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1978 GS1000 overhaul crank twist / Gaskets
Iv'e torn in to my 1978 GS1000 to resolve my low compression numbers. The bike has 14,0000 original miles on it. I'm at the point of no return on this money wise, I have to proceed or what I have put into it will be wasted.
The head is in at Schnitz racing in Decatur, Indiana for a valve job and check-out.
The cylinder bores have rust pits in them, but no gouges or any other issues. The rings were not carboned up or stuck as I originally suspected. The bike sat in a yard shed for 15 years. I'm planning to install a 1085 kit.
What I did find was that the crank is twisted a little between 1 and 4 (over the length of the crank). #1 at TDC (found withn dial indicator) lines up with the timing mark perfectly. #4 piston is about 1/16th down. The machinist at Schnitz told me to check the crank. He worked at the dealership that my uncle bought the bike new at back in 1978 and indicated that crank twisting was not unusual and that Suzuki warranted a lot of these beyond the original warranty period. This same information was repeated by the crank shop that I'm sending the crank to (Pearson Racing in West Alexandria, Ohio). Just wanted to pass this info along. My Uncle did ride it hard back them. He was into the street racing thing, when the bike was king. I suspect it happened in the summer of '78 or '79.
I am getting the crank Indexed, trued, and welded.
What brand of gaskets have you guys had good luck with? Schnitz told me that the fiber base gaskets on these bikes are prone to failure around the pressure ports going up to the head. He reccomended one re-enforced with copper or aluminum. Does anybody have any experience with this? The pressure ports have O-rings around them so maybe I need to ask him for clarification.
I'll keep you all posted on the progress.
Oh yea, he also mentioned inspecting the clutch basket hub where the cushion springs are at. I guess they can fail by breaking and taking the oil pump out. I do remeber seeing my uncle doing holeshots with the bike, which is probably how the crank got twisted.
Is there anything else I need to be aware of or check closely during the overhaul?
Thanks for your indulgence.
The head is in at Schnitz racing in Decatur, Indiana for a valve job and check-out.
The cylinder bores have rust pits in them, but no gouges or any other issues. The rings were not carboned up or stuck as I originally suspected. The bike sat in a yard shed for 15 years. I'm planning to install a 1085 kit.
What I did find was that the crank is twisted a little between 1 and 4 (over the length of the crank). #1 at TDC (found withn dial indicator) lines up with the timing mark perfectly. #4 piston is about 1/16th down. The machinist at Schnitz told me to check the crank. He worked at the dealership that my uncle bought the bike new at back in 1978 and indicated that crank twisting was not unusual and that Suzuki warranted a lot of these beyond the original warranty period. This same information was repeated by the crank shop that I'm sending the crank to (Pearson Racing in West Alexandria, Ohio). Just wanted to pass this info along. My Uncle did ride it hard back them. He was into the street racing thing, when the bike was king. I suspect it happened in the summer of '78 or '79.
I am getting the crank Indexed, trued, and welded.
What brand of gaskets have you guys had good luck with? Schnitz told me that the fiber base gaskets on these bikes are prone to failure around the pressure ports going up to the head. He reccomended one re-enforced with copper or aluminum. Does anybody have any experience with this? The pressure ports have O-rings around them so maybe I need to ask him for clarification.
I'll keep you all posted on the progress.
Oh yea, he also mentioned inspecting the clutch basket hub where the cushion springs are at. I guess they can fail by breaking and taking the oil pump out. I do remeber seeing my uncle doing holeshots with the bike, which is probably how the crank got twisted.
Is there anything else I need to be aware of or check closely during the overhaul?
Thanks for your indulgence.
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