the owner went over the list of components and about the only thing stock was the tank and maybe the seat. Frame and swinger were fabbed by aftermarket house and everything else was either custom made or lightened. We didn't have a scale to weigh it or any reason to doubt the owner after watching it in action and listening to the rider rave about it..
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Joined: 31 Dec 2008
Posts: 46

PostPosted: Sun Jan 17, 2010 9:44 pm    Post subject: Reply with quote

I have built a replica of DeCoster's '72 RN370, custom frame, aluminum swingarm, billet clamps, emulators, Ohlins, with fins,TS crank, modern KX 500 ignition, special head, hand hammered aluminum tank, perfect paint job and lettering. Not built to be as light as possible, it is 208. Easy to start, smooth and fast and stable. It is for sale at the right price, $8,000. If you would like any photos, e-mail me at Thanks, JP.
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Joined: 01 Jan 2009
Posts: 31

PostPosted: Wed Jan 20, 2010 10:33 pm    Post subject: Gordy its not 170lbs. I lied. Its a 171.4 lbs TM400 Reply with quote

Well to all you TM400 experts that think a 170 lb TM400 is not possible?

Your right. Its really 171.4 lbs. with oil.

With enough money you can achive anything. Just to let you know the bike started out at 240 lbs. We have a lot more resorces today than we did back in 1972 when titanium was truely rare. Well this thing has more custom titanium parts than most works bikes with ideas from Bill Clem and lot of help from Eric Cook at Maico Only plus thousands of dollars in just titanium nuts and bolts from Richard at MetTec. I took my fishing scale to Chaparral Motorsports and weighed all the tires to find only the light ones. There is 2 to 4.5 pounds difference between manufacturers in just tires. Aluminum rim locks. The motor and been chopped to remove unwanted weight. The head was cut down, fins removed and reworked. You would be surprised at how much weight you can cut out of a motor that had a oil pump. Almost all the bolts inside and out on the motor are titanium. Yes, special porting and a wicked Pro-Form pipe makes this bike one of the fastest open class bikes around. Now no need for a special fly wheel or extra weight to smooth out the power. The frame is cut down and modified. Its not a TM tank or seat, just looks like one. They were way too heavy. The tank now weights about a pound and the seat is two pounds. The spokes were special custom made at Buchanans SS steped down. Both front and rear hubs are not TM but magnesium hubs. The swingarm was custom built to be light and accept a non-TM rear hub and saved major weight and is super strong. The steering stem was custom fabricated. All the hose clamps are titanium. The kick start lever is aluminum as is the shift lever. The kick lever was really difficult to come up with. I weighed chains to pick out only the light one. Even the brake pads are drilled out. This darn thing took almost a year to build. Eric Cook ask me "Why a TM400?" Well, because I could? Yeah, I could have built 3 or 4 really nice bikes for what I got in this TM. But I have to say its really cool lightweight weapon for all of us big belly guys racing against the flatbelly's. We don't want to stop eating cheese burgers. I have to give credit to Eric Cook for the custom titanium parts and making the front forks and rear shocks work so well. He really knows how to dial in Ohlins. This guy doesn't sleep at night so he can think up new ideas to make bikes faster, better, lighter and stronger.

All the issues of the stock TM were cured. This bike is close to as light as a early Elsinore 125, now with tons of usable power that handles very well. It was never ment to be a works replica, just one kick ass open bike. But as Eric Cook say's its still not a Maico.

My new CZ 380 is almost finished and its really going to be nice too.
Anyway, there is a lot more to making a 171.4 lbs TM400, but with time, todays technology and money it is possible and I have the Certified Scale ticket to prove it. The best part, its dialed in. If you have any questions you could E-mail me or talk to Eric Cook or Bill Clem. BTW: JP's TM400 is a true works replica and a bargin.
Roger P. Granger

Last edited by rogergranger1 on Sat Jan 23, 2010 3:51 am; edited 1 time in total
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Joined: 31 Dec 2008
Posts: 60

PostPosted: Fri Jan 22, 2010 7:33 am    Post subject: Reply with quote

Roger, with a bike like that, you've got to give us some pictures. I'm looking forward to checking that bike out.
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Joined: 31 Dec 2008
Posts: 52

PostPosted: Fri Jan 22, 2010 12:03 pm    Post subject: Re: Gordy its not 170lbs. I lied. Its a 171.4 lbs TM400 Reply with quote

rogergranger1 wrote:
This bike is close to as lite as a early Elsinore 125....

Actually, assuming that your TM-400 weighs what you claim it weighs, and I have no reason to doubt you, your TM-400 is roughly 10lbs. lighter than an early CR-125M Elsinore. A couple of quick Google searches told me that the little Elsie is 180lbs. or 189lbs. with a full tank of gas.

You said that your frame was "cut down and modified". Does that mean that you're using a factory, steel TM-400 frame? Or did you cut down and modify an after-market frame, such as a Cheney?

If anything, a stock TM-400 frame needs to be beefed-up and reinforced. Anybody that's ridden one aggressively knows that they were prone to flexing. Magazine test articles used to joke that the big TM frames had a hinge in the middle, they flexed so much.

I know someone with a Cheney-framed TM-400. He told me that it weighs about 185lbs..

171.4 lbs. with a stock steel Suzuki frame would be most impressive....even if it were lightened up by cutting off all the unnecessary "extras" such as mounting tabs for the oil tank.

