[Scott Newton]

The single-pump setup you’re describing would work – and is the standard setup, but it’s not a pumparound setup. With a pumparound setup you’re removing the floats and needle valve, and instead using the second pump to siphon off the excess fuel from the fuel bowl. The pumparound setup is to prevent possible fueling issues due to sticking floats in hard cornering or bumpy situations.

[Scott Newton]

I used a pumparound on my CR125 – it was just two standard Mikuni pumps, one pumping from the tank to the carb, and another pumping from the carb to the tank. Both pumps were driven off a pulse line from the engine. I don’t know if the carb was modified at all, since the carb was previously used in a pumparound setup before I got it. The system was 100% trouble free for me, and other than having twice as many fuel lines and fuel pumps, didn’t look like that complex a setup.

[Scott Newton]

Any interest in selling just the TPS?

[Scott Newton]

I have one on mine, and used them on Formula 500 cars for years as well (similar vibration), and they work fine. The only issue I had once on an F500 was that I used a toggle switch, and after hitting a curb particularly hard one time, the switch switched itself. I then upgraded to a “firmer” switch (the old one was particularly bad with a rather large toggle arm), and have never had an issue. On the kart I’m actually using an OE Honda part, which is just nicer since it has the correct connector on the end.

That said, I hardly ever use it on the kart. My only real reason for having it is so I can kill the engine in the event of a chain break.

[Scott Newton]

The biggest advantage you’ll gain by making the deck wider is that you can then build a simple clamshell out of thin plywood and 1×1’s to make the trailer weather tight. With the kart hanging off each side, as it is right now, it would be much more difficult to do this.

Another expansion of the second deck idea would be to build the second deck at exactly the right height that you could slide the kart right off the stand and onto the trailer – possibly even slide it “into” the trailer by making the top shelf an enclosed/weather tight area. This should give you 12-16″ of space between the decks to store your stand and everything that goes with the kart.

Of course at this point you’re basically just re-engineering a 6×12″ enclosed trailer – but I suppose you’ll have much less money invested to get you there.

[Scott Newton]

I have that trailer (4×8′ folding Harbor Freight). My full-size shifter kart fits on there just fine with none of the bodywork removed and a full-width plastic bumper. I just have to put it on backwards (front to rear), that way the narrower front fits between the fenders and the legs used when the trailer is folded up. The rear does hang over the edge by about half a tire’s width on both sides, but it’s never been a problem.

[Scott Newton]

I too have the exact same trailer as Ted, except I used a 25% off coupon :-p.

Either way though, just came in to say that I only have a simple plywood sheet on top, not a fancy deck like he has. The kart fits just fine that way, just have to put it on the trailer backwards so the wider rear doesn’t clash with the trailer’s fenders. Doing it this way allows me to still fold the trailer in half to put it away in the off season.

This is actually my second trailer like this – I used to have one with a deck almost exactly like what Ted has that I used to haul my F500 with. That trailer worked great for several years even though my total weight was probably pushing the limits of the trailer’s load capacity.

[Scott Newton]

My flywheel was rubbing enough on the seat that it wore a hole through the seat, through my suit, and through my hip in a few laps…. but never bogged down. My first clue something was up on track was when it felt like my seat was pinching me – came in to explore, only to find the carnage.

Seat now has a thin piece of aluminum in the right spot – and it still doesn’t bog.

tl;dr – you need to look elsewhere.

[Scott Newton]

I’m still new to this, but my process has worked pretty well thus far:

1) Start the kart on the stand and let it get to full operating temperature before even going to grid.
2) Shutdown motor, move kart to grid
3) Depending on time between step 1 and when you’re about to go, maybe refire it again on the stand and let it run for 60 seconds.
4) Put kart on the ground, in neutral
5) When it’s time for me to move from grid to the start line, have someone push me 10-20 feet, and bump start it into first, and then drive to the start line.
6) For 2nd and 3rd runs in a heat, I don’t need any pre-warming, just bump start it when the time is right. I’m almost always running on the cool side anyways, so letting it idle a bit has normally been acceptable.

I am very tempted by the whole electric start idea, but my kart (and driver) is already overweight, and I already have engine::seat clearance issues.

[Scott Newton]

The paddock lot is big enough – I’ve done autocross events there in the past with the SCCA… but it’s not quite as smooth as you would hope:

[URL=http://s1291.photobucket.com/user/Scootin159/media/Forums/IMG_1702_zps6caa99de.jpg.html][IMG]http://i1291.photobucket.com/albums/b548/Scootin159/Forums/IMG_1702_zps6caa99de.jpg[/IMG][/URL]

The better lot to use would be the media lot, which is where the SCCA now does tehir autocrosses (West of the start/finish straight about halfway between start/finish and turn 1).

[Scott Newton]

Some 125cc shifter data from my last autocross that had a “drag” start.  I suspect others can and have done much better…. I’m new to shifters, and haven’t really done much tuning yet.

– 0-50mph (speed before we lifted for first corner) @ launch: 2.7s

– 60ft times: 1.7s @ 43mph

Based on that 0-60 in 3.5s seems very doable.  No idea what top speed is, since I’ve always run out of straightaway long before I was starting to feel any aero drag.

