I AM INSTALLING A CW 434CC BIG BORE KIT. I HAVE A JET KIT, OPEN AIR BOX AND YOSHI FULL EXHAUST. CAN I PUT AN INTAKE CAM IN THE EXHAUST TO GET MORE POWER OR IS IT REVERSE USING STOCK CAMS THAT IS. WHAT WOULD ANYONE SUGGEST TO GET THE MOST OUT OF THE BIG BORE KIT. WANTING TO SMOKE MY BUDDIES 450 YAMAHA.

NO YOU CANNOT JUST SWITCH AROUND CAMS ESPECIALLY STOCK CAMS SINCE THE EXHAUST HAS A DECOMPRESSION DEVICE ON IT. I WOULD JUST GET A FULL SET OF CAMS IF THAT IS REALLY WHAT YOU WANT TO DO, AND GET BOTH NOT JUST ONE. OTHERWISE A FCR CARB WOULD REALLY HELP!

speaking from experience, i would be very surprised if a 434 bbk is going to get you past a 450 yfz. sorry but 450's are PDQ ,you need to get closer to a 484 bbk to really put a surprise to a yfz rider

ok so all that stuff done to your 03 and u cant outrun a yfz 450.

I could run with a YFZ with a 434.
Now with the 462 it will pass them.
It will eat our stock bore/stroke 450R alive.. and it's pretty mean

lol your funny

He don't have a 434.......that'd be 94mm plus he stroked. You won't be close to that. Just like I ain't close to it.

I raced some LTR's up Comp Hill at Dumont recently. Not sure what they had in them but I had better paddles and I got spanked. Of course the kids riding them looked to weigh about 100 lbs......

Do the 434 and go on a diet!

ok so i put the cw jug and piston on. now my motor has a slight knock at idle. i put a 165 main jet and raised my needle a clip. i also took the center metal peice out of the base gasket to raise the compression. i think my needle is to high now. should i change the #25 idle jet

one more question. can i run an stock exhaust cam on my intake cam to be the same as stage 1 or 2 intake cam. seems like a year or 2 ago i heard about this mod on here but i cant find it now. would be a cheap mod

No you cant run the stock exhaust cam on the intake side because it has an auto decomp.

a knock? did you re-set the cam chain tensioner, and your sure your timing is spot on?

Also did you check and make sure the rivets in the headgasket weren't stuck in between the jug and head?

i cut the rivets out when i took the center piece of metal out of the gasket. i think i might have a water leak now though. im almost positive my timing is right. rod felt like it had a little bit of play but did not knock before.

i took 2 of the rivets out of head gasket its clear of the head

Knock, not a loud tick? Did you change your cam chain?
I know everytime I open mine up it seems to make a little more noise everytime I put it back together. I think mostly it just sounds a little different and it kinda freaks you out.

its a knock at the cylinder. it has a new cam chain. valves tick a little. think its to much stress on crank

im just gonna take it back off till i get a new crank i guess. no knock with stock cylinder weird

How good does your piston fit?
It should be a nice tight fit, not any flop.
If you got a true CW kit, with a CW piston, or even put an Athena piston in, it should be tight.
If it's JE I would check fitment.

If it makes noise with bbk but not on stock bore I lean toward that piston having slack.
The crank would make noise regardless.

seems like it had alot of slop before i put rings on. i think its a wiseco piston. it was brand new before install. your supost to have .5 clearance right. im going to tear it apart tonight or tommorrow. i thought piston slap was more of a slap noise than a knock. i had a 2 sroke that had alot of piston slap and this sounds alot deeper, but this is a 4 stroke to. this sux. the rod had play when i tore it apart so i thought the bigger piston might make it knock and it did. it has play up and down. can i get a +4 rod and not have to do any mods to the head or valves. mise well make it outrun a 450 since i cant afford one

JUST A 434 ALONE WON'T BE AS MUCH OF AN IMPROVEMENT OVER STOCK WITHOUT A PROPER CARB.

That crappy piston fit will not only make noise, but will eat that cylinder alive.
Trust me..

A decent fitting piston would help silence it a lot.

I agree about the improvement.... The stock carb won't feed the 434 enough to make big gains.
A 39mm carb will make some good hp numbers.
It's a good balance for woods/mx too.
Larger than 40mm and you will be better for tt/drag racing.

I AGREE BUT THAT WASNT HIS QUESTION


the piston should be "tight" when you put it into the bore without rings. you shouldn't be able to move it around very much at all.

my friend had a crank that we thought the rod was shot, but the tolerances are in the service manual so check and see and it might still be good. Otherwise yes the new hotrods +4 crank you can essentially run with any off the shelf piston and no other mods.

yeah i could move the piston around quite a bit

but the again blueprint specs is .5 clearance and that is quite a bit

I had a je piston that was slapping the counter weight when i first put it together...it lasted about 10 minutes. take it apart and check everything. it sound like the rod bearing may be worn. Btw, if you put a heavier piston in than the stocker and you have a BAD/GOING BAD ROD BEARING, you will hear more noise...and i can assure you the piston you put in was heavier...i have yet to find a piston and wrist pin thats as light as stock. The heavier piston amplified the knock.

okay took it all back apart. the rod has no play, rolled the crank around and could not get no up and down slop in the rod. piston is .1 smaller than the cylinder. can not find any dents dings or anything wrong anywhere. i took the middle part out of the base gasket. im gonna put the gasket back together right. im gonna put it all back together and try one more time. could the carb make it knock? it ran mean as hell but had a knock.

Like I said..........

"Knock, not a loud tick? Did you change your cam chain?
I know everytime I open mine up it seems to make a little more noise everytime I put it back together. I think mostly it just sounds a little different and it kinda freaks you out."