400ex ring problems

[greg_gorrell]

Alright, Im pretty sure I have this figured out but i would like some input on it. I have an 01 400ex its all stock and has been rebuilt a few times. I took out my baffles and then lost them which is why i think i have this problem. So i have been riding it liek that and recently it has started burning oil and blowing blue smoke. So Im pretty sure im gonna need some new rings and im hoping the piston is alright too. I just adjusted my valves so they arent causing any problems. Another thing is that every once in a while ill be riding over some rough terrain in first with the clutch in and out a lot the thing will rev up really high and ill have to let it out a bit to calm it down. It also will idle really low every once in awhile to were it stalls every few revoulutions. Like i said im pretty sure the main cause of all this is the piston rings...and i definately need a new pipe or at least the baffles. So i dont know..just tell me what you all think.

[400ccBanshee]

I am sorry to be the one to tell you this but, you have many problems. First, the rings. This is just too easy to check. Do a compression test. To do this you will need two things a compression Gauge, and a service manual. The compression gauge is availible at many auto parts stores for sale or rent. The manual is to get the compression specs (which should be around 100psi on a decent motor). The rings though are not your only problem. I am going to bet that there are "THINGS" that are not as they should be. In plain terms "RIGGED"......... Is everything properly hooked up? Carb vent hoses? When was the last time you took apart the Carb? In order to keep a carb running right you need to take them apart at least once a year, on a stock atv. Next, part of your smoke problem is the valves. You may think they are adjusted correctly, however if they are wore out you can adjust them all day long with no resolve. Also if the valves are to far out of adjustment you will get a low compression reading. The lack of back pressure due to there not being a good muffler is a good concern, this is also extremely hard on valves. I always get really leary when I hear that a motor has been apart "MANY" times. Every one of those times in my experience you have the tendance to make things worse, not better. SEEK PROFESSIONAL HELP. You may think it costs to much, but if you want it to run right find a good indepentant service tech who is good with atv engines (if he builds expensive race engines, someone thinks hes good) I would shy away from dealers..... They are great for warranty work, but nothing else due to their lack of REAL EXPERIENCE.

[UglyMotha™]

Originally posted by 400ccBanshee
In order to keep a carb running right you need to take them apart at least once a year



:huh :huh hmmm I guess my bike should have quit running a while ago :confused:

[greg_gorrell]

man..im not trying to brag or anything but i know quite a bit on what im doing and nothing is "rigged" on the engine. I dont see how a carb would need "taken apart" like that. Maybe to clean it every once in awhile. But i have already checked it out and its clean and working right. The valves are pretty much new and i know they arent worn out.

[UglyMotha™]

Originally posted by greg_gorrell
man..im not trying to brag or anything but i know quite a bit on what im doing and nothing is "rigged" on the engine. I dont see how a carb would need "taken apart" like that. Maybe to clean it every once in awhile. But i have already checked it out and its clean and working right. The valves are pretty much new and i know they arent worn out.


don't worry bout him, I think he just babbles more than he knows


as far as your bike, the blue smoke could be a few things, your valve seals could be leaking, rings are shot, or you have a score in your cylinder wall these will all cause your bike to burn oil, you can start with a compression test

as far as the erractic idle it sounds more like a air leak somewhere between the head and carb, which is not rare, so you could start by checking that out, if you have an older ex they had poblems with the intake boots cracking

[greg_gorrell]

alright ill check on the compression test and air leak tommorrow and get back on whats up