A&M OFFROAD 52 Posted March 7, 2021 Okay so since the last post I've since changed out all the top end gaskets, I've had no leaks at all through the gaskets. The tip of using the copper spray a gasket did the trick and help along with using a name brand gasket kit. So thank you guys for the help. Now, today was the first longer ride I went on since replacing the gaskets we rode for maybe 2 hours. My quad is now smoking like a mofo. It's billowing out. No more black smoke either just pure white smoke. It's obviously the oil because when I got back home I was barely on the dip stick. When I went out it was full! The motor now is also making a louder ticking noise. My buddy say it's the lifters, and that I should adjust them but he's not a mechanic and I know he knows alot but I just wanted to be sure before I tear into this thing again. I feel like because I out a cheap china top end rebuild in it, that is the reason but who knows. Bad rings could be causing the smoke correct? But it wouldn't be causing such a ruckus is the motor. But again this is the first thing I've ever really worked on, so my knowledge is very minimal. Thank you guys so much for the help! 1 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 The 400ex doesnt have lifters. It has rocker arms. Some call them "tappets". Anyways the ticking is the least of the worries. When you did the topend. Did you properly check and file ring gaps? Stagger rings properly? Check for piston to wall clearance. This china topend rebuild has me very worried. All of the above things are very very important. It could be off by thousandths of an inch and make it last a few hours compared to years. 2 1 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 I know for a fact I didn't stagger the rings like I should have, and I realized after I put everything back together and watched a video on it. And I can honestly say did not file ring gaps because I don't even know what that means. I do know I checked the ring gaps and from what I can remember they were in spec or close to it. But it was also like 5 months ago so I can't remember exactly. I've progressively gotten more comfortable on the quad and have steadily rode it harder and harder. I knew I would probably have problems with the china top end but I didn't have alot of money to spend at the time. Even less now with my little one here. I've rode 8 hours on the thing and put 120 miles on it in a day. I thought to it may have been over heating cause I was on a trails today too going pretty slow. When I realized it was smoking I got off the trails and tried to coast down the big hill to help cool it down but the smoke got worse and worse untill I got home and shut it down Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 I have been in your shoes with the new little one and tight on money bud! But i would suggest avoiding china parts as a whole. Yes the up front price is low. But in the long run you spend more time and money replacing it all. I would bet ring stagger is your problem. The oil scrapers absolutely need to be as far from lined up as possible. If they end up lining up you will have created a smoke machine. Your tick i would bet is because alot of people dont know this but anytime you remove the valve cover on these engines you have to re-adjust valve lash. The reason being the rocker arms are in the valve cover and if it doesnt go back in the 100% identical place it was your lash will be out of adjustment. Filing rings is what you do when your ring gaps arent right. I will tell you the chances of a china kit having proper ring gap right out of the box is slim to none. My CP piston rings werent even right. The wiseco kits i have always used before that never were either. Sadly bud your gunna have to take the topend off and inspect everything. Which means another new headgasket as they are not re-useable. 3 1 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 Did you replace valve seals when you did the topend? Was the kit you purchased just a cylinder and piston? Not a whole new cylinder head correct? 1 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 I did replace the seals and it was just the cylinder and piston nothing else. I'm gonna have to do some research cause I don't even know what a valve lash is! But I know I haven't set it. Also when I was doing my new gaskets I noticed a piece on my cam shaft was loose. It was on the chain side there was a loose thing on the shaft. I'll see if I can find any pic. I'm not sure if this is normal or not. I probably need to replace everything in the motor. I know my crank was on the loose end of the tolerance spectrum. Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 8 minutes ago, A&M OFFROAD said: I did replace the seals and it was just the cylinder and piston nothing else. I'm gonna have to do some research cause I don't even know what a valve lash is! But I know I haven't set it. Also when I was doing my new gaskets I noticed a piece on my cam shaft was loose. It was on the chain side there was a loose thing on the shaft. I'll see if I can find any pic. I'm not sure if this is normal or not. I probably need to replace everything in the motor. I know my crank was on the loose end of the tolerance spectrum. Valve lash is normal maintainance. Remove the 4 round covers on the valve cover and slide a feeler gauge between the tappet and valve stem tip with engine at TDC. .004 intake and .005 exhaust is spec. The loose thing on the cam was your auto decompression mechanism. They will be loose. 1 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 Okay so I have done those before! Only time I've done them tho was when I first did the rebuild. So I'm guessing I'll need to go and do them again. And thanks I had no clue what that was but figured it wasn't supposed to move. I was afraid it would blow up on the next go. Do you think I could just order new rings? Like a actual name brand set and do it proper? Or will I have to get a new piston and cylinder. Again thank you so much for your help man I really do appreciate it! Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 And no real reason to do research. Thats what we are here for bud! Bounce questions off me my man. I will make sure you get the correct answer the first time. I know these quads like that back of my hand. Been building them since i was 18. Did my first bottom end rebuild on a 300ex when i was 15. Pretty much all of my buddies i ride with have used me to build or rebuild or tune or wrench on there quads at one point or another lol. 4 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 3 minutes ago, SlammedRanger said: And no real reason to do research. Thats what we are here for bud! Bounce questions off me my man. I will make sure you get the correct answer the first time. I know these quads like that back of my hand. Been building them since i was 18. Did my first bottom end rebuild on a 300ex when i was 15. Pretty much all of my buddies i ride with have used me to build or rebuild or tune or wrench on there quads at one point or another lol. Thank you! I'll definitely be asking more question than cause this is the first thing I've ever tore into. I have to say it's been fun working on it. In the beginning I think I had more fun working on it than riding it honestly. I still kinda do, just that feeling of doing something my self and not having to have someone else fix it for me. It's like a drug! 2 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 16 minutes ago, A&M OFFROAD said: Okay so I have done those before! Only time I've done them tho was when I first did the rebuild. So I'm guessing I'll need to go and do them again. And thanks I had no clue what that was but figured it wasn't supposed to move. I was afraid it would blow up on the next go. Do you think I could just order new rings? Like a actual name brand set and do it proper? Or will I have to get a new piston and cylinder. Again thank you so much for your help man I really do appreciate it! Well you will want to start by pulling the topend apart. You have me concerned when you say the bottom end is at the topend of spec. If you can grab the rod and you feel up and down play in the big end your in bad bad shape. No matter how much money you put in a topend it will just keep eating them. Period. No questions asked. If you cant feel up and down your good to go. Next i would take the cylinder and take some measurements. Mic the bore in multiple places. Your looking for 85mm. That would be stock bore size. If you see anything passed 85.5mm the china cylinder was bored wrong which would in no way shock me. Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 Okay that will be my first step then. I'll have to get some of those measurement things. I've needed some for a while now.. I'm thinking I measured the crank the wrong way then. I didn't move it up and down I did it side to side. I probably didn't measure the clearance right. It didn't look like this quad had been tore into before I did it so it could be the original stuff in the bottom end. I mean I don't even know how many owners this thing has has. The previous owner had a stick shoved into the oil res because they broke out the bung to drain the oil. I actual took a picture of the stick today I forgot it was in my drain pan 😂 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 If your cylinder mic's 85mm exactly you will want to measure the piston. 84.880 is the maximum it could be to be correct. These 2 measurements will give you your piston-to-wall clearance. Service limit .10mm. This measurement is extremely important. As it has to be perfect or when the piston expands it can seize in the cylinder. Or if its to wide the piston will slap around in the cylinder ruining rings first. Then the cylinder walls. And eventually could bend the rod if left going too long. 2 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 There is a spec for side to side play on a crank rod. But in my experiance that never really matters. Its all about up and down play and i dont use any special tools just my ear and hand lol. If all your measurements come out proper you can just buy a ring set for the piston you have and we can go through the process of measure, file, stagger, and install. 1 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 How are you measuring everything isn't there a tool for that? Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 13 minutes ago, A&M OFFROAD said: Okay that will be my first step then. I'll have to get some of those measurement things. I've needed some for a while now.. I'm thinking I measured the crank the wrong way then. I didn't move it up and down I did it side to side. I probably didn't measure the clearance right. It didn't look like this quad had been tore into before I did it so it could be the original stuff in the bottom end. I mean I don't even know how many owners this thing has has. The previous owner had a stick shoved into the oil res because they broke out the bung to drain the oil. I actual took a picture of the stick today I forgot it was in my drain pan 😂 Poor poor 400ex.........i see this all too often. Glad you got your hands on it and are putting effort to keep it alive. I will tell you these motors are rock solid. Generally the only way to kill a crank is no oil for a long period of time or an oil pump failure. My quad was also owned by an idiot before me. He put car oil in it and the clutch came out like it was in a camp fire. When i got it and dropped the oil it was fully sludged. But i will tell you a buddy of mine rode his 400ex smoking all day. Ran it fully out of oil and we rode the whole day in the summer heat and he was bouncing the rev limiter with zero oil in it. We tore it down and everything was perfectly fine except the piston and cylinder which were the reason it was using oil in the first place. My quad after 6 years of my abuse finally needed a crank. And it was wrist pin hole failing. And im on the limiter more than im off it lol. You got one of the most bullet proof engines your working on. And when we get it back togeather with proper proceedure and measurments made it will be bullet proof again. 