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Bad News

  • Thread starter Thread starter Dave_17954
  • Start date Start date
Man, I know how you feel. I rebuilt a little BSA engine and less than 50 miles later it was trash. All my fault, brute force engineering doesn't work.

Good luck with the bike and the job situation.
 
Dave_17954 said:
actually this was the only failure like that. The original problem was just the fact the #4 bearing was worn quite a bit and the #3 bearing a little bit plus the ring marks from sitting to long in the #4 cylinder. Yes i measured everything when i had it down and everything was well within the original specs for standard bearing replacements which is what i ordered. guess i'll tear it down just to satisfy my curiosity. At least i know the bolts wont be to hard to get out and i wont have to clean anything up in side the motor.....
Click to expand...
I've never replaced bearings on a bike motor before, but I've built lots of car engines. What I used to measure the bearing clearances, while they were installed and torgued down is plastiguage. I didn't take for granted that the bearings I bought were all correct. That's what I was refering to when I asked if you measured the bearing clearances.

I don't understand how this could happen to a motor that was cleaned and prepared as thoroughly as yours. There had to be a problem with that bearing, or the oil delivery to it.

The alternative to plastigauge is to mike the crank throw, then the inside bearing surface on the rod with the cap torqued down, and then subtract the difference. Is that what you did?
 
Reading this bums me out as well. :( If there was anyway I could help I would.

But, I'm one of those people that has a heart as big as Texas, as the ole saying goes. I try to help everyone that I can.
 
I'm assuming the nuts have worked loose somehow. I havent got it torn down that far yet tho. The piston still moves up and down so that tells me the rod hasnt broken in 2 pieces and that the nuts are still on the rod bolts. I can run the piston to tdc then roll it past just a smidge then push down on the piston with my dowell rod and it will drop I'd guess a good 3/16 or so. Even if there was an oiling problem which I dont think there is I dont see how that could affect the nuts. Like i said i double checked my torque when i put them on plus red loctited them to boot. basically wondering since i done them all the same way why is this one the only one that came loose. I ran this engine for about 700 miles before this happend and changed oil in it twice. It always ran as quiet as a mouse except for a little shim noise. I set my clearances at .07 -.09 figuring they would close up a bit once my valves got reseated good. I did use plastic gauge on my bearing clearances to btw. Ive rebuilt many an air cooled engine in the last 10 yrs actually I used to do this as my regular job before i became a machinist even went to school for it. As soon as I get it opened up I'll be posting pix. Something happens to my suzi i take it personally. The top pic is of the # 3 rod cap and nuts during the rebuild and the lower 2 are the rod and bearing during the original motor teardown.
3.jpg

017.jpg

018.jpg
 
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Sorry to hear this Dave :( She's a looker. And, sadly, yet another plain bearing, high pressure mill bites the dust. I replaced the motor in an 83 550ES that suffered the same fate. Same cylinder as a matter of fact. Found it was far quicker and cheaper to simply hunt up another motor instead of tearing it all apart and replacing everything, sending the crank off, etc etc... The 550s were a bit more pleantiful than the 650s perhaps, so maybe in your case it will be your only option. That really sucks dude :( If i can help any, let me know...



Josh
 
Dude!That sucks! That is just too weird for real!! I had the exact same thing happen to my bike after the first build.. Some how the con rod nuts backed off on the #4 cylinder.. I was sure I torqued everything right. When i tore the motor back down, all it needing was some new con rod bearings on the #4 and everything else checked out fine. If you end up needing a crank... let me know.. I will get one to you.

I truly feel your pain Dave, you know, come to think of it, I would suspect your helper.:p
 
Heres a pic of the new style conrod bearings on the left and the new style crank bearings on the right. thanks josh. you putting them service manuals to good use? lol
when your laid off you got a lot of time so i figured I might as well tear it apart curiosity will kill me if I dont do it :). I know it will be easier than the first time around and cleaner to :D. I remember you telling me that brian and that was before i had put mine back together so I was very conscious of the fact to double check them. I can sense some green loctite this time around. I'm hoping it will just be a ruined bearing like yours. I'm going over it with an even finer comb this time. And on a lighter note at least I'll no which way to stick that crank seal in this time......lol. I think shes jealous brian lol.

pix012.jpg
 
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preliminary news

preliminary news

Well so far I've found no damage at all to the valve area. Shims, buckets, cams, cam bearings all look good. Valve area itself looks very good. Found no loose bolts or nuts on the top end anywhere. The cylinder looks great no scoring on the walls in any of the cylinders. You can still see the hone marks in all 4. the pistons all look good so far. no broken rings or any sign of damage on the skirts. Numbers 1,2,4 rods are all tight and #3 is severely loose. Just glancing down inside the case at #3 I can see no sign of metal fragments anywhere but this very preliminary. I'll post up some pix later tonight. Tomorrow if I get a chance I'll pull the lower end out of the frame and split open.
 
