How do you know if the piston is at TDC?

[MudBug]

I have these few pics. I turned the crankshaft clockwise until the notches in the first hole lined up. I also took a pic of the top of my valve. how to I know if the valve clearance / timing is ok? someone said something about the piston being at TDC, but how do I know when it is? someone help

[leevarnado]

take your plug out and stick a skinny screw driver down in the hole,slowly turn over the engine,you will know when the piston is all the way up.go slow and be carefull as not to scratch the piston

[MudBug]

ok, thanks. I was trying to look down the spark plug hole and judge lol. ill tape some foam or something on the tip of the screwdriver.:p

[rdlsz24]

You can look in the spark plug hole and see the piston come up. Use a flashlight if you need to. Also the valves should both be loose at tdc.

Rob

[MudBug]

when the piston is at TDC, do I leave it there and check those markings again? if they dont match up my timing is off right?

[Erics350x]

with the piston a tdc you check the marks on the cam gear under the cover on the side of the head.

[MudBug]

and is the cam gear is off timing, and my valve is off timing. how do I fix both?

[lndy650]

make sure your at TDC on the compression stroke its just after the intake valve closes. so start with your timing... line up the T on the flywheel and with the cam lobes down line up the circle on the sprocket with the notch on the valve cover. now that your timing is set spin the engine counterclockwise with a rachet on the flywheel just after the intake valve closes watch for the T. when the T is lined up adjust your valves.

[MudBug]

do I have to take the engine apart to adjust the valves themselves? and I couldnt find any notches to match up the cam gear with. there are four little notches on it but nothing I can see to match them with.

[lndy650]

is there a circle on your cam sprocket? it has to be pointing straight up. there should be a notch in the valve cover directly above it to line it up with

[MudBug]

ok thanks for that. but when I line it up and have the valves exposed and everythings ready to go, how to I adjust the valves? do I tighten the nut on top of each one? or what?

[lndy650]

you need a set of feeler gauges avaliable at napa advance auto ect...
loosen the nut and back off the screw with a flathead then slide the feeler gauge under and tighten so the feeler gauge fits snug but not tight you should be able to slide it easily. make sure to hold the screw while tightening the nut so it dosent move and recheck when tight.

[MudBug]

alright. do the feeler gauge stay there permanently or do you take it back out after or something? sorry for the dumb questions. haha im trying to figure this out on my own because dad doesnt care about the big red .

[MudBug]

this is where i'm at now..... do I need to take off the top of the cylinder head to expose the cam gears and chain? or no?

[Dirtcrasher]

^ This is a great example of what NOT TO DO to your motor kids.......

Once the tank is off, pressure wash or scrub the dirt off. It's impossible to prevent it from getting in the motor.

Don't be a bad Mudbug :D shens

If you must look at your valves, take off the rocker box cover and have a looksie.

[Macs]

Good post dirtcrasher.

What makes you think it is out of time anyway?

[lndy650]

just remembered the timing on a big red i think theres lines on the cam sprocket that have to line up horizontally with the head. but yes what makes you think its out of time? and yes you remove the feeler gauge its just to establish the correct gap. sounds like maybe you should find someone to help you its much easier to learn from someone than try reading posts on the internet

[MudBug]

i put the piston at TDC on the compression stroke and nothing lined up. not the valves or the cam so shes really out of wack. by the way, that dirt you see is so caked on, you couldnt get it off with a chizel. so none will be going in the engine anytime soon :P

[MudBug]

but when I take the rocker box cover I might sandblast it and clear coat it, if thats ok. it wont ruin anything will it? just the outside.

[lndy650]

did you take off the valve cover? its impossible to see the sprocket otherwise...and why do you suspect the timing is off? it wont start?

[Erics350x]

You are looking at the wrong end of the cam. Get a repair manual or pay someone to come over and help you out.

[lndy650]

thats the right side he just needs to remove the valve cover

[mohadib]

IRT to finding TDC. If you pull the plug and line up the the "T" notch you should be at TDC. Not on the compression stroke necessarily, but no need to put a screw driver in the plug hole or anything like that. Then if you are not on compression stroke, just rotate till you see the T notch again.

