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Smitty55

How to mellow down a yz450f

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Hey everyone, quick question for you guys. I have a 06 yz450f that is awesome love the bike, just replaced the springs front and back for my weight, still working out the kinks to get it set perfect. My question is, this bike makes crazy power! Stage 1 hot cams , full yosh exhaust , and some other motor work all done by the previous owner. It has to much power for me getting back into riding after being off bikes for 5 years with a knee injury. What can I do to mellow it out some and get it feeling more like a 250. I have the stock cams and exhaust gearing is 14 50. I'm thinking of putting in the stock cams and going to a 15 tooth up front. Anything else you guys can think of to tame it down a little.

Jeff

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Hey everyone, quick question for you guys. I have a 06 yz450f that is awesome love the bike, just replaced the springs front and back for my weight, still working out the kinks to get it set perfect. My question is, this bike makes crazy power! Stage 1 hot cams , full yosh exhaust , and some other motor work all done by the previous owner. It has to much power for me getting back into riding after being off bikes for 5 years with a knee injury. What can I do to mellow it out some and get it feeling more like a 250. I have the stock cams and exhaust gearing is 14 50. I'm thinking of putting in the stock cams and going to a 15 tooth up front. Anything else you guys can think of to tame it down a little.

Jeff

 

Yeah, there's this little rubber-coated cylindrical device on the right side of the steering controls, and you rotate it less.  :ride:

 

No, kidding of course.  What is it about it that you want to mellow out?  Is it causing a whiskey-throttle situation, or just comes on too fast in general?  I'm by no means a fast rider, 48 now and just a weekend vet and main track guy, but I've never felt like I need a bike that was slower.  My '14 has aftermarket exhaust on it, and I'd love to have more power.

 

These bikes are so powerful that I get tired at the end of the day I can cruise a vet track in fourth almost the entire track (not so for main tracks, of course), and still clear everything.  They come on really softly in such a high gear, but will build speed and allow you to flow without feeling overly pipey or too powerful.

 

Do you mx or do more single track type of riding?

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I did 2 things on my 2010.

 

- 9oz Steahly flywheel weight: this made a noticeable difference, runs better on low rpm so on trails I don’t stall as easily and the power delivery down low seems smoother

- Change to the less hit map (I know this is not an option for you)

 

Although none of this really made the bike slower the better hookup and power delivery just makes the bike way more ridable. 

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Yes! Smoother throttle is what I'm looking for. it seems very choppy. I just started jumping again and I don't want to loop out again! Looking for less low end torque that's why I was thinking gearing as opposed to changing cams and such

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I don't understand why you just don't get a smaller bike? I can't get enough torque out of my 450r and am in the middle of porting stroker and big bore on it. But I like unbridled power and been riding over 30 years too. I wouldn't try to slow it down...

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I agree, maybe it's more of a mental block or something. I'm going to play with the slack on the throttle and maybe change the front gear and see what happens as far as smoothness and just get the seat time in to get comfortable. Thanks for the advice.

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Jcm3 I ride where I can. The "MX" track at fox valley off road is really not much of a track it's in the center of a off road park and it's not manicured like a regular mx track. Trails are fun but I like to race and enjoy doing it. I need to go to a actual track with nice jumps and see if the whiskey throttle is more the track and not the bike. Thanks again everyone for the responses.

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Jcm3 I ride where I can. The "MX" track at fox valley off road is really not much of a track it's in the center of a off road park and it's not manicured like a regular mx track. Trails are fun but I like to race and enjoy doing it. I need to go to a actual track with nice jumps and see if the whiskey throttle is more the track and not the bike. Thanks again everyone for the responses.

 

Gotcha.  Riding a gear high will definitely tone it down, particularly off the jumps, until you try some of the other things.  Fortunately, the four strokes don't have the hit of some of the two strokes (particularly the big bores), so can be smoother off of the jumps.  I had a KX500 recently, and always tried to hit the jumps a gear high because I was worried about wheelspin off the face or the front end coming up.  I remember reading an article about Jeff Emig at the '96 MXoN races where he had to ride the big factory KX500.  I remember him saying he rode it a gear high and almost coasted off the big jumps because if he didn't, he wasn't sure what it was going to do. 

 

You can really lug a 450 four stroke if you want to, and they'll still pull you over most obstacles.  Except on the really tight turns, you can probably pull fourth gear in most situations while you are learning the bike.  Recently, I was riding at the end of the day and for kicks ran the Milestone vet track completely in fourth gear.  I don't remember if there were any turns where I even downshifted to third that session, and it pulled pretty well.  I could barely get over the big table in the back, since there's a little jump in front of it that stops you from building up enough speed from the previous corner.  Fourth could pull hard enough with a little bit of clutch to get over it.

 

The track was wet and super slick, and it was at the end of the day when I was tired, so don't flame me too much.  :lol:   I'm old and slow.  Try it out and see if it mellows it out for you a bit until you feel more comfortable with it.

