Indy 400 Bigger carbs.

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01mndoo

New member
I am in the middle of building a fun sled out of a 88 Indy 400.. The sled is going to be used as a toy more then anything and I could use some advice on this project. Last summer a tried to put a set of 38's off a Indy 500 on it and had problems getting it to idle down and run right. It runs great with the stock 34's. It idled at 3000 RPM's no matter what I did and I was told that they are just to big for that motor. Has anyone else done this switch? I am also looking for any other ideas to make it lighter faster or increase the fun factor.
Thanks
 
G

G

Guest
If it runs great with the 34s why would you want to change? Leave it alone. You cannot expect any performance improvements by changing only the carbs. It is a lot more involved than that. If you want to increase the fun factor on an '88 Indy the first thing to do would be to get some decent skis on the thing. Next thing would be a newer model track. We have come a long ways in 22 years. You could make that old Indy rail through the turns with some modern equipment. Make sure the clutching is fresh. Maybe gear it down a little. It is already a lot lighter than most new stuff. The center of gravity is much lower than most anything sold these days. It really could be a fun little ride with a few updates. But forget the bigger carb approach. This could be a really good learning experience for you. Good luck.
 
X

xcr440

Well-known member
Yeah, unless you are going to change the porting/cc's with a bore and larger pistons/pipes/air box, stick with the basics as noted above.

Not sure what your expecting, but an Indy 400 is just that, a 400.

I've got a 1993 XCR 440 (Duh) and at present am letting it be my son's sled (He's only 12, so more than enough for him!) but I'm sure he will want it to be "better" some day.

When the sled is fresh (Clutches, shocks, bearings, etc.) through the twisties and with some experience, he'll be a tough kid to keep up with at only 85 pounds. THAT will be the fun factor for him!
 
J

jim_golding

New member
I had a 1990 Indy 400. It was a great machine in the tight trails, none of the bigger bore sleds could keep up since it was so light. In the long runs they were all over me. With that said I would go after clutching, traction, and skis because there is little that can be done with the motor and still make it reliable.
 
F

fredster

New member
If you really want to have fun with that 400, get a Fugi 500 twin, should be a bolt-in, or a 600 triple......

I had an IndyTriumph (600 triple) with 38's. Since your sled has essentially two, 200CC cylinders and two carbs versus the 2 X 200 and three carbs, I would think the cutaway slide and jetting from an XLT or Triumph would put you in the ball park. Unless you are thinking pipes/porting/etc though - why bother? Those 34's will flow plenty of air for a stock 400.....

Have fun!
 
C

crispyknite

New member
indy 400

Go get a 500cc fuji, jug and head off of ebay and buy new piston and rings
for it, use the 38 carbs. It uses the same crank. you mite have to buy a
muffler from a used pars place. thats what I did.
 
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