[Erics350x]

I thought the cam seal was on the opposite side of the cam gear? On the back end of the cam there is four marks, which sounds like what he was describing.

[MudBug]

when i line up the "t" on the flywheel with the mark on the side, the piston is nowhere near TDC. actually, its pretty much as low as it goes. by the way. what thickness of feeler gauge do I use?

[lndy650]

for the big red its .003

[Dirtcrasher]

Based on all your previous posts, this isn't gonna turn out good. And this one with it not being at TDC.

Get some HELP please - try hoosier daddy......... shens

I go over this timing crap twice a week, someone else can have this one :D

[MonroeMike]

Have you read the manual?

http://72.52.143.80/~trikes/Manuals/ATC%20manuals/atc250es-85-87servicemanual.pdf

[MudBug]

I keep reading the manual over and over and its pretty vague. here are things I need to know.

1. When I take the rocker box cover off, will there be marks on the cam sprocket to line up with something?

2. I noticed one or two notches on the flywheel when I rotate it. none of them looks like a "T" , more like a (-) and when I line up either one of them, the piston IS NOT at TDC. why?

3. In what order do I do things to adjust the valves. I know how to adjust them, I just need to know what to do first.

any answers will be greatly appreciated.

[MudBug]

here are a few pics to clear anything up.

pics of the different notched I see in the flywheel when rotating it. the one that looks like = shows up when the piston is at TDC, but NOT on the compression stroke. the other notch, is pretty much useless I guess, but it is more noticeable.

my other big red snuck in a pic or two also.

I sanded and painted the valve covers gloss black

then I took a few pics of when the intake valve was closed all the way and piston was at TDC. there are no notches on the flywheel in sight when the piston is at TDC. can someone tell me whats wrong. and dont ridicule me because I dont know as much as you guys. im probably 1/3 your age anyway.

[Dirtcrasher]

Fark it, now I'm dragged into it :lol:

If the notch at "T" does not put the piston at one of the 2 TDC cycles, then either the flywheel key is off or the notch you see is not the notch you need.

At this point you need to remove the flywheel cover and SEE what the marks actually represent, because either your seeing the wrong marks or something is off........

The onll link between "T" and the piston/con rod is the flywheel - you have to figure out whats wrong.

[MudBug]

and how would I go about adjusting the flywheel key?

[Erics350x]

and how would I go about adjusting the flywheel key?

You need to get a flywheel puller and a new woodruff key. They dont adjust, the just bend or sheer.

[MudBug]

Im gonna let a mechanic in my area take a look at it sometime this week, and ill give him all the info I have. I did put it back together and it runs. not well, but it runs. still backfires a good bit and is bogging out and not idling well.

[night4creeper]

sounds like the carb is dirty and not a timing issue, although adjusting the valves could help if they are out of spec. if it runs there is probably not a problem with the flywheel/woodruff key, you just need to pull the cover off the flywheel and see what marks you are looking at.

Another way to tell TDC is when the piston is all the way up both valves will be up also. ( You will need to have the caps off of the rocker cover to see the valves/rockers) each rocker should have very slight up/down play this is where your .003 in clearance comes in; now go adjust the valves and clean the carb.

[MudBug]

thanks night4creeper, awesome advice. I cleaned the carb not too long ago but I think it got dirty again because the little gas catcher on the bottom of the petcock has never been cleaned, and when I opened it up, there was all brown thick sludge and rusty colored muck inside. I cleaned it out but I would say some entered the carb again. And most of my confusion was because I thought I saw someone say that the intake valve should be closed on TDC. but you say both should be open, and they are. but they could use adjusting because she backfires hard and smokes a little at startup. I will try this tommorow. thanks alot I appreciate the advice :w00t: :D

[MonroeMike]

He said both should be "up", which means closed.

[MudBug]

but when you look at it, I thought that "closed" meant all the way down?

[MonroeMike]

Closed is up, the valves are seated against the head.

Google how a four stroke engine works.

