munched piston, and cylinder......etc

the shop wants 1100.00 to get it running or 3100 to get it running right.

officially: munched piston and cylinder, oil pump, bearings, scored con rod (livable) scored cam, (livable)

hmmmm any suggestions......besides a new 450?


Sorry racemile.....did you conclude what the cause is and/or the final sequence of events? :)

Ohhh man ! Sorry to hear that racemile. If you don't mind rehashing.... could you tell us what you think caused this? Did you do anything out of the ordinary? How many miles on your bike? Give me the skinny! Man this just sends chills down my back.



Drain plug abandon ship during a harescramble!!

Wait til I find him!!!!! Traitor!!!


Sorry to hear the news racemile. Have you priced all of the parts needed to do it yourself? Even if you're in a time crunch, it might be worth saving some cash by rebuilding the engine yourself. What dealer gave you the estimate? That seems really high, but then again, it's been a while since I have rebuilt an engine.

Ouch!! It had to be tough to smile when you typed that, racemile.

My vote would be a big bore kit, 450 cams, new rod/rebuilt crank, new oil pump. The safety wire is no longer optional. (I'm going out to 'just do it' right now after reading this post!)

I figure any bike that wanted to live that bad (the damage could have been worse), deserves a second chance. Besides, it isn't a very old bike.

On the other hand, parted-out, it is worth what? $1,500? Maybe $2,000?

Fixed 'economically': $1100 would get you $2,700(?)for the bike: $1600 net towards a new 450.

If my WAG on these values is anywhere close, you are better off parting it out than fixing it 'just enough' to sell or trade it. Leaving you with the choices of trying to find a cheaper way to rebuild it well enough to restore your confidence or just cutting your considerable loss by parting or selling as is and moving up to the 450.

Man, even I am going to lose sleep pondering that one... Anybody got some better guesses on the values?

$350 will get you a new overbore cylinder w/ Wiseco piston kit.

The 450 cam would be sweet.

Weigh your options...

But do as much yourself as you can. If you are unsure, now IS the time to learn.

If you are refering to the main crank bearings, you can always pull the entire top end off and bring the bottom end into the shop where they will split the cases.

The safety wire is no longer optional.

How do you plan on putting safety wire on the drain plug? Just curious so that the rest of us can maybe prevent this from happening.

There are probably more clever approaches, or maybe I'm missing something, but it looks like the drain bolt heads can be drilled for safety wire to me. It just needs to be a tiny hole, then wire it under clockwise tension to the frame or skidplate, depending on which drain plug. I'm probably going to do it this way, though you've got me thinkin' maybe I can do it a little fancier...

We used to do this on our small block chevy header bolts. There are special locking header bolts that do it in a slicker way, but the goal is the same.

Sorry to hear about your problem, racemile. Perhaps someone else's wrecked unit with a good motor would solve the problem at a fraction of the cost.

If you plan to put yours back together, I'd go aftermarket as much as possible. Orig parts can be dramatically more expensive.

Whatever you decide, good luck.


I have both my plugs safety wired, just because of situations like this...

It's easy.....put each bolt in a vise then drill a hole just big enough through the head of each bolt. I run the White Bros aluminum skid plates on both my WR and YZ so I have good material to drill a hole to secure the end of the wire to. The only thing you have to be careful of is to ensure that you "Positive" safety the wire so that it hold's tension on the bolt head in the direction of being tightened. If you "Negitive" saftey the bolt then vibration will allow the bold to back off and you could loose oil a little at a time until disaster strikes.

Also, Always use a torque wrench to tighten the bolts.

RM, Sorry to hear of your engine problem...Man that really sucks. Hope your back in the saddle again soon.

Bonzai :)

Now would be a great time to buy a KTM. I think I might know where to get a good deal on one. I colud also sell you a "91" XR600 for cheap. All you have to do is fix the top end and put oil in it. Key word there is "oil"

I say do it yourself, including splitting the cases. After what happened I wouldn't even consider not replacing the crank main bearings. Splitting the cases isn't that bad of a job and in my opinion everybody should see what is inside of their machines and how to put it together. It gives you a whole new respect for what could go wrong...a motivator of sorts. Give it a shot, if you get lost then call a shop.

