wr426f help?????????

i just installed a new timing chain and yz timed the bike. it ran when i got it back together but it developed a ticking/clanking noise kind of while its runnig and it sounded like it was coming from the head. it also over heated faster and puked out oil from the breather hose and the drain hole in the head. i was thinking it had too much oil in it cause i didnt drain the spot by the oil filter. i went out to start it and it wont start. when i kicked it oil would start to come out of the hole in the side of the head. i decided to drain the oil a quart or less came out. i think the bike is clogged up some where and oil is not being drained out. i poured some oil in to see if it would come out withe the drain plugs and oil filter out of the bike, nothing seemed to come out. when i kick the biked it kind of kicks back when the kick starter is almost all the way down. that is why i could not get it started. is there some where the oil flow could be clogged up? i pretty sure there was almost 2 quarts in the bike when i filled it last so im thinking oil is trapped some where.would a bike with too much oil have more engine noise? should i unplug the oil line to the head? any advice would be great. thanks:worthy: wanna get the bike ready to ride for spring.:moon:

seems like you have nothing but bad luck with your bike Bakey!

The hole on the side of the head - are you talking about the drain for the plug or are you talking about the decompression lever hole?

If the spark plug drain hole is leaking oil - it could be that you have oil in your cylinder and the plug isn't very tight - that could explain the kickback too.....just not sure how oil would have gotten there in the first place....

Combine that with ticking/clanking from the head...maybe bad valve guides - that's one way to get oil in the cylinder.....

just thinking....maybe take the plug out and dip a screwdriver with a q-tip taped to it into the cylinder (while it's at TDC) to see if it comes out oily.....

i poured oil down the spark plug shaft while i was in the process of timming the bike because i had to order a new flywheel and wanted to keep the cams oiled up and protected but accidently poured some in the spark plug area and it seeped douwn in through the spark plug. that doesnt explain why only a quart or less drained out of the bike unless it all leaked out the few times i rode the bike after putting it back together. it was leaking a fair amount through the breather hose and spark plug drain hole. really hope its not the valves. it ran good before i tore it apart so i think they are ok. the bike was cold when i drained it and i had kicked it over about 20 times before draining. would this cause less oil to drain out?? also when i poured some fresh oil in the frame with the plugs out i didnt see the oil come out of the drain. is this normal, i didnt pour much through the fill hole but enough that it should have drained out i thought. thanks for the response matt, yeah i have had some bad luck with bikes latley lol mabye ill learn something though

Sounds like it is time to tear into it and see where the noise was coming from. Could be one of many causes, timing chain slipping time, timing chain tensioner failed, decompression lever loose or broken, valves not timed properly and striking the head. As for the oil not draining, I wouldn't worry too much about that just yet. Could be that once you find the source of the noise, you my not need to worry about the engine holding any oil.

You should drain the oil out of 3 places - sump drain, front frame and oiul filter - in total that should come to about 1.6 liters - don't know what a quart is - I presume a quarter gallon, which is about 1 L which is normally about what comes out of the sump.

You can check the external lines - remove them and blow them out using compressed air

3 places? i thought there was only the plug under the engine and the bolt by the oil filter. im not wanting to tear this bike down much more than the valve cover right now. where does the oil go first when you pour it into the frame? i poured a few more ounces down the fill hole and no oil came back out with both of the plugs out. when i kick the bike over oil pumps out from a hole it the oil filter area. i can keep kicking and more oil will keep coming. i can kick the bike over all of the way but sometimes it gets stuck near the bottom. was going to change the bike back to wr timing and see if it runs better but im wondering why the oil is not comming out. mabye the strainers clogged?

You need to download an owners manual for this bike and study it. There is a 3rd oil drain plug for the engine sump, it is located on the bottom of the engine, and if the bike sits for more than an hour or so, all of the oil will be in the engine sump. The oil pump will move it back to the Oil Tank (frame) when the engine is running, this is why it is recomended to run the engine a little before checking the oil level with the dipstick. You can find owners manuals to download free on this site in the Sticky at the top of the YZ forum. I highly recomend it. If it was making noise before it died, you need to open it up and identify the source before you do anything else with the timing. You said it was running well before, no reason it shouldn't have unless something internal has failed. I would not recomend changing the timing on a bike that is not running unless you have a good reason to believe that it has jumped. Just my 2 cents worth. Hope this helps.


i have the bottom drain bolt and the oil filter bolt off and looked at the manual and i guess i missed one. havent gone out to drain from that bolt yet cause its gettig late. the bike ran before it got cold and i didnt try that hard to start it so it might of started with more effort. the reason i wanted to changed the timing was because i changed my wr timing to yz timing and when i got it back together and tested it out it had the engine noise. when the bike was wr timed it ran good. i think ill take a look under the valve cover and see if anything looks wrong and check my timing. im almost positive the bike was overfilled with oil by a significant amount thats why oil was puking out the breather and spark plug drain hole in the head. would an overfilled bike cause excess engine noise and the symptom of the kick starter not being able to be kicked all the way through its range of motion sometimes?

took the drain plug on the frame out and the fresh oil i poured in the bike drained out. opened the valve cover and the exhaust cam cap was sticking up. all of the cam cap screws were loose and i could take them out by hand. the screws were all evenly unsrewed it seemmed. i know i torqued them down before the bike was put back together. the cam cap has two metal guides on it and one is sticking out more than the other i dont now if thats normal our not but when i tried to push them down further by hand neither moved. the exhaust cam looks to be unharmed but i still need to inspect it better. the intake cam cam was was on properly and everthing looked normal on it. i still need to get that cam cap off. im going to pull the cams and inspect them and then ill go from there i guess. should i try to pull out the guides or tap them down with a hammer on the cam caps? the guides are diagnal from each other and go in the bolt holes and then the bolts go through them. if i im not explaining them well i tried to take a picture but it didnt turn out good. what damage could have occured from this problem? anything special i should checkmbesides the cams? the bike was still turing over with the exhaust cam cap not srewed on tight and didnt seem to be making any wierd noises. i really hope this doesnt turn into a big repair!!!!!!!!!!!!!

well, that would probably explain the noise...and no, you forgot to torque them down - there's NO way they actually torqued up and then loosened all by themselves - if there are issues with the threads they would never have reached their final torque value.