Here's a animation.

http://www.forgefx.com/casestudies/prenticehall/ph/engine/engine.htm

[MudBug]

ok thanks, im pretty new to this stuff. and its only because my big red is picking this great time to mess up.

[MudBug]

when both of the valves are up (closed) and piston is at TDC, then I can adjust my valves?

[MonroeMike]

Yes, do it according to the manual, since you better understand it now.

[mohadib]

is the T mark lined up with the notch now? If you cant get that and TDC at the same time I would not attempt to adjust the valves. $.02

[litebulblsc]

Are you sure you understand enough about motors to work on one? The valves are in the combustion chamber so when they are down, they are open and when up they are seated/ closed. The caps you took the top of the head exposed the rocker arms. They ride on top of the valve. When the valves are closed, this is when you adjust the tolerance between the valve and rocker arm. To find TDC you first need to identify the correct mark on the flywheel. Then you plug the spark plug hole with your finger. Turn the motor over by hand and yo should eventually feel pressure pushing on your finger. That means your on the compression stroke. Keep spinning it till the mark on the flywheel aligns. It shouldn't be much after you started feeling the pressure

[MudBug]

yes, I know enough, I just dont know what I was thinking. I'll take a look at it today and borrow a set of feeler gauges off a friend. Thanks guys.

[MudBug]

also, which way do I turn the adjusting screw on each valves? I know when adjusting the clucth, it turns counter clockwise. but is it the same?

[Dirtcrasher]

MudBug - this is only gonna affect YOU if it gets screwed up.

You just said this : "yes, I know enough, I just dont know what I was thinking. I'll take a look at it today and borrow a set of feeler gauges off a friend. Thanks guys."

And now this : "also, which way do I turn the adjusting screw on each valves? I know when adjusting the clucth, it turns counter clockwise. but is it the same?"

You don't know what your doing, you may get lucky but you do not seem to have a clear understanding of what makes and how motors work.

Everyone gets on me to "go easy on the newbies" but when I read there posts it's pretty clear to me who knows whats up.

A page ago your "T" did not put the piston at TDC which means that either your doing it wrong or something else is pretty far out of whack.

I wish you the best, I really do. And I hope you get it running. But, these motors have tight tolerances and mthey won't put up with small seemingly insignificant mistakes. You won't feel the valve bend but it will show up in a compression test.

PLEASE get your mechanic buddy to help you.......... We ALL want to ride but if one stupid mistake ruins the topend, you won't be riding for awhile.

[MudBug]

im just looking for good, quick answers, not lectures. just to clear that up

[MudBug]

and I'm pretty sure that I cleared up the confusion about the "T" i was looking at the wrong mark. also I thought the valves were closed when they were down, not up. so now everything matches up good. and my valves need to be adjusted. im not some orphan boy who stole this trike and is working on it in my sweatshop, i DO have people to help me and they probably know more than you (the expert)

[mohadib]

wow, way to be an ass when you are getting good, helpful replies. Fine Work and good luck with your trike.

[Dirtcrasher]

Nobody ever wants to hear the truth, if someone told me not to mess with things when I didn't know what I was doing I would have been thankful.

Thankful that they saved me money, time and aggravation.....

Good luck on your project :beer

[litebulblsc]

im just looking for good, quick answers, not lectures. just to clear that up


But we are doing you a favor by going into dept on what your trike needs. You should apologize to the people posting for wasting there time trying to explain something to you that you don't care to learn.



Just out of curiosity, how old are you?

[daniel_250r]

and I'm pretty sure that I cleared up the confusion about the "T" i was looking at the wrong mark. also I thought the valves were closed when they were down, not up. so now everything matches up good. and my valves need to be adjusted. im not some orphan boy who stole this trike and is working on it in my sweatshop, i DO have people to help me and they probably know more than you (the expert)

i highly doubt your friends have as much experience as dc, and if they were that educated they would know to stay away from you, i find if your kinder to people they are more willing to help

[MudBug]

all you guys gave me good help, but when I ask a simple question like which way to turn a screw, I get an hour long lesson on how I should be smart. how am I ever going to figure my Trike out if I dont try anything. I am kind to people, up until someone ridicules me so much that it pushes me to the edge. DC, do you feel good telling a 15 year old that hes not smart enough for your "standards"? and to work on "MY" trike? And I am sorry if anybody on here thought that my reply was directed toward them. it was only DC.

