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CB750 engine life.

ejohnston

CB750 Enthusiast
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Hopefully this question has not been asked many times before, but i could not find a related topic in the search. I recently purchased a k2 cb750 with 32k miles on the odometer. I was wondering as a general rule, how long these honda SOCH 750's run for? The guy i bought it from claimed he was the third owner and the bike has been taken very well care of. If that is true, are those numbers in the "end of its life" range and i should plan on a rebuild very soon? or is there a possibility I could get some more life out of it. It feels to have great compression.

Also how often/many miles to you guys go in between valve adjustments/replacements?

any advice helps as i am a novice.

Thanks in advance

Eric
 
These engines are well known as 100,000 mile machines without any major problems as long as all maintance and adjustments are kept up. I do valve adjustment every 4 k.
 
Well I have read from what other people say that if taken care of with regular oil changes stock motors have gone well over 100,000 miles. Most of the ones I have owned have been around 15 to 20,000 miles with no issues. The problem with these motors now days is time. After about 40 yrs of being ridden the seals and gaskets have gotten hard. Also the 750 uses rubber wheels on the cam chain tensioner and the primary chain tensioner. Age and constantly being in oil make these wheels tend to start breaking chunks off. Personally if it runs good and seems to have good compression I would run it for a while. Yours is by no means a new motor but its not wore out either.

The factory Honda manual for the cb750 says adjust valves every 3,000 miles, I have a bigger cam so I check every 1000 but rarely need to change the clearance. Honda also recommends adjusting the timing chain at the same interval. Basically every 3000 miles Honda wanted the bike brought in to the shop every 3000 and they would go over all tune up items.

Also If you are going to be doing maintenance keep in mind the points wear out of spec more often then most people realize, ignition timing has a big affect on how the 750 runs and performs....so check timing and point gap. Carbs are supposed to be synced at the same time as all other items.

Anyway long post but keep asking the questions if you aren't sure!
 
Good stuff. I would check the compression with a compression tester, and if good, run it until you find a reason to rebuild it. 32K isn't all that much it's ridden yearly and taken care of. Many times it's better to have a bike with 800-1,000 miles put on a year vs. one that has 15,000 miles put on the first then years, and then sat for the next 30 years. :twocents:
 
Thanks for the advice guys! ill keep you guys posted in the next couple of weeks when i try to start it up! The ignition in it doesn't work so I am ordering the Pamco ultimate ignition package.
 
Good choice on the ignition. I just got my PAMCO the other day. Haven't installed it yet though.
 
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