[richard87]

Hi, im a new member of the forum. I come from Quebec , Candada so my english isnt very good sorry for weird sentences. So im not new to Honda, I grow up on Atc 110 and tr250x. My father have a rancher 2004 with 2200 hours and it still going strong. So i know Honda is a very valuable piece of equipment. My current 4x4 atv is a Vinson. In the past i got a 400ex, i sold it 10 years ago.

5 years ago i bought a 400ex real cheap and abused with a blown gasket ( the studs were strip and the previous didnt why the 400ex always blown gasket hahaha). Long story short, my wife gave birth two time since i bought it so i didnt touch the atv since 4 year. So now we have a new house with a nice 37x25 garage and i want to give a second chance to the quad.

What i want to do quad : It will be a reliable stock trail quad. The federate trails are litterally in my backyard and i have my pass with the Vinson. if i want power i just will go with a Raptor 700. So the setup need to be cost effective. I have some spare parts for 400ex.

Quad : The engine has been modified proffessionnaly with a porting, piston. Im not sure but i really think it have a crank-rod and a cam....... but a stock carb with a good pipe( i hate pipe so i dont care about the brand lol ). Head gasket was blown and i installed hd stud. Im not sure if i changed the sleeve. Threads in head for valve cover were strips sooo a big mess.

I want it just to be a real Honda. A reliable machine !!!! The starter struggle to turn even with a fresh batt. A lot of compression! What is the best route ? LA sleeve bored to stock bore?? with a 9:1 honda oem piston ?? stock pipe and the ported head and the stock cam. I will probaly install a fan toward the oil cooler.... i really need to open the engine to measure the bore. Namura 10:1 or wisecon 10:1 are reliable ?? or honda will be better ?

 

[SlammedRanger]

Welcome to the forums! First things first. We try to keep a family friendly site here. And i did notice you tried to edit your word of choice lol. But edited or not lets keep it family friendly please. Anytime we see it we will change your post just an fyi. As for the quad. I would suggest staying away from namura. Go wiseco. It sounds like it has been pulled apart and put back togeather many times if the bolts were all stripped and the head studs were pulled. I would start by taking it down and checking the rod for any up and down play. If it does then the crank will need to be replaced and at that point i would split cases and go over everything. Check every bearing replace anything in question. If the rod is good i would see what the stock sleeve looks like and if it can be just bored out and get the right size wiseco piston. Stick with 11:1 or under so you can still run regular premium fuel. My .02

 

[richard87]

Ok sorry for my bad manner. Yeah the engine has been open a LOT of time and by newbie wrencher. I know the original owner. This bike cost him more than 12k and i paid it 800$. I rode with this guy with my first 400 ex and we were toe to toe because my stock 400 has holeshot tire and him, razr.He was always spinning and me gripping .......So it was not the sharpest pencil in the pencil box. The stock sleeve is at the last oversize. 436 ??? 426??. Ill probaly need a new sleeve . I dropped a wiseco in my previous 400ex. it ended with a broken wrist and the rod crushed the piston and the sleeve. Pretty bad for a stock 400ex with only a wiseco. Im little affraid of high comp piston.

The atv will be ride in deep forest i want it reliable.Like i said i dont need power if i can keep the repair cost low it will be a great atv for the wife, the daughter and the guests or... maybe the wife will buy a SxS . For now im into rebulding my Skidoo Olympique 72. I'll start the 400ex in fews weeks. This engine need a good inspection. Im pretty sure the swingarm bolt is jam . where are the best palce to buy parts ??? Amazon? Ebay?? Service Honda?? Im canadian and our parts price are higher than yours in USA. It can be easily cheaper to buy another atv... and the atv need rear galiper front fender speedometer tire tail light front bumper clutch wire carb rebuild air filter stock pipe ... and the list continu...

 

[SlammedRanger]

No problem bro! Your new and we will let it slide a few times lol. As far as the wiseco piston failure i would bet the bore job wasnt correct for the piston. Every piston is different. They are precision machined but still tolerances can skew. So the best thing to do is make sure your machine shop has you hand them the piston. They will measure and bore it to the exact size of the piston and make sure clearances for heat expansion are met properly. I have personally installed atleast 20 wiseco pistons. One was over 10 years ago and it is still running strong. My current quad sees the rev limiter almost consistantly and i have zero concern with a wiseco piston in it. Btw where do you get your info that raptors are faster then a 400ex? LoL i guess it all depends where but on a track or trails they are left wishing they had better suspension. Maybe in a straight drag race they would be a contender? Havent ever drag raced one lol. Anyway with your situation i would get a sleeve from LA sleeve like you said and just go stock bore for reliability. Aside from that you would have to remove the hd studs which can be a real pain. If done right that 400ex should be running for 20 more years or so. Cant beat the reliability of the honda engine!