[litebulblsc]

Righty tighty, lefty loosy

[MudBug]

I have it now. but when I start it up it makes this loud ticking noise. dad said its cause the valve is loose. so I tightened it up without it clamping hard on the feeler gauge, and the same thing happens. I quit for tonight and gonna try and figure it out tommorow. any ideas?

[litebulblsc]

The valve is loose.
I will list the procedures in a list so you don't have to do too much reading.

- loosen the nut on the rocker

- slide the feeler gauge in between the valve stem and rocker.

- tighten the screw till their is resistance on the feeler gauge

- now hold the screw stationary, and tighten the nut back down

- just to be sure it is correct, make sure the feeler gauge still slides down there with just a bit of resistance. If not, try again

[MudBug]

you do know that the comment I made about quick answers and not lectures was not directed toward you or any other 3WW member besides DC. Thanks anyway. I have done this several times but you never know I could be doing something wrong. and i CAN read (contrary to popular belief) hahaha :p

[Dirtcrasher]

WOW

I gave you an hour long lecture?? :lol:

Yet you couldn't figure out which way to turn a screw and change a gap. But I'm/we're suppose to have confidence in you??

I backed off with a :beer at the end of my post, but since that didn't work; I'm BACK again :D

I'm only trying to save the trike :D

EDIT - The funny thing is, I'd usually tell you that you have no business even opening a paper envelope. Yet, I try to be respectful and advise you to get some help and you assume you don't fit my standards..... WTF?? I give up......... Someday I learn not to post in threads like this and just watch the aftermath.........

[Erics350x]

WOW

I gave you an hour long lecture?? :lol:

Yet you couldn't figure out which way to turn a screw and change a gap. But I'm/we're suppose to have confidence in you??

I backed off with a :beer at the end of my post, but since that didn't work; I'm BACK again :D

I'm only trying to save the trike :D

EDIT - The funny thing is, I'd usually tell you that you have no business even opening a paper envelope. Yet, I try to be respectful and advise you to get some help and you assume you don't fit my standards..... WTF?? I give up......... Someday I learn not to post in threads like this and just watch the aftermath.........
I thought i was the only one getting a migraine ready threads like this. Heck, i remember being one of the ones who complained to you about being so blunt with the newbs, i can see things more clearly now.

[lndy650]

are you sure your feeler gauge is .003IN .08MM?

[Mosh]

No one has to get bent out of shape over this.

Offer some help without snide comments.
If he gets it fixed, then great.
If something goes amuck, then you know you tried to offer good sound polite advice and that is all you can do from a keyboard miles away from the problem.

DC...You are so good with tech advice, maybe this would be the perfect time for you to offer up a tutorial on Timing Set-ups, and valve adjustments on a 4 stroke and we can get that in the help section with some pics.

That way every time one of these threads pop up, you can just link your article, instead of having to type the same advice over and over again.

DC can come off rash, but he hates to see machines junked up by improper wrenching methods and skills.I agree with his thoughts on the matter.
Trying to "undo" someone's debatchery is the worse thing to battle when turning a wrench..

I am sure he means no harm in some of his comments...They are more like comic relief.

Anyone seen that sign at repair shops?

LABOR RATE:

40$ per hour.

If you watch....75$ per hour.

If you tried to doi it yourself and messed it up........175$ per hour.

That is a good sign...LOL

[MudBug]

mosh is right, I just want my trike fixed, and no arguments. the feeler gauge is 0.003 inches and 0.076 mm. I think on the manual they just rounded it up to 0.08 I guess

[lndy650]

ya thats the right one.

