These replies do make alot of sence. I will look into it a little further. The guy wants $500 for it the way it sits, so maybe it's worth the chance. When the bolts are being pulled through, is it because they are being over torqed? So how much "total" would it cost to do the headbolt thing and where would I get the bolts and what is the part number? Thanks for all the help. RUSS

 

The studs are being pulled though because the medal in the cylinder is soft and Honda used to small of diameter studs. If the engine is keep stock they will work. If the engine is worked on , the studs will come out. The more it has been worked on the faster it will start blowning head gaskets. I got my studs from TC Racing and had my engine builder put them in. You need to check with a local shop to see what they will charge. You can also get all of the studs and work done at GT Thunder. He only wants $59 for the studs. Check out his website for more details.
$500 for a 400ex is almost to low of a price. Check out the a-arms, ball joints, and the rear axle bearings. But, for that price you can afford to put $1000 in the quad and have something good.

 

I'm sorry, I thought you were asking about why it was blowing head gaskets. Well, I can say I encountered one way and there are others that you've read about. It seems way suspicious that he only wants that much for it unless it's stolen! Na, there is something up or it's just one of those things that you can't pass by. Even if it cost you 1k to fix an unknown problem, go for it. You will still be money ahead. Good luck!

 

Ya $500 is not too bad. It does need alot of work. And it's funny you mentioned a arms and axle bearings, because it does need pivot bearings and I did notice a arm moving around and little loose here and there. It is by far a great machine and I agree that around $1000 bucks would get her back into shape, but I have 4 other quads right now and not sure if I want another one sitting collecting dust but I do like the way they ride and handle. I like the power they have since I only weigh 140lbs they move pretty good. I am not trying to compare it to my ds or pred as far as power is concerned because there is no comp, but I can't handle those like I can the 400ex. I might wait to see what next year brings or maybe this could be a project for winter. LOL's Thanks guys, RUSS

 

Since you had this done, and I just blew my first gasket recently (due to the studs pulling out) I was wondering if you knew how the shop went about installing the new studs, and what size they were.

Mostly I need to know if they were just tapping into the new enlarged hole where the old messed up threads are, or if there somehow sleeving it or helicoiling it etc.

Even though the fix I tried didnt work I guess I cant complain since I got over 2 years use running a true comp of 12.6:1 and this is the first time its giving me trouble. Just want to fix it right and not have to pay hundreds of dollars for a couple bucks worth of hardware and some basic machine work.

Also curious if that ex ever got purchased or not, and if so how did it end up being.

 

No, I ended up not buying it because he decided that he would keep it and fix it up to keep riding. With the quads that I have and all the moddifying and upkeep that is involved it was probably better for me anyways. RUSS[img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-sad.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img]

 

You know that was pretty much what I was thinking earlier when you were explaining the other machines you have etc, but hey then again I am prob not the only person who is always in over his head either [img]i/expressions/face-icon-small-happy.gif[/img]

 

y

 

i just helped a buddy do his 440 kit had a pro shop so to say and when he got it back no comperssion..... bent valves and bolts that held jug to motor were in the box of bolts he got back....put in new valves and put boltsa on and now if u give more than half throttle head gasket leaks.......everything is tight...... what gives here????

 

Could be a couple different things.

Do you know exactly what was done, and how it all went back together? If so then answering a few questions may pin point it.

In general it normally leads back to the bolts or studs pulling out of the cylinder. Why I say exactly what was done is due to the fact that I believe it should or does take more than just higher compression (up to a limit) to pull the studs out. I ran mine up above 12.5:1 (actual comp not piston rating) with zero problems, but when messing around to find a better or different combo of bottom end torque and mid to top HP (timing, cams, rev box etc) it became a lot harder to keep it all bolted down tight.

Let me know how much you really know about the rebuild and I will figure out what I can for you.