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Post by byseacall on Jan 18, 2013 21:15:39 GMT -5
I have a 150cc scoot with 7500 miles on it, stock. I've never done the valve adjustment on it. I want to get this done since I'm feeling a little loss of power. The manual says intake 0.12 and outtake 0.12 (in cold states) Everywhere I've looked they say .04 for both. Am I missing something here? 0.12 is almost and 1/8 of an inch. Typo maybe?
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Post by qwertydude on Jan 18, 2013 23:42:32 GMT -5
.12 would be in millimeters. That's about .005 inches. Perfectly acceptable settings but I'd say a little loose for intake which can be in the .003-.004 range without much risk.
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Post by byseacall on Jan 19, 2013 0:21:49 GMT -5
Thanks, that makes sense. Forgot about the mm and the US standard.
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Post by Deleted on Jan 19, 2013 2:48:56 GMT -5
I would CHECK the valve lash before loosening anything and if it's even close to specification I would leave it alone, these engines are VERY delicate, they are PURE aluminum and it takes VERY LITTLE effort to strip a nut or bolt!
But the worst part is, when the bolt hole inside the case itself strips.
And it's not hard to do, I've stripped more than a few to date.
So...
You will NEED a torque wrench for EVERY single nut or bolt you tighten!
Might as well not even use a regular socket wrench at all.
The good news is you can do most with 1 of 2 torque settings.
But if you want to be sure your engine is fit after the repair, I HIGHLY recommend it.
Valve cover bolts> 8 ft.lbs.
Intake manifold nuts> 8 ft.lbs.
Oh yeah I got it memorized.
Most non-critical bolts and nuts take 8 ft.lbs, that includes the transmission cover.
The other setting is 17 ft.lbs., things such as the cylinder head valve train nuts.
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Post by Blueboy5000 on Jan 19, 2013 7:10:03 GMT -5
I would CHECK the valve lash before loosening anything and if it's even close to specification I would leave it alone, these engines are VERY delicate, they are PURE aluminum and it takes VERY LITTLE effort to strip a nut or bolt! But the worst part is, when the bolt hole inside the case itself strips. And it's not hard to do, I've stripped more than a few to date. So... You will NEED a torque wrench for EVERY single nut or bolt you tighten! Might as well not even use a regular socket wrench at all. The good news is you can do most with 1 of 2 torque settings. But if you want to be sure your engine is fit after the repair, I HIGHLY recommend it. Valve cover bolts> 8 ft.lbs. Intake manifold nuts> 8 ft.lbs. Oh yeah I got it memorized. Most non-critical bolts and nuts take 8 ft.lbs, that includes the transmission cover. The other setting is 17 ft.lbs., things such as the cylinder head valve train nuts. Just go ahead and adjust them. Don't be afraid, as the valves require regular adjustment. A valve adjustment is about one of the easiest parts of gy6 maintenance. I never check the valves before I adjust them, because what would be the point? I used to check them, but each time I was suspicious that they might need to be adjusted, they certainly did. Just remember to make sure the rocker nuts are good and tight, as a loose rocker nut can come off and ruin your valves/cam. Adjust only when the bike is FULLY COLD. Adjust to .004" intake and .005" exhaust and you'll be fine. |
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Post by Blueboy5000 on Jan 19, 2013 7:13:43 GMT -5
I also agree that you should use a torque wrench on every bolt/nut. I usually don't, but I've been an automotive technician for 18 years, and am really good at 'feeling' torque. I do not recommend an inexperienced person try to 'feel' torque, just use a torque wrench. But I would torque rocker nuts to 25lbs/ft and no less! The rocker nuts are probably the most critical nuts when it comes to being tight.
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Post by snugglebunny on Jan 19, 2013 9:12:22 GMT -5
BE VERY CAREFUL ON YOUR VALVE COVER BOLTS
i dont use a torque wrench either except on critical bolts
in 2 different adjustments, i stripped 2 different bolts.
theres no way in heck they were at 8ft lbs yet.
