[James McMahon]

Focus on family, fun and value.
Don’t let the “baseball coach dad$ and mom$ dictate how you run your club.

[James McMahon]

Sorry your thread got a little hijacked Howie! I think the gouging came from individuals as well as teams. That’s the free market in effect however.

The amount of “industry apologists” on here amazes me sometimes.

My understanding is that there were about 100 sets of wets available in the US from “whoever supplies MGs”. If this is inaccurate, then please correct me.

At a time when just one  of the races across the entire US  has 600 drivers, there were not enough wets to be found to even cover 10% of ONE of those races. I’m assuming two sets per driver here. Ok you can play semantics and say, Rotax ran mojos so they should not be included. Fine, it doesn’t change the fact that supply was way, way, way off demand.
How does this not strike anyone as a supply issue?

I said it once, and I’ll say it again. If you want to continue to take the stance that it’s the drivers and teams fault and that the spec’d tire supplier are in the clear you can expect to see entries diminish, especially from international drivers and teams.

Having $800 of wets hanging around in your trailer is great, until the spec tire gets changed.

[James McMahon]

Is it too soon for a “thats what she said”?

[James McMahon]

If you pop over to the UAS\Open board on 4cycle.com you will likely find someone thats’ Max’ed a Max. Keep in mind though, most of these guys run ovals with fancy clutches ergo narrower powerbands, so when asking for advice make it clear that you are running “sprint asphalt” as they call it.

Unless you can bag yourself one of these: http://www.karting1.com/continuously-variable-transmission-for-karts-test.htm

Then alky it up to 65HP and call it a track smoker!

[James McMahon]

It’s a single geared kart, HP don’t really matter when it comes down to it. You could tune for nearly 50HP on gas on a dyno, put it on the track and it would be absolutely pathetic. Think of how a shifter pulls (well, doesn’t) when it’s in too low of a gear. With a single gear its how much area you can create under the curve. Actually thats true for gearboxes too but I digress.

Hmm, at $400+ to remove the rev limit. I think I’d spend the 400 looking for ways to make the motor pull better throughout the range. Smaller carb, maybe a little powervalve trickery, reeds widened exhaust ports. More ignition advance (with correct fuel), shaved head.

No idea where you would end up in peak HP, but the times would drop.

[James McMahon]

Ideally long term storage should be in sealed metal cans with the appropriate lining. The big plastic racing jugs you see from VP and so on are porous and will leak the good stuff out of your fuel if you leave it in there long term. They are really just meant for sake of convenience at the track.

Thats not to say lots of people dont keep it stored in porous plastic containers, but given a choice use an appropriate container
I usually keep original fuel drums for a while until the spout starts to leak and store my fuel in those, off the floor as pointed out.

[James McMahon]

Manuals aren’t very common, especially in T5 form, but they are out there. Gotta love the growl from the inline 5.
I’m sure it would fit just fine in a Subaru too…

[James McMahon]

“Thou shalt not spec a tire supplier if said supplier can’t supply the tire.”
anonymous

As a tire supplier, did MG have sufficient tires available for the drivers of this event?
Answer is no, it’s their job to supply tires. Anything beyond that is semantics.
Is that an easy job? Absolutely not! But its a job they took on nonetheless.

Sorry, IMO this is on MG. Biggest event in the US, they were tasked with supplying tires for the event and they failed to supply. . Drivers and teams shouldn’t have to carry $500 of tires around just “in case” it might rain at one of the biggest events of the world that has a clearly designated, spec tire supplier.
Sure, we can put it back on the drivers and teams as much as we like but that’s a surefire to see entries diminish in my opinion, especially for the guys that don’t run in the US or SKUSA regularly.

The whole situation was a crap sandwich, you could argue that SKUSA could have allowed drivers to practice or even run on other rubber, but then that’s unfair to those that had the correct tire. It sucks, but I think SKUSA did the right thing by sticking to their rules. At least you know you can count on them for that in the future.

Bottom line and root cause: MG failed to supply. I’m not saying the fix is trivial or that its not a logistical nightmare for them, but it is still their responsibility as tire suppliers to supply the tire.

FWIW I think wet tires should stay open, or even a controlled spec where drivers choose from a list of brands and specific compounds.

[James McMahon]

What’s your budget and what are your goals exactly?  You could probably make 45HP+ on gas, even more on alky from it but the powerband would make it slower than molasses over a lap on a typical kart track without an oil clutch or CVT to keep the engine  “on the pipe”.

If you want to go full on you could punch it out a few MM, make it drink alky, get some buller dual carbs on there, widen the exhaust port and so on. Tal-Ko in the UK make bigger pistons that may work. You could stroke it too.. a few folk got cought doing that with “sealed” motor LOL.

I don’t think I’d be too keen to change the port heights unless you plan removing the rev limiter somehow. Width have at it, but the powerband is kinda narrow already so I don’t think I’d want to raise the exhaust much.

For a quick pep up, take some volume out of the head. Adjust ignition timing and fuel octane as needed. At least with the head its dead easy to go back to stock.  You might need to start using an external starter however. I’m sure you could get some trick reeds on there too.  If you are running it on a sprint track, I’d be inclined to scrap the stock carb and move to something in the 30mm territory to get some better low end response. Something from KF1, or the VHSH30 that’s used on ICC/KZ motors. Maybe the new tillotson slated for Max use? Thats available in 27mm and 30mm venturi.
There might be gains with the pipe,  either with modification or  someone with specific knowledge on the Rotax setup might be able to tell you.

**disclaimer, I’m not a professional engine builder… more of a tinkerer and observer.

[James McMahon]

epic vid, thanks for posting.

