'05 YZ450F suspension on '05 YZ250F???

9 replies to this topic
  • KillerMedic

Posted October 16, 2005 - 08:53 AM


Hey all. Been a lurker here while I was stationed in Korea for 2 years. Well I am back now and have a dilemma.

I had not been riding for over 3 years and last bike was a '94 YZ 250 (still have it in the garage prepping to sell or part out.) I decided to treat myself to a new bike on return to the states. Well, being 6'3" and 240lbs I decided on an '05 450 and had the suspension sent to Enzo before touching it. I love the suspension. It is incredible what I can do to it (coming up short/long on jumps and hammering in the woods) and it soaks it right up like I never imagined possible with the old bike.

OK, the dilemma part now. I was not expecting the power of the 450. After not riding for so long and being a woods rider in the past, I can only go 1-2 laps on most tracks before my arms pump up so bad and hands become so useless that I need to rest or risk losing control and injuring myself and others. I thought it was mostly not being in riding shape but then I rode my buddies '03 YZ250F after a short rest from abusing myself on mine. Well I did 5 laps and only quit because everyone else had left the track and I went to see why.

Sooooo I am thinking I need to get a 250F for a while until I get my skills up to where I can handle the 450. What I need to know is if I get a stock '05 YZ250F, can I swap my current '05 450 forks and shock to the 250F. I know there may be a slight spring/valving diff on paper due to weight diffs on the bikes, but I had my 450 a bit soft for 60%woods/40%mx riding anyway. What I need to know is are the mounting dimensions compatable on the shock for interchangeability.

I don't want to just send the 250 suspension out to get done due to time constraints for my riding while I am on leave. I need to ride now!!! and can't wait for them to be sent out to get done. Thanks! Posted in Suspension forum also.

  • kgmlifter

Posted October 16, 2005 - 12:28 PM


I think you should just get used to the power. I'm not saying anything about your ability, just that there are times when that extra horsepower comes in handy. It's nice to not have to shift so much in the trails and up hills. I love the low end power. Just my thoughts. If you decide to downsize to the 250, I believe the forks are compatible.

  • kgmlifter

Posted October 16, 2005 - 12:35 PM


just checked out yamaha's website and the specs on the 450F and the 250F front suspention are the same...

48mm Kayaba inverted telescopic fork w/adjustable compression and rebound damping; 11.8" travel

  • mxmark

Posted October 16, 2005 - 12:52 PM


I have a deal working with one of the guys at work for his 2006 YZ450F Shock and Fork springs to go into a YZ250F that I am getting. I weigh 230 and he weighs 140. You will most likely be happy with the Enzo stuff from the 450 to go on the 250.

  • KillerMedic

Posted October 18, 2005 - 08:46 PM


OK, It looks like the '05 450 to '05 250F is dimensionally similar so can bolt up. It also looks like it will work with an '04 250F.

But before I wuss down to the 250F, I am going to try to make the 450 work. I have put an RG3 top triple clamp on with Pro Taper bars. I just installed a DR. D 8 oz. flywheel tonight. I will be putting a Quiet core/tip on my PC TI-4 to tame the power, or put the stock pipe back on. And I will start some serious conditioning and more frequent riding. Wish me luck....I see a long and painful road ahead....lol. But I'll be riding :banghead: so it will all be worth it!! :banghead:

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  • Matt96xr6

Posted October 18, 2005 - 09:53 PM


All the forks on the fullsize YZs will work within the same year.

96-03 are all 46mm interchangeable units.

04-06 are all 48mm units. All interchangeable but major differences each year. Keep in mind that the 125/250F/450F all use the same forks in 05. The 250 uses the same springs as the 250F but it is the ONLY 05 that got the passive bleed valving system. They are interchangeable with all other models, but be aware of the difference.

Now if you want to use the 48mm units on the 96-03 bikes, then get some clamps made for the 48mm units top and bottom. Either aftermarket or stock. Just use the stock steering stem .

  • KillerMedic

Posted October 19, 2005 - 12:13 AM


Thanks, I had figured out the fork situation as being just like you said. It was the shock that I was really not too sure on. I have been told that my '05 450 shock should physically bolt up to any year 250F. But the setup may need tuning to make it work.

  • Matt96xr6

Posted October 19, 2005 - 07:04 AM


Shocks are different lengths through the revisions of the swing arm.

98-01 are the same
02-04 are the same

Then 05

Dont know about the 06 if it works with the 05s, but since there was major revisions to the linkage and swingarms probably not correctly.

Now keep in mind the years that dont interchange may bolt up fine. But the different lengths in the shocks and the valving may cause problems in handling and bottoming

  • grayracer513

Posted October 19, 2005 - 07:13 AM


There's another issue; stem length. If you were to get an '04 250F, you would either have to use the '04 clamps on the '05 fork, or switch out the shorter steering stem from the 250F into the 450 bottom clamp. If you got an '03, you'd have to swap stems.

But, let me offer another solution. Switch the exhaust cam with a WR unit. That will somewhat soften the character of the engine, and then if you add an 8oz Dr.D flywheel, or the heavier GYT-R, you'll have yourself a gentler giant for under $300 that you can convert back into its old self any time you want. :banghead:

  • KillerMedic

Posted October 19, 2005 - 05:02 PM


Thanks all for the good info and suggestions. I have made a few changes and am gonna go try them out this weekend...a long 4 day for me. I'll post up when I get back if I have any magical revelations. :banghead:

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