Also, go to your local bearing house for the bearings. Just give them the number stamped on the original bearing and they'll give you the right thing for a lot cheaper. I once bought crank main bearings from Suzuki for an old RM250 and then decided to try a bearing house. Guess what, both bearings were the exact same bearing. Same manufacturer, same stampings, etc. except that the Suzuki part came in a Suzuki box and cost twice as much. I checked a couple other bearings to convince myself and then took the Suzuki bearings back and bought and replaced every bearing in the engine (from the bearing house of course) for the cost of just the crank main bearings from Suzuki. As far as I was concerned I had an entirely new engine...and it never let me down.


Gentlemen thank you for your advice. I would love to do this myself. I really think it would be a blast to put her back together myself. However, I am writing a business plan so I can control my own destiny soon, I have a three yr old son that needs to be tickled and rough-housed with daily, I also have to try and get in shape so I can ride with my boy when he's old enough, not to mention ride with the 13 yr old daughter. So, I am gonna have someone else fix it........just my priorities right now!!

examination by me found: one very minor "have to really hunt for it" scratch on one cam journal only. The piston is trying to be flat on a side that should be round, same with the cylinder, no heat damage on crank, no heat damage on con rod, journals smooth, wrist pin damaged, rings are history, metal in the oil pump.

Solution: repair to stock, replace wrist pin, all bearings, piston and cylinder, (I will get some pictures of the toasted parts for posting here)replace cam bearings and oil pump. new magnetic drain plug (many thanks to those that offered theirs) with predrilled hole for safety wiring, new bash plate, brake and clutch levers, acerbis barkbusters and guards, 756 dunlops front and rear, new one systems graphics, and YZ time that baby!!!

End of this season I will make a decision about it staying or going. But, I will know it runs and runs well before I sell it to someone. If it blows up again later this season would be a better time for a new bike than now. Or, maybe I will attempt the rebuild next time.

I really tend to agree that if you race its gonna break on occasion. And I will be more prepared next time. The only symptom I had of impending disaster, looking back on it, was the bike got a little stiffer to shift without using the clutch, so pay attention if that happens to you in the future. Pull over and check the levels right then. Dont assume its rider error like I did.

Yamakaze I have never seen or done a drain plug safety wire. If you get bored some time soon, please post a picture of how this is done.

This could have been a lot worse. As it is I will be out and riding by march 1st I hope.


The bearing supply house is very good advice, ogrebelle. I have always checked there first, as bearings are a very standardized thing. Most times I can get a better quality bearing for much less. I really hate "made in China" cheapo bearings, and you'd be surprised how many things come with them these days.

Take your old bearing along with you whenever possible. Same goes for seals.

Nice to hear from you, Yamakaze! Hows the racing going?

What shop gave you the quote on the service? I saw your other post on Excel in Denver.

You could also try Steele's off of Sante Fe near Belleview for the labor and they may be cheaper.

couple of months ago there was a WR400 motor for sale with new Wiseco, skim, flow etc for $3400 aust. dollars 0 kms since build, would it be worth it to buy it and send it over there?



That's exactly what I was talking about, Yamakaze. From the looks of your neat and tight job, I'd say you must have a pair of those safety wire pliers, too..?

I always had 2 smokers before my 426, and I'm really surprised that so few people seem to know about the lockwire thing. Mine didn't shift off the garage floor without it from new......... Stupid maybe, but the coolant drain bolt is also a candidate. You don't need lockwire pliers to do a neat enuf job, but they help. You can get a pair for probly 10 or 15 bucks there. (THey run about 40 oz dollars here). If you don't have a pair, normal ones can be used carefully. One thing tho, don't cheap out on wire. Buy quality s/steel aircraft lockwire. It's cheap enuf and you won't break it on a log or rock. Really sorry to hear about this.

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