Well, just finished rebuilding my gstwinner engine.  First one seized a rod bearing and because I was on freeway trying to get out of being road kill, ended up with entire right cylinder piston disintegrated, block and both cases cracked.  Too much $$$ for dealer to fix, so I thought I could use this as a project to "bond" with my sons. Through the great bruddas' of this board was able to get cases, piston, rod and more stuff.  Through resources from GStwin website was able to get gasket set, bearings and other misc. stuff needed.  The only thing I could not get was the CRANK SHAFT.  Crank shaft had some pretty bad scalling on the right rod journal, as when the disintegration of the piston and cylinder the rod end cap got torn off, nut was laying on bottom of case.  Again as this is a project for bonding with my sons and the GS is a econo bike I did not want to spend the $$$ for a new crank, nor did I want to wait any longer to find a used one.  Most pics I saw of used cranks had the same look as the one I had, burn signs at right rod journal, although mine did have some gouges in it also.  I figured I would just methodically sand out the rough and call it good.  After four weeks, and slow sanding the rough was gone and everything seemed smooth, although I admit when the new rod was installed with new bearings it felt a little sloppy as compared to the left side set up.  Put engine all back together, back into frame, fired up and vvvvrrooom.... yeah right on bike is good.....?
Just a little knock or pong when reving above 5000 rpm.  Rode bike around neighborhood streets for 1/2 day very gingerly and knocking seemed to go away...
Rode today on freeway to get to work after about 15 miles and all hell breaks loose, knocking is heard for miles, engine looses all power.  I limp to the bike parking lot at local train station and park it.  A fellow rider, on rat looking Buell Blast, says "you lost a cylinder what a bummer".
Well don't know right now what to do.  I do know I probably will not tear entire engine apart again, at most find another engine or part this bike out.

Dude, you wanna bond with your kids, get yourself a nice age appropriate entertainment park season tix.

You thought you could hand sand rod bearings and make them round and it will retain oil film and save itself ? That rod bearing needs to be under 1 thousandths of an inch and it has t be round to that size and the rod to bearing clearances are under 1 thousandths. You cannot even measure it without a plastiguage. Its like the consistency of toothpaste, you drop a thin line on the crank and you bolt the con rod on it. The width of the paste now is related to the difference in diameters. Under 1 thou, may be 1/2 thou ... 5 ten thousandths ... nothing in the worls is fine enough to measure that. Plastiguage only.

I have a dozen motors I can buy for pennies if I could rehab them by hand sanding. I have 2 seized up ones sitting in my garage ...
Anyway ... I dunno what to tell ya ... but post here before undertaking such deep and expensive projects. Someone will set you straight. Usually they will also ahve more tact than I do.
Cool.
Buddha.

Did stuff like that with my Dad.  Some of the greatest times in my life. 
Unfortunately, now I can't keep myself out of parts catalogs and toolboxes. 

Great for bonding, but I kinda wish he'd have taught me something different. 

The bonding was terrific.  Hey I can fix anything, just may not last.  After all I kept getting this picture of movie Mad Max, you know the first Road Warrior, and the way the desert scrumms must have worked and wrenched their bikes.  Soooo how bad can that be?  Well about $400.00 in parts total and 1 month in time.  All I can enjoy now is the bonding.

Thanks Buddha, I do appreciate your advice and knowledge.  If you recall I was the one that sent you pictures of the oil cooler pan and the difference that I noticed. 

Send the crank out and have it ground undersize.  $50 max.

Then get undersize bearings and run with it.

Geep - oversized bearings are not available. Not for bikes ... Now in the journals you can get somehting that is fairly close, but rod bearing - forget it.

The one and only solution I have ... If someone put a gun to my head, and I didn't have to guarantee it will work ...

Get it ground and polished, and then take it to some serious engine shop where they can measure everything ... rods, crank, new bearing etc etc to a 1000'th then they can coat engine bearings with a sorta moly impregnated wettable type coating ... that coating has a thickness of some 3 thou or so. If the rod is OK, the inside of the rod and the crank area can be coated ... but rememeber the crank has to be turned till it is the right diameter at the gap ... and just that extra gap can be taken up by the coating.

The idea is that the oil film is held in place by the moly which has a capacity for retaining oil, so oil film is maintained with the help of that moly.
The disadvantage is, how much load will that coating take before it gets tore up ? It may take a lot, nascrap people use it.

I'd still get a motor HGG ...

And yea now I remember about your pics of the oil galley. Thanks. Now toss a motor in that thing ...

Cool.
Buddha.

Quote from: The Buddha on November 10, 2008, 10:14:29 AM
Dude, you wanna bond with your kids, get yourself a nice age appropriate entertainment park season tix.

