New guy here, a few questions!

Long story short, I rode as a kid on a CR80 first then a DR400 till I was about 18- went to college(that sucked) went in the Army, got married, divorced and had a kid- still have my son since about a month old- so I'm 36 now and my son(10yr old) really wanted a dirt bike so after making him earn it I found a used CR80 and got it for him- he's gonna have to grow into it for sure, just learning how to shift and can't quite hold the thing up. Pretty cool watching him learn though.

I thought I found a great deal on a bike, craigslist(yeah stupid me) bought it thinking I could fix it but I don't really have the time or knowhow so I went to the dealer and picked up a 2007 YZ450f for 3k-(120 hours on it, should I be concerned?) When in the hell did they start putting hour meters on bikes? We rode em till they blew up! So this bike is freakin bad ass, bone stock and scares me but I am really impressed, spent the last few days on it and I sure as hell aint a kid anymore i'm sore!

I've been lurking around here for info before I start in with the questions, didn't want to ask too many that have been asked a million times.

First off I'm 6"4" and 280, pretty sure I need to set the suspension to handle my weight etc... I won't be doing anything too crazy on it and so far it's sucked up everything I've thrown at it but I was thinking it would need to be stiffened up front and in the rear?

Hard to find good fuel around here- everyone has 91, 91 with 10%ethanol, 93 with ethanol etc.. so I've just been running straight 91 with some lucas oil octane boost? Anything better out there or suggestions?

Seafoam ok to run through just to keep it clean?

A friend is an AMSOIL dealer was gonna change the oil and filter to start fresh since I don't know when it was changed last- what the interval now? I got five hours on it in the sand trying to keep it upright! 10-40 or 20-50? Weekend rider mostly, planning on riding through late October b4 winter sets in.

In reference to the "other bike" it's an 01 rm250 with a bunch of new parts but wouldn't stay in second gear so I ripped it down and found that the bottom end is worn, each gear is worn and the dogs are rounded, the shift forks are worn and so on- although an older bike I'm looking for parts to get it up and running again so I can sell it or make smoke and just have two toys!

Anything I should know about the 07yz450f ??? back when I was riding "thumpers" were heavy and sluggish----that has all changed!

Thanks for the replies and sorry if I asked a bunch of stupid questions, just glad to be back on a bike

Im 40 and just got back into the dirt too. Had the same experiences as you with thumpers as a kid. Rode the crap out of them and they never blew up. Prolly changed the oil once a year. lol

These days, on todays modern bikes, I would change the oil about every 5 hrs and clean air filter after every ride. Also keep the chain clean and lubed for longevity. Other than that Im not going to worry to much unless I have symptoms.

go with the 10w-40 unless your riding in 100°+ temps, amsoil is a great oil and id recommend changing the oil(with oil filter) every 5-10 hours depending on how hard/where it was ridden. Also like ^^he said, clean the air filter every ride. 120 hours is getting up there for a stock motor, lets hope the dealer had everything inspected.

As far as suspension, at 280 you need stiffer springs, and me being 6'4" myself, renthal RC high fatbars and str lowered footpeg mounts made the bike a lot more comfy for me.

Use only the Amsoil MCF or MCV products specifically made for the job. The above recommendations regarding 10w-40 (MCF) I agree with.

You don't need more than 91 octane, so stop blowing your cash on the booster, but try not to use the E10 if you can. The 95 octane required by the manual is Research Octane, and equates roughly to a US anti-knock index of about 90.

Getting the correct springs for your weight is the single most important thing you can do to the suspension. Without that, it will never do what it should for you.

I picked up a used (approx 60 hours) 07 YZ450F in January. I had the valves adjusted and timing chain replaced. Both of those should be done ASAP if neither has been done. Heavier springs are going to be needed, I am 185 and the stock springs are about right for me. The bike is really sensitive to sag so replacing the springs and servicing the suspension will make a big difference in the handling. I am running MX51 tires front and rear and am very happy with them.

I like the the bike, I use it as a playbike riding with my 19 year old son. Its the ideal Vet bike. Watch the lower oil filter bolt, read the threads relating to how to deal with that. Run 2 inches of chain slack with a good quality chain.

That's about it,

Hope this helps.

KEEP IT COMING, I need all the info I can get!

The sales guy assured me 128 hours was nothing on a bike but everything I read on here is telling me to rebuild the engine, damn what did I get into?

The bike really seems to run great, lots of power, no slipping, no stalling, no leaks etc...

ok so a 07 yz450f with about 128 hours on it- where do I start? the dealer will bend me over for sure! There is a local smaller shop i'll call.

suspension work obviously! any suggestions on brands or places to get what i need?

Oil/filter change!

clean the air filter!

Change the plug?

Have the valves checked?

damn I hate to rebuild something I just got, thought I would be able to ride the thing forever- no symptoms yet but if one of you would list what you think I should have done to this bike to make it last that would be great.

How much are we talking to set up the suspension so its right for me? Again I aint gonna be throwin it in the air 60 feet and racing etc.. but it will run in the sand and dirt and mud and not just puttin around on. I aint too old to rip it up yet!

Before you panic, do two things:

  • Check the valve clearance
  • Have a leak down test done

If the valves are significantly out of spec, correct them and ride a few more hours and check them again. If they hold at the clearance you set, they're OK. If they close up right away, they aren't.

The leak down will give you a pretty good look at the condition of the top end and the valve sealing.

Both my '06's have about this much time on them and they're OK. The '03 I had was well over 300 by the time I sold it, and it was OK at the time, too.

Here's what I'd do if I were you, take a deep breath.. if the bike looks like it's been taken care of then you shouldn't have too much to worry about.

Try to find out if the top end has been replaced at all, no big deal if it hasn't been but I would look at doing that sooner rather than later. Parts-wise on that you're looking at about $135.

I'd also look at replacing the cam chain when you've got the bike apart, they're cheap (around $25 for an OEM chain) and easier to do while the top end is off. The left side engine cover needs to be removed as well as the flywheel to replace the chain (it did on my Honda anyway), which isn't a big deal.

I'm 215 lbs. and ride MX only, I went with heavier springs in the forks & shock. You'll thank yourself later !! And cheap at $150 shipped to your door, the guys at DSP were fantastic to deal with and will tell you exactly which spring rates you should go with for your weight :

Change the oil/filter, you could replace the spark plug - probably wouldn't hurt, check and clean the air filter and like you've guessed check the valves. Checking the valves takes a manual (or youtube vid) and a $4 feeler gauge set, if any of the valves are tight it's a little more work to re-shim.

Good luck !!

I have a 07 yz450f. I ride dirt and ice circle track. High rpms, wide open! I have three race seasons on it and I'm only starting to mildly consider opening up the engine. Change the oil and airfilters, early and often, they are cheap, rebuilding isn't. I've come to the conclusion the yamaha's are close to bullet proof. I doubt with what you are using the bike for, you'd ever have to do anything other than the regular maintenance. Ride safe, ride hard, have fun!

Well, I pick up my bike tomorrow, went with Race Connection springs gotta go in and set the sag and see how much different the bike will be set up for my big ass. I'll also find out about the results of the leak down test and valve adjustments etc.. I changed the oil/filter and put a new air filter in it, the oil that came out was really pretty clean but out in the sun it looked like it had a lot of metal in it so i'm worried, but hopefully it aint bad, otherwise I guess I'll be rebuilding it. I have another thread on here in regards to proper jetting/ carb adj for the pipe I just got (pro circuit t4), thought that might help even out the power a bit. Any other suggestions? I suppose just go ride the damn thing now huh?

I have 2 07 450's and every time I've changed the oil it kinda looked silver-ish, at first it kinda freaked me out a bit, but after many oil changes and no problems, I assume this is normal. apparently the used oil on the new bikes don't have the black dirty look like the old 500s.

I have a suppertrapp full exhaust system (awesome) its wide open with no cap or plates, I'm currently running a 48 pilot, and a 168 main with the needle at the stock setting. I have a works connection air fuel mixture screw I adjust a little depending on the weather. This combo seems to work ok for me, in a dirttrack race application. The t4 seems to work pretty close to the suppertrapp, so this setup might work for you?

Remember that there is a transmission using your engine oil. Transmission gears shed metal in a fine powder as a normal thing. One thing you can do about this is to use a magnetic drain plug to help keep some of it out of the system.

The fine powder is normal. A small amount of aluminum slivers from the clutch is also typical. What is abnormal is a sudden increase in any of it, or the appearance of a significant amount of larger pieces, particularly squarish looking "flakes".

