350X rocker arm adjustment

[Hoosier_Daddy]

When i was turning the enige over by hand it would hit a snag and i couldn't turn it anymore. I checked it out and it looked like the piston may be hitting the exhaust valves. So i backed of the rockers some and it turns over ok. Problem is, the rockers are now a little loose and when the engine is running it will certainly make a tapping sound. If i simply take out a little play out of the rockers so they aren't loose, then the piston bottoms out on the valves again. What am I doing wrong?

p.s. this is quickly reminding me why I love 2 strokes so much. lol

[3Razors]

You have to adjust the valves while the piston is at TDC. Grab a feeler gauge and set them in spec.

[Hoosier_Daddy]

You have to adjust the valves while the piston is at TDC. Grab a feeler gauge and set them in spec.

Thanks. I'll do that. Any easy ways to check for the piston to be at at TDC?

[3Razors]

Setting the valves on a motor reassembly is just standard procedure on any fourstroke rebuild. You have use the access hole on the engine cover to line up the tdc mark on the the flywheel with the mark on the cover. Again the manual explains all of this step by step.

Another very important note. Make sure that you set the cam sprocket to the correct mark at tdc. Or things will really get messy.

[Hoosier_Daddy]

Setting the valves on a motor reassembly is just standard procedure on any fourstroke rebuild. You have use the access hole on the engine cover to line up the tdc mark on the the flywheel with the mark on the cover. Again the manual explains all of this step by step.

Another very important note. Make sure that you set the cam sprocket to the correct mark at tdc. Or things will really get messy.

I went by the manual when i set the timing chain back in. The flywheel has a t mark that matches up and the timing sprocket has marks as well. So that is all matched up. I was having a bit of a time finding rocker adjustments in the manual but I'll go snoop through it a little more thorough again.

[Brad200X]

Another thing to add is, if it's anything like my 200X, make sure it's on the "T" mark during the compression stroke, (rockers loose) but you probably know this.

[MonroeMike]

I went by the manual when i set the timing chain back in. The flywheel has a t mark that matches up and the timing sprocket has marks as well. So that is all matched up. I was having a bit of a time finding rocker adjustments in the manual but I'll go snoop through it a little more thorough again.

If you're using the Honda service manual from here, it's starts on page 3-5.

[Dirtcrasher]

Man, I love ya and I try to help but sometimes I'm here shaking my head?? I feel like HOW..... HOW..... HOW...... Could you possibly have read a shop manual or ANYTHING and have these issues??

NOTE TO EVERYONE - PUT YOUR SHOP MANUALS IN THE BATHROOM AND READ EVERY PAGE TIME AND TIME AGAIN (WHILE YOUR DROP A LOAF) BEFORE YOU EVEN TRY TO CHANGE A SPARK PLUG!!!!!!!!!!!


I mean how far out of whack was it that a exhaust valve was hitting unless it was not in time?? Those flywheels DO NOT show you that "T" very easy and allot of guys mistake other machining marks for that "T". It doesn't take much to bend that valve either..... (lets hope thats NOT the next post )

Honest FK the T, I don't even use it. It's easy to get to TDC, easy to point lobes away from the rocker arms and set them perfectly horizontal, then it's all gravy.

And always turn them over with no plug or decomp cable installed and turn that puppy as gently and slowly as you can.....

I really feel like some of you guys have no issue dropping 500$ but just hate to read or double check things........

Furthermore (still trying to be nice here ) - How can anyone expect valve adjustments after things are dicked with to remain even close? It should be and IF IT'S NOT, common knowledge to begin with those adjusters all the way backed out so an issue like this does not happen.

And see, once again I'm a JERK

[Hoosier_Daddy]

Man, I love ya and I try to help but sometimes I'm here shaking my head?? I feel like HOW..... HOW..... HOW...... Could you possibly have read a shop manual or ANYTHING and have these issues??

NOTE TO EVERYONE - PUT YOUR SHOP MANUALS IN THE BATHROOM AND READ EVERY PAGE TIME AND TIME AGAIN (WHILE YOUR DROP A LOAF) BEFORE YOU EVEN TRY TO CHANGE A SPARK PLUG!!!!!!!!!!!