2 1 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 9 minutes ago, A&M OFFROAD said: How are you measuring everything isn't there a tool for that? I use these exact calipers. Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 And this is the bore gauge i use. They sell alot cheaper ones. But i have had these for many years Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 😱😱😱 yea not sure if I'm gonna be able to afford those just yet it may be a hot min before I can fix this thing. The guy I bought it from had never changed the oil per say cause it leaked so much. He always had to out oil in it... Which he told me he used his old car motor oil cause he wasn't gonna spend money on replacing the oil all the time! He used jet black oil from his car..... Like wtf 😒 But that's why I got this thing for $500 1 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 16 minutes ago, A&M OFFROAD said: 😱😱😱 yea not sure if I'm gonna be able to afford those just yet it may be a hot min before I can fix this thing. The guy I bought it from had never changed the oil per say cause it leaked so much. He always had to out oil in it... Which he told me he used his old car motor oil cause he wasn't gonna spend money on replacing the oil all the time! He used jet black oil from his car..... Like wtf 😒 But that's why I got this thing for $500 Other option is to take it to an engine machine shop. Im kinda lucky in those reguards as i live in a town with one of the top rated nhra drag strips. So there are alot of engine machine shops to choose from. Any of them should be able to get your measurements and alot cheaper than buying the special tools. Honestly if it needs bored or just a quick hone you will need a machine shop anyway. Those jobs need such precision i dont even attempt them. I do the final assembly but leave that stuff to the professionals. I do always measure it all myself after since i have the tools. And even professionals can make mistakes. I learned years ago to trust no one but my measurement tools and my own eyes i can usually trust haha. 500.00 is still a bang up deal. But im gunna say he had to have been lying. If he was using old car oil it would have killed clutches like crazy. You absoluetly have to use wet clutch approved oil. The clutch will slip like crazy and look like mine did in short order if not. 1 1 Share this post Link to post Share on other sites
LedFTed 1,142 Posted March 7, 2021 (edited) i just have to ask a question? can oil cause white smoke? i read something the other day that said that last week, an just wanted to confirm it. never hurts to learn something new... i thought it was carb, or water. i had a head crack on a truck. [different beast mind-ya], the water getting in, left large clouds of white smoke. the good thing is, i didnt have no tailgaters. 🙃 Edited March 7, 2021 by LedFTed Share this post Link to post Share on other sites
Fishfiles 20,147 Posted March 7, 2021 @LedFTedWhite smoke is caused by oil or coolant fluid 1 Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 7, 2021 6 hours ago, LedFTed said: i just have to ask a question? can oil cause white smoke? i read something the other day that said that last week, an just wanted to confirm it. never hurts to learn something new... i thought it was carb, or water. i had a head crack on a truck. [different beast mind-ya], the water getting in, left large clouds of white smoke. the good thing is, i didnt have no tailgaters. 🙃 Yep when your burning alot of oil it can be white. Also a little known one is burning excessive amounts of fuel can create blue smoke aswell. But being the 400ex is oil cooled and there is no coolant anywhere in this motor its impossible to be coolant. And condensation is only when it first starts up so since it continued for the whole ride we know its not that. 2 Share this post Link to post Share on other sites
A&M OFFROAD 52 Posted March 7, 2021 Okay so today another friend of mine came over and I was tell him about it, and wanted to show him how much it smoked. So I started it and a puff of white smoke came out at first and then nothing else. It was back to black smoke again after about ten mins tho a very light black smoke. The motor noise did sound louder to me but I was also not wearing my helmet so that could be the reason why. I'm going to adjust the valve gaps here in a while after it cools down. Not sure why but I can't get the little covers off where u can adjust the valves, and I figure it's because it's warm still. So I'm gonna let it cool all the way down and see how bad off they Are and maybe that's why it's making so much noise. Share this post Link to post Share on other sites
SlammedRanger 1,560 Posted March 8, 2021 1 hour ago, A&M OFFROAD said: Okay so today another friend of mine came over and I was tell him about it, and wanted to show him how much it smoked. So I started it and a puff of white smoke came out at first and then nothing else. It was back to black smoke again after about ten mins tho a very light black smoke. The motor noise did sound louder to me but I was also not wearing my helmet so that could be the reason why. I'm going to adjust the valve gaps here in a while after it cools down. Not sure why but I can't get the little covers off where u can adjust the valves, and I figure it's because it's warm still. So I'm gonna let it cool all the way down and see how bad off they Are and maybe that's why it's making so much noise. Hmmmm. But you said the oil level is going down and its not leaking anymore so..........its burning it. Has to be? If its rings generally it wont smoke until it warms up good. And the longer you ride it the more it smokes. Share this post Link to post Share on other sites