Stage 1 hop up? After all these years?

The Stinger, here. That’s right. like the title says, after riding the same HD Softail for nearly 10 years+, I finally got around to completing a stage 1 hop up on it, with the use of the Dynojet Thunderslide.


Who knows why? Maybe it’s a premature midlife crisis of some sort. Anyway, I suddenly found myself with a new “need for speed,” a thirst for power!
Until now, I’ve ridden with basically half of a stage 1 hop up: high-flow slip on exhaust pipes with slight rejetting of the carburetor, and part of a stage 2 hop up: Dyna S ignition with single fire coil. But, I hadn’t really messed with the carb much, until now.

I thought about the YOST power tube, but eventually elected to go with the Thunderslide, an item I almost purchased ages ago.
Seeking immediate gratification, I set out on the trusty hog to search for a Thunderslide kit at the local HD dealers. Well, times have changed. Not only does the mention of an Evolution engine meet with shrugs and head scratching from the staff, but dealers these days seem to stock only genuine HD parts. No aftermarket parts. Go figure. In the end, I was able to obtain it via net shopping, and the kit arrived in no time.

So, during the past Golden Week holiday, I welcomed Big Ben over to the
Stinger motor pool, and together we spent a bright sunny newly dubbed “Showa no Hi” (Showa Day) installing the Thunderslide kit.


Almost immediately, we hit a snag. Although the air cleaner assembly came
off with no trouble at all, we could find no way to disconnect the choke
cable. So, plans to remove the carb completely and work on it on a workbench were shelved and we performed all the remaining steps with the carb still attached to the bike. Not the most professional method, but it works.


With the hot sun beating down, we soon found ourselves thirsty and hungry.

Leave it to my old lady to hop on our backup Kawasaki Zephyr and get us some KFC take out. That and a cool bottle of Corona really hit the spot.

After that, it was back to work.


Through trial and error, we finally got all the parts installed in their
proper places.

Then it was time for a test run.

While I definitely noticed an increase in power in the high RPM range, there
was a definite loss of power in the low range. This baffled me since we
didn’t do anything to the slow jet. Fortunately, Big Ben came to rescue with
some spare slow jets of varying sizes. After replacing the existing size 45
with a 48, the low-end power was back with a fury.

After subsequent trial runs on the expressway, I can confidently say the
bike runs better than it ever has. Almost like there’s a completely
different engine pulling it along. The Stinger gives the Thunderslide two
thumbs up!

6 thoughts on “Stage 1 hop up? After all these years?”

  1. I’m glad I could be part of bringing your shiny new garage (that you built that expensive house on top of) into full operation. A biker needs a righteous workspace like that.

  2. Owen, the choke cable comes off with the carb. On the left side you lossen the jam nut that holds the cable to it’s mount and take the carb off the bike. During the winter take it off and send it next door and I can two more tweaks to the carb to make it even better. The vacuum vent on the CV carb slider can be drilled to 1/8″ for better throttle response and the slider itself can be blended at the bottom to make a smoother intake transition increasing the venturi effect and reducing the intake turbulence that work wonders.

  3. BTW, big twins that have any changes from stock like pipes or mufflers and free flowing intakes NEED a 48 slow jet to make the bike happy.

  4. My new house has a garage area with nice stone tiles and textured walls, like you’re not supposed to get it dirty or scratched up or anything. I’m gonna have to do something about that.

  5. Rich, thanks for the tips on the CV carb. I was able to loosen the jam nut, but the wire itself was threaded through another hole attached to either the frame or the underside of the fuel tank and I couldn’t get it to budge. I think I’ll ride with the mods I have for a while before doing anything further to the carb.

    GB, that is a situation that definitely needs rectifying. Let me or Big Ben know if you need help “antiquing” your garage.

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