2002 250 I got for free has engine issues advice needed

[daverdfw]

Originally Posted by Triple Jim

Can the machine shop grind the journal one size under, and you use matching undersize bearings, and it'll be like new?

so a stupid question, what would the size be that I tell them to grind it to? The service manual doesn't seem to specify the different bearing sizes. Thanks for all the advice!

[Ram Jet]

Originally Posted by daverdfw

so we had it checked, all of the journals are within spec. The journal with the failed bearing has a gouge, the person at the machine shop said he would have to take enough off that it would be at the minimum. \

The gouge runs long ways, its smooth. I am sure it would work in the short term, and this will only be a track bike. Just not sure what else to do at this point.

So if I went with a crank off like eBay, what would the process be as far as what main and conrod bearings I would have to use?

If you buy a crankshaft on eBay it's a pig in a poke. You'll have to measure the main and con-rod journals before you know if you need standard or oversize replacement bearings. Possibly the seller will certify the crank is serviceable and if not refund your money. A new crank will cost you $475.43 (that's probably the best price you're going to find.) You might be better off buying an entire eBay engine, at least you would have a-lot of spare parts.

[Triple Jim]

Originally Posted by daverdfw

so a stupid question, what would the size be that I tell them to grind it to? The service manual doesn't seem to specify the different bearing sizes. Thanks for all the advice!

I don't know the available undersized bearings (sorry). With an American V-8, I normally buy a set of 0.010" undersized bearings and take them to the machine shop that's going to grind the crankshaft. The shop then does its magic and grinds very accurately so the bearing clearance is as I asked for. The last one I had done was a 289 Ford, which needed 0.0015" clearance on all the journals except the rear main, which was specified at 0.0010". I used Plastigage to check their work, and it was dead on.

Any decent automotive machine shop is very familiar with the stuff I'm saying, so they should be able to help answer your questions. You just have to find out what undersized bearings are available for our 250s. Or buy an eBay engine.

[juliusmichaelhonrada]

if your planning to fix the crank , ask the machinist what might be the cause of failure , show him the bearings and the journal , then go check the engine it could be debris in the oil , clogged oil passageways or lack of oil/oil filter etc , you must first fix the underlying cause of the bearing failure or else this repaired crank life may suffer the same fate again

[daverdfw]

I will take it to a machine shop and see what they say. None of the bearings are discolored , the oil and filter were new. So no idea if anything broke, but visually inspecting things everything looks ok. Only concern is the failed bearing connecting rod cap is snug and gotta really pull it to get it off. Make me wonder if it might be a little twisted or tweaked.

[Triple Jim]

Originally Posted by daverdfw

I will take it to a machine shop and see what they say. None of the bearings are discolored , the oil and filter were new. So no idea if anything broke, but visually inspecting things everything looks ok. Only concern is the failed bearing connecting rod cap is snug and gotta really pull it to get it off. Make me wonder if it might be a little twisted or tweaked.

The shop can put the cap on and measure the bore to let you know.

[daverdfw]

based one what I posted earlier, did I read the manual correctly in terms of which part # I need for the connecting rod bearing replacement?

[juliusmichaelhonrada]

Originally Posted by daverdfw

based one what I posted earlier, did I read the manual correctly in terms of which part # I need for the connecting rod bearing replacement?

you need a bearing that will give you the proper journal to bearing clearance(0.031mm -0.059mm) after the journal had been worked on. 1st you need to know how much mm of material the machinist will remove on the journal then find your stock bearing size , then add the material that was remove to the stock bearing size



example your crank big end journal was 30.00mm your stock bearing was a brown color coded so its 1.480mm-1.485mm thick, the machinist needs to remove about 0.005mm - 0.010mm of material from the crank journal. so the bearing you need will be the next color code black(oversize) with the size of 1.485mm-1.490mm .

After that, to further confirm this you need to use plastigage to measure the bearing to journal clearance when the conrod caps are torqued to spec 27 N-m(20 ft/lb).



The acceptable journal to bearing clearance is 0.031mm-0.059mm

[daverdfw]

Originally Posted by juliusmichaelhonrada

you need a bearing that will give you the proper journal to bearing clearance(0.031mm -0.059mm) after the journal had been worked on. 1st you need to know how much mm of material the machinist will remove on the journal then find your stock bearing size , then add the material that was remove to the stock bearing size



example your crank big end journal was 30.00mm your stock bearing was a brown color coded so its 1.480mm-1.485mm thick, the machinist needs to remove about 0.005mm - 0.010mm of material from the crank journal. so the bearing you need will be the next color code black(oversize) with the size of 1.485mm-1.490mm .

