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Post by chink on Dec 6, 2012 14:15:11 GMT -5
Hi everyone, my new Naraku cylinder head is on its way from Germany to me and as I have never changed a head on a scooter I really need your expert advice here. I have done this numerous times on cars but from what I can make of my scoot is that the engine will need to be removed due to the frame going over the engine by the carb hence restricting the head being lifted off whilst on the scoot. Also I need to know the correct procedure for removing the engine too as from I have seen and read appear to be very conflicting. I would like to full of knowledge before I even attempt this job so all help is greatly appreciated even if its a tiny contribution. My scoot is a 125cc gy6, thanks people
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Post by scootercapecod on Dec 6, 2012 14:23:24 GMT -5
You may not need to remove the engine but you'll surely have to remove the seat bucket, the plastics and the like but yes, unplugging the wiring and taking off a few bolts might save time actually
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Post by Fox on Dec 6, 2012 15:31:10 GMT -5
You can try disconnecting the rear shock(s) and lift the rear wheel up and support it on 2x4 blocks to swing the front of the engine downward to clear that frame tube.
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Post by Scooter Elements on Dec 6, 2012 15:39:00 GMT -5
nah you dont need to. It makes it easier but not required. you will need to remove the bucket storage area under the seat and the front plastics and thats it really. We replaced my cylinder kit and head like that.
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Post by jazzman on Dec 6, 2012 15:39:47 GMT -5
Also check if the Tube going across is bolted on or welded. Some are bolted on and just need to unbolt the tube from both sides to get it out of the way.
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Post by chink on Dec 7, 2012 0:47:17 GMT -5
Plastics are already removed and unbolting the rear shock sounds much simpler than removing and the tubular part is welded not bolted.
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Post by urbanmadness on Dec 7, 2012 11:33:33 GMT -5
Plastics are already removed and unbolting the rear shock sounds much simpler than removing and the tubular part is welded not bolted. If you don't do them every day, I'd say diffidently remove the engine. Remember you have to have enough room to swing wrenches, not just slide the head off and they pull real easy, especially compared to a car and it will save you time in the long run (again unless you do them everyday and know all the tricks) Use a torque wench when you do the head and when you get it back together, pull it thru a few revolutions, very gently in case the valve timing is off. |
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Post by chink on Dec 11, 2012 3:27:48 GMT -5
Head arrived this morning so hopefully will start the swap at the weekend as I'm too busy with work. It looks so tiny when its not attached to the scoot ;D
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Post by rockynv on Dec 11, 2012 4:38:03 GMT -5
It depends on the frame style. On my Lance Vintage the lower front crossmember that the bucket rested on prevented it so it was simpler to disconnect the intake from the engine without removing the carb and hanging it from the frame without disconnecting the carb from the fuel pump or throttle. Then you unplugged the electrical harness, unbolt starter lead and spark plug. Remove the shock absorber(s) lower mount bolt(s) and the rear brake caliper without disconnecting the brake line or if drums brakes the brake cable. If there is a right side swing arm it will have to be removed along with the muffler. Double check for any carb drain line or other electical connectors or ground straps. Remove the one nut off the pivot pin and then the engine will slide right out when you pull the pivot pin with the rear wheel still attached.
Leaving the tire on makes it so you can lightly clamp it in a WorkMate type vise and easily work on it now.
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Post by chink on Dec 11, 2012 10:52:00 GMT -5
I'll put some pics up then you guys will be able to advise me on the best way to do it. Need as much info as possible on this before I start it
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Post by dude on Dec 11, 2012 11:03:26 GMT -5
Be sure to put a rag in the case when you remove the c-clips from the piston.
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Post by chink on Dec 23, 2012 7:05:41 GMT -5
So I have finally found the time around my hectic work schedule to do the swap. Old head is off, new one is in place but nothing tightened down yet as I'm double checking I have done everything correctly and giving everything a nice clean too. It's amazing how much more of an idea you get in regards to the operation of each individual piece when it's in your hands. Anybody know the head bolt torque settings please?
