750 SF2 piston and cylinder wear

Might be of interest that in Scio Oregon about an hour south of Portland a very experienced motorcycle and racing machine shop is about to reopen after relocating from Chico Ca . I have done business with HRT in chico for over 30 years and he's about to reopen in Scio . Crankshaft rebuilding lightening balancing full machine shop services geared towards motorcycle performance tuning and he's done Laverda cranks in the past so tooled up for laverda . My 750 crank is in need of some attention . They said in about four or five weeks from now he'd be ready to start accepting work at new shop . PM me if need contact info I only have private phone number at moment .
 
(y) That's a very good advice.

I have a concern that this needs a couple steps further than discussed to get a properly working engine that actually works also in serious use.
I think the focus should be checking the oil pump, the whole lubrication system (not just the crank), probably changing to other oil brand, possibly something to be done for the ignition system (like maintaining the often neglected auto advance unit, check for strong spark, correct plugs, etc.), and checking the carburettors and their settings for current fuels, and many many other tasks.

-Jouni
 
Thank you,
I,m waiting on the results of the oil analysis to either prove or disprove the problem being gas wash, and if it isn’t I’ll distmantle the crankcase and inspect everything. As I noted, the carbs have been totally rebuilt, the timing and points have been checked, and the B8ES plugs burn clean after several inspections. The bike fires up instantly and holds a steady idle w minimal enricher needed. However, I’ll use a modern blended 20/50 oil instead of the old mineral oil. From all the things I’ve corrected on the bike, it’s safe to assume the oil was rarely changed within 1500 miles, and probably clogged up the slingers.
 
sfrattler said:
Might be of interest that in Scio Oregon about an hour south of Portland a very experienced motorcycle and racing machine shop is about to reopen after relocating from Chico Ca . I have done business with HRT in chico for over 30 years and he's about to reopen in Scio . Crankshaft rebuilding lightening balancing full machine shop services geared towards motorcycle performance tuning and he's done Laverda cranks in the past so tooled up for laverda . My 750 crank is in need of some attention . They said in about four or five weeks from now he'd be ready to start accepting work at new shop . PM me if need contact info I only have private phone number at moment .
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Thanks for calling me Steve with Craig,s contact whom I will call
 
TeddyG said:
From all the things I’ve corrected on the bike, it’s safe to assume the oil was rarely changed within 1500 miles, and probably clogged up the slingers.
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My take isn't that the oil wasn't changed in its 15,000 miles - because i don't believe that would fill the slingers. it's that - IF the slingers are overfull - the actual mileage is considerably higher.
 
Dont know much about twins, but if you're going into the triple oil pump, you might as well upgrade to the latest 9mm or 10mm pump. From what I have read, it's important to assemble and time the pump correctly if mucked with.
 
Since It's impossible to tell for certain what caused the piston wear, I'm going to split the case and see what's going on w/ those slingers. A friend with more mechanical experience will help me.
Thank you everyone for the input.
 

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