High Altitude Riding

[norman]

Hi, I was wondering, is there a rule of thumb about carb. jet size for high altitude riding ? It will between 6,000 and 12,000 feet I will be riding a CL-77 . Thanks Norman

[Geeky160]

I don't remember about the jets but my CL77 was a dog at 12,000 Ft. 3% HP loss per 1000 feet is what I do remember. I run stock jets here at 6500 though.

[norman]

Thanks Geeky, I figured smaller jets would help ,I just don't know where to start

[G-Man]

You could try dropping the needle a notch and seeing what happens. That won't affect the wide open jetting but it might help you work out what to do .

http://cdn.powerequipment.honda.com/pe/ ... i54675.pdf

G

[marzini]

+1 for G-Man's recommendation. That's what is working for me after a lot of experimentation.

Some have recommended #120 or #125 main jet above 5k feet for the CB77, but that's not what is working for me so far.

I would have figured changing to smaller main and slow jets would be a given, but (at 6~7k feet) I'm finding that just a drop in the needle one notch from stock (leaner) seems to be working for me so far. My '62 CB77 is stock except for Dunstall reverse-cone mufflers and K+N RE-0240 air filters mounted on short radius 1.5" diameter radiator hoses I got from Napa.

My main jet is #135 (I tried a #125 and #130). The slow jet is #42 (I tried a #38).

There was a big difference (improvement) just raising the needle from the 2nd notch from the top to the middle slot (richer) with the #135 main jet in place. I was all over the place on the needle with the various slow and main jet changes I tried. Raising the needle another notch is back to the stock setting as recommended by the masters.

LM (at 6k feet) said his CB77 uses #135/#42/2nd notch from the bottom which is the same as Bill Silver's tune-up recommendation.

[rrietman]

off topic a bit but interesting. I have a bike that the ecu stops working at 8000 ft. shuts down. anybody have a guess?
Randy

[brewsky]

1. pre recall FJR?

2. Sensor problem?