downsides to a 465 big bore?

[hotex28]

I am due a top end rebuild,and I was thinking about going bigger.I am not going to stroke the crank,but I wanted to know if anyone has had trouble from a sparks 465(92mm bore).Right now it is a 13-1 426 with all the extras.

[cheetah]

I think you have to stoke it to get to 465? I think 440 is the highest you can go in a bore. Some correct me if I'm wrong.

[honda350r]

If it is a 92 mm bore it will be much bigger than a 440! A 440 is only 89 mm!

[quadman21]

I am pretty sure 90mm is the largest bore people are going with for the 440 sleeve. The sleeve is too thin as it is. The 465 is achieved by sroking the crank and combining it with the already exsisting 440 sleeve.

[Burden7]

You can use a 92mm piston in the 400ex to get it too a 465cc. I'm not for sure how thin the sleeve will be after that, but it is possible. That is how they get to 505cc's. They use a 92mm piston with a 6mm stroke.

[quadman21]

Thanks for the info Burden7

[Sandragggen]

I have a 92mm 465 that is not stroked. There are not anymore bores left to the 465 sleeve. You will have to resleeve each time. The 14:1 compression gave me alot of fits trying to stop head leakage. Sparks first sent me 2 copper head gaskets that leaked. I was about to have the cylinder o-ringed, but Sparks then came up with a shim type head gasket that fixed the problem. I would advise sending out the motor to a well known builder and let them do it completely. There are alot of things a shade tree mechanic could mess up without the right tools/knowledge. Some of the better known EX big bore builders are Sparks, TC, FDO, Trinity, Mickey Dunlap, just to mention a few....the list could go on and on. The up side of the 465 is the huge increase in power. If I had to do it over I probably would have not spent the money on a EX. It's fast, but there are alot of other machines out there with alot more potential. For example...It is not uncommon to see a 80+hp DS650 and a few of my freinds are closing in on the 100hp mark. The statement "No replacement for displacement" is so very true. The cost for a 465 will be around $3000 once the dust settles.

JMiller

[hotex28]

I already have everything except the sparks piston,head gasket, and the sleeve.I motocross this quad,so I will machine the piston down until the compression ratio is about 12.5-1 or 13-1.Will this setup still blow a lot of head gaskets?

[shaneb]

i thought the ds made 130hp !!!!

[Chef]

Originally posted by shaneb
i thought the ds made 130hp !!!!

Yea, Scooby's turbo did. Thats about it though I think?

[hotex28]

any advice?

[shaneb]

chef I was just kidding scoby made 119 I think ...

80hp ds's are few and far between ...

[Chef]

Originally posted by shaneb
chef I was just kidding scoby made 119 I think ...

80hp ds's are few and far between ...

LOL. After I posted that I figured you were jokin...but I didnt want to take the time to edit the post. :rolleyes:

[Juggalo]

yeah did scooby ever get that mess figured out after his accident?

[Chef]

What accident?

[Sandragggen]

80hp ds's are few and far between ...

They are becoming more common in the midwest. It's amazing what a little or alot of nitrous can do.

JMiller