I hope one of ya can set me right here. Looking in a shop book on the 1987 1.3 Samurai it says the main bearing journals differ in size by a letter number stamped on the block. Like A, B, C, etc.... Does it make a difference in the bearing you buy??? I see no option on buying main bearings, but the size of the crank size (like .10, .20 undersize ) for how much you have turned the crankshaft.

suzuki was really smart about matching tolerances with tolerances. think of it as a competition shooter who weighs bullets and groups them by weight. piston bores to pistons, as well as bearing journals to bearings, have machining tolerances. suzuki would take a slightly undersized bore and put a slightly undersized piston in it, while the adjacent bore might have been on the larger side of tolerance, so they would put a piston that is also on the strong side in it. that's where the A, B markings come from on the deck. the crank journals work the same way. suzuki was able to maintain outstanding clearance tolerances by using this strategy.

when you bore your block or grind your crank, the machine shop will match their cuts to the bearing undersize and piston oversize you provide (or specify). the A,B sorting from suzuki does not matter at that point. it is in the hands of the machine shop, capable or not, to judge those tolerances for you. uniformity is only possible up to a certain level of precision.

if you are doing your crank, specify your tolerances based on how you run the engine. if your freeway cruising RPM (if you can even make it on the freeway :P ) is over 3000, ask the machine shop to grind for bearing clearance on the loose side of the spec (within spec, of course). that has been my experience, anyway. otherwise, keep everything within the nominal dimension and trust the machine shop's skill and equipment to stay well within tolerance. often, you get what you pay for in that department.

so the answer is no, the letters don't matter when you are machining for a rebuild.

Thanks for the quick reply!!! I had the crank polished, as it was in spec for standard bearings. Also the bore is standard size even after a honing as are the rod bearings. I am going to do the rest myself. Getting the total kit from Petroworks Monday. Its only about 20 miles from here where I live.
I just sold my Rincon ATV the other day and bought the Tin Top, 1987. The motor is weak, but got a spare engine with it. Thats the one I am rebuilding.

http://img.photobucket.com/albums/v311/hogcat/Img0072-1.jpg

just 'cause the motor is weak doesn't mean it's in need of a rebuild... your rincon had a better power-to-weight ratio than your new tintop. it's a samurai thing. get some gears to go with those 31's if you don't have them already.

welcome to the club. read up, wheel hard, and have fun.

just 'cause the motor is weak doesn't mean it's in need of a rebuild... your rincon had a better power-to-weight ratio than your new tintop. it's a samurai thing. get some gears to go with those 31's if you don't have them already.

welcome to the club. read up, wheel hard, and have fun.

Its weak!! The compression varies between 100 and 150 PSI between the four cylinders. It has extreme blowby out the valve cover and it smokes like crazy going down the road!!!

adjust your valves. blowby is a relative thing, check your pcv.

...unless you are dying to spend the dough... in that case, i have a brand new short block that you can PM me about.