Bad News

[Dave_17954]

yes and i hope i didnt get them mixed up. that was right before I was laid off and under a ton of stress. could very well have happened and if I did well hard lesson learned. my suzi will rise up again no doubt about it

[reddirtrider]

yes and i hope i didnt get them mixed up. that was right before I was laid off and under a ton of stress. could very well have happened and if I did well hard lesson learned. my suzi will rise up again no doubt about it

Well, if it is the problem at least you've identified it. There's nothing worse than putting a failed motor back together without knowing the reason why.

[TheCafeKid]

Ok, my thoughts were centered around PBC's in general, while you were refering to a specific set of years and model. It appears we were talking about 2 different issues.

You may be right about the 80-82 750's. I don't own any and I usually don't get involved in threads unless they interest me, so in general a lot of them go by without notice.

Ahhh.. ok No I know that most modern motors use PBC, but my point was directed toward Suzuki's oil mapping...and perhaps IT was the cause of all these failures... I dont REALLY know, but that would be my assumption...

[Dave8338]

Something isn't right here (obvious I know) but is there a chance that you 'dinged' the crand while putting things together. I've had it happen where a rod bolt will put a ever-so-slight ding in the crank journal and that if left to 'work it self out', you would see the same thing happen. Did you do a VERY close inspection of the crank prior to the new bearings going in?

Though the Kid brings up some valid points...I know that the split rods/cap set up is up to the task and then some. Sure a roller crank is a 'better' choice only for the fact that there needs to be very little oil on the bearings in order for them to do there thing.

If it were a general oil issue (pressure or otherwise) the rest of your motor would be showing the same signs as the #3 rod bearing.

As the bearings were new when they went in, it leaves only the crank journal on the #3 hole, as suspect... if everything else was done correctly. Nice photos by the way.

[Dave_17954]

dam thats a nice 650 there in your pic....wanna trade even up . I seen the suzuki dealer had some of the red engine rebuild grease on close out. I may go up and nab a tub of it. I did use molypaste on everything. I got at advance auto. I thought changing my oil twice would have flushed it all out. everything else in the motor doesnt look bad as far as oiling goes just this one bearing makes me wonder if it was packaged right at the factory....... Or I dunno strange.....one bad one out of all that I changed and all the other parts I put in it are fine. If there was an oiling issue wouldnt it have showed up with the other bearing bearings. I know 3 and 4 both had bad bearings before the overhaul and 1 and 2 looked pretty decent.

[Dave8338]

dam thats a nice 650 there in your pic....wanna trade even up . I seen the suzuki dealer had some of the red engine rebuild grease on close out. I may go up and nab a tub of it. I did use molypaste on everything that i had got at advance auto. I thought changing my oil twice would have flushed it all out. everything else in the motor doesnt look bad as far as oiling goes just this one bearing makes me wonder if it was packaged right at the factory......

Thanks though, I think I'll hang on to it as the clock hasn't even hit the 10k mark yet and it's all original.

It is possible that a screw up at the factory did occure. I quickly read through the first six pages and didn't notice: Did you mic the crank and or use plasti-gauge? I've run into bad bearings before where after a race, things were torn down and just for grins (when time wasn't measured in seconds) pulled the rod caps, one at a time and saw bronze where there should have been silver...

[Dave_17954]

i used the plastic. thats a pretty sweet ride i'm jealous. how did you ever find one with that low of miles? my trusty assistant says shes jealous also.....

[Nessism]

I'm in the camp with the others thinking something is out of spec with that particular rod/bearing/crank throw. Isn't that the same rod what chewed up the bearing before? If so, I don't think this is a coincidence. Oh, and that business with the bearings being different from stock is a red flag to my knowledgeable mind. Why would Suzuki do this?

Regarding that crank, the wear doesn't look too bad - it might polish out. An automotive machine shop would know. Also, check that rod for alignment and out of round on the big end. Of course, finding a good used crank and rod would solve the problem as well.

Good luck and don't give up Dave.

[mark_vaughn]

Dave, Try Rotella bro. 15/40, i dont use anything else, never will. Modern oils have a crap load of detergents and additives in them that are no good for these old girls. Diesel oil is where its AT!

I know this is not the topic in question on this thread and it is always a controversial topic... But there are always two sides to the story.

All new oils are made to exceed the oils of yesterday. To disreguard technological improvements in oils could be like sticking to the typewriter because it gets the job done... but it only types... not quite the PC.

The fact is you can't get oil that is to the original specifications of these bikes. That includes Rotella.

Those detergents keep your engine cleaner. Keep the oil passages clear. At the very least, they do no harm. Multi-grade is better than standard weight oils and everyone accepts that now, but there were those who hesitated to accept that change too.

