I'm taking a look at a BME 50 that was put in pretty hard. I have not seen the motor yet but a couple of the cooling fins snapped off on the back side from hitting the fire wall. One of the stacks on the stock muffler is slightly bent and the prop broke which may have bent the spindle. I plan to clean it up real good and bench run it and see how she runs. I would like some advice from some of you veterens out there. Should I tear this thing down? How can I check the spindle? Will the missing cooling fins allow the motor to over heat? I noticed there are a lot of folks selling BME's but can someone tell me who services them? I really need to know what kind of tempature range it should be running at. Prop size at what RPM. Come on vets...am I missing anything?

I would think the fins can be re welded on if you can find someone that welds aluminum in your area. If the prop was wood you are probably OK on the crank but you may want to consider sending it to keith at BME and having him look it over
http://www.bmeengine.com/html/contact.htm

I think I would pass on that one. I just crashed a bme 50. I had no broke fins but when I checked the runout on the crank in was 14 thouands. A new crank,bearings and seals cost about $225.00

still less than half the price of any new fifty. Why would you pass?

Don't weld the fins on. Don't worry about them. I can almost guarantee you the shaft is bent. The BME 50 sticks way out there without much support, it doesn't take much to bend it.

The shaft if bent can be straightened by any competent machinist, with little to no affect on performance. That's provided it's not to far out. .014 is pretty far out though, and it must have taken a good jolt to bend that far.
If it's a decent enough price it might be worth it. If it does need a new shaft...well...that would shed a whole new light on the subject though. Do you have access to this engine, or is it off the internet?

The guy is supposed to mail it to me today. I told him that I would take a look at it and if I didn't like it I would send it back to him. I plan on taking it to someone local to see if the shaft is bent. Unless there is a way to check it myself. Can some one tell me how to tell if the shaft is bent? One guy told me to start the motor and hold a screwdriver on the shaft and I would be able to feel the movement in the shaft. I might have been born yesterday but I was up all night you know what I meen?? Don't know about that. I'm open to suggestions though. (good ones)

If you dont have access to the tools you need like a "dial indcator". the i would take it to a machine shop that has these kind of tool's and have them set it up for you to see if the crank is bent. that's the only true way to tell. i know of someone else on the forum's here that had a crank straighten. and it wasn't that costly.......but it was a brison engine they might repair your's. it's worth a shot.

i beleive "RCIGN1" an RCU member straightens cranks on regular basis.

TLH, Where do you fly in Corpus. Do you have a website?

Bodyman Dennis is right for sure here. You need someone with the tools and expertise to check that shaft out with a dial-indicator. Basically that will tell you how far it's off, and the machinist probably could give you opinion on if it's worth straightening or in need of a new shaft. He will know how close he can get it to acceptable tolerance. Good luck... they are good engines.

To easily check for a bent shaft, get a piece of very flat, 1/4" thick or thicker, sheet plastic, aluminum, smooth surface plywood, or whatever. Cut a 14 inch circle out of the material and drill a hole for the prop shaft dead center in the circle. Mount the circle and bolt it down snugly, but not excessively tight. Remove the spark plug and rotate the circle.

If you can see any wobble as the circle rotates, it's pretty bent. Using a dial indicator on top of that lets you find small differences.

Use a dial indicator directly on the shaft. I could not cut a large cirle within .001"!

I put my BME 44 in hard. Broke off some rear cooling fins and bent the crank. Sent it to Keith at BME. It took awhile, but he replaced the crank, cleaned it up, and sent it back. Something like $200 to fix it. He did not fix the cooling fins, so I assume they are not critical. I'll be hopefully flying it again this summer. I'd send the engine back to BME.
Sam