How many hours on your 450 before rings?


26 replies to this topic
  • qwik12beat

Posted November 06, 2008 - 02:51 PM

#1

Im starting this thread to see how many hours you guys get out of your bikes before you have to replace the rings. Be sure to include your riding style. Thanks

Im going on 45hours on original rings. Is that bad? I ride pretty hard. The bike seems to be losing power, but im thinkin that im just getting used to the power. BTW jetting is dead on.

  • KJ790

Posted November 06, 2008 - 03:03 PM

#2

I change piston, rings, and cam chain every 50 hours on the hour meter. I race MX in the A class, so my bike gets run pretty hard. A lot of people run them for 100 hours or more. I would change the cam chain at least every 50 hours though.

In my mind there isn't really a reason to change rings and not the piston. If the rings are so worn that they need replacing, the piston can't be too far behind. Even if your piston isn't worn at all, why go through all the work of taking it apart and spending money on gaskets and rings and not just spend the extra $80 on a piston?

  • qwik12beat

Posted November 06, 2008 - 03:15 PM

#3

What district are you in? I raced 250A district 11 a couple years back. I mostly woods race anymore, but im still hard on the bike:smirk: This is my first four stroke. I've had it for 2months:thumbsup:I completely agree about changing the piston and rings at the same time.

  • Justin89

Posted November 06, 2008 - 03:23 PM

#4

I went 200+ hrs (all racing) on my 2006 before I did a top end rebuild. It ran like a top until the day I tore it down. :eek: :worthy:

  • KJ790

Posted November 06, 2008 - 03:26 PM

#5

What district are you in? I raced 250A district 11 a couple years back. I mostly woods race anymore, but im still hard on the bike:smirk: This is my first four stroke. I've had it for 2months:thumbsup:I completely agree about changing the piston and rings at the same time.


I mostly stick to district 3. I live right in the middle of the district, so to go to any other districts it is a long drive in every direction.

  • qwik12beat

Posted November 06, 2008 - 03:27 PM

#6

I went 200+ hrs (all racing) on my 2006 before I did a top end rebuild. It ran like a top until the day I tore it down. :eek: :worthy:


Sounds good to me:ride:

  • qwik12beat

Posted November 06, 2008 - 03:29 PM

#7

Where i live now im in district 5. I havent raced here in a long time though.

  • grayracer513

Posted November 06, 2008 - 04:00 PM

#8

Roughly 200 before I did the rings on my son's '06, which I only did because of the head gasket losing water very slowly.

On my '03, I racked up about 400, and never had it apart.

  • Smokeslider

Posted November 06, 2008 - 07:07 PM

#9

hey gray, during those 200 and 400 hours, how often did you change cam chains?

  • grayracer513

Posted November 06, 2008 - 09:04 PM

#10

Twice on the '03, once on the older '06.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • KAS

Posted November 07, 2008 - 12:09 PM

#11

FWIW, anybody check out the lastest issue of MXA?

The Yamaha has the longest service interval recommendation for top end jobs, 40 hours vs. 12-15 hours on all the other Jap bikes. KTM recommends 40 hours.

Same goes for valve adjustments, too.

Interesting!

  • qwik12beat

Posted November 07, 2008 - 03:52 PM

#12

Some very good info guys. I know on my 07 the piston/ring inspection is supposed to be around 15 race hrs. They must have realized that people are getting more time out of them, and that 15hrs is for the most extreme conditions.^^^The yamaha also has one of the softest motors of its class. Less tear more wear:)

  • grayracer513

Posted November 07, 2008 - 09:09 PM

#13

The yamaha also has one of the softest motors of its class. Less tear more wear:)

That logic doesn't apply to the '03-'04 very well, I'm afraid.

The truth is the engine is a solid design, executed well, using quality materials. Simple as that.

  • KAS

Posted November 07, 2008 - 10:39 PM

#14

The yamaha also has one of the softest motors of its class. Less tear more wear:)


Its a magazine's opinion, so take it for what its worth, but Dirt Bike claimed that once you ditch the restrictive muffler, the '08 YZ motor was similar to an '08 CRF.

