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End of season maintenance YZ250

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Hello everyone, 

 

I have a 2012 YZ250 that I bought used at the beginning of last year and currently have 263.5 hours on it. The previous maintenance is as follows:

 

64 hours new piston and rings

84 hours new rings

117 hours new Jug and piston and rings

146.5 hours new piston and rings and crank

183.6 hours new piston and rings

199 hours new rings

226 hours new piston and rings

 

Everything above was done by previous owner and logged in service manual.

 

Mods done by previous owner:

FMF Gnarly pipe

Pro-circuit 304 silencer (to be replaced)

V-force 3 reeds

 

Bought the bike at 228 hours.

 

When I got the bike home I tore everything down except the engine.

 

All new bearings from the wheels to the linkages to steering head (none inside the engine)

refreshed the suspension, forks and shock with new fluid and seals.

Cleaned out the FMF Gnarly pipe with kerosene

Added a FMF Q stealth silencer

Added a Rekluse EXP 3.0

Added a Scotts steering stabilizer

Added CRF250R front brake, full system

Added Tusk oversized front rotor

New brake fluid front and back plus steel braided lines

Replaced clutch basket

Added TMV 9oz fly wheel weight

 

(I know some of this info may be unnecessary but I'm trying to paint the full picture of my bike to get the most helpful responses)

 

I race the bike in a 250c class in hare scrambles (I'm not very fast) and trail ride with it and also hit the occasional MX track.

 

The routine maintenance I do is clean the air filter after every ride and replace the trans oil every 4 hours or less, I use Shell Rotella 15w-40

I run a premix of 32:1 using Amsoil Interceptor, 3 gallons of leaded 112 octane, mixed with 2 gallons of 93 octane from the pump.

 

 

So my question is what kind of maintenance should I do to the bike before my first race of the new season on March 20th?

 

I was planning on Piston and rings at least, but I'm not really sure what the life of the crank and bearings are? Any suggestions about engine maintenance or chassis maintenance would be greatly appreciated!

 

So as of now the bike has 35.5 hours on it since I tore it down last as far as bearings go, and 37.5 hours on the piston and rings, and 117 hours on the crank.

 

 

 

If I missed any details let me know and I will be sure to add them.

 

And of course a picture of the bike because who doesn't like looking at YZ's

YZ250.jpg

 

Thanks!

 

 

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Wow. That is one lucky used bike to get that much love.

Youre right on the money and going an excellent direction.

Crank bearings can last the lifetime of the bike. Most people dont replace them until they have an issue. Its more of an insurance thing if theyre still good.

If you choose to do a bearing change anyway, theres a ton of offroaders that also love the WR gear upgrade at the same time.

Other good ways to spend your money:

-check squish and experiment with timing

-suspension revalve/respring (EXCELLENT investment)

-needle and slide changes/experiments/lectron carb

-porting and governor mods to mimic the X model

-that Rtech plastic update kit here on TT (i also like the white cycra kit)

-buy yourself some spare maintenance parts/experiment with tires,pipes (DEP), and gearing

-a larger tank/reserve petcock/lighting coils

-seats/bars/pegs

-a spare wheel for fast n easy tire/gearing changes

-the F swingarm mod for weight

-RG3 22mm offset triple clamps for sharper handling

I havent done ALL these mods to my own personal bike, but i have stalked enough threads to see lots of positive results.

Is the hour meter accurate? Ive heard of some showing triple the actual hours.

Edited by SellYour4Stroke
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Wow, thanks for an awesome reply.

 

I would say the hour meter is pretty accurate, it's got 10 races + my leisure riding on it so I'd say 35.5 hours is pretty spot on.

 

I am going to have to read more about the squish, I'm sure there are countless threads on here about it. (because I don't really know what it is) I have heard it referenced a dozen times but never knew what it was.

 

I did have the suspension set up for my weight and riding style by total control, forgot to add that.