but all 5"1' 130 lb weak as& woman, me, stripped 'em
i think i lined 'em up just a hair off, so thats what stripped 'em
and if you do that, well then its FUN time
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Post by Deleted on Jan 19, 2013 12:19:44 GMT -5
Actually... I wouldn't adjust the valves unless you are sure it needs it, the gy6 engine can run different from one day to the next and it may have nothing to do with nothing, maybe you're low on power and maybe you're not but I still wouldn't fix it unless it's broken and be glad you got as many miles as you do. That's how they used to tell us when engines first came out, you won't hear this advice much because it comes around before everybody who gets a hold of one comes around with their sage advice with things such as... Just go ahead and adjust them. Don't be afraid, as the valves require regular adjustment. A valve adjustment is about one of the easiest parts of gy6 maintenance. I never check the valves before I adjust them, because what would be the point? I used to check them, but each time I was suspicious that they might need to be adjusted, they certainly did. Just remember to make sure the rocker nuts are good and tight, as a loose rocker nut can come off and ruin your valves/cam. You do it however you want but a new GY6 is almost $400. Trust me, I know. These young whippersnappers think it's as easy as 1-2-3 throw the old piston out by the workbench and slap the crankshaft near the stroker and plop and drop and voila there you go. Yeah, right. I also agree that you should use a torque wrench on every bolt/nut. I usually don't, but I've been an automotive technician for 18 years, and am really good at 'feeling' torque. I do not recommend an inexperienced person try to 'feel' torque, just use a torque wrench. But I would torque rocker nuts to 25lbs/ft and no less! The rocker nuts are probably the most critical nuts when it comes to being tight. Are you sure you are who you say you are, and not some kind of troll? You don't strike me as a very experienced or responsible individual, young perhaps. What you suggest is very likely to cause severe internal engine damage. Even as a 24-7 auto-mechanic I would not feel torque, ever. Why would you recommend such things? Rocker nuts are 17 ft.lbs and I wouldn't go a hair over 20 and that is only if you need extra torque due to power options to keep the head gasket from blowing out. The reason is that around 22 foot pounds the studs that go all the way through the head and the lower portion will start to twist and bend, and at 25 foot pounds you're asking for critical damage to occur. You'll end up with a repair bill somewhere in the $50 to $100 just in parts. Then, after you get it all back together, you still have to hope it runs. No sir. Unless that engine's ticking or all the power is gone and you've checked everything else? I wouldn't touch the valves. |
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Post by qwertydude on Jan 19, 2013 15:01:12 GMT -5
The valves are almost always the first thing you check. The reason you check them often and adjust them is once you let the valves get too tight that it starts being hard to start you've already done valve seat damage.
The hot gasses that seep through the loose valve seats not only overheat the valve, remember exhaust valves are cooled almost entirely by contact with the valve seat so a tight valve means in actuality minimal valve seat contact and an overheated exhaust valve,. That heat and gas corrodes the seat surface. So even with an adjustment you have a rough valve seat. This will serve to wear the seat surface quicker.
This means the valves will recede faster the next time around.
So the best thing to do is check the valve lash often and adjust before it becomes absolutely necessary. When you get past break in valves will recede at a predictable rate. But if you let it become hard to start then you'll adjust it and find out soon you need to adjust it again because it becomes hard to start again. Keep doing this and that's what makes valves fail early.
Whereas regular valve lash checks and adjustment will prevent the hard starts and early valve recession problems in the first place.
So if you don't want to buy a new engine or a new head for big money why wouldn't you check valves? It's completely free to do, costs nothing.
And who was talking about tightening the head bolts that holds the rockers? you do that one time on installation and maybe retorque it during the first valve adjustment, after that no more don't touch the head bolts.
The only adjustment necessary are the tappets.
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Post by Deleted on Jan 19, 2013 18:41:59 GMT -5
If the top of the engine were openly available and it wasn't so effing difficult to get the feeler gauge in there (especially the exhaust valve), along with some other issues... First you have to use two wrenches in very close proximity, I've actually gotten to hold the bolt with needle nose grips while I tighten the nut, but it's such a tight close fit, it doesn't take much, one little movement the wrong way and the adjustment is off.
However, that post brings up some good points.
I can see checking them, regularly.
But the guy's gone 7,500 miles stock never done it.
Maybe I would have gotten 7,500 out of mine if I had just left it alone.
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Post by snugglebunny on Jan 19, 2013 19:12:17 GMT -5
when i did my 1st one
i was scared to death id screw something up
'member now im not a mech at all,
put gas in the one hole, check oil, when i 'membered to
etc
im a woman
the 1st time i had my laptop out side, pausing, checking etc.
took a hour.
now that ive done about 5
the thing that take the longest is getting the plastics off
once i get that all outa the way and loosen my floorboard back 2 bolts
so i can lean it outa the way?
10 mins i can check and re-do any adjustment i have to make.
just always gotta make sure you tighten the 'tappets' (i think they are called) w/o letting the other piece slip.
and before you put ALL the freaking plastic back on,
put the flywheel cover , valve cover etc all back on.
start the engine and listen for tapping.
if none, put plastics back on
if so you saved yourself some time
JUST ALWAYS 'MEMBER
stone dead cold engine
both timing marks (w/e they are called) on cam sproket and by flywheel , lined up and its cake
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Post by byseacall on Jan 19, 2013 22:28:00 GMT -5
Hey, thanks everyone. Very informative indeed. I should get this done anyway because of the mileage on the bike. I will do the 4 and 5 setup. The reason of me doing this is because as I've read here it needs to be done frequently, at least to check them, and because when at a red light scooter takes off fine but there is a mid range there that it seems that it hangs in limbo and then it slowly starts to pick up speed again. I do also have a set of rollers to put on cause they've never been changed.
