HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
nucular

2008 YZ450 - locked her up

28 posts in this topic

I was doing some trail riding this past weekend and was coming up to a small hill in 2nd when the engine just immediately shut off and locked up.  I was able to push the kicker down once but once it came back up, it was stuck.  I bought this bike last summer and the PO could not tell me how many hours were on it.  Everything looked great - clean oil, clean radiator fluid, good chain, good valve clearances.  I checked everything and put an hour meter on so I would at least know how many hours I have put on it.  It always ran strong and no out of the ordinary noises as far as I could tell.  I have put exactly 6 hours on it this spring.

 

Now, to be honest, I found some magnetic shavings in the filter the last time I changed the oil.  Not a lot but enough to show up on my magnet pen.  I was hoping maybe transmission gears or something.  Just a small amount, no gold flakes or anything.  So my mistake, I should have probably torn it down immediately.

 

Anyway, I started the tear down last night.  I have not removed and split the bottom end but the head and cylinder are off.  The head looks fine, the cylinder has a small scratch on the exhaust side (I'm not sure if it is from this incident or not) but the rod does not spin freely on the crank so at least the big end bearing is shot.

 

Not knowing how many hours were on the bike, I think my plan is to just go ahead and replace the crank with a new OEM one, do a cylinder/piston swap from MT, and replace the cam chain.  Is there anything else I should do while I am in there?

 

 

Here is what I found in the filter cavity:

IMAG1370_zpsnzsdp40r.jpg

 

IMAG1372_zps5jsczibs.jpg

Share this post


Link to post
Share on other sites

Have the cylinder inspected and measured.  It might be alright. 

 

The chips in the second picture do definitely look like bearing flakes. 

1 person likes this

Share this post


Link to post
Share on other sites

OK, I should be splitting the case this weekend.  I haven't disassembled the head yet but I have not had any valve issues so i'm hoping that is OK and I only need to do the bottom end, piston, and maybe cylinder.  I think right now my plan is to R&R the following:

 

OEM Crank

Crank Bearings

transmission Bearings (4)

transmission oil seals and O-rings

bottom end gasket kit (includes many seals and orings)

top end gasket kit

cam chain

water pump oil seals and bearing

oem piston/rings/pin/circlip

possibly an oem cylinder depending on how mine cleans up

 

My questions are:

 

1) Does this sound like overkill or is this all the proper stuff to do? 

 

2) I plan on reusing all of the circlips for things like the oil pump, kick shaft gear, etc. so hopefully that is not a bad idea.  It's only another $5 or so if I did replace them all. 

 

3) The bottom end gasket kit has a note about other things that need replaced and it lists the 'water pump' and 'oil pump rotors'.  Are those commonly replaced during a bottom end build?  I was planning on reusing both.

 

4) If I do have to have the cylinder re-lined or replaced, would it be best to just buy a new OEM cylinder?  It seems like the cost to buy the OEM standard size cylinder, piston, rings, pin, and circlips is around $385 which is less than an athena replacement.  Doing a Millennium Tech cylinder replacement even seems more expensive than just buying a new one.  MT wants $215 + shipping for a cylinder swap and you can get an OEM cylinder for less than $250.

 

5) I'm looking at at least $700 in parts (not including a cylinder).  The rest of the bike is in good shape IMO.   Is this worth it or would I be better off parting it out and getting another one?  I had considered that but I would still be buying used which is always a gamble.  At least this way, I know that the motor is practically new.

Share this post


Link to post
Share on other sites

  1. Don't forget the chain tensioner

You can reuse most of the circlips other than the piston clips IF they are are not even slightly deformed by removing them.  Be critical.

The bottom set does not include the crankshaft oiling seal, the water pump seals, output shaft seal, or clutch arm seal.  These should be replaced.  The oil pump needs to be inspected and evaluated.

Most of the time with the 450's, it's near the same price to buy new OEM as opposed to replating, so that's how I roll it.  Might as well be new.

1 person likes this

Share this post


Link to post
Share on other sites

Thanks, Gray.

 

 

So I should replace the ACCT?  It looks like those run another $60 or so.  Here is my full list. I tried to go through the manual and identify everything they have marked as needing replaced and then I tagged the ones that were included in the bottom end gasket kit with an XXXX.  I'm leaning toward doing the rebuild.  $1000 (including the cylinder) or so doesn't seem bad since the bike is in pretty good shape overall.


