well we opened my motor up today and the piston and sleve are scratched up (scored can't spell) almost looks like sand got in it.

thanks

kc

 

How does your air-filter look?

 

its pretty clean, why? and we matched part #'s and found out it already had a 416 piston, so is there a way i can rebore it just small anuff to stillput a 416 piston or do i have to go to a 426 or 440??

thanks
kc

 

You may be able to go 425 if the damage isnt too bad but let your machinist look at it first. The 440 requires the original sleeve be removed, the cyl resized and a new sleeve installed. Its not a lot of work but the price depends a lot on who does it etc.

You will deff get more power from a 440 than a 416 when comparing apples to apples, but there are those who will allways look to the hundreds or more of poorly built 440's with compression, cam, intake and various issues that caused it to perform poorly. They will rev very similar etc when built correctlly but the 440 will allways have allmost 10% more volume in its favor.

The advice you have received so for is good and the only thing I would add is that you have more controll over the outcome and end result etc if you spec in the various parts over just buying a kit, and you can also save a few $$$ if your not getting hosed by the people you buy from (much more poplular in this business than any of us like to admit). The piston from either JE or Ross (the only two Iwould consider) without any special machining or pins etc should run under 120.00 with all the normal stuff and the sleeve should be 40-90 depending on which brand (quality is about the same so??) .

Where the expense comes into being on the 440 is that if you want national level power at top rpm etc you will need to port n polish, fcr carb, hard face rockers, valves, springs, retainers, lighten and mod the piston, use race fuel and some other stuff to get it to that level. Sure most of this is required or would be great to have with the 416 but you can get away with a lot that stuff and save a ton of $$$ just in the cam and valve train mods as it will still work very well for any local racer or weekend warrior.

My question is how did you seize it, and what if any warning signs did it give you?

 

One other thing to keep in mind is that the cam mention earlier is a great suggestion as its one of the most copied or maybe better to say that its sold by many people under various p/n or names.

The WB track, GT thunder and even one or two of the "builders" cams are the exact same or very close copies.

The only one with any advantage is the Hotcam stage2 that isnt made by Web far as I know and it isnt a hardface reweld either so no hardened rockers to buy or core charge either and when you consider you can get one for 99-120 without any core charge its one to think about. I run one and though a little small of a profile for my machine it has not givin me any problems and worked very well for what it is etc. so no complaints.

Remember that proper cam choice is very much related to how you want to ride or where you want the power to be and how the rest of the engine is set up, so take a little time and ask questions to the mfg's and here to be sure you end up with a cam you dont like. An example is that I had done some investigating and found that the web 479 grind would be about the best overall for how I wanted to power to come on etc but then I got another spec to consider and that was a 3-5 week lead time so I tried something else.

 

The last few rides I noticed a loss in power when running hard on the dunes. I mainly run in the sand and like racing up hills. I could hear what sounded like piston slap but it was only now and than. I've only had the bike a couple months and maybe 4-5 rides. The first plug I replaced several weeks ago looked dark like it might be alittle rich so I figured better rich than lean, after the engine went I pulled the plug and it was white and clean looking like it was lean, go figure. The piston looks like it got hot and melted the rings togather with slight rubbing on the walls. I did a compression test before I pulled it a part and got almost 120psi and this is a 10:1 piston, with the throttal opened. One more thing, the spark plug had been stripped out by the last owner and helicoil installed, it seemed like the plug had loosened up this last time.
I don't really want to run race gas but think cams will help, it's just that $$$ thing being young with limited resoures. What would be best to get back riding now with the abilty to eaisly add to it later as I get more $$. ?

 

Hey listen to 440ex026 the man is a freaking a genious when it comes to a 400ex and a 440ex he has help me out tremendously. I would have made a few mistakes if it wasn't for him ya know get thinking of horsepower and forget about the little things.

 

KC,

Call up Chuck tomorrow. Tell him I sent you. Tell him I said you can have free access to any spare parts that are left over from my build. If he recommends any new parts, tell him I will be happy to furnish them for my cost. If you're gonna be in school, have your dad call him. Ok?

Marky

 

you guys should really see his piston it looks like it was melted but it also looks like it had sand in it both at the same time. hey kc i found you a 426 kit for $625 ill bring it to scool tomarrow.

 

OMG Marky you are SO AWSOME!!!!!
thanks alot man!! I PMed you

kc