Building a Racer

[Don]

If you can find a junk air cooled engine with CDI, it will make it much easier on you. Make sure you use the fan housing from the CDI unit. The mounting holes for the stator plate are about 90 degrees off compared to the point fired engines. You can drill and tap the old housing to make them work, but you have be very close to dead-on; a couple degrees off will make a big difference.

[smudvapor]

Building a Racer update

Got it all apart and the frame needs some help. I have to replace and reinforce a couple of places. I have the Jugs coming for the engine but having a little trouble finding a decent set of heads. No problem, plenty of time. The body is in bad shape but on the plus side this is a racer so I don't need to worry about it being water tight. Should I stay with the original fuel tank (steel) or go with something smaller?
We have a snow day today so I will have some fresh pics up later today.

[smudvapor]

Sounds cool but I think for now I will stay with the points, I don't want to get so involved that I end up not having it ready in June. I will keep my eyes and ears open though.

[George]

Some folks are running with tanks just big enough to run races with. I run with the original fuel cell but with only about a gallon of gas in it.

I'd check the steel tank for leaks. It's not unusual for them to rust to the point of leaking.

[smudvapor]

Some folks are running with tanks just big enough to run races with. I run with the original fuel cell but with only about a gallon of gas in it.

I'd check the steel tank for leaks. It's not unusual for them to rust to the point of leaking.

I haven't checked the tank yet but this thing is weird. It sat outside for many years and looked like it was going to be a real challenge to take apart. Not the case, came apart with not problem. Never seen anything like it. I plan to clean and reseal the take just for fun.

[Tomo]

hi ,
Old steel tanks can have a rust patch on the inside from water/condensation in the fuel .
This will start to discolour fuel from the finest rust particles ,enough to block jets after a while of operation . The discolouration will not be noticed in a 2 stroke oil fuel mix .
tomo

[smudvapor]

hi ,
Old steel tanks can have a rust patch on the inside from water/condensation in the fuel .
This will start to discolour fuel from the finest rust particles ,enough to block jets after a while of operation . The discolouration will not be noticed in a 2 stroke oil fuel mix .
tomo

Not taking any chances, I am going to clean it out and seal it before it goes back in.

[smudvapor]

Building a Racer update

Here are some pics I took today. I did not get to work on it because I spent the day working on the other one.

[smudvapor]

Use a pipe off a Scorpion 440 snowmobile. If I remember correctly, one flows better than the other model......the Whip I think is the model to get one from, although I can't say for sure. Also, if your JLO 440 is a 4 bolt head, upgrade the heads and jugs to 6 bolt ones/5 port. This makes for a very potent engine. My 440 Thunderchief racer has a 440 5 port/6 bolt head and it will outrun a Superchief.........ask Hydromike, he has the same engine in one of his racers and his will do the same.

Here are most of the parts you'll need to build one hell of a 440. These will all simply bolt right onto your JLO 440 bottom end.


Scorpion Cuyuna 440 6 Bolt Cylinder Jug 1 PTO | eBay

Scorpion Cuyuna 440 6 Bolt Cylinder Jug 2 Mag | eBay

1979 Arctic Cat Scorpion 440 Cuyuna Exhaust Manifold w Muffler | eBay

Thanks for the info, I ordered all three. The jugs came today and they look like new! Great price too!

[jpswift1]

Glad I could help! You're going to love the performance of a fresh a fresh 5 port, 6 bolt head 440. It's going to make for one fast racer! Are you going to run dual carbs on it? If not, you'll need the Cuyuna 440 intake manifold and plastic intake manifold spacers. Keep us updated on it.......looking forward to seeing it at Ashtabua!

[millerperf]

I was thinking of trying to come to astabua if I can finish my max iv I have it mocked up with the apex Yamaha motor , my buddys say I should take it out !I have a new 503 rotax aircraft engine , a 670.rotax and a 3 cyclinder 700 rotax what would you guys do can I race it with the big engine time is getting short!what do you think jeff

[hydromike]

what would you guys do can I race it with the big engine time is getting short!what do you think jeff

If you really want to race it at Ashtabula, I'd keep it simple and throw the air cooled 503 in it and put some 21" tires on it to get it down low. You can change the primary spring in the clutch to a two stroke spring and you'd be in good shape. Of course, you need a roll cage and a seat belt, too. You could probably get a way with the stock gearing; the rpms of the Rotax will make up for the 26 tooth sprockets.


We've had folks make it up from Florida before. It's a long haul, but you can get there early and make a week out of it.

[smudvapor]

Glad I could help! You're going to love the performance of a fresh a fresh 5 port, 6 bolt head 440. It's going to make for one fast racer! Are you going to run dual carbs on it? If not, you'll need the Cuyuna 440 intake manifold and plastic intake manifold spacers. Keep us updated on it.......looking forward to seeing it at Ashtabua!

I am going to run a dual carb set up. I bought it all a while back and I haven't taken it out of the box yet.

[hydromike]

So you have the intakes and the carb flanges for the 5-port? Where did you pick those up? There have been folks looking for them for a couple years, and outside of Zerkle, I didn't know where to forward them....

[jpswift1]

I've got two Mikuni carbs, intakes, and everything required to run dual carbs on a 5 port, 6 bolt head Cuyuna if anyone needs them.....I'll sell the complete setup for what I bought it for, $99........intakes, spacers, carbs, and all.