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bluebreadtruck

My wr400 siezed today

19 posts in this topic

I was riding on a neighborhood road about to hit a dirt trail when i noticed my bike was bogging when i cracked the throttle a bit. I pulled over and put it in neutral while I turned the screw in a 1/2 turn..... while it neutral the idle seemed to drop, then it "clunk" died....I turned the kick starter over with my hand with the decomp lever in, and it kicked one full stroke, then HARD seized! Ran great all weekend! (although it got ridden hard)

Damn.... I'm pulling it apart now....Im thinking possibly an oil pump failure? how much does this happen? I checked the oil, it was full and still clean 300 miles ago changed.

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whell, I pulled it down. A bunch of metal shavings in the oil filter. The piston had some pretty good scoring along with the bore, but I think the problem lies in the bottom end, it turns over HARD without the piston and makes a metal-to-grinding feel sound!

looking at a 450 tommorow

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I took a look at a bike and realized that possibly i can save $2000 buying another bike just to swap out the engine.......

Anyone have a good way to verify i have a good oil pump, and if my crank is junk?

thanks again

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Ok, here is another Idea I just had.... What parts would I have to get for my 400 engine to install a 450 crank, 450 sleeve, and 450 piston?

Is this possible? I could just buy OEM and hopefully come in cheaper than buying another used 450 bike just for the engine. I figure if im gonna spend the coin, might as well make 450 power?

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Here is another option, actually two options for you. You could convert your engine over to a 426, I think your crank would have to be good. Or you could go with a 440 kit in it.

Check this website.

http://www.powroll.com/P_YAMAHA_YZFWR426F.htm

Try pricing out the parts on the list through the TT store. You may have to call them if the parts aren't listed on the website.

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Can't get from a 400 to a 450 using stock parts...cranks and stroke are too different. You can throw in a 426 crank (about 450 bux from the TT store, 50 bucks for main bearings from Motion Pro , and twenty or so bucks for the splined primary/counterbalance gears), and about 500 or 550 for a big bore kit (cylinder, piston, rings and gaskets) from Luke's Racing. That'll get ya to 444 and you will love it. Go with the 13.5:1 compression piston, too. The 400 head will bolt right up to the 426 barrel as well. I would suggest tearing apart the oil pump and measuring it (procedures and clearances are in the manual) and replacing the cam chain while the motor is apart. Also, as long as you have the cases split, I would replace ALL of the bearings inthe transmission and the balance shaft bearings as well. Motion Pro can match up bearings if you bring in the old ones or write down the AFBM number (stamped on the outer race most of the time) for about 1/2 to 1/3 of the OEM cost...it's cheap insurance that you won't be tearing the motor apart again to fix a transmission bearing.

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I hope some one can help me here. I removed my flywheel and found a broken peice of metal stuck to the magnet! Now the crank turns smooth and has no play....This may have been why it was binding up... BUT where did this metal come from? Any ideas? its thin and about 2" long, broke at the ends. I havent completely split the case, but was wondering if anyone woild recognize it. here is a pic of my piston and sleeve that had a bit of wear.... the oil pump seems to spin smoothly

wrbroke008.jpg

wrbroke011.jpg

wrbroke010.jpg

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I hope some one can help me here. I removed my flywheel and found a broken peice of metal stuck to the magnet! Now the crank turns smooth and has no play....This may have been why it was binding up... BUT where did this metal come from? Any ideas? its thin and about 2" long, broke at the ends. I havent completely split the case, but was wondering if anyone woild recognize it. here is a pic of my piston and sleeve that had a bit of wear.... the oil pump seems to spin smoothly

It looks like it may be a part of the 3 piece oil ring, especially since the piston and cylinder are damaged. If all your rings are intact, my next guess would be that it is one of the clips that locate the camshaft bearings in the head. There are 2 half round clips, one for each cam, and they look a lot like that.

Is it thin enough to bend easily by hand? If so, it's probably a piece of the ring.

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no its pretty thick. its not a ring...HOWEVER I realized that when i took the bike apart it NEVER HAD THE CAMSHAFT centering rings.... this explains alot... Anyone have a picture of what they look like? It looks as if the P/O never installed them, and this is where they may have ended up.... Ill go check the slots in the cam and see if this fits.....and aplit the case and see if i can find the otehr one!

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thanks very much. I just found the other one still attached to the cam, and yes that is exacly what it was. SO.... I just need to find a new sleeve and piston, replace that keeper and install a new timing chain and im back in buisness!

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It's not a sleeve...it's a Nikasil plated cylinder. Is the bore beat up? If it's not too bad, it may clean up with a hone. If it's galled or the plating is damaged, it will need to be stripped and replated. When I did my 426, it was a bit cheaper to buy a big bore kit from Luke's Racing than to either buy a new barrel, piston, etc or to send mine out to be stripped and replated, then buy a new piston, rings, gaskets, etc. Lukes makes a 420 kit for the 400. Give 'em a look...

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Thanks, yeah i ment jug.

Its torn up enough to catch a fingernail on, so i decided to order a 420 kit from lukes.... cheaper than just a NEW jug!!

I asked for the 13.5:1 piston, and ordered a set of hotcams, so i should be pretty good to go when this is done, at least i'll get some more power out of it!

What valve shims do i buy to swap cams, or do i have to buy the whole ~$80 shim kit? thanks!

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You will have to buy the kit or you might be able to swap or buy single shims from a local shop. You probable won't know what size until you install new cams and check valve clearances.

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You will LOVE that set up! As far as shims, you will have to measure your clearances and then get new shims. Your dealer or local shop should sell individual shims in the thicknesses that you need. If it's a shop that you give a lot of business to, the mechanic may just swap one for one...

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Thanks, yeah i ment jug.

Its torn up enough to catch a fingernail on, so i decided to order a 420 kit from lukes.... cheaper than just a NEW jug!!

I asked for the 13.5:1 piston, and ordered a set of hotcams, so i should be pretty good to go when this is done, at least i'll get some more power out of it!

What valve shims do i buy to swap cams, or do i have to buy the whole ~$80 shim kit? thanks!

Remember to get a new cam chain as well, it could have been damaged by the cam bearing ring.

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thanks, yeah I ordered one...I figured since its a 2000' it could use one anyway! thanks very much for all the help guys...!

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thanks, yeah I ordered one...I figured since its a 2000' it could use one anyway! thanks very much for all the help guys...!

Glad to hear it was less painful than it could have been.:)

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