Likely, once the engine started to turn over, the chain naturally pulled on the cam down at the gear, so the back side would push up against the caps.

(the exh. cam should seat fine again if you push on the cam once you've removed the tensioner).

Ok, you need to inspect the following VERY carefully:

Chain - likely of but the cam was on an angle so check the chain for wear inside where the teeth run.

Cam gear for wear on the teeth.

Cam lobes - edges - they would push on the buckets at an angle.

Buckets for score marks

Cam bearing surfaces - absolutely NO scoring allowed

Cam caps and seats for bearing surfaces - also need to be spotless.

If everything checks out, put it back together from scratch - TDC - cams set right for the timing you want, tighten the cam caps cris cross (like a wheel on a car) in increments of 1/3 torque value up to final torque value - remember to set the final torque value about 8 IN/LBS less than the manual specifies. NEVER overtighten cam caps!

im almost positive i torqued the cam caps down to 7.2lbs each so it could be a thread problem, but the bolts were unscrewing when i took them out fine. if it is the treads what are me options to fix them? ill remove it all and takes some pics of the parts and post them. thanx for the help. atleast i found what the source of the problem is i guess thats half the battle.

i pulled the cams and the exhaust cam is slightly scored on one of the lobes but you cant feels the mark when you run your finger acrossed it. the exhaust cam cap looks fine. the intake cam looks uharmed but the center lobe surface on the cam cap was scracthed up pretty bad. the bukets appers to be alright as well. where do i go from here. how can i get the intake cam cap refinished? im thinking of taking the bike somewhere to get it fixed but moneys tight and i dont want to spend a lot. do i need a new cam even if you cant feel the scratch/mark on the cam lobe? if i could get it fixed for 200-300 dollars i would be willing to do that. if i have to but a new cam thats about 150 dollars i think. hw many hours of labor do you think it would take a shop to fix my problem? ho do they resurface cam caps? could i just take the caps to a shop that repairs heads?

there is really no way they could all have pulled out that far - the gear side of the cam has nearly no vertical lift available once the chain and tensioner are on - meaning there's no real physical way for the cap to get pushed up enough to yank the bolts out. The rear ones - yes but SO unlikely, the front ones - there's physically no real way for that to happen, if the cam lobe were to push down on a bucket that doesn't move, your gear would spin on teh end of the cam - there's no way the lobe would push through popping out 4+ bolts...I just can't see it

Pull the bolts - if there is any sign of aluminum between the threads, it pulled the threads out of the head - but I really don't think you'll find anything on them.....

If you inspect everything and the bolts thread in and there is no side to side wiggle on them once they are in 6 turns or so (check that before reassembly) then I REALLY suspect you forgot to torque them - did you happen to get distracted at any time while you were doing this (phone call, wife bitching, kids being kids????.....)?

take some pics - cam caps need to be replaced as a set with the head - they are bored as a unit (head and caps) and cannot be replaced separately.

Once you post up some pics - we can determine more...






the cam cap still feels smooth

You say that the cam cap still feels smooth, so it must look worse than it is. Does the cap still fit the cam bearings tightly all the way around? If so, then I don't see anythign that would keep the bike from running for a while yet. But you may be in for a new head and cams in the future. I'm not sure about the exhaust cam lobe, one of them almost looks like it is cracked in the picture. If there is any concern about that then I may be in a position to help out. I put a hotcam in my 02WR426 several years ago, and I think I still have my exhaust cam if you want it. I'd give it to you if you pay shipping, given that I can find it again.

If the cam still fits all of the bearing surfaces tightly, both on the cam cap and in the head, I would run it. Keep a regular eye on it to make sure things aren't getting worse quickly for the next 50 hours or so, and if it isn't showing any signs of wear I would not worry any longer. Worst case scenario, you will begin to wear into the cam bearing surfaces, the cam might get loose and begin to knock, and your valves will begin to get tight. In all instances you will have to replace the head. I would take a good hard look at the cam chain, simply because if it breaks, it could take out the crank sprocket, and possibly crack the case. Other than that, I would just re-assemble, and ride it. Good luck, hope this helps.


i just replaced the cam chain but it could have been damaged so ill inspect it. ill try putting everthing back together after i inspect it all again. the the line you saw in the can lobe was a thread or something on the cam not damage. the only mark i saw on the exhaust cam was i black schratch on the top edge of one lobe. you can see the mark a little in the forth picture. its the light spot along the right edge of the first lobe. there was also oil in the holes in the head where the threads are for the cam caps to be bolted down.i wonder if this caused the bolts to not get tightened down right. thank you for the offer on your cam jbrook ill try mine first and see if it works and if it doesnt i will proboly take you up on your offer if you can find it. thanks again,, ill try puting the bike back together, its worth a try before i take it some where

No problem, I hope it works out for you. I really don't think you will have any problems, but you are very lucky that it died when it did. If the cam had come completely loose you would have trashed the head and possibly much, much more. I wouldn't worry too much about how the bolts came loose. As I said before, Just monitor it on a regular basis and you should be fine. At first I would probably try to pull the head at least after every day of riding, if not after the first several rides. Good luck.


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