View single post by DonBurns
 Posted: 12-28-2016 12:22 am
PM Quote Reply Full Topic


Joined: 09-18-2015
Location: Fullerton, California USA
Posts: 75

Thanks for the feedback. I had to step away for a few weeks due to some work travel (China!) and holiday duties. I have made a little progress, though, and thought I would provide an interim update.

First, although this belongs in a different forum, of course the overheating was not due to being out of tune. I ordered a 160F thermostat to try, and when I went to install it discovered my engine rebuilder had not bothered to put one in at all. Same shop that sent me on my way with a freshly rebuilt 4-speed with no oil, and about a dozen other issues. Anyway, the overheating seems to be taken care of with the presence of a thermostat.

I fiddled with the tuning some more, and found my best results were obtained by adjusting each cylinder by RPM. Set to 1000, and adjust the idle mixture to max RPM, reset to 1000 and repeat for the next cylinder and so on, then go through the cylinders again 1 through 4. This seemed to give me more sensitivity to adjustments than watching my CarbTune Pro, and now the JH is drivable (and not overheating in 2 miles!), but I don't think it feels perfect.

I have the week off had planed to get the bung installed for the A/F meter, but unfortunately my local exhaust shop is off this week. I'll try to get that done next week.

My Dellortos are from the JHPS site store. What I have now is-

Chokes 37mm
Venturi ??

Air Correctors 230
Emulsion Tubes 7772.8
Main Jets 160

Idle Jet Housing 7850.9
Idle Jet 62

Based on recommendations above these might not be ideal.

I believe I have finally found a local shop that claims to be Dellorto gurus, which I hope means they have the magic box with all of the tubes and jets and stuff to allow trial and error testing. I plan to play with the A/F meter myself for a little while, and then probably get it over to them.

I'll update when I have more results.