View Full Version : Well Even Im Stumped
1. I think Ive been burning oil. Thought it might be the CFM oversized tank I just recently put on is kinda hard to get filled right for some reason. Seems full when I change the oil but when I ride and check it after its warmed up its either to low or to high. Supposed to hold 3.25qts but Ive put in less and its been fine-and yes I let it run after I changed it and verified it was good, so IDK for sure.
2. Me and the EX took a swim about 2 months ago. It sucked in a good bit of water and locked it up but I got it all out and flushed the engine multiple times.
I took the entire topend apart and noted no problems. No scarring of the top of piston (bent valves), no problems in the cylinder or rings. Removed the valves, seats looked fine, none of the valves seemed bent and I reground them to be sure everything was fine. Springs seemed in specs too. I also replaced the valve seals. I installed the CFM tank after this as well.
3. Checked compression, using the test outlined in the manual of fully open throttle and cranking for 4-7 secs, 4 secs reveals 180psi everytime which is what (if i recall) it has always been with my 11:1 setup.
4. I just dont understand where the oil is going, Im getting very slight smoke but no copious amounts, just little puffs. But how could that be if I have good compression? Good compression means the pistonr ings are sealing right-thus no oil should get thru.
I just put the stock tank back on and verified after an oil change that its exactly full with the 2qts. I also made sure there were no shavings inside the oil at this time as well. The quad starts right up with no issues at all, has plenty of power, doesnt stall or hiccup, idles fine, I just adjusted the valves too. No issues with it running or starting up . Just seems like Im burning oil slightly. After a day riding I needed to fill it about 1/4-1/2 a qt. Was gonna ride today and check it to make sure exactly wtf is going on but its raining like hell :(
So yea im stumped :confused:
DnB_racing
08-14-2011, 09:16 AM
you could be getting some blow by when it gets hot,,, just for grins try taking a compression test when hot, and if possible do a leak down test, it will yeild better info then the compression test
Did a comp test when hot and cold, same 180 psi. Ill have to do a leak down.
DnB_racing
08-14-2011, 09:38 AM
Originally posted by CJM
Did a comp test when hot and cold, same 180 psi. Ill have to do a leak down. another thing you might want to try, is take some 2 stroke oil and spay it in the cylinder,when cold and check your compression, it will tell for sure, if its higher the rings are letting some by
Honda#4
08-14-2011, 09:56 AM
I'd concur about the blow by.
Okay this is interesting. I built a leak down tester and it seems to work just fine Im getting alot of loss. When I connect it after pressurizing the tester it just leaks right out so quick its hard to tell exactly where its coming from. I can hear it hissing. Its not the tester b/c thats airtight I checked it.
Remember I just cleaned up the topend when I drowned it maybe 2 months ago. That included honing the cyl, checking ring gap, new valve seals and lapping the valves. It seems to have plenty of power, no outward signs of seepage of oil either.
I also rechecked comp-still 180psi, then I added some 2 stroke oil-still 180 psi. I check it like 10x to be sure.
Im going to ride it hopefully next week and check the oil and see if it consumes any. After that if it still does Im going to take it to a friend whose a better mechanic than I am and see wtf he thinks. Im stumped. I mean it could be the leak down tester I made (I didnt check it on anything else) or just maybe its that stupid oil tank, stil doesnt explain the smoke. This is very frustrating for me since I usually can fix problems like these!
DnB_racing
08-14-2011, 01:12 PM
Originally posted by CJM
Okay this is interesting. I built a leak down tester and it seems to work just fine Im getting alot of loss. When I connect it after pressurizing the tester it just leaks right out so quick its hard to tell exactly where its coming from. I can hear it hissing. Its not the tester b/c thats airtight I checked it.
Remember I just cleaned up the topend when I drowned it maybe 2 months ago. That included honing the cyl, checking ring gap, new valve seals and lapping the valves. It seems to have plenty of power, no outward signs of seepage of oil either.
I also rechecked comp-still 180psi, then I added some 2 stroke oil-still 180 psi. I check it like 10x to be sure.
Im going to ride it hopefully next week and check the oil and see if it consumes any. After that if it still does Im going to take it to a friend whose a better mechanic than I am and see wtf he thinks. Im stumped. I mean it could be the leak down tester I made (I didnt check it on anything else) or just maybe its that stupid oil tank, stil doesnt explain the smoke. This is very frustrating for me since I usually can fix problems like these! im sure you did this but just incase, when you did the leak down you were at TDC
Yes I was at TDC, checked it 3x just to be sure.