I mean how far out of whack was it that a exhaust valve was hitting unless it was not in time?? Those flywheels DO NOT show you that "T" very easy and allot of guys mistake other machining marks for that "T". It doesn't take much to bend that valve either..... (lets hope thats NOT the next post )

Honest FK the T, I don't even use it. It's easy to get to TDC, easy to point lobes away from the rocker arms and set them perfectly horizontal, then it's all gravy.

And always turn them over with no plug or decomp cable installed and turn that puppy as gently and slowly as you can.....

I really feel like some of you guys have no issue dropping 500$ but just hate to read or double check things........

Furthermore (still trying to be nice here ) - How can anyone expect valve adjustments after things are dicked with to remain even close? It should be and IF IT'S NOT, common knowledge to begin with those adjusters all the way backed out so an issue like this does not happen.

And see, once again I'm a JERK

Well, here is the thing. I went by the manual exactly. It told me to match the t on the flywheel with the mark on the case. Did it. Then it said make sure the dot on the timing sprocket was on the top. Did it. Then it said make sure the cam lobes were facing down. Did it. Then it said make sure the marks on the cam sprocket match the machine part of the head. Did it. So what exactly did I miss? I don't think i could follow the instructions any better then that.

[racerxxx]

TDC GAUGE

http://www.microtouchinc.com/html/tdc_dial.html

Probably won't fit but you can look for something like this, I think I saw somewhere an extended version. Or the old stand by:

http://en.wikipedia.org/wiki/Drinking_straw



Just for SH!ts and Giggs did you happen to sit the orig piston next to the wiesco piston to check heights?? Specficaly wrist pin center to top of piston? I'm pretty anal when it come to crap like that, I never trust anyone!!!! Bombardier Rotax 2 strokes actually have different base gasket thicknesses for adjustments. Not saying your base gasket could be a different thickness, but once again I trust no one. I agree with DC on leave the valves loose and turn over super slow. I also didn't think that these were interference motors, that if the cam chain breaks the piston would slap the valves?? Makes me wonder about the piston height????? Oh yeah, did you put new valves in?? was the Overall length checked?? Ya never know??? Just throwing some ideas out there for ya.

[Hoosier_Daddy]

TDC GAUGE

http://www.microtouchinc.com/html/tdc_dial.html

Probably won't fit but you can look for something like this, I think I saw somewhere an extended version. Or the old stand by:

http://en.wikipedia.org/wiki/Drinking_straw



Just for SH!ts and Giggs did you happen to sit the orig piston next to the wiesco piston to check heights?? Specficaly wrist pin center to top of piston? I'm pretty anal when it come to crap like that, I never trust anyone!!!! Bombardier Rotax 2 strokes actually have different base gasket thicknesses for adjustments. Not saying your base gasket could be a different thickness, but once again I trust no one. I agree with DC on leave the valves loose and turn over super slow. I also didn't think that these were interference motors, that if the cam chain breaks the piston would slap the valves?? Makes me wonder about the piston height????? Oh yeah, did you put new valves in?? was the Overall length checked?? Ya never know??? Just throwing some ideas out there for ya.

Problem I ran into is, I did nothing more then put new rings on and new gaskets and that's all i did. the cylinder was in good shape and measureed within spec everywhere and the piston was withing spec and i just honed the cylinder and re-ringed it. I laped the valves and added new valve seals. So you can understand my surprise whn the valves seemed to be bottoming out after it ran fine beofre disassemply. You have me thinking though with you statement about the base gasket. I put a new one on. Is it possible the new base gasket is thinner? I'm kind of pinpointing that as the problem. I really don't want to tear that whole thing apart again to put on another bas gasket either. PITA!