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Post by 50cc on Dec 23, 2012 7:14:07 GMT -5
Around 25 to 35 Nm as I could remember. Just tighten them in a cross pattern and take your time.
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Post by tvnacman on Dec 23, 2012 7:18:59 GMT -5
from the hip I think 12-15ftlbs
double check that number !!!
John
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Post by 50cc on Dec 23, 2012 7:23:09 GMT -5
15ftlbs is 20nm. That's too less. Go for at least 25nm, but not more than 30-35nm
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Post by Deleted on Dec 23, 2012 12:35:36 GMT -5
No but you really ought to google up the procedure because there's more than one part that if you miss doing things a specific way you are likely to incur extra expense and frustration, things such as the timing chain tensioner and the plastic engine shroud... Google it up now.
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Post by chink on Dec 23, 2012 14:26:02 GMT -5
No but you really ought to google up the procedure because there's more than one part that if you miss doing things a specific way you are likely to incur extra expense and frustration, things such as the timing chain tensioner and the plastic engine shroud... Google it up now. Hence the reason I have taken my time installing the new head as I needed as much knowledge as possible |
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Post by Deleted on Dec 24, 2012 9:31:43 GMT -5
Sounds good, there exist only two torque settings on the entire scooter to remember:
17 ft.lbs.
And 8 ft.lbs.
You can, and I would to a point recommend mostly because things strip so dang easy, fix the entire scooter with a torque wrench and those settings.
The head bolts are 17 and if you want a little extra insurance against the next head gasket blowing go with 18.
The exhaust stud nuts are 8 !!!
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Post by rockynv on Dec 24, 2012 21:10:03 GMT -5
Just be extremly carefull with the two fasteners on outside of the timing chain cover. Many will put locktite on them and just lightly snug them with a nut runner screw driver and refrain from putting any kindof wrench on them. I had 2 heads crack in that area when those 2 bolts going from head to block were torqued to spec.
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Post by chink on Dec 25, 2012 4:50:03 GMT -5
Finished the install and it started straight away but now it will not start at all. When I press the ignition button and the engine turns over, I seem to get a very loud bang (like metal on metal) coming from the variator area almost like a bad kick start. Also, when I reinstalled the tensioner I made sure I put it in with the extension part retracted and wound it slowly outwards until it touched the guide and then gave it a tiny bit more so it was in place. Is this correct? Head bolts are at 18 ft. lbs, bolts at the side of the head are at 8 ft lbs, new head gasket, new exhaust studs etc I have made sure I did this correctly but it is demoralizing me. I'm ready to ride this off of a cliff, Please help
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Post by chink on Dec 30, 2012 11:40:05 GMT -5
Had another play with it today, double checked timing and valve clearances and they are perfect. Its now up for sale as a non runner unless I can get it running
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Post by chink on Jan 6, 2013 6:00:22 GMT -5
well I had another tinker yesterday but this time with the fuel system. Took the vacuum line off of the inlet and sucked the tube to see if the fuel was getting to the filter, guess what its not and the filter is EMPTY but there is fuel in the tank. Faulty petcock? You can hear the diaphragm in the petcock moving and bubbles appear in the tank when sucking on the vacuum line! Should the filter fill up easily when sucking the vacuum hose? Would a faulty petcock cause serious sputtering?
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Post by scootnwinn on Jan 6, 2013 6:44:09 GMT -5
Maybe, yes, and yes
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Post by chink on Jan 6, 2013 7:15:15 GMT -5
If I remove the fuel line from the carb it will flow nice and smoothly but put the line back onto the carb and nothing will flow. So I filled the fuel filter with fuel, managed to suck it through to the carb, refilled the filter again, reconnected every and it fired up for about 2 seconds. Blocked carb maybe? I'm inspecting the carb as we speak but focusing on the pilot jet as the main jet is clear, diaphragm isn't torn, float level seems ok and all hoses appear to be good. Anything else I should check?
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