83 Factory Welded Crankshafts

[gs11ezrydr]

I was wondering if the stock factory welded 83 gs1100 big end crankshafts will hold up to a mildly modified motor, approx. 135hp, mostly street driven with an occasional trip to the dragstrip? No slick or bar. Or does it need to have all of the other pins and drive gear welded like I have seen others to insure not twisting? (fully welded) Or did the factory weld all the right pins that were needed to correct there problem with the earlier cranks that were twisting? Thanks in advance I had a customer ask me this question so I replied (as always) I will ask the GS gurus on GSResources and get the real scoop

[Guest]

135 rear wheel no problem.

[ArttuH]

I had about 200hp on my previous turbo engine. 83 engine and the clutch was only modified part in the bottom end. No problems with the crank.

Though local crank builder told me that there are quite lot variation in the cranks from the factory. Some of them even exceed the factory limit for straightness and the limit is quite sloppy for performance use. So your results may vary depending on how good sample you have got.

[trippivot]

the big end cranks are pretty tough. but there is nothing you can do if the left #1 end scatters. more common than I like to admit. big or small end.

[geek]

I would be more concerned about running with 30 year old bearings. I used to have some high mileage rods where the cage for the needles wore grooves into the races.

[storm 64]

I would be more concerned about running with 30 year old bearings. I used to have some high mileage rods where the cage for the needles wore grooves into the races.

Good point Geek. Unless you know the true history of the crankshaft, anything bought on e-bay or such would be a must candidate for a rebuild. ?

[gs11ezrydr]

Yes besides seeing the rods do what you say, The cages wearing into the rods, etc. I have inspected several of the main bearings on the inside of them (with mirrors etc.) and where the races contact the rollers and have noticed that they start to chip or gall horizontally right at the small oiling holes, causing a bad spot on the main bearing races, even after indexing, checking the run out, and the rod deflection were all within specs, But had those spots on the mains. Anyone else ever noticed the main bearings failing in that area also? Just wondering. And if so did you still run them? Any noises, vibrations etc. The cranks I have sent off have returned those bearings back to me marked (bad).Even though it was so slight in couple cases. (just starting) I also bought one on ebay that was perfect but two of the center mains showed these signs. Pearson said since it was welded that it would be pretty costly just to replace the two mains. Re weld etc. Again anyone ever seen this or had these repairs done in the past? If so what was your approx. cost.

[Blower]

Yes besides seeing the rods do what you say, The cages wearing into the rods, etc. I have inspected several of the main bearings on the inside of them (with mirrors etc.) and where the races contact the rollers and have noticed that they start to chip or gall horizontally right at the small oiling holes, causing a bad spot on the main bearing races, even after indexing, checking the run out, and the rod deflection were all within specs, But had those spots on the mains. Anyone else ever noticed the main bearings failing in that area also? Just wondering. And if so did you still run them? Any noises, vibrations etc. The cranks I have sent off have returned those bearings back to me marked (bad).Even though it was so slight in couple cases. (just starting) I also bought one on ebay that was perfect but two of the center mains showed these signs. Pearson said since it was welded that it would be pretty costly just to replace the two mains. Re weld etc. Again anyone ever seen this or had these repairs done in the past? If so what was your approx. cost.

I get my GS1150 crank back few weeks ago from main bearing change. One of the center mains was really bad. The guy who did the crank job changed two more main bearings because he find small surface failures around the oil holes. All this dismantling whole crank, cleaning, inspection bearing change (good used bearings), truing and welding cost about 400$.

[mac1170]

gday mate,have seen this a lot, on engines that do not have regular oil change, my original et, which I bought in 81, second hand, had the crank pulled apart at 180,000kms kms, nearly twice around the clock here, my main man, said it would probably need a couple of bearings, but was quite astounded to find they were fine, no pitting around oil holes, and he said, to quote,:because I have known you since then, and I know you change oil, and filter, every 3000kms,or less if it's sitting around" and this bike still gets flat out runs, and track days, best motors ever built.