I vote carbs. Having it sit over the winter only exacerbates the problem, probably a bit of varnish in the jetted areas and orifices. If it hasn't had a rebuild recently, then this would be a good time to completely rebuild the carbs. Very good safety insurance against fire damage.
Terry, you said it wasn't the same plugs fouling, right? So all your carbs have a jamming/stuck part? That makes no sense to me. I wish I had a better clue what it is (electrical?), but I'm thinking it's NOT carbs since the problem isn't limited to any particular cylinders. Ken
Not sure if there is a newer thread on this subject but I am having a few issues like this on a Daytona Spider myself. Getting a slight hesitation under load in all gears at around 4.8-4K RPM. Car ran fine on the dyno and did not have this problem. Normally run slightly different Jet setup on the dyno as no airbox on the carbs. Have checked timing and all is spot on, running optical dizzy for timing. I have also swapped over caps and HT leads from another car to check. Engine is fully rebuilt, rebuilt Carbs, new filters all round, etc etc...... I am going to change the setup on the idle/main jet circuit to see if it makes a difference. Don't have my notes with me so cannot remember exactly what is in there at the moment but I think it has 60 Idle's and 135 Main's Anyway, I'll let you know what I find
Terry. I'm so sorry to hear of your overwhelming Daytona problems. Rather than make yourself completely nuts ... why not wholesale the car to me ? LOL I'd be more than happy to 'take on' the headaches !
the problems with my Weber carbs were in the distributors.... All those carbs, all those screws...for decades guys just can't help themselves-they always want to grab the screw drivers and start twisting on those screws!!! What most EVERYONE has missed in the OP description of this motor is: HOT cams, Bigger SS valves, port work(bet you made 'em bigger-right? ex ports always are way too big...not enough velocity with a lobe center not set up for this...), "special liners", probably higher compression (static-what is MEP?), event horizons? This thing needs to go back to the guy who built this thing-as he will have-or better have done, all the math and have charting done for cam centerlines, duration, overlap issues, "blow down" on exhaust valve opening/intake closing issues, idle jetting, main jets and emulsion tubes-all should be tracked with the changes which would've been required when the 6-wire sensors indicated where the lean/flat spots, and fat zones were, when run in on the dyno-it WAS run in and tuned on a dyno... with all the mods done to this thing? Right? If not... with the amount of modifications done to this thing, it is going to be an arduous journey to get this thing so you are satisfied...in my experience, with mods like ones stated, one would expect 105-110 hp/liter...or you wasted a boat load of dollars-IMO A note on carbs-the criticality of proper axle bushings and the progression holes cannot be under stressed as earlier poster noted(the sharpshooter) If the distributor curves are caddy-whompus...and nearly mirrored, you are wasting time and money-MOST of the optical aftermarket stuff is junk that I have seen...truly....a std. S85a/15x Marelli with properly curved advances, PHASED to a degree or LESS, and 75% of carb problems disappear...that said, I suspect that there are more critical issues in play with this build... FWIW....
FWIW I was the owner of the Daytona prior to Terry and had the engine work done after about 60,000 miles and 30 plus years of ownership. Car ran like a freight train at the time of sale so suspect the issue was Terry's application of the toolbox to tweek what was already a great running car. As I mentioned, I owned the car for 30 plus years and after the rebuild it it ran like a scaled dog with absolutely no issues at all - great low end torque and massive high end power which I fondly remember to this day. We amateur mechanics often tried to literally screw with the carbs and usually in the hand of amateurs it makes a fine running steed into a nag. To this day I have many fond memories of the car. Cheers
Forgot to mention that the cams were not changed-standard European cams, pistons were replaced with factory higher compression units by Borgo, liners were same spec as original and valve changes were to use a better albeit slightly larger equivalent made of updated improved material. Porting and polishing was mostly clean up not massive enlargement
I learned from my two stroke motocross days that you can never clean a fuel fouled plug. Plugs at cheap. Always use a new one. I keep at least an extra set on hand. So try some new plugs and drain the tank.