 

https://www.youtube.com/watch?v=6Uv9--WHjig

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How about a G2 throttle cam system?  That way you can tailor the throttle control to meet your style better.

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I would definitely ditch the cams and put the heaviest flywheel weight they make for it. It will be more controlable and more fun to ride.

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Find a CDI and OEM slip-on from an 08' or 09'. The shorty muffler and slightly different map really tamed the later model carb bikes. I think the header on the 08'- 09' models were slightly different also.

Edited by xcbuckeyeguy
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Leave the cams and exhaust alone, buy the heavier flywheel, and trade the CDI box out for one from either an '08 or an '05.  The CDI will make the most difference.  The bike, however, as is in stock trim, while very powerful on the whole, is also very linear, smooth, and predictable, and with just a little seat time, you can learn to manage it quite well.

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Thank you all very much! great info and i appreciate you taking the time to give honest feedback.  jcm3 that place your at is what i need to find! a few hundred laps around a place like that would really get me comfortable on the bike, and your not slow at all, I'm impressed! i feel like confidence is a big issue, but like everyone says seat time will make a hug difference along with a few mods.  I just ordered a new front sprocket 15T and now i will have 3 total i can change out and see what that does.  Im going to keep my eyes open for a cdi box on eBay.  Thanks again everyone.  I will check back soon after i go to a proper track and let you guys know how it is going.  

 

Jeff  

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So i know everyone said it but i will again GET A FLYWHEEL yamaha makes a +9oz and its makes a world of difference, less stalling, smoother power, easier to control in slow speed situations. Besided springs that was the best mod ive ever done to my yz.

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Got a Colorado CORCS series podium season finish on this bike 2 years ago , so have 100s of hours on it . One of the sweetest and gnarliest dirt bikes ever produced, and I've been blessed to try almost all of the modern bikes. More like surfing than turning a motorcycle, likes to slide the rear wheel like an old Husqvarna.

The flywheel weight is a huge bonus for everything other than Supercross/Tight moto.

I would leave the motor alone, add a 9 0z. flywheel weight, FMFQ silencer, and drop one or two teeth on the  rear sprocket.

Thin, light, feels like a 125 with 55 HP! Awesome fork and rear shock, slight Yamaspike in fork in midstroke without mod.(Matt Hoskins RG3 303-242-4314 took care of it)

 

06-09 YZ450f probably the most neutral, user friendly bikes of the time. Work with it. reliable as hell. Baja, Dakar winner. Worth putting money into as chassis is significantly better than earlier steel frames.

 

It's 2015 and theres not a $9000 difference between these bikes. I have a 2011 which rocks, but I like the slimness and turn-in on your year better. The fuel injection is priceless however, and the Jay Marmont map rips. But the Keihin  FCR on your bike is the pinnacle of 4-stroke carb tech and is crisp and seamless on the 2006-2009 once jetted properly.

Enjoy brother!

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Hey everyone, quick question for you guys. I have a 06 yz450f that is awesome love the bike, just replaced the springs front and back for my weight, still working out the kinks to get it set perfect. My question is, this bike makes crazy power! Stage 1 hot cams , full yosh exhaust , and some other motor work all done by the previous owner. It has to much power for me getting back into riding after being off bikes for 5 years with a knee injury. What can I do to mellow it out some and get it feeling more like a 250. I have the stock cams and exhaust gearing is 14 50. I'm thinking of putting in the stock cams and going to a 15 tooth up front. Anything else you guys can think of to tame it down a little.

Jeff

I put an 06 CDI on my 09 to give it some more go through out the power spread. I've still got my 09 CDI laying around if you want it. It was really smooth & mellow.

On another note, I'm selling my 06 CDI if anyone wants that one too. I just got a new bike, so I'm selling my 09 & all the extra parts.

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Yes! Smoother throttle is what I'm looking for. it seems very choppy. I just started jumping again and I don't want to loop out again! Looking for less low end torque that's why I was thinking gearing as opposed to changing cams and such

 

 

Keep in mind that the stock 2006 cams are very aggressive down at low to mid RPM.  Yamaha mellowed that engine out a ton in 2008 and 2009.   I really liked the stock 2006 engine, but plenty of people think it's too gnarly.

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When the '06 first came out, "everyone" said it was too mellow, even though it made 2 more peak HP than the '04.  That was based experiences with the '03 and '04, which "everyone" said were too aggressive.

 

The '08-'09 actually has a more aggressive cam set than the '06, and produce almost 2 more HP at peak, but the low/mid power delivery was softened by the timing map in the CDI.  Then, of course, "everyone" said that was too mellow, so the map was altered again slightly in '09 to beef up the bottom a bit.  The '09 was different than the '08, and was a kind of a nice compromise.  "Everyone" is still not happy, of course.

 

IMO, the '06 power curve is nearly perfect.  It's linear and predictable, when you open the throttle by any amount, you get exactly the results you expect at any RPM.  Pretty much if you can hear the engine, it's in the power range.  All you have to do is learn not to yank on the throttle like it was a 250 two-stroke or something, and the bike will be nice to you.

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