After that, to further confirm this you need to use plastigage to measure the bearing to journal clearance when the conrod caps are torqued to spec 27 N-m(20 ft/lb).



The acceptable journal to bearing clearance is 0.031mm-0.059mm

makes sense, I have plastigauge from my last 250 rebuild. 20ft on the conrod caps? The ones I took off were definitely not at 20, they took quite a bit of strength for me to bust them loose. I wonder if thats why the one failed? connrod torqued down too tightly?

[juliusmichaelhonrada]

it could be , too much torque will cause the bearing to bend and the clearance will change , you can inspect it by looking in the surface of the journal and the bearing.

this will give you some clues:
http://www.tribology.co.uk/services/...ring-failures/

[juliusmichaelhonrada]

when torquing the con rod caps you need the area to be oiled up or else it will read different torque values and might destroy your engine

[daverdfw]

here is a pic of the good conn-rod bearing
http://imgur.com/PMeH86N
and here is a pic of the failed one, looks like the one in the pic that says Causes: Inadequate bearing clearance, overheating, insufficient oil supply, excessive load, or operation with a non-cylindrical journal

http://imgur.com/NwLwmrO

[juliusmichaelhonrada]

Originally Posted by daverdfw

here is a pic of the good conn-rod bearing
http://imgur.com/PMeH86N
and here is a pic of the failed one, looks like the one in the pic that says Causes: Inadequate bearing clearance, overheating, insufficient oil supply, excessive load, or operation with a non-cylindrical journal

http://imgur.com/NwLwmrO

did your oil looks like this and smell like rotten eggs?

i believe the con rod caps tightness even without the bolts are correct just notice the teeth o the bolt where the caps sits its meant to be tight

if in doubt you can replace the con rod bolts

the bearings are cheap we got brand new bearings here in the philippines for around 2$(92 pesos) genuine from kawasaki assembly plant

[daverdfw]

Originally Posted by juliusmichaelhonrada

did your oil looks like this and smell like rotten eggs?

i believe the con rod caps tightness even without the bolts are correct just notice the teeth o the bolt where the caps sits its meant to be tight

if in doubt you can replace the con rod bolts

the bearings are cheap we got brand new bearings here in the philippines for around 2$(92 pesos) genuine from kawasaki assembly plant

the oil had been drained and filled with new oil before I got it. however I see in your pic near the oil screen how dark your oil is, and take a look at mine.

http://imgur.com/tPGi5GR
http://imgur.com/XG0KT7a

looks pretty think and sludgy to me.

[juliusmichaelhonrada]

mine was changed too before we got it but the metal particles remained at the bottom there was no black thick oil but the smell was of that of rotten eggs near the broken bearings, were not sure about the cause but heres my theory the bike had no oil filter in it particles may got into the bearing surfaces and destroyed the oil film

[daverdfw]

Originally Posted by juliusmichaelhonrada

mine was changed too before we got it but the metal particles remained at the bottom there was no black thick oil but the smell was of that of rotten eggs near the broken bearings, were not sure about the cause but heres my theory the bike had no oil filter in it particles may got into the bearing surfaces and destroyed the oil film

I just took my magnet, and there are tons of small metal fragments in that oil in the bottom, likely from the bearing. at this point I am going to take the crank to a machine shop, get it cleaned up and see where I stand from a tolerances perspective. Then plastigauge every bearing in there and if it is in good shape put it back together.

[juliusmichaelhonrada]

Originally Posted by daverdfw

I just took my magnet, and there are tons of small metal fragments in that oil in the bottom, likely from the bearing. at this point I am going to take the crank to a machine shop, get it cleaned up and see where I stand from a tolerances perspective. Then plastigauge every bearing in there and if it is in good shape put it back together.

The bearings are all consumable parts , you dont need to plastigage it, its cheaper to replace them all at once like they are 2$ a piece , what you need to measure are the journals

[daverdfw]

Originally Posted by juliusmichaelhonrada

The bearings are all consumable parts , you dont need to plastigage it, its cheaper to replace them all at once like they are 2$ a piece , what you need to measure are the journals

the bearings I looked up are like $12 a set. where are you getting them that cheap?

[juliusmichaelhonrada]

Originally Posted by daverdfw

the bearings I looked up are like $12 a set. where are you getting them that cheap?

from kawasaki here:
http://kawasaki.ph/commuter/about-us.php

[Triple Jim]

I'm not so sure how good that good bearing looks. It has some scratches and other marks that I'm not used to seeing on good used bearing inserts. The photo may be making it look worse than it really is, but it might be worth showing the guys in the machine shop.

[daverdfw]

so I took the crank to a machine shop. Its 5 thousandths below service limit as it is. So looks like I will be looking for either a new crank, and if cheap enough a new motor and keep this one for parts.