Posts by gearhead

My 2cents... The speedo may indeed be somewhat accurate. I find that cruising at any speeds at or above 75 MPH, the rear tire starts to lose traction and starts spinning/scrubbing a bit -- especially over bumpy concrete. With super-soft Mickey Thompson tires, 75+ MPH cruising leaves little rubber strings all over the tread. At cruising speeds at or under 70 MPH, the tire tread is smooth. This is in both hot and cold cruising conditions. I try and keep cruising speeds down to where I don't see any little rubber strings on the tread. This may also explain why I can still see the nibs on the tread on my MT ET Street-R rear tire with over 1500 miles on it and why the stock Kendas started feeling "greasy" at higher cruising speeds -- they were continually slipping.

Maybe time for a rear wing?

I replaced the master cylinder brake pressure sensors myself... The trick for an easy DIY brake pressure sensor replacement is the following kit:

Phoenix Systems 2104-B V-5 One Man Reverse Brake and Clutch Bleeder Kit | eBay

WIth the above, a fresh can of DOT-4 brake fluid and replacement (new part#) brake pressure sensors and 4 washers, I was able to replace the sensors in just an hour or so. The quick process description:

Using the Reverse Brake Bleeder, drain the master cylinder reservoirs (front and back chambers). You do not need to remove the reservoir from the master cylinder. Replace the caps after draining to avert moisture from entering the brake system.

Disconnect the 2 brake fluid level and the 2 brake pressure sensor electrical connectors.

Unclip the brake pedal from master cylinder pushrod. There's a re-useable retainer clip on the pin coupling the brake arm to the master cylinder pushrod. Pop that, pull the pin.

Remove the two bolts holding the master cylinder to the firewall.

Pull the master cylinder forward a bit, then rotate it 90 degrees so that the pressure sensors are facing up.

Replace the pressure sensors and washers.

Reattach the master cylinder to the firewall.

Reconnect the brake pressure sensor and brake fluid level electrical connectors.

Re-install the brake pin and retainer clip to the brake pedal arm.

Loosen the brake fluid reservoir caps on the brake master cylinder (to allow you to easily pump fluid up into the reservoirs).

Use the reverse brake bleeder to pump fresh brake fluid into the rear brake caliper. I pumped enough fluid into the rear brake caliper to fill the master cylinder reservoir for the rear brake to 1/3'd full.

Use the reverse brake bleeder to pump fresh brake fluid into the front passenger side brake caliper. Pump enough fluid to fill the master cylinder reservoir for the front brakes to at least 1/3'd full.

Top off the master cylinder reservoirs to correct level.

Horsepower is one thing... But, in my opinion, you gotta have "big meat" in the rear! You just can't get enough traction during acceleration...

I'd just slightly change the position of the steering arm ball-joint on the front knuckle (item#14 in the following pic)...

You could alter where item#17 bolts to item#14 in the above pic. Make it a bit closer and you'll have "faster" steering.

Wheels Stolen off Slingshot...

My 2 cents on harnesses... If you use a sternum strap, a 4/5 point harness will stay in place and work with stock seats. But, it's not just about the harness... Wearing a harness subjects your neck to incredible strain if you hit something or if something hits you. Myself, I use a Hans device with my helmet when using a harness -- these keep your neck from overextending in a high-G stop. They also make it difficult to swivel your head around, so it's not optimal using one while driving in lots of cross traffic.

The standard seat belts on the Slingshot will "bend/throw" your torso towards the inside of the cab in a high-G stop. Which is perferable to throwing your torso towards the outside of the vehicle I guess. But, either way the driver's head or torso is going to impact the steering wheel first. A 4/5 point harness will prevent this, but I'd strongly recommend using one with a Hans device.

Quote from SaltyClownNY

My issue is that the stock 255mm tire gets squirrely on me all the time. I can fish tail the thing going out of a parking lot real easy and I have a stock engine. I can chirp the tire real easy going to 2nd and 3rd. I know I have a lead foot, but I worry increasing the HP to over 525HP so I can compete with @rabtech ( ) is never going to happen unless I can get a grip on my ass end. And yes, I know some of it comes down to knowing HOW to drive, but in my case with a stock engine, the 255mm tire just sucks.

I've used two different Mickey Thompson rear tires -- a Sportsman SR and a ET Street R. The Sportsman SR is 26x12R18 mounted on an Enkei PF01 and the ET Street R is a P325/35R18 mounted on a 12" wide ForgeStar. The MT Sportsman had a bit more grip -- less squirmy and greasy feeling than the stock Kendas. These didn't make any squealing noises. With a Supercharger, the MT Sportsmans could easily be spun. But, the ET Street R has WAY WAAAYYY more grip run at 15 PSI. I've got a hard time breaking it loose with a Supercharger just using the gas pedal.

