Break in procedure on Wiseco piston, 1990 250


22 replies to this topic
  • wingrider02

Posted December 18, 2008 - 07:46 AM

#1

Hey all,

I tried to do a search on how to properly break in a Wiseco piston in my new to me 90 250, but I couldn't find any info on it here, or on Wiseco's website. I have read of a few folks on here that seem very knowledgable about these pistons, and undoubtedly know the proper break in, as I understand if this isn't followed, it tends to lead to premature break down.

So, this bike I bought has had a fresh top end rebuild in terms of hours (I'm not sure if it's been started more than once, and it quickly sheared the woodruff key) but it has been about 5 years since this has been done. I put a little bit of oil in the cylinder to help lube the upper cylinder, and I've changed the fluids, cleaned the carb, and added new fuel,but that is about it. I still need the woodruff key to show up for me to fire it up.

Looks like the jetting is all stock but the needle clip was all the way to the top of the needle. It also has some type of aftermarket pipe...looks like the signiture on it is a Pst racing...I've never heard of it, but maybe someone has. Also has a FMF shorty silencer on it. Do I need to adjust the jetting for the pipe like I would with a snowmobile, or does it stay the same?

Thanks for any help you can offer! :thumbsup:

  • 1BLUEsky

Posted December 18, 2008 - 08:25 AM

#2

I recently put one in my YZ so ill do the best I can. If I recall you ride it at varying speeds but only at part throttle for about 10 minutes.Do this three times rechecking all you fasteners between each time.Next using your regular fuel mix ride at a moderate pace for at least 20 min then come back and do a plug test by chopping your throttle,pulling in your clutch,and hitting the kill switch.If its looking good go out again and ride agressively for another 20-30 min and do another plug test. Thats about it , but Im guessing that needle setting is way as that would be very lean.
good luck

  • wingrider02

Posted December 18, 2008 - 08:38 AM

#3

That was my thought on the needle as well....Supposidly stock is the middle groove, but I wondered if the pipe required it to be leaned out?

  • hodgkins

Posted December 18, 2008 - 11:31 AM

#4

The pipe is probably a PSI. I used to run em on my CR500's. Great low end pipe for those, not sure what they did for a KX250. Haven't seen one in many moons.

  • wingrider02

Posted December 18, 2008 - 02:53 PM

#5

Thanks for the heads up on what the pipe might be....I'll have to try to snap a picture of the signature on the pipe and see if anyone recognizes it.

  • monster-04

Posted December 18, 2008 - 02:58 PM

#6

just take it easy for the first tank of gas, but at times go though all the power, thats just a normal way to break in any motor a motor is a motor just cuz its got a wiscoe in it doesnt mean its different... and that their procedure is better

  • wingrider02

Posted December 18, 2008 - 03:45 PM

#7

just take it easy for the first tank of gas, but at times go though all the power, thats just a normal way to break in any motor a motor is a motor just cuz its got a wiscoe in it doesnt mean its different... and that their procedure is better


I wasn't sure being I had read on some of the posts here that the wiseco's needed some sort of a break-in that was different than what I was accustomed to, but I figured it had to be something along the lines of heating it up, and letting it cool down a few times, and take it easy the first few rides.

Thanks for the reply! :thumbsup:

  • Chokey

Posted December 18, 2008 - 06:37 PM

#8

[color=blue]From Moto814[/color]

1) Assemble the engine properly and torque all fasteners to specs.

2) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

3) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

4) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), shut it off.

5) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

6) Start the engine with the bike on a stand and allow the engine to come up to operating temperature (top of the raidator hot to the touch). Do not allow the engine to run at one RPM at all. Constantly vary the RPM and do not allow the engine to idle. When then engine reaches operating temperature (about 3 to 5 minutes of running time), take the bike off the stand and put it in gear. Take it for a ride. During this ride you want to keep the engine under a load at all times. Do not coast. Do not let the bike idle. Do not allow the engine to stay at one RPM. Riding on a mild slope is fine for this, as is slightly dragging the rear brake the entire time. Do this for about 15-20 minutes. Then shut the bike off.

7) Let the engine cool completely (at LEAST one hour). You want the engine to be dead-stone cold. Longer is better.

8 ) Re-torque the head and base nuts.

9) Go ride.

The cool-down steps are crucial to this operation. You must let the engine cool completely for the break in process to work properly.

Also, do the warm up procedure I outline here before EVERY ride. Your top ends will last much longer if you do.