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Post by Blueboy5000 on Jan 20, 2013 7:17:22 GMT -5
Actually... I wouldn't adjust the valves unless you are sure it needs it, the gy6 engine can run different from one day to the next and it may have nothing to do with nothing, maybe you're low on power and maybe you're not but I still wouldn't fix it unless it's broken and be glad you got as many miles as you do. That's how they used to tell us when engines first came out, you won't hear this advice much because it comes around before everybody who gets a hold of one comes around with their sage advice with things such as... Just go ahead and adjust them. Don't be afraid, as the valves require regular adjustment. A valve adjustment is about one of the easiest parts of gy6 maintenance. I never check the valves before I adjust them, because what would be the point? I used to check them, but each time I was suspicious that they might need to be adjusted, they certainly did. Just remember to make sure the rocker nuts are good and tight, as a loose rocker nut can come off and ruin your valves/cam. You do it however you want but a new GY6 is almost $400. Trust me, I know. These young whippersnappers think it's as easy as 1-2-3 throw the old piston out by the workbench and slap the crankshaft near the stroker and plop and drop and voila there you go. Yeah, right. I also agree that you should use a torque wrench on every bolt/nut. I usually don't, but I've been an automotive technician for 18 years, and am really good at 'feeling' torque. I do not recommend an inexperienced person try to 'feel' torque, just use a torque wrench. But I would torque rocker nuts to 25lbs/ft and no less! The rocker nuts are probably the most critical nuts when it comes to being tight. Are you sure you are who you say you are, and not some kind of troll? You don't strike me as a very experienced or responsible individual, young perhaps. What you suggest is very likely to cause severe internal engine damage. Even as a 24-7 auto-mechanic I would not feel torque, ever. Why would you recommend such things? Rocker nuts are 17 ft.lbs and I wouldn't go a hair over 20 and that is only if you need extra torque due to power options to keep the head gasket from blowing out. The reason is that around 22 foot pounds the studs that go all the way through the head and the lower portion will start to twist and bend, and at 25 foot pounds you're asking for critical damage to occur. You'll end up with a repair bill somewhere in the $50 to $100 just in parts. Then, after you get it all back together, you still have to hope it runs. No sir. Unless that engine's ticking or all the power is gone and you've checked everything else? I wouldn't touch the valves. You know what? F*** you buddy. I own SEVEN gy6 bikes. Yes adjust the rockers to 25 ft/lbs tightness or sling a rocker nut off while running and destroy you engine. I'm not a troll, but you are jerk, I come on here and tell people the right way to do this, only to have you tell me I don't know what I'm doing. Well my bikes are all running, and running excellent I might add. At first I was not going to tell you to go f*** yourself, but I figured, why not? You deserve it you ignorant moron. 17 years is along time to be professional mechanic, you learn a thing a two, like how to properly tighten a bolt. Notice I did not say not to use a torque wrench, I said that I usually don't. I spent 15 years as a transmission rebuilder, so I know a thing or two about torque. In conclusion: up yours! |
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Post by byseacall on Jan 23, 2013 23:46:14 GMT -5
OK.
Aside from all the bitching, I do have another questions and since it is my post, if you guys want to make a date and settle this go ahead, but this is not helping ME. sh!t!!
Anyway, If everything is tight and gaped correctly at factory, hopefully, why do they get tighter?
Shouldn't they get looser?
I took everything apart and put it in position and there was no gap. Loosen and set everything and it still runs good. Not a big improvement though. So I'm thinking, from wear wouldn't things get looser?
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Post by MEAN_MOTOFINO on Jan 23, 2013 23:50:50 GMT -5
I adjust both to .004" on my 150's and have never had a problem.
Yours Truly,
House of Scoot
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Post by yosemite on Jan 24, 2013 0:00:32 GMT -5
OK. Aside from all the bitching, I do have another questions and since it is my post, if you guys want to make a date and settle this go ahead, but this is not helping ME. sh!t!! Anyway, If everything is tight and gaped correctly at factory, hopefully, why do they get tighter? Shouldn't they get looser? I took everything apart and put it in position and there was no gap. Loosen and set everything and it still runs good. Not a big improvement though. So I'm thinking, from wear wouldn't things get looser? The reason they get tighter is of the poor head metal quality as well as the valve itself. What happens is as the valves are banging open and closed the metal in the head starts to compress and or the valve head itself and that makes the gap go to nothing. Now the Valve is seating deeper in the head, the rockers and studs didn't change just that now the Valve stem was moved up toward the Rocker Adjustment stud. Hope that explains why they get tight and not loose. Sam |
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