OMG what now

[Shift_450R]

well i was riding today for the first time in 7 weeks and i had just got my fixed about 8 weeks ago, they had to re-time it and since they have done that it has been nothing but problems. My 400 ran PERFECT before the dealership donkey machanics touched it. First of all the played with my jetting while it was in there....Backed the fuel mix screw way off which made it really lean. Then i get it back and its so lean its popping really hard on de-cel. Whatever ill deal with it later. So i go for a quick ride to my gf's and the damn thing would stall whenever i left off the gas. I thought it was my plug, nope.....my air/fuel screw had completly fallen out. So now i wait for it to come in. Get it in, quad runs fine. Go for a quick test ride and all of a sudden it starting making a really bad ticking noise. I thought i just picked up a rock in the chain. Shut my quad off looked it over and nothing. Weird. So i start it up again and on idle and in gear it tick really loud. I checked oil and its perfect and i dont think a rod would go that instantaneous so maybe im thinknig i dropped a valve and the pistons hitting it? All i know is im pissed off because ever since those douchebag mechanics so called "fixed" my quad there has been nothing but problems. Anybody know what could possibly be wrong with it?

[Shift_450R]

Is it possible that it could be a loose cam chain causing it to retard the timing enough that the valves are hitting the piston?:confused: Im only 16 and havent had much expierence with motors so you might expect some dumb questions:p

[GPracer2500]

Extremely unlikely if not impossible. Even being off a full tooth on the cam timing I don't believe the piston will contact the valves with a stock piston on the 400EX.

A "dropped valve" typically means the valve has actually broken off or in some way become completely disconnected from the valvetrain. It would be obvious if that happened--the engine will not run and there would be a lot more noise than just a tick.

First step is probably to check the valve lash clearences and be sure they are in spec.

[cop292]

If the dealership changed the air/fuel setting, jetting, etc. this could have caused the bike to run too lean. By running the bike in this condition you could have burnt a valve or the piston among other things.

[Shift_450R]

Originally posted by cop292
If the dealership changed the air/fuel setting, jetting, etc. this could have caused the bike to run too lean. By running the bike in this condition you could have burnt a valve or the piston among other things.

so would it be their fault that something f'ed up in my quad? Because after they fixed it they gave it a 30 day warentty but right as soon as i got it hom i busted my hand at work and i havent ridden it until yesterday when i got my cast off.....I think they better cover it for free beacuse if it wasnt for them this would have never happend

[Shift_450R]

Originally posted by GPracer2500
A "dropped valve" typically means the valve has actually broken off or in some way become completely disconnected from the valvetrain. It would be obvious if that happened--the engine will not run and there would be a lot more noise than just a tick.
but do you think it could be my cam chain thats making the noise? And im sorry when i said dropped valve i mean that its stuck....which i should have wrote stuck valve:p is it possible that the valve is stuck?

[Shift_450R]

I went and took a soundclip of it.

http://media.putfile.com/400EX-noise

[GPracer2500]

Originally posted by Shift_450R
but do you think it could be my cam chain thats making the noise? And im sorry when i said dropped valve i mean that its stuck....which i should have wrote stuck valve:p is it possible that the valve is stuck?

Anything is possible--but I doubt you've got a stuck valve. A stuck valve is likely to cause so much loss in compression that the engine either won't run or runs very poorly.

What you need to do is troubleshoot. Taking somewhat wild guesses about what's wrong will get you nowhere. Start by checking the simple/easy things first and then dig deeper and deeper until you figure out what's wrong. Or, take it back to whoever did the original work if you're not prepared to be your own mechanic.

What was wrong with it in the first place? You said they had to re-time it? What happened that made that necessary?

[GPracer2500]

Originally posted by Shift_450R
I went and took a soundclip of it.

http://media.putfile.com/400EX-noise

That doesn't sound good--that's for sure. I'd remove the valve cover and inspect the valvetrain.

[Shift_450R]

Originally posted by GPracer2500
Anything is possible--but I doubt you've got a stuck valve. A stuck valve is likely to cause so much loss in compression that the engine either won't run or runs very poorly.

What you need to do is troubleshoot. Taking somewhat wild guesses about what's wrong will get you nowhere. Start by checking the simple/easy things first and then dig deeper and deeper until you figure out what's wrong. Or, take it back to whoever did the original work if you're not prepared to be your own mechanic.

What was wrong with it in the first place? You said they had to re-time it? What happened that made that necessary?

I'm unable to do engine work myself...thats out of my league, i can do simple stuff like carb work and valve adjustments but when it comes to internals....i dont touch it lol:p But anywho The thing that made them have to retime it, is I was at my friends house and he has a 50 foot table top. and i hit it a tad too slow and i was gonna case it so i got on the throttle and soon as i hit it started bogging in every gear. The mechanic told me the timing was out 4 teeth or cogs. So he went and re-timed it and played with my carb and stuff when they were trying to figure out what was wrong with it.

[Shift_450R]

Originally posted by GPracer2500
That doesn't sound good--that's for sure. I'd remove the valve cover and inspect the valvetrain.

Yeah im gonna have to wait until my dad comes home from work tuesday to do this, but could it be the rod knocking? It really doesnt sound like it....but what do i know?