You thought you could hand sand rod bearings and make them round and it will retain oil film and save itself ? That rod bearing needs to be under 1 thousandths of an inch and it has t be round to that size and the rod to bearing clearances are under 1 thousandths. You cannot even measure it without a plastiguage.

I am just looking at the specs in the manual......big-end journals should have an oil clearance of between 0.0009"min  and 0.0019"max....call it 1 to 2 Thou`.

Like Buddha says the bearing tolerances are far too tight to let you polish away highspots etc with a bit of wet or dry and bearings have to be matched to the journal size.

There are 4 sizes of big-end bearing available, it allows for manufacturing tollerances and they are colour coded. They vary in 4 stages of thickness between 1.484mm and 1.500mm. To select the correct size for your engine (assuming no journal wear) you need to identify the number on the side of con-rod, (1 or 2) with the number on the crank-web next to the journal (1 2 or 3) and then cross reference it with the table in the shop manual. This will ID the correct size bearing. Or you can look for a coloured spot on the shell itself, Green, Black, Brown, Yellow.

The way I read the manual ......IF.....the journal can be ground down to restore finish and concentricity without going below 33.976mm (1.3376") dia it can be classed as a "3" and IF you can ID the number on the side of the rod....... it can all be saved..... IF you select the correct sized bearing from the table.

Get a used engine 

Quote from: sledge on November 10, 2008, 12:13:46 PM
The way I read the manual ......IF.....the journal can be ground down to restore finish and concentricity without going below 33.976mm (1.3376") dia it can be classed as a "3" and IF you can ID the number on the side of the rod....... it can all be saved..... IF you select the correct sized bearing from the table.

My thinking exactly.

Alternatively...  There's always the metal spraying.  Rough it out, spray it up, grind it down, back to new size.   

Quote from: heygawgaw on November 10, 2008, 10:02:14 AM
...  After four weeks, and slow sanding the rough was gone and everything seemed smooth, although I admit when the new rod was installed with new bearings it felt a little sloppy as compared to the left side set up. 

Wow - I have never heard of anything like this before...  absolutely unbelievable!     I'm amazed it didn't do a hand grenade impression the first time you fired it up.

You can get lightly used motors for about what you had in parts. I found out with the GS that I have that if there is anything major wrong with the motor it is MUCH cheaper to buy another off the net than fix the one you have. My bike (my sons at the time) did nearly the same thing except it wasn't nearly as bad. Started knocking at 6500 miles and 4 months old. The real pisser is it was under warrenty and the scum at Strites Motor Sports in Gainsville Florida lied through their teeth and said the bike was ran out of oil. IT WAS NOT!!! And Suzuki coorprate wouldn't lift a finger either. One other thing, they got the bike the last day of feburary and didn't turn a wrench on it until May 16 and still tried to hose me for 2800 dollars to rebuild it. It still cost 550 to get the motor back in a box. I took the box of parts to 2 different machinacs and they both said the same thing, one bad right side rod bearing and it definately was not ran out of oil. I think I'll start a thread on this but I wanted to feel the place out first.

Thanks to all my GStwin bruddas... Great input, I love this forum.  I will be on the look out for a decent priced motor .  In the mean time I would appreciate any input about a Suzuki Bandit 1250.  I might be able to get deal on a new, yet 2007 model still on dealer floor.  Any opinions on the Bandit 1250S or SA (ABS) would be appreciated.  Loved my GS500, however if I buy another bike it would be a little bigger and hopefully better?  If I do get another bike before an engine pops up then I will part the GS out.

Buddha, as always I covet your input, I'm not kissing up too much am I?

They are seriously trying to give the damn bandits away around here.
I am not sure what is wrong ... maybe they are too big and powerful ...
Anyway, look at a ninja 650.

Geep - If a rod bearing has been normally worn with just regular miles you can do over size. You go take a dinged up crank with a broken rod that has flailed around and beat up everything, its going to be impossible to turn it enough to fit a new bearing. And .9 thou was that inches or mm ? just curious, I am staying with ... the "get a motor" idea.
BTW the crank turns black with heat, is the crank hardened to begin with, and does the new round of heat hurt it.
Cool.
Buddha.

This bump is for you Nikonandy.
Cool.
Buddha,

Buddha, I have already recommended replacing an engine over trying to "rebuild".

For the time and materials, its just not worth it when you can get an engine really cheap sometimes.

I have all the tools I need to rebuild one and I still wouldnt do it.

Quote from: weedahoe on October 12, 2013, 08:41:16 PM
Buddha, I have already recommended replacing an engine over trying to "rebuild".

For the time and materials, its just not worth it when you can get an engine really cheap sometimes.

I have all the tools I need to rebuild one and I still wouldnt do it.

agreed sir agreed

I pulled out in time