Funny, did you know that if you leave off the inspection and crank bolt covers it will escape put of them? :eek:
DnB_racing
08-14-2011, 02:57 PM
Originally posted by CJM
Yes I was at TDC, checked it 3x just to be sure.
Funny, did you know that if you leave off the inspection and crank bolt covers it will escape put of them? :eek: sorry to say but you got bad rings buddy, some leakage isn't to bad but if its actually strong enough to feel they are leaking too much... make sure you only put around 6-10 psi when checking, and you shouldn't have any more then 10% loss ,or if you use under 5 psi it should hold it for at least a minute, but some people do it different ... but ether way you shouldn't feel the air in the crank
some people use high pressure and lock the crank so the pressure doesn't move the piston... but I prefer the low pressure and it should hold the air really even up to 10psi
Ill give it a shot with low pressure. I was running 100psi like Ive done on cars in the past. Ill do 5psi and see whats going on. Ill post back with the results.
EDIT: Ok I checked it at 5, 10, 20, 30, 40, 50 and 60 psi Its def the rings leaking. It will not not hold any of it. Maybe my gauge isnt good IDK. Ill have to see if I can borrow a good one sometime this week (if not dropping coin on this one looks like a good idea: http://www.amazon.com/Star-Hoffmann-Cylinder-Leak-Tester/dp/B000Q6P7GU ) .
This is what I built and trust me it holds pressure. One end hooks to your air compressor and the other hooks to your compression tester hose. http://www.youtube.com/watch?v=7UcOn8OEt0Y&feature=mh_lolz&list=FLHiqUXxr6XW8
Anyways I guess Ill pick the brain of my buddy to be sure, order a set of rings, see what happens this week when i go riding and take it from there. its certainly not like my buddies that was smoking worse than a 2 stroke tho.
Thanks for the help DnB
matts27
08-14-2011, 04:30 PM
The blow by can happen multiple ways, meaning valves, piston, rings, bore and gasket. Sounds like a ring job but I've seen on forged & cast pistons BOTH the rings and Piston goe. Meaning the side gap on the piston goes due to wear along with the rings. Not trying to ruin your day but just reminding you that order if you can after the inspection. Nothing worse than waiting on parts but unless you want to by both sometimes you gotta stare at a tear down to fix what you need. Good luck, just my experience, Matt
What I really dont understand is when I had it all apart and checked it out with a fine tooth comb about 2 months back everything seemed fine. Ring gaps were good, piston looked good as did rings, valves were ok, piston had no play in cyl, etc.
Soon as I tear it down Ill be checking it all over again to be sure and scrutinizing everything.
matts27
08-14-2011, 05:53 PM
Water can do funning things, coulda killed the spring/expansion rate to a ring. Post some pics of what you find if you got time. Matt
Funny how everything looked good when cracked it open a month ago. Ill begin tearing into it in a week or so and post pics for sure.
Thanks for your help.
honda400ex2003
08-14-2011, 08:33 PM
i still think theres a valve that is bent ever so slightly and making it blow past your seals.
steve
crownandmonster
08-14-2011, 09:53 PM
I am also wondering why it would pump up to 180psi if air is rushing out that badly. I would also lean towards a bent valve...easy way to check for a bent/improperly seated valve is to take the head off leaving it fully assembled and then just poor some solvent from your parts washer into the intake and exhaust ports. Obviously you want no solvent to leak past the valve, but some seepage is ok.
Thats a good idea crown.
I think Ill start the tear down in a few weeks. I got school coming up and that means less work so I will have more freetime then. Until then I want to monitor the oil and see what happens with the stock tank vs the CFM tank.
DnB_racing
08-15-2011, 07:57 AM
CJM when monitoring your oil remember the more oil your running the more oil to expand,get the oil up to temp and check and add to full ..
dont fill to full when cold, when it heats up it will be to full and it could be causing your smoking also
Thats how I usually do it DnB.
I fill to 1.5 qts and let run till warm, then add the other 1/2 qt and check.
The problem of the other tank was it said it was 3.25qts, tried to fill it to that several times and everytime I either over or under filled it it seems.
Like I said, Ill be keeping a close eye on it and if it stops burning oil I think Ill leave it be, if not its getting torn apart and inspected.
