66cc raw motor head,traded out slant head for stock after torching top of piston,having problem with gasket not sealing.I have ran her hot and tightened,a few times over and still no luck.Anyone got a start to finish approach to seating gasket? Thanks
Head gasket,head ache
- Thread starter Skyline
- Start date
Remove the cylinder head, lay a sheet of 320 grit sandpaper on a known flat surface such as a piece of glass and rub the head over the sandpaper. You will easily see if the sealing surface is flat. The sandpaper will show high or low spots. You can do the same with the cylinder. be careful and don't sand in an angle. Rotate the part while sanding so you keep things flat.
Torque the cylinder head nuts down to about 110 to 120 inch pounds, run the engine until it reaches operating temperature a couple of times then recheck the torque. Don't try to get a turn on the wrench/socket, just make sure you're still at that 110 to 120 inch pound torque then go enjoy the ride.
Tom
Edit: If you're using the kit supplied acorn nuts on the cylinder head throw them away and replace them with shouldered hex nuts. Use flat and lock washers under them. No thread locker (Loctite) necessary.
Torque the cylinder head nuts down to about 110 to 120 inch pounds, run the engine until it reaches operating temperature a couple of times then recheck the torque. Don't try to get a turn on the wrench/socket, just make sure you're still at that 110 to 120 inch pound torque then go enjoy the ride.
Tom
Edit: If you're using the kit supplied acorn nuts on the cylinder head throw them away and replace them with shouldered hex nuts. Use flat and lock washers under them. No thread locker (Loctite) necessary.
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Thanks for the tip,I am out of town this week,but I will try friday afternoon.My wrench is in ft.lbs I usually tighten to 15lbs?
Is 10 ft lbs enough? I was trying to check other threads and I'm reading between 12-17ft Lbs?when the head is properly tightened,does the raised center circle in head compress into gadget?
I mill ALL my heads before installing them. Have never had a blown gasket after milling the head. I also trash ALL Chinese supplied studs and nuts they are about a grade 3, I replace (8mm and 6mm) with grade 8.8 which is equivalent to a US grade 5. I torque 6mm from 60 to 70 inch pounds. 8mm I torque to 150 to 175 inch pounds. These cast aluminum cases can withstand a MAX torque of 200 inch pounds for 8mm. Oh I install locking nuts along with the studs. And I've never had to re torque..checked but didn't have to.
When I torque a head I begin with a ratchet and take the bolts down to where I start to feel resistance and stop and go to the torque wrench and cross torque to 2/3 of the specified amount then set the wrench to the full torque amount and go back through the cross torque again to pull them to where they are suppose to be.
If a head is properly trued as Tom told you 120 is enough to seal it.. You might have to retorque after it is heated up though. and maybe a couple of times. Too much torque will over compress the base gasket and in some cases cause the piston to hit the head.
If a head is properly trued as Tom told you 120 is enough to seal it.. You might have to retorque after it is heated up though. and maybe a couple of times. Too much torque will over compress the base gasket and in some cases cause the piston to hit the head.
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Thanks guys for the help.I noticed sbp has upgraded stud kits.I will try to tame her again Friday afternoon.
Hey al,when you say you mill your own heads does this mean you are lightly sanding or are you sanding off the small circular lip on bottom of head.email me again I lost your contact info,well breaks over ,check back this evening..
Lightly sand or if more compression is your goal then yes, take off that ring. Another helpful hint is to use Permatex Copper Spray-a-Gasket. Use some form of a "Z" or "X" pattern when torqueing. This helps to keep tension even.
The first motor I got leaked above the exhaust port, black crap running all over the motor. Did all the steps and no more leak
The first motor I got leaked above the exhaust port, black crap running all over the motor. Did all the steps and no more leak
Well sanded head and jug installed, no leaks,presure tested at 120, now wet black oil filled plug.Re jetted all the way down from 68 to 62,still wet with oil. Died now and won't start, checked for spark,very weak.will change magneto this weekend.Are all magnetos the same(universal)?
skyline try drainng your gas and putting it back in the container and shaking it up to redistribute the oil mix and change out the plug.
That sounds like too much jet. The most I ever have to go is a size or two above or below stock.
Try going back to a 'closer to stock' jet.
Found out why it would not start, found jet laying in float bowl. Went back to one smaller jet than stock(68mm) starts great runs decent gets to 32mp. Checked plug and seems lean,white insulator whith a black oil spot (dark black burn) on one side of insulator.still running slant head, black area is towards piston.I'm getting a rich oil smell ( trail) when I'm riding, I'm sure it's getting enough oil,red line 32/1. Also I have changed the gas, not sure were to go next???
