Thunderslide Kit

[reckless kelly]

My local guy finally talked me into buying a thunderslide kit for my bike (although I'm still not convinced it's worth the money):

1991 FXRS
24,000 miles
Stock Keihin Carb
S&S Air Cleaner with K&N filter
EV3 cam
Screamin Eagle Adjustable pushrods
Stock Exhaust
Screamin Eagle Iginition Module
Screamin Eagle Ignition Coil
Stock ignition
Magnecor Wires
I live at around 4,500-5000' elevation

So anyways, I installed the kit and started with the needle in the #3 notch (there are 7 total notches on the needle). My guy told me to start with the 175 main jet and keep the stock 42 slow jet.

So I took it for a spin.........all kinds of farting on deceleration.

Went back and shimmed it in #4 (shims are numbered from #1 being at the top of the needle and #7 being at the bottom, so going from notch #3 to notch #4 would "raise" the needle).

Took it out for a spin.............little less farting on deceleration.

So by the time I finally eliminated the popping on deceleration I was all the way into the last notch (#7). My thoughts are that my needle is shimmed way to high and that I should switch to a 180 main jet and a 45 slow and raise the shim back up to #3 or #4 again.

My local guy told me to leave it as is and ride it. Problem is that when I run wide open I'm frying plugs and then the bike runs like hell (sputters on acceleration) until I put in new plugs.

With the current set up the front plug is starting to tan up a bit, but the rear plug is black and sootey.

Any thoughts???

[Don Camillo]

Spark plug reading is not always so evident.I would put in 45 slow jet, leave the main alone (or put in 185 - float bowl will be removed anyway) , set the needle at 3 notch. Do the test ride.

P.S. check for air leaks at manifold, VOES switch, air filter.

[tx_shooter]

My Dad had the close to the same problem - putting in the larger slow jet did the trick. But I would still check for an air leak at the manifold; Evos are bad about that.

[reckless kelly]

Thanks for the reply guys. Last night I threw in a 185 main and a 48 slow and moved the needle back up to #3. It ran great on a short 5 mile test ride. Good power and response throughout the rpm range. No backfire. I'll hopefully open it up a little bit on the highway today.

Thanks