A long time back, I did some calculations as to the available traction vs. HP -- and how much tractive force you could get out of a single tire with the weight and balance of a Slingshot. The basic problem, is that the Slingshot is a forward weight biased reverse trike with a low CG. That low CG results in poor weight transfer under acelleration. Anyway, I've attached the old calculations below:

All of the above calculations were for a standard ultra high performance road tire (CF of 1.0). An R compound drag tire will up the coefficient of friction to 1.3 or maybe 1.4 -- which means you can get over 1200 lbs of tractive force to the ground. This added traction could take most of the added torque from a turbo or S/C in 2nd gear on up.

This mostly about straight line acceleration. With just one rear wheel, you can't use negative wheel camber or other tricks to help with lateral acelleration in corners. But, having a nice pliable rear tire with a lot of contact surface area and narrow sidewalls helps in the twisty bits. I find that I can accelerate out of corners with the ET Street R's -- something I couldn't do with my other rear tires. Of course, hard acelleration out of a corner is something a reverse trike probably shouldn't do -- as it can rock back on a tilt axis. Similarly, a regular trike shouldn't brake hard going into a corner as it can rock forward on a tilt axis. Sidecar motorcycles have to be very careful about any braking while turning left as they have asymmetric tilt axes... Thankfully, I haven't lifted a front wheel yet. I have no idea what ESC will do if that happens...

Quote from Bubblehead

Had a little problem coming home this past weekend from Murphy, NC. Stopped at a gas station and somehow I must of hit the panic alarm on my Viper Bob, I assume it was the panic alarm because the bike would still start. NOTHING I did would silence the alarm until I pulled the damn wires out of the speaker. I NEVER use the system so I am going to remove it completely from the bike. Does anyone know if I disconnect the control box will that allow me to remove it without it locking up my ignition?

You should be able to press "the button" on your Viper car transciever (the small fob like thingie with the tiny antenna with the button that flashes blue -- it's typically velcro'd somewhere by the dash) -- and press that button "the correct number of times" to silence the alarm. I have a proximity sensor on mine and if lookie-lous trigger the proximity alarm over 3x the alarm goes into a permanently "pissed off" state where the alarm will sound whenever you turn the ignition key. You just have to press "the button" "the correct number of times" to silence the alarm.

Removing the Viper without it disabling the ignition depends on how it was wired up. I know that mine is wired so that it detects when the key is turned and can also disable the starter. Other installs only sound the alarm with a proximity or motion/vibration sensor and little else. If yours started with the alarm blaring -- I'd think you could just remove the control box without disabling the starter.

Quote from SaltyClownNY

@gearhead - the Mickey Thompson ET Street-R 325/35R18 you have... I went to the site and it gives no numbers on OD. I was curious as you are the second person who has spoken about this tire on an 18" wheel. They have the OD listed as TBD. Know the approximate size?
I don't really use my SS when it's raining, but if you hit any wet roads, how does it hold up with that tire?

... OK, I see on the site it's around 27X13.50R18, but this is an estimate.... so around 27".

How does it do with water on the roads?

Not much rain out here in Kalifornia... I don't risk any water with drag tires, DOT or not. If I were to run into any rain on the road with the MT ET Street-R -- I'd just park it where it's dry and hang out. I did run across some wet pavement with one of my other rear tires, a Mickey Thompson Sportsman SR (in 26x12x18). Wet, that tire felt like the stock base model Kendas -- squirmy and greasy. And, the MT Sportsman SR's are steel belted all weather rated and have a pretty good and deep tread pattern. The rear end of the Slingshot is very light, so even the best of tires would be challenged in the rain. The weather apps have become pretty good, so you can accurately predict rain ahead of time. If you do get a MT Street-R, keep your other rear wheel/tire (you'll have to get another rim in 12x18 with a +45mm offset for the MT Street-R's anyway). If you anticipate rain, just swap wheels. If it's going to be dry, run with the drag tire. If you're planning on going on any long trips, you probably wouldn't wanna run the MT Street-R's -- they're glass belted and have little puncture resistance.

Hope this helps...

Just as a quick addendum, on base models you can run up to an 8% tire diameter difference front/rear. At 9%+, you'll get a warning light on the dash. The SL's can go up to an 11% tire diameter difference front/rear before the warning light goes off. You can use the MT ET-Street-R 325/35R18 on a base model with stock sized front wheels -- no warning light.

Quote from supermoto292

I need a better tire in the rear because my nitto 555 just spins to much on hard acceleration making me go know were. What is a good tire for a super charger kind of power so I can accelerate in a straight line better. The nitto 555 is not bad when its 90 out here in Indiana, but much of the year I ride in 50-70 degrees and it spins. The tires corner excellent all the time.

