what gaskets to change during engine tear down?

[ebrammer252]

I know obviously the head gasket and block base gasket need to be changed out. What about the valve cover gasket, is it reusable? the camshaft journal gaskets? the water pump o-ring and housing gaskets? oil pump o-rings?

[ebrammer252]

Also, what's the this I hear about the bushings and color? I wasn't having any issues with the motor previously, tearing down just to access the transmission.

[CZroe]

Valve cover gasket is made with liquid gasket. It needs to be scraped off and remade. You can buy gasket paper and print your own gaskets.

Thanks to @n4mwd:
http://n4mwd.blogspot.com/2013/08/do...t-for.html?m=1

[jschorr]

gaskets are so cheap why reuse any? besides most are ment to be one use, even if they look good they are already crushed.

learned this the hard way when i was a kid, had to re-build a motor twice in one year because i didn't feel like waiting for the parts to come.

[ebrammer252]

Thanks for all the replies so far! I took the crankcase to a shop today and they pulled the flywheel off for me. I'm almost down to the transmission but I'm getting rather worried that I'll have to mess with the crankshaft bushings when I pop the case open. I can't tell from my FSM very well but it sure looks like it. Anything in particular to pay attention to when I get down that far?

[jschorr]

what are you worried about? your still in the easy part, the break down. it is after you put it back together and find extra parts that you should worry.

organization is the key. take a ton of pictures and label some egg crates to keep yours parts in order.

[ebrammer252]

Originally Posted by jschorr

what are you worried about? your still in the easy part, the break down. it is after you put it back together and find extra parts that you should worry.

organization is the key. take a ton of pictures and label some egg crates to keep yours parts in order.

Thanks for that! I've actually got a buddy coming over tomorrow who's a machinist to take a look at those bushings and make sure they're still usable. I'm just hoping this thing runs after I get it back together

[ebrammer252]

Originally Posted by jschorr

what are you worried about? your still in the easy part, the break down. it is after you put it back together and find extra parts that you should worry.

organization is the key. take a ton of pictures and label some egg crates to keep yours parts in order.

jschorr can I get you to take a look at my recent post with pictures here and see what you think about those bushings?

http://www.svrider.com/forum/showthread.php?t=261713

They no longer (if they ever did) have any color markings on them, so even if I wanted to replace them I wouldn't know what's what.

[cbinker]

i would say replace all of them since you got it apart.

[ebrammer252]

Originally Posted by cbinker

i would say replace all of them since you got it apart.

No way to know which ones are which.

[jschorr]

Wow, well you know that your head was good from all that carbon. It looks like your motor was abused a bit, Nothing terrible just normal starter bike abuse.
You know, lugged, fluids neglected.

So the crank bushings. That one is junk, I know you know that already. The others have a polished look to them, hard to tell with pics. Where that is not good it might be doable. Probably get 15k out of them if there set right.... Probably.

Not sure what you mean when you say you don't know where they go. Do you mean you forgot? I have not had a ninja broken down this far but if it like other things they should all be the same pairs of bushings. I checked eBay and looks like they go for around $10 a set. That isn't to much but idk how much you want to put into this.

[ebrammer252]

Originally Posted by jschorr

Wow, well you know that your head was good from all that carbon. It looks like your motor was abused a bit, Nothing terrible just normal starter bike abuse.
You know, lugged, fluids neglected.

So the crank bushings. That one is junk, I know you know that already. The others have a polished look to them, hard to tell with pics. Where that is not good it might be doable. Probably get 15k out of them if there set right.... Probably.

Not sure what you mean when you say you don't know where they go. Do you mean you forgot? I have not had a ninja broken down this far but if it like other things they should all be the same pairs of bushings. I checked eBay and looks like they go for around $10 a set. That isn't to much but idk how much you want to put into this.

The bushings are color coded from the factory as to their exact thickness. I assume (I don't know) this is done because tolerances might be different across the motors due to different molds, production runs etc. From what I understand there was from the factory a color splotch on there to indicate which the bushing is, but they wear off pretty quickly with use.

If you look at the parts diagram here you can see there are three different possibilities of color or "thickness" that the bushing could be.

http://forums.ninja250.org/posting.p...&t=69902&tro=1

[jschorr]

I did not know that one., Sorry. do you think you could get the information from your serial number? If not it looks like your going to have to measure them.

[ebrammer252]

Originally Posted by jschorr

I did not know that one., Sorry. do you think you could get the information from your serial number? If not it looks like your going to have to measure them.

I'm sitting in front of the engine right now. I pulled each bushing and cannot see any markings anywhere. I measured each one with a digital caliper and they all measured the same (1.50mm). Which according to the manual indicates that they are the 'blue' variety of bushings. So, assuming this is correct... my next step would be to plastigauge the current bushings and if they are in the acceptable limits then replace the damaged ones and if they are above the service limit then change to another 'color' or size? Does that sound correct to you?

[jschorr]

Yes, It sounds right. Though I am not sure why you would change sizes....unless because of damage to the crank...I might just be dense right now.

[ebrammer252]

Originally Posted by jschorr

Yes, It sounds right. Though I am not sure why you would change sizes....unless because of damage to the crank...I might just be dense right now.

I'm not even sure to be honest haha! I was just assuming if the camshaft journal wore you might have to change to a different bushing to accommodate that difference.

[cuong-nutz]

My understanding from what @mgentz told me is that most if not all 250s have the following:
Balancer = Blue
Mains = Yellow
Rods = Brown

[ebrammer252]

Originally Posted by cuong-nutz

My understanding from what @mgentz told me is that most if not all 250s have the following:
Balancer = Blue
Mains = Yellow
Rods = Brown

The manual doesn't even show the specs for yellow bushings....

For "Crankshaft main bearing insert thickness" it only lists :

Blue 1.499 - 1.503
Black 1.495-1.499
Brown 1.491 - 1.495

[cuong-nutz]

Originally Posted by ebrammer252

The manual doesn't even show the specs for yellow bushings....

For "Crankshaft main bearing insert thickness" it only lists :

Blue 1.499 - 1.503
Black 1.495-1.499
Brown 1.491 - 1.495

Hmm Interesting. I'm not well informed of the older generation 250s.

[mgentz]

Originally Posted by ebrammer252

The manual doesn't even show the specs for yellow bushings....

For "Crankshaft main bearing insert thickness" it only lists :

Blue 1.499 - 1.503
Black 1.495-1.499
Brown 1.491 - 1.495

If you cannot see the markings on the side of the bearing then do this. Look at the markings on the crank and compare them to the manual. This gives you an immediate indication of what bearings SHOULD go in. Buy those and plastigage them.

Another thing to do is to Mic the crank itself and use math and the manual to determine the size needed.

Any questions on this feel free to PM me.