[DieselBoy]

keep us posted, im curious to see what it turns out to be

[Shift_450R]

Originally posted by DieselBoy
keep us posted, im curious to see what it turns out to be

Ill be sure to, my dad comes home on tuesday so monday morning he's taking it to the dealership to get fixed...im praying to god that its an easy fix, i want the damn thing out my garage and be replaced with a sexy black 450r

[DieselBoy]

i hear ya

[RezoD]

Sounds to me like something my quad just went through/still going through. My timing jumped about 40* causing my valves to smack my piston and bent one of my exhaust valves. My timing chain tensioner was broken, the spring was worn out and wouldn't keep tension. I would pull that and see if it's broken, allowing your quad to jump timing intermittently.

Travis

[pual0101]

thank god , mines sounds exactly like that. im glad someone else is fighting it, ive been tuning on the carb, so it could be valves?

[RezoD]

For my experience, yes, it was the valves. It's a VERY loud tick, sounding like it's coming from the head (specifically the exhaust side, not intake).

I'm going to suggest you pull your head, but only if your compotent enough to do so. I don't want you to get it all torn apart, and then blame me for not being able to find where that extra bolt goes (extras are BAD!)... Just pull the head, and you should easily be able to see if the valves have hit the piston, or if there's a gap.

Travis

[krt400ex]

Originally posted by GPracer2500
That doesn't sound good--that's for sure. I'd remove the valve cover and inspect the valvetrain.



is it detoing??? i can't tell..... but that might be it???? i have never heard a noise like that before

[DieselBoy]

could it be the crank?? or the rod???

a mechanics stethascope helps.

[Shift_450R]

Originally posted by DieselBoy
could it be the crank?? or the rod???

a mechanics stethascope helps.

My pops talked to the mechanic today and he said hes gonna take a look at it and it sounds like a valve problem...plus if it was a crank why would the sound be coming from way up top near the cam/valve area

[DieselBoy]

Originally posted by Shift_450R
My pops talked to the mechanic today and he said hes gonna take a look at it and it sounds like a valve problem...plus if it was a crank why would the sound be coming from way up top near the cam/valve area

no idea. sounds are deceiving sometimes, but it could be. let me know when you find out, im interested to see.

[Shift_450R]

Originally posted by DieselBoy
no idea. sounds are deceiving sometimes, but it could be. let me know when you find out, im interested to see.

yeah man the mech. said he'll have it done by friday at the latest

[Shift_450R]

well talked to the mechanic and he said that my wristpin on my connecting rod is jacked up and the rod is slappin the piston. So hes just gonna replace it and see if anything else is messed up.. I hope its just the wrist pin:eek: but ill keep you updated because hes gonna call back tommorow after he phones

[Metzroth]

It's really simple to do yourself. If you can turn a wrench/screw driver you can adjust your valves. You will need to buy a gap guage and i think you will need a 10mm wrench and a flat head screw driver. (i haven't adjusted my valves in awhile so i dont remember for sure). Start by removing your rear plastics, then your fronts. After the remove the gas tank(make sure to shut the gas off) and then remove the plastic heat shield. There should be 4 caps, one on each corner of the valve cover. Remove them, put your quad in 5th gear. Then on the right side of your quad there are 2 timing covers. Remove the smaller one and roll the quad forward in gear (may take a little work but its easier than removing the big timing cover and finding a large enough allen wrench). Roll it forward till you see a timing mark, If i remember correctly there should be a T above or below the mark, line it up with the timing mark on the motor. After you do this you need to check and make sure you are on your compression stroke. To do this. with the covers off, reach in and pull up on each rocker arm and see if there is clearance on each valve It has to be on compression stroke because all the valves need to be closed at once to adjust them correctly. If it is on the exhaust/intake stroke just roll it over again and that should be your compression stroke. Reach in again and make sure that you are on the correct stroke (there should be a little clearance and you will feel/hear it). If everything is a go, start on the exhaust side by loosening both of the 10mm nuts and take your gap guage and put it on .005 for stock cam (on exhaust side only, and you should double check that just to make sure). Tighten the screw that goes through the nut until you cannot move the gap guage easily then back off to where there is a small amount of resistance on the gap guage and then tighten down the 10mm nut. Check clearance again and make sure there is a small amount of resistance. Then repeat this process on the other exhaust valve. For the intake valves loosen the 10mm bolt and follow the process exactly like you did the exhaust valves, except you are going to use clearance .004 instead. After you complete adjusting the valves, triple check your work, make sure there is about the same resistance on the gap guage for each valve (on their specified measurement). After you do this replace your timing cover, valve adjustment caps, your plastic heatshield, your gas tank, and connect the wires on your front plastics and fire your quad up to see if the valves have gotten quiter. If they are, quiter and the quad revs smooth and has no wierd noises coming from the top end you are good to reassemble your quad (bolt on front plastics, re-attach rear plastics) and go ride. Hopefully this helps someone. Remember to double check those measurements for your specific cam and make sure that I did not make a mistake. Good luck and happy riding!

[Shift_450R]

mechanic called back....wrist pin is 100% the problem was that a gear on the crankshaft broke 2 cogs off:eek: so now im just waiting for the retardedly crazy bill and for the new gear to come in:mad: :ermm: