Another YZ-to-WR triple clamp question

24 replies to this topic
  • RockerYZWR

Posted May 17, 2015 - 08:28 AM


Can anyone tell me if a upper and lower triple for an '04-'05 YZ250F and 450F will fit the '07-'11 WR450? Looking at some 22.5 mm offset clamps used, and wondering if they'll fit.

Also willing to hear other advice in the realm of clamps and making this bike steer accurately and feel more planted up front (like my YZ250). I thought there was a cross reference chart on here somewhere on this subject but couldn't find it.

  • Krannie McKranface

Posted May 17, 2015 - 10:59 AM


Fork damping is 90% of the 'planted' feel.

If you have stock forks, it will never feel planted.


22.5's will make the front wheel have a larger contact patch when turning (trail), but if the forks are still not controlling the wheel, it will only feel better on smooth ground.


I took my 22.5's off and went back to stock, and with YZ forks properly tuned, it sticks like glue in everything but silt.

Edited by KRANNIE, May 17, 2015 - 11:02 AM.

  • Krannie McKranface

Posted May 17, 2015 - 11:01 AM


Oh, and the clamps are only 1mm wider, which you can ignore if you want, or , make a new spacer for the right side of the hub.

  • RockerYZWR

Posted May 17, 2015 - 06:24 PM


I'm running SSS forks on the WR, still with the stock shock, everything sprung just for me and around 105 mm sag.  I moved from the western desert and dunes to the eastern woods (there's actually still plenty of sand out here but no silt, thank goodness) and have really been loving my two stroke YZ.  Only thing is I have to drive an hour and a half to legally ride that bike, but can ride on hundreds of square miles of reserve land from pretty much right out of my garage, but you have to be on a plated bike, which I am.  So I'm going to start a little lightening up project and overall refresh on the WR soon, and thought about looking into clamps.  I started up this thread because I saw a solid deal on some used aftermarket triple clamps on eBay which is now over, but I really want to start trimming the bike down and making it handle in a more nimble fashion -- I would love to get down to YZ weights, but that's not realistic for me - I need a headlight/tail light/blinkers, kickstand, and protective gear, and I like having the odometer.  Hoping for the 260 lb range.


Now to completely derail and hijack my own thread, here's what I'm planing for this bike (later this summer):

- Remove starter (still kind of on the fence on this one because it starts up perfectly with either the button or kick and the button is nice sometimes -- if I keep the starter, then I'll get a Shorai for sure)

- Rekluse Core EXP 3.0

- YZ shock

- Send suspension out for revalve (probably Factory Connection since they did my YZ also)

- Enduro Engineering radiator braces (trading out my Mohards for some lighter-duty braces)

- Swapping out Flexx bars for normal/lighter weight bars

- Ironman sprockets

- Going back to standard tubes (from Tubliss), with new tires

- New plastics and graphics

- Lighter weight hand guards

- Eventually a YZ exhaust cam and Dynatek ignition


All in all, hoping to lose a few L-Bs, maybe make a bit more power, and give the bike a face lift.

  • Krannie McKranface

Posted May 17, 2015 - 07:48 PM


Get an Acerbis skid plate, and TMD shark fin and chain guide and you can remove another 4 lbs.

Factory connection radiator braces are very light (but are only good for light work)


It's not going to matter much in the end.


It's a top heavy bike with a massively heavy internal rotating mass (compared to a KTM for example) so it feels heavier the faster the motor is spinning......


Firm suspension and a great seat and ergos make the bike much easier to manange than trying to throw 'weight saving money' at the bike....


Getting it to come on the power as early as possible also helps a lot, as you can shift much less, and keep the motor spinning slower.

Carb tuning (apump especially) and the Dynatek make huge improvements.

  • grayracer513

Posted May 20, 2015 - 01:48 PM


22.5's will make the front wheel have a larger contact patch when turning (trail), ...


Not really.  It increases trail, but that has no effect on the amount of tire contacting the ground. 

  • toten

Posted May 20, 2015 - 06:01 PM


Is the WR crank/flywheel a lot heavier than a KTM 450?

  • Krannie McKranface

Posted May 20, 2015 - 06:35 PM


Is the WR crank/flywheel a lot heavier than a KTM 450?



I would guess double the weight

  • toten

Posted May 21, 2015 - 06:29 AM


Wow, why? Vibration or something else? Are YZ-Fs similar?

  • grayracer513

Posted May 21, 2015 - 09:45 AM


I seriously doubt that the cranks are much different in weight if at all.  YZF flywheels (magneto rotors, technically) are smaller than your gas cap, and the stators are little 4-pole items that produce only enough juice for the ignition.  WR450's sport a massive (comparatively) stator with 12 or more wound coil poles capable of delivering over 100w of DC power, and a flywheel to match, and that you can feel as smooth operation and good engine manners at low speed.  Except for the length of the left side axle, the cranks of the WR and YZF are the same. Can't say regarding the KTM, but I think it's safe to say that the crank will weigh pretty close to the same, while the weight of the mag rotor will depend on the specific model, as with the Yamaha.  Note, though, that even the SX-F is electric start, so the electrical system is much more robust than the pre-EFI YZF.


On the EFI model YZ450F's the generator was upgraded to be capable of a 140w output so as to be able to generate enough current at kicking speeds to run the fuel pump without a battery.  This puts the rotating mass of the WR and YZF on a much more equal footing, and yet the YZ feels much lighter and more nimble even than the older YZ's


The rotating mass of the engine is not really a factor in the maneuverability of the bike in any case.  If the engine's rotating assemblies produced a significant gyroscopic effect, you should be able to hold the bike upright without your feet by revving the engine up to 5 or 6 grand.  But you can't.   The wheels and tires produce much more of this effect than the whole of the engine does. 


