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New 2013 yz450f rear wheel hop plus a couple questions


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Hey so while I was breaking in my bike on an old abandoned street, I noticed whenever I got up to speed (4th 5th gear) and was engine braking, the rear wheel would sorta hop up and down. Not terrible but definitely noticeable. Any ideas? Bikes brand new and it was on smooth roads, the road was wet.

 

Also just gotta add, holy shit this bike is fast. Scary fast! I also had the bike flame out quite a bit on me, whenever doing u-turns it would stall if I wasn't on the gas, and sometimes just cracking the throttle in neutral it would stall. Most likely gonna send my TB in to injectioneering

Debating gearing, 49 or 50? I ride mainly tight trails but occasionally do long dirt road trips. I want my cake haha haven't decided for sure but I'm considering either full wr trans swap or hybrid 4th and 5th with a rekluse exp. I've searched lots and read lots of info, very helpful site.

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Turn up your idle it will help with the flame outs I had a13 and now a 14 I loved my 13 I think as it breaks in you'll see less flame outs and raising the idle. The back wheel hopping had to be with partial grab by the tire on the road surface congrats on the new bike. The bike has so much power going up one tooth won't make a difference.

Edited by cas747
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I forgot to mention about the idle, I'd read that on here I will def do that. Regarding the tire that's good to hear thanks! Kinda what I was thinking, partially grabbing because of the wet asphalt.

The gearing I'm thinking more along the lines of a slower first gear for gnarly obstacles, I don't wanna give up too much top speed though. I guess what I'm asking is how much difference does one tooth make for 1st gear and 5th gear?

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The hopping is from the wheel being out of balance due to the rim lock mostly. Also the tire and the wheel itself can contribute to this. Nothing to be concerned about, it's a dirt bike. Just be sure to check the rim run-out and spoke tension after break in.

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I doubt it's a wheel balance issue.  Probably has more to do with the the behavior of the knobby on wet pavement and rear suspension adjustment.

 

Before you take it out for some serious foolin' around, set the sag.  Start with it at 110-115mm.  YZ's in general have notoriously weak shock rebound and stiffish HS compression.  Start with the rebound out only about 7-10 clicks and the high speed comp at 1 3/4 out.  LS compression someplace in the middle of the range at 10-12.  Go from there.

 

A lot of people, particularly those who have a lot of seat time on older YZ450's, complain the the bike is light, or loose, or just weird in the front, but it's mostly because it's set up to be much more willing to turn than the older bikes ('09 and before), and it's very fussy about little changes in setup.  Talk to other guys, find out what they like, experiment, enjoy. ?

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I was out on it yesterday and noticed it while cruising on smooth gravel roads, maintaining speed. Leads me to believe it is the rim lock throwing it out of balance. Pretty minor. I have to set my sag and will try those adjustments Gray, thanks. Without setting sag I noticed pretty bad headshake at high speed. Probably not enough sag. What weight rider is the stock setup for? I'm 185 plus gear and it seemed pretty spot on. Also after riding it yesterday, I'm very happy with this bike! The down low power isn't an issue for me, I didn't feel it was too much. I turned the idle up 2 clicks and it never flame out once. It started very easily, 1 or 2 easy kicks every time. I found if I kick slower it works better, a medium speed full kick vs hard and fast. The power is unreal, wheelies are so much easier than on my wr250f. Same with jumps, this thing just wants to launch whereas the old bike would absorb too much on takeoff and wouldn't get much air. In the gnarly shit it wasn't bad, but I definitely need to go to a 50t rear sprocket. I was thinking a rekluse before but now that I've ridden it I'll probably leave it stock, and am seriously considering a wr tranny swap. I loved the low first and high 5th gear of the wr. I'm not sure I'm even going to get the injectioneering mod done, we'll see once I do the rear sprocket.

I wonder if yamaha is going to come out with a yz450fx like they are with the 250? 6 speed, e start racebike. That would be the perfect bike imo.

Gray when you say 7clicks out, that's from fully in position correct?

Edited by Zackdocks
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If you lower the forks in the triple clamps plus setting your race sag should help out with that steering wobble. I found about .350-400 from the top of the fork to the top of the triple clamp to be a good baseline for me. Also be careful when you set your sag, if that preload collar adjuster even feels like it's binding up I would consider you stop immediately. There's been a few cases in here where they seize up on the shock and ruin a couple of threads.

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Hey Gray where should I start with the Fork clickers? I went with your suggested starting points for the shock and sag.

Also, if I turn all the way in it usually goes half a click further. If I go back out to that first click, I assume that's zero, not one, correct?

Edited by Zackdocks
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 if I turn all the way in it usually goes half a click further. If I go back out to that first click, I assume that's zero, not one, correct?

 

Exactly.

 

On the forks, just start with the OEM baseline and tinker 'til it works.  For lumpy off-road, open the compression up anywhere from 5-8 to even farther, and back off the rebound 2-4 from wherever you put it for MX type stuff.

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Ok thanks Gray. Susp tuning is new to me, only thing I ever did on my wr was a little more compression and more oil on the forks, never touched the shock settings. I buggered up the preload collar on the yz, didn't realize I was supposed to just turn the spring to turn the collar and used a punch and hammer. Now the collar doesn't want to spin, need to order a new collar. Hopefully the threads on the shock body aren't mangled, I'll file them back into shape if they're damaged. Live and learn. Gonna grease it next time before adjusting.

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Two things on the preload ring problem that keeps coming up:

 

Use a good, strong penetrating oil/spray on the order of PB Blaster before breaking the lock ring loose, and then soak the adjuster ring before you try to move it.

 

Always do any adjustment with the wheel off the ground.  It's easier and keeps the pressure on the threads to a minimum.

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