Let it warm up and rode a bit. Not enough for the oil to be burnt off (its still full from when I changed it saturday)-but enough to see the smoke. Riding along its hard to see, its not alot of smoke. Let it sit in one spot and rev it up and bingo. Its not very strong but you can clearly see whitish-blue smoke after revving it up several times. Jetting is spot on so its not rich-thats for sure.
So I ordered some rings and probably will yank the thing apart in the next month or so when I get some free time.
crownandmonster
08-15-2011, 05:28 PM
Yea we do that to all our heads, be it off a small block chevy or a 400ex. Like I said best case senario there will be no leakage, but a small amount isn't anything to worry about.
Originally posted by crownandmonster
Yea we do that to all our heads, be it off a small block chevy or a 400ex. Like I said best case senario there will be no leakage, but a small amount isn't anything to worry about.
Soon as I got it all apart Im gonna do that :) Thanks for the good advice.
So it continues. Got my first good ride in since I put the stock oil tank on since I wasnt sure I was filling the CFM one properly.
6 hours and I was missing a about 3/4 of a quart and I changed the oil 3 weeks ago and didnt ride it before today.
No massive amounts of smoke. Im guessing the rings could be bad, probably the oil ring is not seating right is my guess specifically. Im also thinking the head/valves might be an issue. Im sure I would have seen any bent since I last had it apart 3 months ago-my guess is one of them isnt sealing properly. Valve guide, valve itself, seals are brand new 3 months ago..IDK
So wish me luck and offer any suggestions-cause Im damned stumped on this one. If it needs a piston Ill be doing a 426.
powerbomb400
09-05-2011, 06:40 AM
We have a 250ex that we have done everything we could think of. From rebuilding the head to boring and several ring changes. It will smoke at start-up and use a slight amount of oil but runs great. After several atempts of trying to stop the problem we just ride like we stole it.:macho
Id say I would be inclined to do the same thing, but burning almost 1 quart out of the two it holds in 6 hours doesnt work. Imagine I hadnt stopped and checked it when i did?
powerbomb400
09-05-2011, 08:20 AM
I agree. Its the wondering part that I hate. When you done something several times then "Boom" out of nowhere a problem comes up and then you can't find the solution its a pain. Hopefully its just a little something that's a simple fix.
crownandmonster
09-05-2011, 09:39 AM
I suppose if a scraper ring was stuck it would allow oil to pass by, but I would also think there would be visible amounts of smoke if that was the case. Is there any oil getting pushed out the crankcase breather?
Crankcase breather is clean.
IDK maybe one of the vavles just isnt sealing. I mean i did drown it pretty good, still I examined everything and it seemed ok. Guess when I finally rip it apart Ill see wtf is going on hopefully. This weekend is probably gonna be it.
crownandmonster
09-05-2011, 01:48 PM
Yea man its hard to say. Usually 200 degree aluminium doesn't get along with 70 degree water. There is no telling what bent /warped /distorted when that cool water introduced it self to your internals.
Yea, IDK really. Its gotta be the topend as the bottomend doesnt have much to do with the burning oil.
Now, it is possible the rings didnt seat well. Without realizing it I forgot to hone the bore when I put it all back together after the water. Really should have done that.
I figure Ill tear into it, check everything over again, new rings and measure them and see wtf is up.
FWIW My buddys EX was burning oil but didnt have bad smoke till it was burning about a quart every 2-3 hours.
Worst case is I do a 426 if the bore is shot. Still id figure more smoke if it was.
I hate this game of trying to figure it out.
Got my answer:
Removed everything but the jug, sleeve has alot of oil in it and alot of carbon build up. Im going to have to look at the play it has a bit more-but I can physically see oil pushing past the rings.
Gonna check it further tomorrow and the head for leakage as well.
YAY..more money to spend if it needs a piston!
Another update:
-Valves arent leaking, bit carboned up but not leaking at all.
-Stupid dowel pins didnt want to come off, ruined one and salvaged the other one. No idea why, think Ill lube them up super well next time I assemble it.
I mic'd the bore a bit and it seems in spec, piston has more play than I would like it seems. Once I tear it fully down Ill mic the piston and see about the rings. But Im thinking Ill be needing to do an 88mm piston this time around. It still burns oil Im sorry to say but a 450r is possibly in the future.
