top end rebuild kits?? and other questions??

[trailrider894]

i want to know when buying all the stuff for when i bore out my cylinder do i have to use special gaskets??? my plan is to go to a 416 or 426, witch one is better???

now when i take the cylinder in to be bored and honed. how much should i tell them to bore it over if it was for a 416 or 426?? and all i have to have done is it bored and honed right??? there is no special coating or something that will be ruined by doing this is there?? just a plain bore and hone?

[honda400ex2003]

there really isnt a kit per say, we just use a ccombo of stuff. boring has to be done to get the cylinder bigger. the 440 needs a new sleeve pressed into the cylinder and the stock one pressed out. stage 2 hotcam would work great with a 416 it gives alot of mid and a bit more higher end power than the stage 1 which is for low end and some mid. look into a new cam chain from a crf 450 motor and let the spending begin it is truely an addiction. steve

[trailrider894]

well then do you need a sleeve to do the 416 bore?? and i would either like to know a 416 and stock bore top end rebuild kit or give me a list of the best brands with everything i need i'm on a tight budget!!

[honda400ex2003]

no, they just bore the stock one. I would use my list in my sig again with the wiseco pistons or a JE piston (87mm for a 416), hotcam, and a cometic gasket top end kit for the rebuild. /you can choose your compression. 11:1 is good if you can get a decent 93 octane gas. The timing chain can be found on ebay it can be from any year crf 450 motor. A good clutch may need to be added if yours is wore out. Dbay this stuff and you can find some good prices. I found all of mine on there it takes some time to get the deals though. There are other options like a 406 and a 426 to. These can be done on the stock cylinder also, a 406 leaves 2 bores, 416 leaves 1 bore, and 426 is the last bore you can get on the stock cylinder. Depending on where you want the power you can choose a stage 1 or 2 hotcam. most of the pistons can be in any compression. 12:1 compression would require heavy duty head studs to be installed so they don't pull out of the cylinder. This leads to blown gaskets and such with the stock studs. If you have any other ?'s let us know and we can help. good luck and you will like the results when done. If you don't have at least a slip on exhaust you will need that too. A full would be good too. I did not check to see if you had anything before I got this far in the reply. Steve

[trailrider894]

changed up the info so please read the top post !!!

[honda400ex2003]

alright lets see what we can do, xr400 gaskets will be the best to use but any 400ex will work for them. I am not sure on the 416 or 426 since i have not had a 426. the only thing i know is that they can get hotter than a 416 but it not a huge worry. if you take the piston in at teh time of bore they will take care of it or should at least. when i did mine that is what i did. theres no coatings or anything so no worries there. if you do a 426 there is a set of gaskets that you can get that is a 88mm. if you want you can use them for the 416 too. it doesn't matter they all seal. i would not use a 440 gasket kit on a 416 though. just my opinion though, i guess. if you think of anything else just ask. Steve

[Sanddraging28]

i would suggest the 416 JE piston. In my opinion JE makes the best powersports piston out there. match that with a stage 2 cam, 450r carb, crf450r cam chain and a good gasket set you will have a really strong running bike.

look on ebay for the parts. and try servicehonda.com for the cam chain and the OEM parts you need.
i would suggest that you stay under 11 to 1 compression, that way you dont need race fuel or an octane booster, HD head studs are not required at this point(but i would suggest them anyway)

[trailrider894]

so should i go 416 or 426??? will one cost more than the other??

[RaceinCircles]

A good machinist will know what to bore to if you give him your cylinder and a piston...so don't worry about that at all :)

[honda400ex2003]

i think the 416 piston is more than the 426 but it like 10 bucks maybe. price it out on paper before you do it. I am not really sure. Let us know what you choose. steve

[honda400ex2003]

i thought about and i say try a 426. It should run good witha stage 2. steve

[trailrider894]

what are the gains of the 426 over the 416??

[honda400ex2003]

bigger piston i am not sure, it could rev different and have more torque. It may rev a bit slower but the torque may be better with more momentum going around and cause the power to be more broad. steve

[Sanddraging28]

you have to pick what size you want to run. by running a 416 you still have the option of going to a 426 if you need or want to. by going right to the 426 the next step is having a new sleeve put in and going to a 440. there is not much of a power difference between the 416 and 426 when you are at 11 to 1 compression. the real gains of a 426 come when you are at or above 13 to 1 compression, with a real big cam. but doing that requires things like race fuel, hardfaced rockers, valve springs, shortened guides.

for you a 416 is the way to go. its not worth the money of a bigger piston that you really wont see a difference in power.

[honda400ex2003]

perfect.^^^ steve

[Grizzy]

can someone list the piston/bore sizes for:

402
406
416
426

etc

[honda400ex2003]

397 - 85mm
406-86mm
416-87mm
426-88mm
440-89mm

There you go, not sure what the .5's are since they are just rings for most of them. They are to just clean up the cylinder. These are the common sizes. with a +4mm stroke addition it changes them by 20CC to the better. This is using a hotrods crank. That would make a 440 a 460 with the stroker. and each the same i believe, steve

[Sanddraging28]

Originally posted by Grizzy
can someone list the piston/bore sizes for:

402
406
416
426

etc

stock is 85mm
402 is 85.5mm
406 is 86mm
416 is 87mm
426 is 88mm
440 is 89mm

[Grizzy]

thanks