 

This is my first 2 stroke so I am still learning stuff about it, but so far I love it.

 

Thanks again!

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- First thing is to replace the reeds. I just replaced my VF3 reeds with 130 hours on them, they were all sorts of open...

- With the AMSOil Dominator, you can easily go to 40:1 or 44:1 and never look back. You might have to rejet, but well worth it.

- No need for race fuel. Bikes with std compression do not benefit. Other than the sweet smell, doesn't help.

- 18" rear wheel - Better tire options, and the ability to run lower air pressure without pinching the tube

- Engine - I just replaced the piston at 130 hours, looked like it could do another 50 hours...

- Optional - Upgrade the plastics to the 2015 model...Group buy going on now 🙂

 

Other than that, can't think of anything earth shattering...Sounds like you have the hang of things.

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At the very least I would put rings in. Measure the gap when you take them out and log it for future reference.

Piston is probably fine but measure it any way.

Using a dial indicator to set your timing is a good way to check your bottom rod bearing. Otherwise just pulling up and pushing down on it will let you know if there is play in it. ...but the rod bearing with only that much time on it probably isn't ready with the oil and mix you're running.

Crank bearings with proper oil mix and no contamination from dirty air filter or an air leak or a water drowning should last 300-400 hours.

Hope this helps.

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- First thing is to replace the reeds. I just replaced my VF3 reeds with 130 hours on them, they were all sorts of open...

- With the AMSOil Dominator, you can easily go to 40:1 or 44:1 and never look back. You might have to rejet, but well worth it.

- No need for race fuel. Bikes with std compression do not benefit. Other than the sweet smell, doesn't help.

- 18" rear wheel - Better tire options, and the ability to run lower air pressure without pinching the tube

- Engine - I just replaced the piston at 130 hours, looked like it could do another 50 hours...

- Optional - Upgrade the plastics to the 2015 model...Group buy going on now 🙂

 

Other than that, can't think of anything earth shattering...Sounds like you have the hang of things.

+1 on everything... I will say that when I bought my yz it was completely stock and was detonating with out race gas. I went 3:1 with 100LL and it cured the problem. I would HIGHLY recommend you check the ignition timing and squish before you try going to 91. I was 4 degrees advanced. Its a pretty simple process there's a good write up here

https://thumpertalk.com/topic/584339-yz250-timing-thread/?hl=%20timing

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At the end of each race season I check the parts that wear the most and replace them if they aren't in spec. For example I check piston/rings, clutch plates/springs, chain and sprockets, reeds, spark plug...etc. to just freshen up the bike you don't need to get too crazy if it's not needed

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I did have to run 1/2 gal of 110 to 4 gal of 93 oct of 36:1 of Amsoil Dominator to keep from detonating . I got about 400-500 hours out of my first YZ that I did not buy new ( It barley finished thece  I was on at the time , but it did .. And 400 hours on the mark out of my 2011 that I purchased new , out of the crank and bearings .I'm anal about checking stuff though . Flywheel side had no movement . In my experience if if you think your loosing oil from the trans to the crank its probably time for bearing at least . But , I had one race that took out the original wrist pin and bearing at 125 hrs . Nothing but powder that got through the filter . Several KTM's did not finish this one . Mine did but, was making a hint of noise . I am currently  Super Slow Senior A rider . I have a good day occasionally . This is just my experience , may not be yours .

I

+1 on everything... I will say that when I bought my yz it was completely stock and was detonating with out race gas. I went 3:1 with 100LL and it cured the problem. I would HIGHLY recommend you check the ignition timing and squish before you try going to 91. I was 4 degrees advanced. Its a pretty simple process there's a good write up here

https://thumpertalk.com/topic/584339-yz250-timing-thread/?hl=%20timing

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Seem to be on top of most everything. I know you mentioned replacing your linkage bearings, but at the end of the season I would clean and repack them along with the swingarm. They can get pretty dirty after a season of riding/pressure washing.

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