I have owned a few old european cars and there was always concern about new gear oils destroying engines and transmissions because they used brass bushings (the additives actually protect those yellow metals). There are guys out there who find 30 year old cans of oil for their engines...

Rotella has it's own Triple Protection technology, which are additives.

I have used Rotella because it is just as good as the next oil if you are changing it regularly. Even the Super-Tech oils at Wal-mart are good(made by Quaker State). They are all basically the same until you get into Synthetics, but that is probably overkill and may not work well with the transmission.

I would avoid using additional additives. But IMHO the major concern with using new oils (synthetic specificly) is that they can be too slipery and leak out of your old engine.

[Nessism]

I know this is not the topic in question on this thread and it is always a controversial topic... But there are always two sides to the story.

All new oils are made to exceed the oils of yesterday. To disreguard technological improvements in oils could be like sticking to the typewriter because it gets the job done... but it only types... not quite the PC.

The fact is you can't get oil that is to the original specifications of these bikes. That includes Rotella.

Those detergents keep your engine cleaner. Keep the oil passages clear. At the very least, they do no harm. Multi-grade is better than standard weight oils and everyone accepts that now, but there were those who hesitated to accept that change too.

I have owned a few old european cars and there was always concern about new gear oils destroying engines and transmissions because they used brass bushings (the additives actually protect those yellow metals). There are guys out there who find 30 year old cans of oil for their engines...

Rotella has it's own Triple Protection technology, which are additives.

I have used Rotella because it is just as good as the next oil if you are changing it regularly. Even the Super-Tech oils at Wal-mart are good(made by Quaker State). They are all basically the same until you get into Synthetics, but that is probably overkill and may not work well with the transmission.

I would avoid using additional additives. But IMHO the major concern with using new oils (synthetic specificly) is that they can be too slipery and leak out of your old engine.

Not trying to turn this into another oil thread but some misconceptions floating around in this thread. Diesel oil has more additives than the typical auto oil - including more detergent. The important additives are things like zinc and this is where diesel oil is superior to auto oils - GTX has about 25% less zinc than Rotella.

Regarding new oils being better than old, I'm not sure about that. The new oils have less and less zinc these days in order to extend the life of catalytic converters. Even the new formulation of diesel oil has less zinc than the old formula. The new oils are not bad per say, but saying they are superior to the old stuff is not necessarily true.

[mark_vaughn]

The new oils are not bad per say, but saying they are superior to the old stuff is not necessarily true.

Ed,

I will close my thoughts with this point and we will agree to disagree.

If the new oils are not superior then the old oils must be better... I disagree.

It is a matter of opinion at this point. But I will stick with the new oils (including Rotella) over the old oils any day.

I think there is one thing we can all agree on. Any engine will eventually fail no matter what oil you use unless you never start it.

[Steve]

I did use molypaste on everything. I got at advance auto. I thought changing my oil twice would have flushed it all out.

This scares me.

NEVER use moly anything in an engine with a wet clutch.
Moly will embed itself into the clutch fibers and will never be "flushed out", no matter how many oil changes.

It has been quite a while since I have rebuilt some car engines, have never done a bike engine from scratch.
Never had any problems just using regular engine oil on the bearings during assembly.
Don't know if the bikes would be different, but can't see why they would be.

.

[reddirtrider]

This scares me.

NEVER use moly anything in an engine with a wet clutch.
Moly will embed itself into the clutch fibers and will never be "flushed out", no matter how many oil changes.

It has been quite a while since I have rebuilt some car engines, have never done a bike engine from scratch.
Never had any problems just using regular engine oil on the bearings during assembly.
Don't know if the bikes would be different, but can't see why they would be.

.

The only thing I ever used moly on in a car engine is new camshafts and that was just a dab on each lobe, not on the hearing surfaces. For bearings I used a mixture of STP and oil (half and half).

I've done the same on 3 bike engines and haven't had any problems. Well, one was a 2-cycle so no moly there.

[Nessism]

Suzuki specs the use of "Moly Paste" inside the engine in certain places. No reason to be concerned as long as you are not slathering the stuff on everything.

[Nessism]

Ed,

I will close my thoughts with this point and we will agree to disagree.

If the new oils are not superior then the old oils must be better... I disagree.

It is a matter of opinion at this point. But I will stick with the new oils (including Rotella) over the old oils any day.

I think there is one thing we can all agree on. Any engine will eventually fail no matter what oil you use unless you never start it.

I use Rotella in my engines as well. The old formula has about 25% more zinc than the Triple Protection formula, thus I don't consider this "new" formula to be better than the old.