416cc

[johnnynonails]

hi all.im in the middle of stripping down my stock 400ex engine,i was looking into putting a high comp piston with the stock bore.
but ive been reading about big bore kits,i know the 440 has its troubles so wont be going that far up,so im thinking 416,is there enough meat on the stock cylinder to take out the 2mm needed to make it a 416.

would like any input on either high comp or 416 plz

many thanks john

ps i'll have to order from the states as the uk is more for the 450's now.any good dealers/ebay companies you have had good dealings with . thanks

[Snipe]

You can do a 416 or a 426 over the stock bore.

[dragex400]

I did a 416 with 12.5:1 comp. Had no problem at. To get the full build you want to at least run a stage 2 hot cam and full system exhaust. I heard the 426 is not at reliable but I never did so I don't know for sure. The 416 I had ran good with no complaints.

[honda729]

i did a 416, it seems to a good balance between performance and reliability.
yes you can do a 416 build on the stock sleeve. i also did a 12.5:1 sparks pistion but unless you want to mess with race gas, hd head studs, and a 450r timing chain go with the 11.1. i would recomend a stage 2 cam and if you feel like you need more bottom end then drop a tooth on the front sprocket. also i would recommend a 450r carb, it really is as good as everyone says, almost instant response, sounds better and really eats on top end.

[Thumpin]

My 416 was an awesome improvement over the stock engine.
I had C&D racing do the machine work with a Ross 11:1 piston, (I think JE pistons would work just as good), stg2 HotCam, Ported head with valve job, CRF450 timing chain, stock carb with a K&N, just a slip on pipe and it had great tork gains and upper rpm pull over stock. Money well spent.

But the 416 really came alive with CT Racing full exhaust! I can run with my buddys stock YFZs pretty good. I think a 450r carb would finish it off nicely.

The only thing I might add is I had to run a 50/50 mix of VP110 race fuel with pump gas. Its hard to find fuel over 89-91 octane around here. E-85 might be my cheaper alternative!

As far as reliability goes, I run the crap out of my 416 and not one problem with it, doesn't seem to run much hoter than stock, so the 2mm over bores are easy on 400ex's, she just likes higher octane fuel cuz the compression must be right up to or over 11:1.

[johnnynonails]

hi all,well i did a total u turn on my thoughts about 440 kits.
i got offered a kit at a very cheap price from a mate.

fingers crossed up until now the quad hasnt missed a beat.
also did the 450 cam chain and new clutch,couldnt afford the stage 2 cam so that will have to wait.

what im after now is some good rear fender graphics,sfe looks a bit bare on the rear,and as ive said before here in the uk there are not alot of dealers doing any thing for the ex.

so im hoping you guy will post up pics and tell me were you got them from or know were i can find some.

[3or4HONDA]

Originally posted by Thumpin
My 416 was an awesome improvement over the stock engine.
I had C&D racing do the machine work with a Ross 11:1 piston, (I think JE pistons would work just as good), stg2 HotCam, Ported head with valve job, CRF450 timing chain, stock carb with a K&N, just a slip on pipe and it had great tork gains and upper rpm pull over stock. Money well spent.

But the 416 really came alive with CT Racing full exhaust! I can run with my buddys stock YFZs pretty good. I think a 450r carb would finish it off nicely.

The only thing I might add is I had to run a 50/50 mix of VP110 race fuel with pump gas. Its hard to find fuel over 89-91 octane around here. E-85 might be my cheaper alternative!

As far as reliability goes, I run the crap out of my 416 and not one problem with it, doesn't seem to run much hoter than stock, so the 2mm over bores are easy on 400ex's, she just likes higher octane fuel cuz the compression must be right up to or over 11:1.


I was wondering how much it cost you to have C&D do your machinne work? And were they easy to work with and have a fast turn around? Im doing a 416 this winter and not sure who is going to do my machine work.

[jeepthing07]

I am building a 426 I thought i could just bore out my stock sleeve and then found out its possiable but for reliabality i shuld put a big bore sleeve in so i did. If i was to do it over again i would have just went with a 416 and saved money on the resleeve. But now i can claim to have a 426 HEMI :D (Mopar fan)

[honda400-4-ever]

how well do 426 run compared to the 416 with 11:1 compression on both

[Sanddraging28]

when i built my 426 i resleeved with a LA sleeve big bore sleeve. it comes with a 88mm bore. that means you can start at 426 and if you ever want or need you can go to a 440.
i have never had any reliability or heat issue's with mine
i went with a 13 to 1 compression piston in mine. but it is a race gas only motor. i have no problems outrunning lightly modded 450r's and will give a well modded 450r a run for its money...
when it comes to the difference between a 416 and a 426 running 11 to 1 compression, the truth is not much. you wont be able to tell a difference. the real power of a 426 comes with high compression, high lift cams and heavy port and polish work

[jcs003]

i run a JE 89mm hi-comp kit. makes the motor 435cc. had the motor built for 5 years with only regular maintainance. very reliable. port/polish web cam high performance valve train. but to be fair i been mostly riding the 250r for the last two years