i'm gonna pick up a 440ex later this month.my buddy has it sitting in his garage and has just been rebuilding it trying to figure out the bugs in the 440 kit. why are these kits so unreliable. I've seen companies selling what they claim to be a reliable kit, but everyone i know that has one spends most of their time working on them. he's upgraded the timing chain,head studs,gasket,etc. what other weak spots can there be??? anyone have these problems and found a sure fire way to fix em.

 

I have a 440ex in my stable that I built 5 years ago, no problems what-so-ever. I ride the $hit out of it and all I do is add gas to the tank and change the oil, the 400 based motor is bullet-proof as long as you don't go beyond 440cc's.
No need to do all the stuff you are stating on a 440, you have a case of too many hands tinkering with it, a regular ole 440 will run respectiful, don't try and mod it to do things it won't do, these motors are very simple and easy to build and maintain, if you want more power, just shove a 650L motor in it, that will do the trick.

 

hey my budddy bought the quad a year ago. previous owner put a ton of work into it,but we had no idea to what extent. timing chain streched and kept jumping time, he replaced that. right after that the head gasket popped. tore it down and found it needed valves too. he fixed everything and got another couple months of riding in before it started jumping time again. the chain tensioner was good so he just got fed up and started rebuilding the top end so that he knew what was going into it. I couldn't say for sure that they were unreliable and it's good to hear someones running one with no problems. I don't want to buy this thing and have to wrench more than i ride. maybe theres something else wrong we keep over looking?