-Steve


  • wingrider02

Posted December 18, 2008 - 06:46 PM

#9

Thank you much...that was what I was wondering, as far as how many times you need to run it, and let it cool down.

Like I said, I don't know how much it has been run since the rebuild, but I'm going to treat it like it was once.

I appreciate the help! :thumbsup:

  • mihylo33

Posted December 19, 2008 - 04:37 AM

#10

The important parts, warm it up really well with out over revving. let it cool down which is important. warm it up again and let it cool down. total time about 2hrs. don't switch gas or anything unless you are using a full synthetic oil and didn't assemble it with a petroleum based oil or equivelent. The cool down process is important because thats what seats the parts properly.

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  • wingrider02

Posted December 19, 2008 - 07:48 PM

#11

I'm not real sure how this one was put together...heck, I don't even know for sure it's a Wiseco in her, they put stickers all over the bike which look new, so I can only guess they got the stickers from the piston package.

Either way, I figure it can't hurt to break it in like it's got a Wiseco in it.

Is there a reason I shouldn't use a synthetic oil?

  • Ho450

Posted December 19, 2008 - 07:52 PM

#12

WFO,:thumbsup:

  • Chokey

Posted December 20, 2008 - 07:09 PM

#13

Is there a reason I shouldn't use a synthetic oil?

No reason at all. Use the same oil you will be using all the time.

Not using a synthetic oil for break-in is nothing more than a myth. It won't hurt a thing.

  • mihylo33

Posted December 21, 2008 - 03:36 AM

#14

No reason at all. Use the same oil you will be using all the time.

Not using a synthetic oil for break-in is nothing more than a myth. It won't hurt a thing.



Chokey, I have read your posts before and they are always right on the money. I have to ask you this question though.
Is it a myth or is one supposed to use non synthetic to help etch the bearings and remove any glaze that might be on the machined parts.

The reason I ask is that We all know that synthetics have special polymers in them to glaze over parts to make them move more efficiently. For example when I bought my truck I was told not to use synthetic oil in the engine for atleast 10 to 15k because the parts needed to be broken in properly.

not to create a ruckus..... but I assemble with atf and break in with the same fuel I race with which is a synthetic blend.

  • Chokey

Posted December 21, 2008 - 05:15 AM

#15

There is no reason to not use synthetic oils, during break-in or otherwise. If it were true that synthetics interfered with the break-in process, how could some cars come with synthetic oil from the factory? How would these engines ever break in properly?

  • mihylo33

Posted December 21, 2008 - 07:21 AM

#16

There is no reason to not use synthetic oils, during break-in or otherwise. If it were true that synthetics interfered with the break-in process, how could some cars come with synthetic oil from the factory? How would these engines ever break in properly?


Maybe they pre run the engines???? I don't know, but I do know glazed bearings are not a good thing.
Maybe some research is in order for this. It could be just a myth like you said.

  • moto814

Posted December 21, 2008 - 08:13 AM

#17

Bearings require ZERO break-in.

Using synthetic is fine. Like Chokey said, use the same oil at the same mix ratio with the same fuel you will use all the time.

-Steve

  • Chokey

Posted December 21, 2008 - 09:54 AM

#18

Maybe they pre run the engines???? I don't know, but I do know glazed bearings are not a good thing.
Maybe some research is in order for this. It could be just a myth like you said.

I'm not sure were you're getting this "glazed bearing" issue from. I think you are referring to the esthers that some synthetic oils contain. They are polar molecules, and as such will "bind" to the metal surface of the parts. That is a completely different phenomenon than "glazing", which refers to a layer of carbon and partially burned oil that coats the bore surface.

  • mihylo33

Posted December 21, 2008 - 02:55 PM

#19

I'm not sure were you're getting this "glazed bearing" issue from. I think you are referring to the esthers that some synthetic oils contain. They are polar molecules, and as such will "bind" to the metal surface of the parts. That is a completely different phenomenon than "glazing", which refers to a layer of carbon and partially burned oil that coats the bore surface.


I must be thinking of something else entirely, but I do know that certain oils (maybe esther based or even castor based???) will cause a glazing of the bearings which leads to premature failure. Which one I don't know. Forgive my stubborness, but this is in pursuit of knowledge. I will research this some more and will post any findings.

  • CR480R

Posted December 21, 2008 - 04:00 PM

#20

The only case where I would avoid synthetic oil for break-in would be in an automotive engine with a flat-tappets...

I have used this procedure a few times with good results on 2-strokes:

http://cr500riders.c...um=1174005625/0





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