Top heaviness is another matter.

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  • Krannie McKranface

Posted May 21, 2015 - 11:07 AM


  • Spinning wheels (and crankshafts, sprockets and gears) possess a quantity known as angular momentum (l = mvr)  The greater the mass, the radius or the speed of the spinning wheel the greater the angular momentum (and the greater the rotational inertia). The greater the angular momentum, the greater the amount of torque required to initiate a change in direction or lean angle in a spinning wheel.

  • grayracer513

Posted May 21, 2015 - 02:47 PM


No kidding. That's vector angular momentum, expressed as:  196af07f76dd370f8d47467640322f18.png right?


And after all that, you still have no ability to have the angular momentum of the engine's rotating mass hold the bike upright unassisted, nor even detect any difference in its tendency to remain upright with the engine on or off, nor any documentation regarding the comparative weights of the cranks you mentioned.


The crank is a relatively heavy assembly, so your numbers for m may be relatively large compared with your rear wheel, but the position of the mass, specifically how distant it is from the rotational axis ( r ), is far more important because it is squared twice, increasing its influence at those points tremendously, and is a multiplier of both mass and velocity, v. The crank is only about 6 inches in diameter, and the bulk of its mass is not concentrated at the outer edge of that dimension.  Shove an axle through your rear wheel, have someone give it a spin, then try and rotate the axle position.  The wheels, at roughly 27" in diameter produce a much more pronounced gyroscopic resistance to torque.  People who blame the effect of rotating crankshafts for difficulty in maneuvering a bike are fooling no one more thoroughly than themselves. 

  • RockerYZWR

Posted May 21, 2015 - 04:00 PM


Wow, science.  :thumbsup:


Where the engine is placed is the real key and all the parts of the motorcycle, including the engine, each have a moment about a point (CG).  Regarding angular momentum, because wheels, engine parts, and sprockets all spin in the vertical plane, they have a gyroscopic effect about the longitudinal axis of the motorcycle.  This is obviously what provides stability for a moving motorcycle.  This is part of why a whip can be brought back in and doesn't just send you off into space.  Like Gray said, wheels and tires create the effect far beyond engine rotating assemblies - a 2nd gear panic rev doesn't do nearly as much for you as does one in 4th gear.  


But the moment of the force of each component with respect to CG and the effect on handling is why Yamaha (and e'rybody else) spends so much R&D time and money on mass centralization.  The engine itself, regardless of the mass of the internals (relative to modern dirt bikes), doesn't drastically change the handling as long as the engine is at or very close to and oriented to CG.  The further from CG it is (being the heaviest component on the bike, besides the rider, which is a whole other topic), the greater the moment arm effect and shift in CG and the more significant effect it has on handling.

  • Krannie McKranface

Posted May 23, 2015 - 05:40 PM







Sure looks like one crank is waaaaay heavier than the other...........

Edited by KRANNIE, May 23, 2015 - 05:41 PM.

  • grayracer513

Posted May 24, 2015 - 07:37 AM


Obviously.  Just as obvious is the fact that one is nowhere near twice the weight of the other.  In either case, neither one will develop angular momentum (or "gyroscopic effect") sufficient to detectably modify the bike's overall maneuverability.


Less obvious is the fact that neither of those is a picture of the crank from a WR/YZ450.

  • toten

Posted May 26, 2015 - 06:06 AM


The engine is spinning a lot faster than the wheels, which contributes. While static weight at the center of mass doesn't do much, the gyroscopic action of the crank still does. 


I haven't ridden dirtbikes or supermotos enough to say, but on the track the reason a 600 turns quicker than a 1000 is mostly the crank. 

  • grayracer513

Posted May 26, 2015 - 09:37 AM


No, it actually isn't.  Once again, if the crank had a significant gyro effect, you would be able to feel the difference in the bike's tendency to fall over at a standstill between the engine revving and the engine idling or shut off.


When a motorcycle banks for a turn, it does not rotate freely around its roll center of gravity (the X axis of the CG), but rather, the bike's mass, including the engine swings through an arc with the pivot centered at the tire contact points.  The engines of the 1 liter bikes are considerably heavier than the 600's, and the banking is therefore harder to initiate and to arrest.  Because the tires are somewhat free at speed to move laterally out from under the bike, it ends up being a mixed motion, which does include some roll on center, but the 1000's are also wider, and that, combined with their extra weight, adds to the inertia that must be overcome in order to initiate a bank.

  • Krannie McKranface

Posted May 26, 2015 - 10:13 AM


It's more about top heaviness, than rotating mass, as mentioned.

  • MidlifeCrisisGuy

Posted June 15, 2015 - 01:37 PM


The stock WR450F TCs have 25mm offset.  The newer YZ250F/450F TCs have 22mm offset.   The bike handles quite a bit better with less offset and with the back end jacked up and the front end let down a bit.  Much faster handling, much better for in the trees.  Feels quite a bit lighter.


It takes a bit of machining to fit the WR forks to the YZ TCs.   The tube diameters are slightly different.  The YZ TCs need to be bored out.   I posted a thread on doing it, search is your friend.

Edited by MidlifeCrisisGuy, June 15, 2015 - 01:37 PM.

  • Krannie McKranface

Posted June 15, 2015 - 01:45 PM


The stock WR450F TCs have 25mm offset.  The newer YZ250F/450F TCs have 22mm offset.   The bike handles quite a bit better with less offset and with the back end jacked up and the front end let down a bit.  Much faster handling, much better for in the trees.  Feels quite a bit lighter.


It takes a bit of machining to fit the WR forks to the YZ TCs.   The tube diameters are slightly different.  The YZ TCs need to be bored out.   I posted a thread on doing it, search is your friend.


'12 - '14 ?


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