Cover Gaskets
    XXXX 5TA-15453-00-00 clutch cover gasket ($10)
    XXXX 2S2-15462-10-00 crankcase cover 3 ($13.25)
    XXXX 2S2-15451-00-00 crankcase cover 1 ($8.57)

Crank
    crank - 2S2-11400-01-00 ($300)

 

Crank Bearings
    crank bearings - 93306-30633-00 ($40 X 2)

Cam Chain
     94591-57118-00 Chain ($18)

Oil Cleaner
    XXXXX 93210-47675-00 O-Ring ($4.25)
    XXXXX 93210-07135-00 O-Ring ($3 X 3)

Transmission Bearings:
    93306-20532-00 ($25)
    93306-00431-00 ($16.50)
    93306-00426-00 ($16.50)
    93306-205A5-00 ($24)

Transmission Seals/Orings
    XXXX 93102-32480-00 Oil Seal ($8)
    XXXX 93210-22298-00 O-Ring($5)

Gaskets
    bottom end gaskets - 5TG-W0002-00-00 $50
    top end gaskets - 5TA-W0001-00-00 $50


Water Pump
    93109-11073-00 Oil Seal ($8)
    93102-12321-00 Oil Seal ($7)
    93306-00105-00 Bearing ($11.15)
    XXXX 93210-19758-00 O-Ring ($3)
    XXXX 5BE-12439-00-00 O-Ring ($10.50)
    XXXX 90430-06014-00 Gasket ($3)
    XXXX 93210-16500-00 Water Pipe O-Ring ($5)
Oil Pump
    93440-10153-00 Circlip ($1)
    99009-12400-00 Circlip ($1)

Balancer
     90215-14287-00 Lock Washer ($4)
    90208-25045-00 Primary gear washer ($8.50)

Kick Shaft
    93410-20038-00 Circlip ($1)
    99009-16400-00 Circlip ($1.25)
    99009-20400-00 Circlip ($1.25)
    XXXX 93102-20108-00 oil seal ($7.25)

Misc
    XXXX 93210-10197-00 O-Ring ($4.25)
    XXXX 93210-08003-00 crankcase cover o-ring ($3)
    XXXX 90430-08119-00 drain bolt gasket ($3)
    XXXX 90430-06014-00 drain bolt gasket ($3)
    XXXX 90430-10188-00 drain bolt gasket ($3)

OEM Cylinder - 2S2-11311-11-00 ($238.55)
OEM Piston - 2S2-11631-20-00 ($95)
OEM Piston Rings 5JG-11603-00-00 ($33)
OEM Piston Pin - 5TA-11633-00-00 ($16)
OEM Piston Circlip  93420-18082-00 (.61 X 2)
 

Share this post


Link to post
Share on other sites

I didn't see the crankshaft oiling seal (93101-14164-00 ) on your list.  The first three cover gaskets you listed are included in the bottom end set.  In fact, you have quite a bit of duplication going on there.  Yamaha 's online fiche shows the contents of the two kits on the Alternate Parts; Gasket Kits page.

 

http://www.yamahamotorsports.com/partviewer/default.aspx?ls=sport

 

here's the list:

 

bottom.pngtop.png

Share this post


Link to post
Share on other sites

I didn't see the crankshaft oiling seal (93101-14164-00 ) on your list.  The first three cover gaskets you listed are included in the bottom end set.  In fact, you have quite a bit of duplication going on there.  Yamaha 's online fiche shows the contents of the two kits on the Alternate Parts; Gasket Kits page.

 

http://www.yamahamotorsports.com/partviewer/default.aspx?ls=sport

 

here's the list:

 

attachicon.gifbottom.pngattachicon.giftop.png

 

 

Hmmm... not sure how I missed the crank seal. thank you. 

 

Yeah, everything that is preceded with an XXXX is included in one of the two gasket kits.  I didn't include them in my cost.  I just wanted to make sure I had everything listed out.

Share this post


Link to post
Share on other sites

OK, last question I hope.  I split and disassembled the crank case and realized I was about 4 bearings short on my list.  There are a total of 10 bearings in the cases.  I missed:

 

balancer bearing - 93304-20310-00 (2 of these)
shift cam fork bearing 93306-90509-00
shift cam fork bearing 93306-80501-00

 

I presume I should knock out all of the bearings and replace them all, right?  My plan was to remove the bearings, clean up the cases in the dishwasher on hot, hand clean all of the gears, etc, and start the install/reassembly process.

