Got my DTT ignition ordered, thanks for the tips guys. Once I get it I'll post up an update on how she's running!

 

Ok, I got the ignition installed, set to multispark, 2/2, 6000 like hillside cycles said (THANKS!), and started her up. Runs good in the garage, but I'm too busy to ride today. Tomorrow I'll actually ride it and hopefully the 2400 rpm stuttering is gone!

 

Turn off multi spark..

 

The instructions that came with it said to enable it on high compression engines (10.5:1 is high I thought?), and so did Hillside Cyles..why do you say that?

 

I've got nearly the same build (98", 10.75:1, ported heads, 585 cam) with the DTT ignition except I have a Mikuni HSR45. The thing I've found with the 585s is that they offer useable power down low, but really "turn on" above 3k. It will pull like a freight train when everything is dialed in right. Dyno tuning may help to get it as perfect as possible.

 

Oops. I missed what Scott said.. I guess if it works give it a shot. I've always left it off.. I was actually led to believe at one time that it could cause detonation from some experts. Made sense to me at the time.. The newer coils have plenty of juice to light the fire so it wasn't needed.

Also since higher compression motors didn't need the extra spark down low since the cylinder pressure was higher at idle.

The only thing I get from DTT is this..

This kinda leads me to believe multi-spark was only useful at idle.. Since I'n not fouling plugs at idle, it's not needed.

 

I took it out last night, and the problem persists. It seems like it runs better though, great throttle response. Still a dead spot with stumbling around 2400-2800 rpm in the higher gears, when I give it a good whack on the throttle. I can get through that rev range without it missing if I slowly increase throttle..I needed to richen up the idle mixture a quarter turn because it was popping a bit. Once I'm past 2800 it wants to take off and runs like a champ. . I tried changing the timing from 2/2 to 2/1 and it made no difference. I've taken the carb apart multiple times, nothing looks pinched, float angle is correct, maybe I should shim the needle? running out of ideas here

 

Do you still have the stock carb parts, needle and emulsion tube?
Was the emulsion tube removed?
Is the needle jet installed correctly? (Assuming emulsion was removed)
How do the plugs look?
I would try returning the carb to stock and using a 48 pilot and 220 main.

 

I still have everything. I changed the emulsion tube to the cv performance one. I removed the emulsion tube from the carb, and screwed the new one in, then the 195 main behind the emulsion tube. I'm pretty sure the needle jet stayed intact inside the carb itself, I never removed it. Stock it was 45 and 190, now it's 48 and 195. New slide, new accelerator pump, cv performance needle and spring

 

If your heads are decent.. 200 may not be enough.. While this ain't a max effort street build, it definitely ain't a mouse build either.

You should be able to see the brass part of the needle jet sticking up around the needle.. don't know what the CV perf emulsion tube dies but the stock one does pretty well.

When you have a hesitation like that and it's jetting. One jet size may not make much difference.. If you think it's rich, go lean a couple. I suspect it's lean. 220 may be too big but it will point you in the right direction.