[Hoosier_Daddy]

The Hondas shop manuals tee-totally suck in a lot of areas.
Lay out, simplicity in following. Heck Clymers manuals correct Honda's shop manuals several times in different machines.
Okay, if you sat in a Honda schooling class room and was told to "note" chapter 6 (6.6 to be exact for the readers digest version of saving me typing, it says to take it apart.
Skip all that crap about taking the valves out because most folk don't have a clue or the tools or the thought that may be causing the smoking in the first place (quite often is IMO but rings will solve that ` right O chap - what ever)
Anyway, skipping up to 6 dash 14 the Honda factory manual gives you a some what start to re-assembly. Some what.
In the 3 following pages it gives the "tech" (ya right) precise info as to how to clean the cam chain tension er and in the last page of "cylinder head/valves the torque values of the bolts.
No where in that chapter do it mention a darn thing about TDC, how to find it,.
yep, GET a manual, READ it,, yep you betcha ya.

get a clymer for the layman's info because ya know what Honda shop manuals ain't so good for the week end warrior.
If you are like me, broke enough stuff, asked enough questions ya kinda know about the parts that are NOT wrote in the assembly chapter.

john

The advice you gave my over the phone seems to have worked well, John. I think i have it set up now. We'll see for sure when I get to fire it up, but I think i got it with your advice. Thanks.

[Dirtcrasher]

So, what was wrong?? what was binding up??

[Hoosier_Daddy]

So, what was wrong?? what was binding up??

I would turn it over slowly by hand and when the exhaust valves would open, the piston seemed to hit them and I just couldn't crank it any farther. I never put a lot of pressure on it. When i backed off the valves, it stopped doing it. Strange, huh?

[Dirtcrasher]

IDK why this even came apart to start with etc etc, I'm sure it's in another post.

Not necessarily strange at all. As an example:

Lets say a motor ran buyt someone wanted to freshen it up. The cam was worn but the rockers were adjusted to .003 cold and someone tore it down and replaced some parts. Now with parts in spec, the previous adjustment would be far too much for the fresh cam and would push the EX and or IN valve a bit further and could create a problem.

You still didn't say what John told you to do? but I'm assuming he said to back off the rocker adjustments, put it at TDC and start fresh. I wasn't blowing smoke about the "T" and "F" on those flywheels, they really can be very hard to see. The cam is a piece of cake and even if it were installed lobes UP, it would not harm anything. BUT, it would put the pickup magnet on the flywheel 180 degrees out and it wouldn't run because the ignition timing would be 180 degrees off. But, it wouldn't bend valves as 4 strokes have 2 TDC cycles either firing or just finishing releasing exhaust gas and starting the intake cycle all over again.

I usually help guys for very little cash or beer or whatever, so I ask them to do the simple stuff which I double check. Many times the guys miss that timing mark and sometimes I'll yank the engine cover and take a dremel to that "T" and form a line that is easily seen. Missing the "T" by a given amount of degrees can and will bend things.

If you merely changed the piston - (again, I forget the exact details) then even the previous rocker adjustment should not have caused parts to interfere. So, to me, something else got messed with, replaced or was done wrong.

Don't rule out the decompression setup as it's job is to hold OPEN the exhaust valve just a bit when your kicking it at the top of the kicker stroke. Did the clutch cover come off? Was the cable adjustment changed? You had to take it off to get the valve cover off so is this possibly the problem?? I'd imagine that if the cam in the clutch cover were way off that it could cause an issue when kicking it over?? Again, the 350X has punch marks and can be screwed up, the 200X has a flat that only goes one way. I'm not sure why they didn't make the 350X dummy proof, but I've even seen the 86/87 200X motor done wrong and they had to beat the chit out of the cam to put it on wrong but they SUCCEEDED!!!

Also, there is a long pin in the head that holds that decompression shaft in the correct place. If it isn't in there or something else is dicked with, it can and will hold the exhaust valve open and cause an interference issue. Without the right pin, the decomp lever pushes inwards and the larger diameter surface contacts the rocker arm instead of the half cam itself.

None of these manuals explain everything and I myself have become a victim during my learning curve days Believe me, I have made and still make mistakes all the time. But, after doing a hundred topends you usually figure out whats basic and don't forget it. Thats why since I was a kid, I picked up junk stuff at the dump and took it all apart just to see how stuff works. Like the time I was 8yo and dads CB didn't work so I cut out every resistor trying to be an electrical repair man Boy did I get BEAT for that one, LMFAO!!!!!!!!!!!!!!