Share this post


Link to post
Share on other sites

There's rarely a need to replace the shift cam bearings, but the balancer shaft bearings do lead a tough life.

 

If I had ever even spoken openly about cleaning parts in the dishwasher, I would not be here now.

1 person likes this

Share this post


Link to post
Share on other sites

Cleaned a q-jet carb in my dishwasher. Worked great. Just about ruined the dishwasher. Makes wife's really happy.

Share this post


Link to post
Share on other sites

Well, the plan was to clean it off with some simple green and a hose first and then use the dishwasher to finish it up.  I was also planning on sticking the cases in the oven to try to pop some of the bearings out so as long as I don't break the stove or dishwasher or stink up the house, I shouldn't take too much heat.  Our dishwasher is on its last leg anyway.  She may thank me.

Share this post


Link to post
Share on other sites

Using an oven, or even a gas grill with a thermometer on it (if you keep an eye on it) is a good way to manage the removal and installation of bearings, and even the crank, but be careful.  Keep the heat between 220-275, no higher.  Heat the cases for 15-20 minutes at that temp to even out the heat distribution in the part.  Repeat this when it comes time to install the new bearings, having placed the bearings in the freezer for at least 20-30 minutes and they'll drop right into their pockets.

Share this post


Link to post
Share on other sites

Have you found that you can easily get that bearing out that sits in a blind pocket with this method?  I was planning on renting or buying a blind bearing puller.  Also realized the clutch mechanism hides a little roller bearing down in there.  I'm hoping I can extract and re-use that one as well.

Share this post


Link to post
Share on other sites

I will recomended not using the dishwasher. Buy a new one first and put the old one in the garage. It is a pretty hillbilly parts cleaner, but it does work. My entire house stunk of old gas for days.

Share this post


Link to post
Share on other sites

Did you scrub the case out with gas before you put it in the washer? I sprayed mine out with simple green and rises it so it is already pretty clean. I was just planning on letting the soap do it's job and get it spotless.

Did you scrub the case out with gas before you put it in the washer? I sprayed mine out with simple green and rinsed it so it is already pretty clean. I was just planning on letting the soap do it's job and get it spotless.

Share this post


Link to post
Share on other sites

I was just planning on letting the soap do it's job and get it spotless.

 

So that you can fill it back up with motor oil?  Very well.  No reason to do that.

 

 

Have you found that you can easily get that bearing out that sits in a blind pocket with this method?  I was planning on renting or buying a blind bearing puller.  Also realized the clutch mechanism hides a little roller bearing down in there.  I'm hoping I can extract and re-use that one as well.

 

Yes.  The bearing you're wondering about is the left side main shaft bearing, which sits in a blind pocket, with the case heated, wearing gloves, slamming the center joint surface down on a flat sheet of wood, like the top of a wood work bench, will usually pop it out.   Again, don't exceed 275 ℉.

Share this post


Link to post
Share on other sites

So that you can fill it back up with motor oil? Very well. No reason to do that.

True. I suppose that's overboard. With all the bearings out and the hose down I'm sure all the bearing shards are gone.

Share this post


Link to post
Share on other sites

Does anyone know what the torque value is for the idler gear shaft Oil Pump Drive Gear shaft?  I don't see it in the manual.  The gear just sits on the shaft which is bolted to from the inside of the case.  Also should I use red loctite for the bearing retainers?  The manual just says loctite.

Edited by nucular

Share this post


Link to post
Share on other sites

That value is listed on 2-11 as "oil pump drive gear shaft": 7.2 ft lb/86 in lb/10 Nm.

 

Use red Loc-Tite, and use it on the retainer screws, too.

 

When using Loc-Tite, two things are important.  The threads have to be clean and oil free.  Use carb spray, then brake cleaner.  The other thing is to give it the full cure time on the label so oil doesn't degrade it before it sets up.

1 person likes this

Share this post


Link to post
Share on other sites

Thanks once again, gray. I had tried cleaning them up with carb cleaner but it didn't do much. I'll try some brake cleaner too. Would it be worthwhile to try running a bolt or tap through with the brake cleaner?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0