[James McMahon]

Volvo V70 (850 will work  same)
Here’s my ’98 T5 with a shifter shoved in it. Sadly RIP since spinning rod bearing at 228K.

[James McMahon]

For your MyChron 3…

http://racerender.com/Products/index.html

[James McMahon]

Well for what it’s worth ive read that it was run for 24hrs as part of a 24hr event. So I guess 20 on the piston is safe. Will it still be fast after 20hrs? That’s the question and the answer is probably where the 10/20 answers you are getting are coming from.

[James McMahon]

I think Keith’s point is about the long, long straights that shift the empahsis from cornering to drafting skill. Example, Road America.

A while back I started making a video for COTA. Need to dig up the source files, in the meantime all I have for now is a couple of short hand-shot vids:

https://drive.google.com/file/d/0B5O3efMkqXjzd2ZGWl9BT25IS28/edit?usp=sharing
https://drive.google.com/file/d/0B5O3efMkqXjzWDltSlhWbVJfN2M/edit?usp=sharing

If I get more time I’ll make a decent one, but I’d be lying if I didn’t say the total lack of information and communication on this is pi$$ing me off to the point of saying ***k it, I couldn’t be bothered.

[James McMahon]

I think it’s time to discuss a big midwest event…. For venue I’d suggest Autobahn. Although its expensive to rent, it is located nicely, has good facilities, nice wide track. All of these lend themselves to hosting a good road race event. Blackhawk while awesome to drive, for a big once-off I feel we can safely get more karts out at once at Autobahn.

It’s early days yet, but our group are talking about possibly running Hastings and Topeka in ’14. We’ve been wanted to do Topeka for some time.

My opinion is that entries are spread too thin up in these parts. I’d rather see less events and have bigger ones, but its up to us as drivers to vote with our feet.

[James McMahon]

A little loose is fine, you want them to be able to move around a little. Be sure you have a good nylock nut, or blue threadlocker on the threads so that the bolt doesnt back out.

[James McMahon]

Unsubstantiated rumor….. COTA requested to wait until after USGP to talk to Bernie about USKGP. Well, here we are….watch this space.

[James McMahon]

Gateway isnt happening this year, probably not in the near future. Expensive to rent and feedback from drivers that stayed this year was mixed.

CES has Two main shifter classes. CIK125 and G125.  There’s rarely less than 25 shifters on the grid, at blackhawk in August last year we had almost 50.

In CIK 125, Stock Honda’s can run at 375lbs, all others (ICC, KZ Mod) run at 385. Open tires. Run what you like, in a 30min race softies aren’t gonna last :)
The G125 class is for older, more “statured” drivers. 420lbs for all motor packages, 30 years plus. Tires are same as CIK.
IIRC gearing for a stocker at Blackhawk is 18:22/18:23

Stock Honda as a separate class was dropped for ’13 onwards due to lack of interest. If enough drivers got together and regularly turned up, I’m sure that would change. In any case the stockers have no issues getting up to the front of the field.

[James McMahon]

Doubtful   $$$$

[James McMahon]

After second read of the site (look like they are based up my way in MN too)….
You also need to consider what you plan using it for, racing or just testing. It might not pass tech for most kart races, any oxygenates tend to make the digatron go nuts. I could be wrong but, afterall they do mention karting on their site but motors in karting start at 40BHPp/L and go to as much as 350! Thats a big range in specific output. Kart motors also tend to see very high rpms which combined with small bores generally require faster burn times and lower octanes.

[James McMahon]

What kind of motor do you have?

Haven’t used it and wouldn’t advise it for a kart having read their site. “Real” race gas is about consistency of batches and performance additives. Octane numbers for race gas vary depending on the application its intended for. A higher octane number doesnt make it a race fuel. VP have many 87MON racing fuels for example.

Bottom line is that, at least with a carb’d engine and especially with a stroke putting out semi-decent HP, I’d very hesitant to use that stuff because you are blending it with pump gas which is a mixed bag in terms of composition and specific gravity. What works one day may not work the next.
If you have EFI with O2 sensors and so on, you can get away with that, but I would still say it’s sub optimal.

Last thing to consider is the presence of lead, which while not healthy for your or me, is great for the internals of a two stroke.

[James McMahon]

Dry…borrrring… spice it up with a few tinkles!

[James McMahon]

Not a hope in hell of any 125 making 60BHP on gas, at least not in any way that would be useful when you take it off the dyno and bolt it to a kart. Methanol, maybe, gas hell no. Even 50 is darn close to a trophy pull anyway.

That said, on your average sprint track the 250 is going to be squabbling for grip, usually the 125s are just as quick, if not quicker for that reason. Bigger tracks its a different story. If you’re powerful in HP but not torque then you have to be spinning higher RPMs, whilst keeping torque up.

For dyno sheets, unless you know a lot of the factors behind the data it’s not going to be all that meaningful. Fuel especially and of course if the TM you are dealing with has been modified, the “stock” curve is useless. Also, you cant use the motorcycle curves for the kart application, as they generally have much different pipes.
Try Italian motors for more info on the TM moto. Very good package, IMO a better motor that the CR125, but Honda won that battle. I think of it as VHS vs BetaMax LOL.

[James McMahon]

Give this a go….
Credit goes to John Denman and his original “gearmaster.xls” that he made for the CR125….
https://www.dropbox.com/s/t5zh3uc9g46bnz6/CR250%20GearMaster.xls

Actually Ian if you’d error check this sheet I’d be much obliged!

[James McMahon]

Well that escalated quickly!

[Author]

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