For truely Heroic levels of grip, you can run a Mickey Thompson ET Street-R 325/35R18. This is a nice pliable glass belted drag tire -- not a heavy less pliable steel belted drag tire. There are variances in how "wide" tires run with respect to the tread width numbers -- and this tire is the widest tire you can run without rubbing the swingarm or shock using the stock +45mm offset. The nibs just graze the swingarm. Even in this size, the tire+rim weight is 2 lbs less than the stock base model Kenda tire+rim. I run mine at 15 PSI all the time. This gives a big fat footprint so the tire stays planted -- and I'm showing very little wear. I snapped a pic at 250+ miles, and the center seam and nibs were still showing. The tire's lower profile allows it to handle the twistys decently even at this low PSI. I find it very hard to break this tire loose in 2nd gear with a supercharger. I just get a nice satisfying head snapping acceleration...

Rumor has it that Mickey Thompson came out with this size specifically for the Dodge Demon. At the strip, this wrinkle-wall tire really struts it's stuff. Some Mustang guys run their MT ET Street-R's at 17 PSI all the time -- street or strip.

Just my 2 cents...

Just my 2 cents... I've used turbo scavenge pumps and they work awesome. No chance of any oil drain backups, even with foamy-oil from heavy exhaust-side turbo pressures...

Electric Oil Feed and Scavenge Pumps

I used the above rbracing scavenge pump for 6 years, never an issue. It de-foamed the oil and I "drained" it back with a snap-on fitting on the oil fill cap.

Myself, I wouldn't recommend mounting that beauty in a very visible area... It might "disappear" if you leave your SlingShot parked unattended. If you have an alarm system, the internal passenger areas can be covered by a proximity sensor. Should someone reach inside the vehicle -- an alarm might dissuade them from taking anything.

For driving around in a Slingshot in 100+F temps, what I've got and tried was the phase-change cooling vest by Techniche (their Techkewl Phase Change Cooling Vest). I got mine through Amazon:

ref=sr_1_3?s=hi&ie=UTF8&qid=1495859283&sr=1-3&keywords=TechKewl+Phase+Change+Cooling+Vest&th=1&psc=1

These work great! But, there's one gotcha (which probably won't apply in Palm Springs, more on that in a bit). This vest comes with a real nice insulated carry bag, so you can stow a vest with pre-cooled phase change inserts in the Slingshot -- and pull it out to wear when you need it. I used it on a 100+F day, sitting in stop & go traffic with a full face helmet on. I was nice & cool all through rush hour. I even tooled around town and re-fueled on the way home. This would have been absolutely intolerable without this cooling vest. Would a roof help? Yes that would help a lot too (but I currently don't have one).

The one gotcha was when I got home -- still nice & cool -- my shirt was all wet from the condensation on the phase change inserts. Granted, Techniche probably didn't anticipate this vest being used by someone sitting in a humid wind blast. But, if I need to use this vest to go to a meeting somewhere, I'll just pack an extra shirt. The phase change vest remained nice & dry on the outside. But, going to a meeting wearing something that looks like a bullet-proof vest would probably not go over too well...

The condensation would probably not be a problem in the high desert -- places like Palm Springs or Las Vegas. On the plus side, this condensation probably helps with the cooling a bit too.

There are a myriad of cooling vests on the market, some of which use plain water in their inserts. The plain water ice inserts are way too cold when you put them on and lose their cooling in just 30 minutes or so. The paraffin/glycol phase change medium used by Techniche feels cool -- not cold -- and keeps cooling for 2 hours or so. I keep the inserts in a tupperware container in the fridge or freezer so it's always ready to go.

There are cooling vests which use circulating water from a pump, using an ice chest reservoir. Those would probably last for more than 2 hours. But, for quick trips this Techkewl Phase Change Vest is very convenient. Just pack a dry shirt if you need to go to a meeting.

Install it to the passenger seat rail bolts in front. Easy to fab a bracket for this.

Currently using RE-71R's on the fronts on a base model -- stock size. I chose to stay with the stock size as I was trying to minimize unsprung weight. Using very light Enkei RPF1 wheels and top-hat brake rotors, I removed over 10lbs from each front wheel. Handles great. Floats over bumps, doesn't get upset when cornering hard on rough roads. These tires have great grip without any need to warm them up. Like other soft rubber tires, these tend to toss rocks and gravel. I managed to remove almost 20 lbs from the rear wheel, which really got rid of a lot of the clunkyness from the rear. The RPF1 model wheel will not clear the brakes on the rear -- had to use an Enkei PF01 (slightly heavier). I got rid of over 7 lbs from the rear wheel assembly by replacing the heavy cast iron drive sprocket with an alloy one. Currently running a Mickey Thompson Sportsman tire on the rear, but will be switching it out to a wider Mickey Thompson DOT drag tire. Just can't get enough grip in the rear...

Where's the gas tank on that thing? It's not going anywhere without 3 to 5 gallons of gas...

Long ago, I remember trying to locate valve-like tapping noises on a different engine and it turned out to be a tiny exhaust leak from a faulty gasket. It often helps to poke around with an engine stethoscope or even just a tube held to one's ear. On the LE9, I seem to remember the EGR valve can also make some weird noises. I debugged the latter by listening to the engine while removing the oil fill cap.