[490 13:1] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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490 13:1
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Posted by: FAQ654

I was just wondering if anyone here has had any problems with a 490 kit with 13:1 compression.

Posted by: joe1l

I'm looking at a similar kit, does anyone have one of these yet??

Posted by: chad502ex

I've not seen anyone use this kit yet, but i would add that this would be the next best kit to the 500; especially, since there have been cylinder cracking issues on the larger 500 big bore on the stock jug.

Posted by: jeepnrocks

who makes the 490 kit ?

Posted by: FAQ654

I got mine from Gt Thunder. It seems to be working great but there is snow on the ground here so I have not really been able to feel any difference yet. The pistion is from J.E.

Posted by: jeepnrocks

is it a different jug or is it just a bored out stock jug ?

Posted by: FAQ654

Bored out stock jug!

Posted by: kazpr

Ya next winter I will go with the 490 kit!!
13:1 and ported head that thing should rip!!

Posted by: jeepnrocks

so how many mm bore is a 500 and 490 as opposed to stock

Posted by: chad502ex

quote:
Originally posted by jeepnrocks
so how many mm bore is a 500 and 490 as opposed to stock

98 x 64.8 = 489cc

99 x 64.8 = 499cc

go to http://www.chad502ex.com
under tech talk section and use the displacement calculator

chad502ex.com

Posted by: savage_bob

it might be a risk still I had my 500cc 13.5:1 cylinder sleeved because the wall thickness was only 2mm. This 490 kit will still leave a 2.5mm wall thickness with less comp it could be better/safer, but still pushing it?

Bigger gains would be had through higher comp, even with out going big bore.... not all people like going bigger, just 2 sides of a coin here. 13.8 stock bore has definate power gains, a 470/480 bore with 13.5 or 14:1 comp would be a good setup as well just more expensive. My $.02 invest in a setup that will burn race gas, more power is always welcome, and spend what you feel comfortable with both should make you happy.

Posted by: kgbg

I like the sound of it. I am curious to hear the results.
What piston is GT using?
Savage, who did you have resleve your jug? Was it an aluminum sleve?

Posted by: the_hulkamaniac

Hey Kam I keep forgetting when I'm at my bro's, that's why it's under savage. I finaly have my parts so hopefuly I get to build this weekend.

Posted by: mattonln

just run 110 octane and you should be fine

Posted by: Punk'd

Man I want a 490/500 kit down the road too. How much would they run me?

Posted by: FAQ654

It cost me about $520 to put mine back togather with the 490 kit.

Posted by: joe1l

what cam are you running ? is the power increase significant?