Keep your head up Dave. Hopefully the damage won't be too bad. There is at least one guy parting a 650 in the For Sale forum, maybe you can pick up a cheap crank from him?
 
pix

pix

heres some pix of the upper end...these are the good ones. the ugly ones will come when I open the cases lol
003.jpg

020.jpg

015.jpg

017-1.jpg
 
WOW! and i am worried about changing my Clutch cable...

WOW! and i am worried about changing my Clutch cable...

You are a pro. I hope you get this fixed. It seems to me that you have tore this engine down within a few mins. "internet time". I am worried bout my clutch cable and am still trying to believe everyone about the "Carb Rebuild" is an easy thing. I didnt even now there were such parts in a bike. Good photos and I hope the best for you. Me I'da sold it but as i said earlier "YOU ARE A PRO!". Good Skills! ( I don't believe in "Good Luck" ).


Man those pictures scare me!

Whew!

Deivets Cetdar
 
Thanks for the kudos....I sleep with my suzuki service manual under my pillow so I can absorb all the knowledge :D. I'd guess not being afraid to dive in and getting your hands dirty gives you good feeling of satisfaction when it comes to your bike. I actually felt a little nervous when brian was dialing in my carbs last sat in Indy not that i doubted his ability but that someone else was wrenching on her. I've learned alot from all the guys here in the forums so never be afraid to ask questions and btw they do like pictures lol. I've spent so much time studying this motor its kinda like when your in the service and they blindfold you when you tear down your rifle and put it back together. I actually could have had this thing apart alot sooner but I bought a used minivan that needed brake work done so I'd at least have some wheels in the meantime. Luckily its all metric to so when i get tired of working on one I just turn my stool around and start on the other ;). I was lucky and never had to clean my carbs (yet) but any of the guys or gals on here would be glad to help just remember pictures man they love pictures.........:p
 
In those pics of the first time you rebuilt the engine is that the same #3 con rod that failed this time around? It sounds like you know what your doing so I assume you had ALL of the rods rehoned and the crank polished out after the bearing failed the first time. The heat from a failed bearing will cause the rod to warp out of round and you will get an incorrect reading for your clearances. You said you set them at .07 - .09!:eek: I hope you meant .0007 to .0009. And that is a little tight imho. Especially for a high revving engine like that. I would open them up to .0009 to .0012 AFTER you hone the rods and polish or cut the crank again.
 
when i said .07-.09 thats in mm. according to my notes the #3 shims are set at intake .06mm and exhaust is .08mm. If you convert those to inches they would be intake .0024 and exhaust .0032. Just use the "magic" conversion number that all good machinist learn early on lol (25.4). I used a dial indicater to check my crank and rod cap end and both were well within spec according to factory service manual. the original reason i tore motor down wasnt because the bearings were bad it was because of the tapping noise from the rings running over marks inside the cylinder on #4 and actually although the bearings were worn down the #4 bearing was far worse than #3. There was no lower end noise at all. Numbers 1,2 and 4 are all still tight even tho #4 was the worst off. Will check my torques on those 3 to see where there at when I open it up here very soon.
041.jpg

015-1.jpg
 
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lower end pictures

lower end pictures

Ok I'm posting a link to all the lower end pictures instead of trying to show them all here. Hopefully this will work. First off all the cap nuts were torqued to spec including number 3. looks to be a bearing failure. I'm open for ideas on this one.......By the way the crank looks I'd say its shot along with the #3 rod and bearing or whats left of the bearing. Rest of the motor looks good.
http://s489.photobucket.com/albums/rr252/dave_17531/
 
I was wondering about that since them new bearings have no oil holes in them but then again why did none of the others fail? I remember asking the suzki guys about not having that oil hole in the new bearing and they said there was sufficient lube there and wasnt needed anymore and that was where all the older bearings were failing like mine on 3 and 4 because of that hole being there. yet on the crank bearings they actually increased the oiling capacity with the new style bearings.
 
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The oil holes in the rod bearings are to lubricate the pistons. If the new bearings don't have them, they are not correct. Lack of those holes shouldn't cause a rod bearing failure, but would have long term consequences for your pistons.

The oil gets to the rod big ends through the crank. No obstructions in the oil galleries in the crank? Were there oil holes in the crank mains, and were they positioned correctly?
 
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