If someone took every single nut, bolt, and screw that comes stock on a TM-400, put them in a pile and weighed it....what would that weigh? How much weight would be saved by replacing ALL of these with titanium? Not including the axles and swing-arm pivot, of course, unless those are also titanium on you bike.

You said that your motor was chopped to remove unwanted weight. What exactly was chopped off? The excessive aluminum around the oil pump enclosure? My TM-400 runs on pre-mix too...I'm aware of removing the mechanism that drives the pump through the transmission...but that can't be more than...what...a few pounds? The pump certainly weighs almost nothing. The oil tank and lines are plastic....greatest individual weight savings in removing the oil injection system is probably the weight of the oil inside the tank.

As for the cylinder head fins being lightened...even if you totally removed every single fin, how much weight savings is there?
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Joined: 31 Dec 2008
Posts: 791

PostPosted: Fri Jan 22, 2010 1:50 pm    Post subject: Reply with quote

171.4 lbs. That's just way too cool. Yes, Roger, you have to post pics.

Titanium hose clamps? I'm impressed, you're serious about it if you go to that extent. You have to have a fortune in this bike. Care to give us a ballpark figure?
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Joined: 01 Jan 2009
Posts: 31

PostPosted: Sat Jan 23, 2010 3:48 am    Post subject: Just for Gordy. Reply with quote

This one's for you Gordy.
Like all good engineers we keep detailed records. This is how the rounded off weight savings breaks down.

Motor/head Mods Savings 3lbs
Steering stem/hard. Savings .75lb
Handle bars Savings 1lb
Front Forks Savings 3lbs
Seat/harware Savings 5lbs
Gas Tank/hardware Savings 6lbs
Shifter/kick lever Savings 1lb
Chain Savings .75lb
Front wheel assem. Savings 8.75lbs
Rear wheel assem. Savings 11.75lbs
Expansion/silencer Savings 3lbs
Shocks Savings 1.5lbs
Front axle/hard. Savings .75lb
Rear axle/hard. Savings 1.25lbs
Torque arm Savings .25lb
Kick stand Savings 1.75lbs
Swing arm/tens Savings 6.25lbs
Frame Difference Savings 6lbs
Misc. nuts/bolts/inject. Savings 6.85lbs

I'M embarrassed to tell you how much I spent. But keep in mind I have more access today to exotic materials and first class machining than they did back in the 70's. It just shows that it all adds up. A little here and little there. The TM400 motor weighs in at 73lbs stock and the rest of the bike now weighs a little over 100lbs. It is extremely strong and can take one hellava beating and has. BTW: It wasn't the frame that flexes, it is the swing arm.

I bet I could get one more pound out of it with a custom rear brake lever and a couple more tricks?

I never owned a 125 Elsinore but I just figured it was lightest bike to compare too and my TM400 should be 10 to 20lbs lighter because I spent enough time and money to make it lighter.

Gordy, If you're a decent rider, I invite you to Southern California to a CAlVMX race where you can race it? Just bring your own gear. I'll even provide a cheese burger lunch?

Roger P. Granger Cell 626-484-7199
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Joined: 31 Dec 2008
Posts: 52

PostPosted: Sat Jan 23, 2010 6:01 pm    Post subject: Reply with quote


Thank you for that offer. At one time, I would have jumped at the chance to ride a bike like that. However, I had a total right hip replacement on Jan. 5th. My orthopaedic surgeon told me "no more running or jumping". I think that probably rules out vintage MX racing too.

I have two TM-400's...a 71 and a 74. The 71 is pretty much original but the 74 I built from the ground up for racing. I won two regional championships on it about ten years ago....+40 and 500 Sportsman Intermediate (1999 and 2000). Mostly because I went to most of the races. Haven't raced much at all since '04 for various reasons.

My 74 is a pretty competitive bike. It's got the TS crank and was ported by Wes Gilbert of Boyesen Precision Porting. I've also helped other people build TM-400's out of spare parts that I had laying around.

I have to congratulate you on building a 170lb. TM-400, especially considering that you're using the stock frame.
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Joined: 01 Jan 2009
Posts: 31

PostPosted: Sat Jan 23, 2010 10:33 pm    Post subject: Reply with quote

Come on down anyway and be my guest. We can watch some fine racing we have over here on the West Coast. My good friend and Ex-pro racer Dan Berg puts on one hellava show. He beats the likes of Kent Howerton and Rex Staten. He's that fast.

Roger P. Granger
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Joined: 06 Apr 2010
Posts: 5

PostPosted: Tue Apr 06, 2010 7:57 pm    Post subject: Reply with quote

i have read articles in cycle guide mag 1971,72 on how to make
your yamaha dt2, rt2mx under 200lbs. the rt2 mx with a stock frame.
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Joined: 08 Jun 2010
Posts: 52

PostPosted: Thu Jun 10, 2010 9:49 am    Post subject: Roger please post up some pictures of your Suzuki 170lbs Reply with quote

I am a big fan of light bikes but it seems yours may be the ultimate example of such. I had a super light bike back in 74-75 made from a OW12 Yamaha works bike out of Canada. The frame was broken as they had a problem with that and Profab made one for me that took all the works parts, timken bearing fork stem, mag clamps, hubs, mag engine etc. but I bagged the monoshock as the works shock parts were just not available and went with a laydown setup. Bike weighed 184 dry. It was awesome to ride and you could get out of shape etc and have little fear. It did take some time to get used as everything happened so fast on that bike. Body positioning frt to rear was super important and you had to move quick as the front would come up in corners etc. very quickly. I would like to look a pics of yours if you have them.
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