Maintenance and Carburetor Tuning

I also removed the front and rear bumpers to have them re-chromed again at Chrome Dazzler (still under warranty). I haven't put them back ever since I removed them last January...waiting for the vintage racing series to start the season. And also to follow the Lotus philosophy: "Add lightness." I'll put the bumpers back, but probably after I get to race the Fairlady.

I just recently replaced the "fried" contact point. The engine wasn't starting the other night. With newly cleaned and rebuilt twin carburetors, I greatly suspected that it was an ignition problem. The next day, I also replaced the Bosch condenser with another NOS one. Engine still wouldn't start so next up was the contact points. After replacing it, the engine fired right up and idled really high. It seems that the spark was much hotter, thus giving more horsepower at idle than it was with the old contact point.

I also used the same Mitsubishi brand of contact points to replace the old one. I cleaned up the cam lobe in the distributor and applied the white grease included with the contact point. I also cleaned the rotor tips as well as the metal tips in the distributor cap with sand paper..they were covered with some sort of white dust.

I then adjusted the spring tension in the butterfly valves to ease up the pedal pressure by putting another hole much nearer to the bolt to bring the spring much closer to the throttle lever. This will hopefully keep the valves from bending/flexing when it's being opened or closed. I also reset the balance on the carburetors and adjusted the idle to about 1,300-1,500 rpm...a bit higher than before. The reason for this is to keep the oil pressure high at idle at around 50-60 PSI so that oil circulation will be adequate. I noticed that at the original idle of about 1,000-1,200 rpm, the oil pressure was at 40 PSI. It's still okay I suppose, but I just wanted to make sure that more oil was reaching the cams and other internal parts at idle for proper lubrication. I also adjusted the pilot jets about 3 turns to keep the carburetors from backfiring.


I had a nice morning drive with my dad today. The engine was performing very well. It was running really smooth especially at 3,000 rpm down the highway at about 80 km/h. The engine had good pull even in 4th gear at an incline going up the flyover in C5, Libis. Pedal pressure was so much improved and smoother. Before it was just like an on-off switch! Backfiring from the carburetors were considerably reduced and the exhaust now has a nice burble at deceleration. I can now also keep the engine at a steady pace of 3,000 rpm. Before it was shuddering and wouldn't want to cruise nicely along the highway. Great performance today from the Mikuni R16! Can't wait to drive the roadster again and keep on grinning!