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Post by natedoggaz on May 5, 2013 17:33:11 GMT -5
Hello, Many of you have seen the issues I experienced in one of my past posts.. So I replaced the head gasket, and low and behold it "tried" to start. Sputtering, backfiring, and turning over ever so briefly. It did not want to take gas at times, and I was able to ride it about 100 yards until it stopped on me and I had to push it back to my house... Sometimes it ran for a few seconds, then it died and did not want to start again. I also replaced the exhaust gasket as seen below. I could hear and feel exhaust air coming from somewhere - like it was not all going through the pipe... Almost like there was a leak somewhere, but the 2 bolts were nice and tight into the head. I am starting to think that the head could be warped, but would like other opinions as to what may be going on here. I can feel and hear air escaping from somewhere around the gasket - but it is on very tight! Here is the gasket I am using:  Brand new head gasket - almost burned up!  Gasket totally warped!  Major exhaust/carbon buildup on the bottom of the head:  Burn marks all over the cylinder and on the lower left corner, as well as around the cylinder:  Burn marks and charring on the exhaust outlet:  It looks like it has been driven for 100's of miles instead of 100 yards. I have tried to start it quite a few times, but still a lot of wear. It was cleaned up to the best of my ability when I took it off the first time. Here was the "before" picture when I took it off the first time:  I made marks with a marker on the cam and timing chain before I took it off and put it back EXACTLY in the same spot. What is causing this? Is it a warped head - or something else?? Thanks! ND |
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Post by tvnacman on May 5, 2013 17:41:12 GMT -5
nate , do you own a tork wrench ?
John
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Post by natedoggaz on May 5, 2013 17:44:43 GMT -5
Hello - Yes, I do have one..
One of the lower end 1/2" wrenches from HF.
It works, but not sure on its accuracy?
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Post by cytoruck on May 5, 2013 19:47:56 GMT -5
i used a harbor freight torque wrench and i set everything to 10lbs more, to check if a head is warped you measure the distance between the corners of the bolt holes crossing and they should be the same, measure upper left to lower right and upper right to lower left if the distance is off, it COULD be warped, its hard to tell with smaller heads
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Post by justbuggin2 on May 5, 2013 21:22:52 GMT -5
if the alignment pin are not all the way in can cause the head not to seal and to check the head for warpness use a straight edge and feeler gauge place the straight edge on the head and see if you can slide a feeler gauge under it do this in all directions
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Post by jeepsteve92xj on May 5, 2013 21:34:32 GMT -5
I took my Harborfreight torque wrench to work and checked 3 or 4 settings and according to the calibration equipment, the cheap wrench was right on.
I'd also check the alignment pins...
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Post by onewheeldrive on May 6, 2013 0:28:29 GMT -5
I'll tell you what I'd do just out of frustration (I've read your last 2 threads). As much as I would want to tell you to: recheck torque---what did you torque all bolts to(criss cross pattern?), make sure you didn't torque the cylinder bolts all the way down before putting the head on...etc...etc. My final answer is just get a whole top end including the head. Not sure what else I have to add. I mean if I did exactly what you say you did from what you post, then I'd just get it over with, enough bs.  Someone else can chime in on that, as I'm no professional. Obviously something is wrong there somewhere---either you are missing something or you're not. Last, and I MEAN LAST resort, is just buy a new engine---but to me that seems like a waste of money. Edit: Nothing you've said up until points to anything in the crankcase. I'd be taking the cylinder off---what else besides the rings and a jacked/warped head. You said the dude that you got it off of did some "repair" work, maybe it wasn't the greatest job. The thing is, you may rip the base gasket while doing that(removing the cylinder)---the gasket between the bottom of the cylinder and the crankcase. Another gasket you'll need to replace. |
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Post by natedoggaz on May 6, 2013 15:58:49 GMT -5
Thanks for your input and advice onewheel and the rest!
It may ultimately come to purchasing a whole new cylinder and head kit...
I do want to try one more time though - although I will need a new head gasket first probably - URGH!
Does anyone have the torque specs for the head (the 4 in the middle and 2 on the side) and I will put it back together. Also the torque for the 2 exhaust bolts.
I did tighten it via the criss-cross method, so I don't think that I was responsible for warping it - if in fact it is warped. I will check it today with a straight edge and see if it is bent in any way.
Thank you!
ND
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Post by natedoggaz on May 9, 2013 17:43:10 GMT -5
My new head gasket should arrive any day...
Now, what can I use or do to ensure I have clean and debris free surfaces so the gasket has no gaps and nothing can escape around it?
Also, can someone pleas provide the torque specs for the 6 bolts?
...and which I should tighten first (the 2 long side bolts or the 4 main head bolts...
Thanks!
ND
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Post by urbanmadness on May 9, 2013 20:02:29 GMT -5
26 ft lbs seems to be what I've seen on the 150's. I do 20 in a criss cross pattern then do them again to 26. I'd just get a head for it. On a 150 they are cheap... scrappy has em for like 50 bucks and it sure beats pulling the engine out again to change a head. Your time has to be worth something... right?
On the exhaust, I've always just snugg em down evenly with a new gasket and make sure you aren't hanging the exhaust off just the studs.
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Post by devo344a on May 9, 2013 22:58:06 GMT -5
On my exaust I always put the red silicone a little bead around and i have never had an exaust leak
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Post by ramblinman on May 10, 2013 6:10:50 GMT -5
ok, i am basically a noob when it comes to engine repair so perhaps someone with more knowledge can confirm or deny my thoughts.
the 5th and 7th pic are of the piston, correct? is it normal to have that much carbon build up?
i saw a vid the other day with similar problem and a small piece of the carbon eventually broke off and tore up the cylinder.
it looks like a slightly smaller piece has broke off in your pics which could have damaged the cylinder.
here is the vid so you can see for yourself. it's not a scooter engine:
he also mentions the oil ring was jammed in tight which may have been the reason his engine was burning oil.
but like i said, i don't know anything so get a second opinion.
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Post by natedoggaz on May 13, 2013 3:32:46 GMT -5
When I took the valve cover off the 2nd time (after the new gasket went in) I did notice that there was 1-2 small black pieces stuck on the inside. It looked kinda like ash so I pulled them out.
They were pretty small - so I don't think they caused any damage.
Does anyone know what I can use to clean those parts up?
Going to try 1 more time before I get a new head with a new gasket.
Thanks!
ND
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