Attex Racers Pushing The Limits!

[jpswift1]

Today was an absolute blast and a total adreneline rush! I got to drive 3 super fast Attex racers. Forum members, Don, Hydromike, and myself got together with all our racers at Mike's folk's house and pushed the racers to their limits and beyond. There was a really nice flat soybean field right in their backyard which combined with the inch or two of snow on the ground made a great surface to run the machines on.
Mike's D/Stock 440 Cuyuna unfortunately had a spark plug come loose while I was behind the sticks and it toasted the piston/rings pretty bad after we tore the engine down to investigate. I suppose the good thing about it is that now Mike has a reason to bore it out, have some port work done, and get a dual carb set up for it. I also drove Don's legendary McKay racer with a 484cc Chap. G50B twin and it flew! I really liked the straight shaft race transmission in that machine and I look forward to seeing what it will be like in my racer. I also got to drive Mike's 503cc Rotax powered "ST/503R" racer and it was extremely loud and fast. I believe Mike GPS'ed the machine at around 50+ mph. These machines really have the potential to scare the heck out of you. Don and I will be posting up pics and videos soon. Unfortunately my racer still needs to be completed before it can run with these guys, but we got a lot of work done on it today as well. Thanks guys!

[Meinfield]

Those are great looking machines. I have an old hustler with a K-440 I can't wait to get going, there's nothing like the rush of a two stroke machine!

[jpswift1]

Hey Meinfield, how many machines do you have and what do you have planned for this Hustler restoration? Those two strokes combined with cold weather do indeed give you quite a rush! After I drove Mike and Don's racers I really have some motivation to get mine going.

[hydromike]

Mike's D/Stock 440 Cuyuna unfortunately had a spark plug come loose while I was behind the sticks and it toasted the piston/rings pretty bad after we tore the engine down to investigate.

Uhhhh... yeah... pretty bad....

A little background before I post a pic of the carnage. I was confident that the 503 was considerably faster than the D/stock when I handed the reigns of Little Boy over to Jeff for his experimentation. He blasted up and down the field a few times and it, as always, sounded purrrrrfect. It runs just insanely well. I cranked up the Fat Man (aka the 503...yeah, these are nuclear bomb references.... keep reading...) to give proper chase to the racer rookie. Now the R is a completely different animal altogether. While the D/stock's clutch engages a little slower, it does so with purpose. The 503 is basically idling at 20 mph at all times. It's obnoxious. So yeah... Jeff takes off, I jump in the R, and try to run him over. It took Jeff about 3.5 seconds before he was comfortable enough in the machine to be doing 45mph power slides across the snow. It's one of the greatest feelings to be able to be screaming right along side him in the R. He straightens the beast out, and really hammers down. MUCH to my surprise, the 503 really had to try to catch up/pass him on several occasions. I wish I had a helmet cam; the Little Boy (again, the machine; not Jeff) looked GREAT humming along side me. I was so proud.

On one particular event, I noticed that I passed him particularly quickly, but didn't give it much thought. I cruised back to see what had happened, and he said "it just died out"....

Uh oh... The D/stock doesn't "just die out".... I figured it was a fuel issue, a kill wire came loose, etc.

I gave it a couple pulls, and there it was... the death rattle. Hmmm.. and what's this? A loose spark plug? Bud and Q. Kinyon gave me a tow back up to the garage with the Li'l Truck (nice tow job, Bud) and I yanked the mag-side head off.

CARNAGE!

The entire exhaust side of the mag piston was gone. Not just "toasted", more like... gone out the exhaust port along with about 1/3 of the top piston ring. Jeff was really hammering on it, so when the ring let go, it did a little 6000 rpm dance between the piston and the cylinder head. Piston rings are just a "little" bit harder than the head or the piston, so significant damage was done before the engine even had a chance to die out.

So what happened? The culprit was the loose spark plug. That loose plug let too much air into the cylinder and caused that side to run lean. WAY lean. The piston overheated, which eroded the top of the piston, the top ring wasn't held in place anymore, it let go, traveled out the intake side of the mag side cylinder (yes, the INTAKE side) and back in the PTO side intake, causing a little damage to the PTO side head as well. I could get away with a hone job if the ring didn't catch one of the transfer ports. But it did. <sigh> Jeff certainly isn't to blame for this; he was doing just as I asked him to. He was pushing it.

Pics of the day, including carnage are here.

It was a great day. Thanks to Jeff and Don & The Boys for making it up.

~m

[Roger S]

Wish I had been there to

Or now, to

That's unfortunate. But we know speed/adrelaline rush cost $. You have my sympathy

[Meinfield]

Hydro,

I feel your pain, those pictures of your pistons and cylinder head are hard to look at. Kind of sobbed up a little when I saw them.

Do you think the K-440AS twin is a good 2 stroke motor? The porting on the heads looks to be 5 port, and I think it has been re-sleeved because the cylinders are no longer chrome. I am still undecided whether to use it in my 76 Hustler.

[liflod]

Doesn't the engine in Jeff's racer look the same as the one he so rudely blew up in yours ? A real good guy would just give you a replacement engine if he had one he wasn't actively using

[hydromike]

Doesn't the engine in Jeff's racer look the same as the one he so rudely blew up in yours ? ...

Very, very close, but my jugs and heads are a little bit more fancy. The intakes won't swap, either. I was bummed out this AM when I checked my Cuyuna twin carb setup to find that my ULII-02 is too new for the new manifolds. I'll have to put the twin Mikunis on another 440 JLO. Now where to find another JLO 440? Oh wait, there's one right over there.... and one over there... and there....

Where's my 13mm socket?

~m

[whipper-ag]

I think you should find a nice gold chain and attach the piston to make a cool necklace for Jeff to wear at any future outings for the next year. Don't those 2-strokes really scream just before they grenade. At least you didn't bend an axle,too. Waiting for the videos.
Whipper

[hydromike]

I think you should find a nice gold chain and attach the piston to make a cool necklace for Jeff to wear at any future outings for the next year.

Yeah, it would be the ultimate in bling-bling, or more like bling-bang! Every time I coaxed the R up to a full throttle pull across the field, I had my hand ready to snag the master kill switch just in case anything sounded the least bit funny. But you know, what's the point? At that engine speed, it's already too late.

I'm still waiting for the videos, too. Both Don and Jeff took video, and they sound really really cool. Jeff showed me some of the vid in the garage. The pipe on the R all but hides the other machines' sounds, and when the echo bounces back off the woods and hits the mic at the same time the direct sound does.... oh baby.... That's the sweet spot...

C'mon dudes... get the videos up...
~M