’83 Honda GL650, Post-Jetting

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It’s alive!

My ’83 Honda GL650 Interstate – with the cleaned and re-jetted carbs (Keihins) installed. The results are good all around.

No, great all around.

The bike pulls noticeably harder than it did before – and (based on two rides so far) seems to run cooler, too. The gauge indicates just past “warm” whereas before it ran noticeably hotter. I attribute this to the richened-up mixture, which I am betting compensates for the leaner mixture it was running before, courtesy of the ethanol-laden “gas” in circulation. GL jets1J

I upped the main jet from the factory 118 to 120s – and the “slow” jet to 80 from 78. No other deviations from stock. Air screws turned out about 2 turns from lightly seated.

Based on my results, I’d recommend this mod to anyone who has one of these bikes – even if (like mine) it’s completely stock. The early ’80s was 30 years ago – and the gas then is not what “gas” is today. Plus, during the late Carter/early Reagan years, the manufacturers (cars and bikes) often set their products to run lean as a way to squeak past emissions regs. If they were lean then – running 100 percent gas – they are really running lean now, running 90 percent gas and 10 percent ethanol.

Of course, your mileage may vary…

Throw it in the Woods?  

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  1. Eric, did you calculate, guess, or ask around to determine which jets to use?
    Are you going to check MPG change long term as well?

    PS – Lauuudy, lookin’ good, and a real CB antenna.

    • Just a guess!

      I went up two numbers from stock – so just a slight step in the “richer” direction. The bike is not modified. It still has the factory air box and air cleaner (no holes drilled, etc.), stock exhaust system, etc. I suspect anything more (richer) would be too much. The bike seems to be very happy now. Certainly, some of that has to be credited to the thorough cleaning I gave the carbs while they were off the bike (my bet is they had not been off the bike since 1983, when the bike was built) but it feels stronger/pulls harder now and – by the gauge – appears to be running about 5-10 degrees cooler.


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