[MudBug]

Im going to get the dealership to look at it tommorow. dad thinks I might have bent a rod or something. but I dont think so because the engine starts up and runs great but that ticking noise is pretty loud and the valves open and close perfectly. but that ticking noise is driving me mad. there is no way that valve is loose. and if it would be too tight there would be no compression, not a ticking noise, so im very confused...:wondering

[Dirtcrasher]

Thank you Mosh for relating :beer

I would like to write something up, I do need a pic of the 83-85 200X though, that pulse generator and cam sprocket screw people up. But, it would be nice to refer to a whole topic rather than repeat it.

Anyhow Mudbug:

Too tight valves can make noise too. They have no clearance and are being forced around. This is the whole "T" thing - even if you thought you were at the right place to adjust valves, you may have not been. If they get adjusted 180 out or a bit before/past the right place, they'll get adjusted too tight and or too loose. They'll still open and close, make noise and run; But they might be completely off and that can cause some damage.

The only other usual noise could come from a cam chain flapping around but if something else were loose, you could be hearing that.

[MudBug]

thanks DC. I have the notches lined up perfectly and the valves have a little bit of play.

[Russell 350X]

If you are confident the valves are 100%, then pull the cam chain tensioner, it might not be working properly, causing the chain to slap making the ticking sound.

[MudBug]

would the chain slap even when the bike is idling in neutral? and when I look in through the valve cover, the chain dont look to have any slack.

[daniel_250r]

maybe what you are hearing is actually a rod knock or some sort of worn bearing

[Saul]

Mudbug - what part of Newfoundland are you from? There are some other Newfoundlanders on the board who might be able to help you out 'in person' - Brockey, Newfiebish, Biggreenmachine etc etc

[MudBug]

im on the west coast about an hour from corner brook. I think im gonna book an appointment for my bike at the dealership if I can get one this week. friday were going on a big trip (if my bike is fixed)

[leokendall]

lol i'm from corner brook, i have fixed many bikes. if trailprotrailpro ever around give me a hollar.

[MudBug]

the bike is fixed now thank god, turns out the header pipe was loose from the engine and there was a leak. it was forcing the valve causing it to make the sound. just curious, what kind of trikes do you have leokendall?

[daniel_250r]

good to hear some times its just the simplest things

[MudBug]

wow. reading back over this makes me feel so stupid, and also make me realize just how much I learned on here. Since this unspeakable incident, I have fixed many bikes. my own and my friends. Some fine members told me what to do and I lost my temper, and I apologize to any member who felt offended by my remarks, especially Dirtcrasher. Hope there are no hard feelings here though, I was just a kid :lol:

[Dirtcrasher]

wow. reading back over this makes me feel so stupid, and also make me realize just how much I learned on here. Since this unspeakable incident, I have fixed many bikes. my own and my friends. Some fine members told me what to do and I lost my temper, and I apologize to any member who felt offended by my remarks, especially Dirtcrasher. Hope there are no hard feelings here though, I was just a kid :lol:

Don't sweat it, I'm just glad you learned something and your AOK...

Allot of guys think I'm a f&!!*&^g! jerk; They just don't understand me. Almost all of my posts are informational, not just useless garbage.

You can't read whether someone is being a jerk or a jerk in a helpful manner on the WEB.....

I merely want people to LISTEN, read the manual and TRY to preserve these things for as long as we can. What will this be like in 20 years?? Who knows................

Take it easy :D I'll have a :beer with ya, lol..............

[MudBug]

I must admit you were and still are a great help! If I never would have joined this site I would still be sitting wondering about valves. To me now, that stuff is minor. I just hope I can soon get my project one running to see what Im capable of :lol:

[RodKnockRacing]

Don't sweat it, I'm just glad you learned something and your AOK...

Allot of guys think I'm a f&!!*&^g! jerk; They just don't understand me. Almost all of my posts are informational, not just useless garbage.

You can't read whether someone is being a jerk or a jerk in a helpful manner on the WEB.....

I merely want people to LISTEN, read the manual and TRY to preserve these things for as long as we can. What will this be like in 20 years?? Who knows................

Take it easy :D I'll have a :beer with ya, lol..............

your definitely not a jerk DirtCrasher