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Newbie question

Daneel

CB750 New member
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Port Elizabeth, South Africa
Hi folks

A newbie question and sorry if I annoy anyone with this.

I have recently purchased a CB750K 1982/83 model.
This bike was used inland and I live coastal area. The bike is running a little crappy and seems to have a misfire at mid range.

Must I look at rejetting the carbs?
What jetts should I be using at sea level with standard airfilters?

Thanks in advance for the advice.
Daneel
 
Proximity to the coast has nothing to do with carb mixture. Altitude does to some extent. However, if it is as-stock, it should be fine. An 82/83 might just need cleaning. You can try running a couple tanks of REAL gasoline (no ethanol) with Seafoam or similar fuel additive in the specified concentration.
 
Actually altitude is a big effect of fuel ratios. Sea level will require more fuel then higher elevations. Humidity also contributes to fuel mixture, maybe not as much as temperature and elevation but it absolutely affects fuel ratio. Very humid air will cause a rich mixture compared to dryer air. The dohc with the type of carb they have is very sensitive to just about everything. They ran leaner then older carbs from the factory and air is what affects them the most. Air box type and to some extent the air filter and condition (new vs plugged)affects how they run. But Dohc are terrible for valve clearance issues affecting compression. Very first thing to do is verify engine condition. Check compression and absolutely check and adjust valve clearances as that is the primary contributor to low compression on these motors. Once mechanically fit then you can determine if it has carb issues.
 
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