Well so far the bike checks out pretty good as far as compression and valve clearance, the bad news is the clutch plates at some point were installed backwards and the inner hub and basket are shot, so I'm waiting on parts. Changed the suspension and got new tires MX51 front and rear and added a race connection skid plate and twin air cleaner. Don't get to ride this weekend which reallly sucks! Went with the Hinson clutch set up, good or bad?

Got the T-4 off ebay for a hundred bucks but need the mid pipe and I figured what the hell I'm a little ahead so I may as well look at getting the header too- yes I know after it's all said and done I could have bought a complete MRD cheaper but my bad.

New Hinson clutch made a big improvement on my bike. Really helped out with overheating on narly technical climbs. Get Ironman steel sprockets, the 450 while really wear aluminum sprokets and you will always have chain stretch. They pay for themselves. Check the steering stem bearings, the top seal is weak, especially if you power wash. If your in rocky conditions go tubliss and get radiator gaurds. Quick shot for carb is well worth it. Condition fuel in winter.

... the 450 while really wear aluminum sprokets and you will always have chain stretch.

Really? News to me.

If you ride in sand and run standard Renthals or something cheaper, then you might have a point as to the sprocket wear. But the truth is that what wears out sprockets in a hurry is a chain that wears too easily and becomes longer than it should be ("stretches"). Once you prevent that by buying a high quality, really durable chain like the Regina ORN6, you'll find that middle to top tier aluminum sprockets will hold up quite nicely for much less than the Ironman costs. I typically get two years from a chain and a Tag rear. During that time, the chain will usually need adjustment no more than twice after the initial run in.

So I've got it backwards? I thought the curving of the teeth caused chain stretch. Your saying chain stretch cases curving of the sprocket teeth. I used to go thru 3 sets of sprockets and chain a year, standard stuff, not expensive but not bottom of line. I up graded to o-ring chain & ironman sprocket, that lasts a year.

Yes, the chain is the culprit in that. A 520 chain is made with a pitch of 5/8" (0.625"). The means it's .626" from one pin to another, and from the driven face of one roller to another. The sprocket teeth are, obviously, made to the same pitch, so the driving face of each tooth is .625" apart.

To begin with, the roller spaces between each tooth are true half round, following a center point exactly between each tooth. With a new chain, the drive load is applied equally to all teeth that contact the chain, and at about the vertical center of each tooth, below the "chisel point" section. If the chain does not stretch, but the sprocket wears for whatever reason, the wear on the rear will occur on the drive faces of the tooth, and be properly centered vertically. This will cause the tooth spaces to become elongated so that they look more oval than round, and the teeth will become thin, but not "hooked" or "pulled over". On the front, the wear would occur on the driving (forward facing) side of the tooth, still vertically centered below the tooth point. Eventually, the face of the tooth will be worn into until it appeared hooked forward .

Normally, though, what happens is that the pins and internal bushings of the chain wear, and this increases the pitch of the chain to the point that it no longer fits the sprocket. The first result of this is that fewer and fewer teeth bear the drive load until only the first tooth in contact with the top of the front sprocket and the last tooth rolling off the rear sprocket are in contact with the sprockets at any given moment. At the front, as the sprocket turns, the next tooth up, instead of being able to glide smoothly between the rollers of the chain and engage, finds the roller farther back than it should be, and strikes it with the top of the tooth. This wears off the top off the drive side of the tooth, making it appear hooked backward.

Similarly, at the rear, the chain has become so long that that last tooth is still carrying a significant load as it rolls out of mesh with the chain. Whereas the next several teeth should be carrying the drive load so the last one can drop away from the chain line smoothly, the overlong chain wears at the top of the driven side of the tooth, giving it the familiar pulled forward look.

WOW! GREY, EVERYDAY i GET ON HERE AND i AM JUST AMAZED AT THE LEVEL OF INFORMATION! I'm well on my way to becoming an addict! My bike will be done friday with fresh clutch, tires, suspension(race tech) chain(regina oring) and sprockets, skid plate etc... snagged a full FMF Ti-4 system with powerbomb off ebay for 165 too! Hell yeah can't wait to learn how to ride the damn thing! I'm afraid to go to the track just yet as I know the little buggers on 80s are gonna blow right by me but screw it I'm almost 37 and excited to get back into it.

Thanks Gray. I 'll see if I can save some weight by loosing the ironman next year.

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