  • gtxkid

Posted November 08, 2008 - 07:10 AM

#15

My 2 cents
Change oil every 8 hours on a 4 stroke
You must change oil every 2 hours on 2 stroke and also must have a magnetic drain plug because of no filter in them like a 4 stroke.
Lot of people i know still try to apply what they had to do on 2 stroke to the 4 stroke ( Do not carry over the same info learned )

Best thing to do is a compression test and cycl. leak.

  • qwik12beat

Posted November 08, 2008 - 09:06 AM

#16

That logic doesn't apply to the '03-'04 very well, I'm afraid.

The truth is the engine is a solid design, executed well, using quality materials. Simple as that.


Ive rode them all, and i cant tell if the others are really making more power or if the yamaha just has a smoother hit.With my yz compared to my buddys kx450, my 450 feels like it has a flywheel weight on it compared to his. My friend ben has an "03yz and they are pretty darn mean. My 07 has a much softer hit than his, and they are both stock. I know the 03's are bad ass.What makes the 03-04's rip so good?On a sidenote,whats the stock compression ratio on the 07's?

  • qwik12beat

Posted November 08, 2008 - 09:19 AM

#17

Its a magazine's opinion, so take it for what its worth, but Dirt Bike claimed that once you ditch the restrictive muffler, the '08 YZ motor was similar to an '08 CRF.


Actually its just an observation i dont read mx mags. So what your saying is that in stock form a yz wont run with a crf unless you fit the yz with a slipon. Dont get me wrong i love the yz, but im just stating the my opinion.

  • grayracer513

Posted November 09, 2008 - 12:22 PM

#18

My friend ben has an '03yz and they are pretty darn mean. My 07 has a much softer hit than his, and they are both stock. I know the 03's are bad ass.What makes the 03-04's rip so good?On a sidenote,whats the stock compression ratio on the 07's?

It's the ignition advance map in the CDI. To some extent, it's the cam timing, too, as the cams on the '06, '07' and '08 are each recentered to have a greater bias toward top end power. An eye-opening comparison is an '03/4 vs. an '05. They all use the same cams, but you'd never know it.

i cant tell if the others are really making more power or if the yamaha just has a smoother hit.

Ah, see, you're onto something. The truth is that anyone who rides both would say that the '03 has more power, based on the huge hit it has, but the '06 produces about 49.5-50 hp, and an '07 produces about a half horse more, while the '03 cranks out only 47.

I ran my '03 against my first '06 from a rolling start on asphalt, and it was dead even 'til we got close to top gear, and the '06 started pulling away.

The thing is "butt dynos" aren't very accurate.

  • qwik12beat

Posted November 09, 2008 - 01:49 PM

#19

Thanks for the good info. I would also like to say that i re-jetted my bike today(170main)(45pilot), and it is running much better. The weather is really starting to change. I think the high today was 40 degree's.:worthy:

  • steve 112

Posted November 09, 2008 - 05:19 PM

#20

Since were off subject abit ill add my 1.5 cents.I have an 07 and I was pretty happy with it(pro moto end cap stock exhaust) untill I bought my son an 06 yz450f and rode that.I loved the bottom end hit it had.

Now for slippery tracks the 07 powerband probaply would be better but thats not what I wanted.

Put a DR.D pipe on it and it added to the bottom some and overall better except changing oil filter.Still not quite what I wanted so I put in a cp 13.5 to 1 piston and bored the carb out to 41mm.Little more bottom yet and a much improved mid to top hit.Id say it was real close to the hit of the 06 off the botom with more top.lastly I had a spare 06 cdi that I bought awhile back and slapped that on,seemed to add just off idle into the midrange.

Very happy with the power now I no longer need to use the clutch comming out of tight corners with little run at the next jump.Just lug it right down swat the throttle and it rips!





Related Content

 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.