Baileygunns
09-06-2011, 07:42 PM
Little trick for dowel pins... Take a drill bit that fits snug into the center (put the smooth end into the dowel) then grab the dowel with pliers and work it out. The bit will keep you from crushing or deforming the dowel.
In my case Baily it was stuck on the head studs, still deformed. No big deal since they are cheap to replace-I ordered 4.
Anyways so heres the end result. I consider this result unacceptable and will probably buy a new piston and bore it out. I need to more accurately measure it, but this initial check doesnt look good.
First ring according to spec and my bore size of 3.43 inches should be 3.43 x .0040, second should be 3.43 x .0050. This works out to about .014 and .017 (this is all in inches, its a wiseco piston). Instead im getting, 1st ring: .019 and and .023.
Those numbers are totally unacceptable imho. I could understand if they were off a little but not that much. NOW the honda service manual states the stock rings could have as much as a .006" of a gap. Even so my rings are near the end of that service limit stock or not.
I think Im gonna have to bore it to 426.
Ordered an 88mm 11:1 426 piston. This sucks, 30 bucks for rings I cant use now.
All finished and fired her up, runs good. Probably needs a larger pilot. I have a 42 I used with the 416 setup and had the a/f out 3 turns but still had popping, gonna go up to a 45 and see how it goes.
Otherwise ran well except the damn hotcam is LOUD sounds exactly like nacs bike does in the video: http://www.youtube.com/watch?v=5cLmVB7IGCg&feature=BFa&list=WL0013183E973DC542&lf=mh_lolz
Its not the valves, they are excellent, and the springs are brand new kibblewhites. I might try to snug the valve lash up a bit.
Oh and for those wondering, I fixed the exhaust stud. Had it welded up after I cleaned it all up and drilled and tapped for the old stud size. Stupid welder left some air pockets and the drill went slightly off center, resulting in the stud being slightly off, but its all good. I have a back up head should I ever have an issues
Stickman400
10-13-2011, 07:25 PM
Mine almost sounds like that video too. Not that bad, but almost.
Originally posted by Stickman400
Mine almost sounds like that video too. Not that bad, but almost.
I usually make the valves slightly tighter and it cures most of the noise. Most people think you need a valve job when you pull up if it sounds like the video lol
Rohr397
10-13-2011, 11:28 PM
So I know this probably going to sound stupid but, do you turn your gas off after every ride? And also does the valve shut off properly? I had the same problem you did on my Trx450r and I couldn't figure it out so I took it to the shop. The mechanics told me that my shut-off valve wasn't working correctly and all it took was a little gas getting into the engine through the carburetor to cause my oil to burn up. Like I said it sounds really stupid but they replaced the valve and the blue smoke never came back. Sounds like you already figured your problem out but I thought I'd share that input and hopefully someone finds that info useful.
01boneless
10-14-2011, 06:47 AM
i higly doubt thats your problem with the blue smoke if its only on startup its your valve seals never had to shut my gas off try it and see i guess:confused:
Originally posted by 01boneless
i higly doubt thats your problem with the blue smoke if its only on startup its your valve seals never had to shut my gas off try it and see i guess:confused:
Never heard of such a thing, gas will not flow from the carb into the engine unless you pump the throttle.
F-16Guy
10-14-2011, 09:12 PM
Originally posted by CJM
Never heard of such a thing, gas will not flow from the carb into the engine unless you pump the throttle.
The gas tank is a lot higher than the carb. If the needle and seat isn't sealing perfectly, what's preventing the fuel from overfilling the bowl, flowing up through the needle jet, and trickling down into the cylinder (assuming an intake valve is at least slightly open)? I'm not saying that's definitely the case with yours, but I can see how it could happen. Oil with fuel in it would lose its viscosity and get by the rings very easily. I just had an issue with mine smoking a little - the oil was water thin, I changed it, and it's now smoke free.
You bring up some good points, its indeed a possibility if things were worn out in the carb.
Rohr397
10-15-2011, 12:20 AM
Ahhh see that's where things get really interesting. The carburetor setup Honda used on the 450r in those years the and the 400ex had this issue from the get-go. On other quads the gas would leak through the overflow tubes in the carburetor but with these carburetors (for whatever reason) they let gas into the cylinder. Like mentioned earlier the oil looses its viscosity and burns in the cylinder. Another problem is that the gas gets so hot that it burns while it's in your low end so the gas is igniting all over the engine and burning up oil every time that happens. Obviously that's a big problem.
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