[Scott Newton]

Long ago there used to be kart races held right on the track itself at Watkins Glen – then somebody figured out it was a bad idea to run karts on Armco-lined tracks.  The track itself owns a LOT of land – a lot of which was last used for overflow camping in the F1 days.  They could easily allocate enough land to build a world class karting facility, with multiple tracks and layouts if they wanted – the only question would be if they feel it makes business sense to them.

On a related note – I have it on good authority that the new track being built near Syracuse NY (www.cnyrp.com) will be building a dedicated karting track as well.

[Scott Newton]

I’ve wondered the same thing – would eliminate the seat clearance issue.

Here’s a link to the ad: http://www.ebay.com/itm/Evett-Motorsports-custom-shifter-race-karts-INSANELY-FAST-not-for-children-/261565366153?

It looks like this kart has a lot of other modifications as well – such as having a front suspension.  Would be interested to know what was involved in bolting the starter up though…

 

 

[Scott Newton]

While this incident is certainly a trigger to review safety measures – I hope they aren’t isolated to just Junior Karts (as they were in the email that the national office sent out a few days ago).  Things like stuck throttles and failed brakes can, and do, happen in any class – and with just as much (if not more) potential for serious injury.  As bad as a fatality from a mechanical failure in an FJ is… a 3000# car with a stuck throttle plowing into a crowded paddock could be much worse.

Also what would be much more useful than just a generic “check everything” reminder, would be some specific and detailed guides of what has gone wrong in the past, so we know what to look for in the future.

[Scott Newton]

Has there ever been any movement to have a second KM class for 125 TaG karts (or perhaps a third KM class for KT100’s)?  Regionally around here they’re all you ever see at the local kart tracks – but those guys normally don’t bother coming out to the autocrosses since they know they don’t stand a chance against the shifter karts (or the shifter kart PAX).  Whereas for autocross, you really need a shifter if you want to compete.  This means people who want to compete wheel to wheel AND compete at autocross, really need to buy two karts.

I’m sure it’s a different story elsewhere in the country however, as the popularity of the classes shifts.

[Scott Newton]

I too am curious on what the general knowledge is on how this applies to karting…

I know in the Formula 500/600 world, the answer is generally defined by how reliable you want the chain to be.  A longer chain generally means a cooler chain (since each link makes fewer RPM, it has more time to cool each trip around)… but a longer chain also means a heavier chain, which translates into rotating mass and lost horsepower.  For the F500/600 cars, which have a similar power::weight ratio, but roughly double of both – it’s generally preferable to go for the maximum chain length practical.  This is done by either increasing the center to center distance, or by running the largest rear gear practical and then selecting the appropriate front gear for the track.  A longer chain made by gear selection is also preferable to a longer chain made by c2c distance – since this also means the chain needs to bend less around the front gear (and thus less heat, less wear & tear, less parasitic drag).

[Scott Newton]

I shopped these for a while and just recently gave up and bought a folding Harbor Freight 4×8 trailer.  I have a large enclosed trailer/toy hauler for long trips, but for just quick trips to the local track that was mega overkill.  I just wanted something small & light that didn’t take up much room for storage to use on short trips – which is why a hitch carrier would’ve been perfect, but pre-made ones were way overpriced IMHO, and I’ve got too many projects to take on building my own right now.

I had this same HF trailer a few years ago with my formula 500 car (about 600#, 55″ wide, ~9′ long), and it worked great.  It only takes up about a 5′ x 2′ area in the shed for storage once folded, and has proven to be easily capable of handling the load for several years of service – all for about $230 out the door if you find the right coupon.

[Scott Newton]

I’d be interested, just would depend on pricing and timing.

[Scott Newton]

As a follow-up for whoever reads this in the future with the same issue:   I pulled the clutch cover and found that the outermost plate of the clutch was dislodged and stuck between the pressure plate and the clutch basket.  I just pulled the clutch lever and gave it a little tap with a screwdriver, and it popped right back in.  Works fine now – still a little drag while it’s in gear w/ lever pulled, but I think it’s “within spec” – just not used to how bike clutches work.

[Scott Newton]

Does anyone have any pictures of this installed – or weight distribution info with the motor moved over?  I’d love to have this for autocross (where there’s a lot of engine start/stops, and not always room for a push start) – but right now I’ve got less than zero clearance between the engine and seat (the corner of my seat is just slightly cutaway to clear the front lip of the flywheel housing), so I know making room will be something non-trival for me.

Also – any chance of someone posting up the dimensions of that plastic cover?  In particular I’d be looking for the thickness of the two “steps” in the cover so I can make a wood block the right size to test fittment before buying the kit.

[Scott Newton]

A dual MC setup gives you an extra brake circuit in case one fails (i.e., if the rear brake line bursts, you’ll still have front brakes, and vice versa).  I’m too new to karting to know if this is a safety requirement by many series, but I know in the formula car world it’s almost a universal requirement on safety grounds.

A dual MC setup will also allow you a larger range of adjustment.  With a single MC if your rear brake pistons are the same size and quantity as either front wheel, you’ll basically have the option of 66/33 F-R split to 100/0 F-R split.  If you have two MC’s you can basically run anything from 100/0 to 0/100.

[Scott Newton]

Sent you an email

[Scott Newton]

FWIW, I run Race Studio using Windows 8.1 on my bootcamp’d Macbook.  Zero issues at all

[Author]

Posts