Can I reuse my head gasket? By rscotth (Read 10,402 times)

[rscotth]

The head gasket looks to be a thin sheet of metal and appears to be in good shape. I've seen people reuse the head gaskets on other small engines but is that an accepted practice on the gy6?
Thanks
RSH

[Bashan]

Nope, sorry RSH, a few guys have tried that and it flamed out every time. I know they look like they can be reused but for some reason they're toast once you torque them down. I think they get stretched somehow and lose their mrrphglubmumblecrap after that. Anybody have any insight other than that on this? Rich

[sprocket]

Replace the gasket always.. and coat both sides with copper spray...follow the directions that come with the spray...

[rscotth]

Excellent- thanks guys!

[Kaveman]

Just wondering : can reusing the same head gasket cause an engine to idle rough ?
will c.
;D A mechanics last tool of choice if things still don't work right : C4 !!

[sprocket]

If it is leaking it sure will...

[jhbietz]

I'm haven't tried it on a 150 but have reused head gaskets many times on the 50cc engines. Always clean everything spotless and remove any oil film with break cleaner. I then coat both sides of the gasket with copper coat.

[rscotth]

Since my scooter has been down way too long and my gasket set is on backorder I decided to reuse the head gasket since it looked to be in good condition.

That Permatex copper spray-a-gasket is great stuff. I did a 100 mile shakedown today and it's running well. Oh yea- I am running about a whole point higher on compression as well. Should be around 9.8-1 now and the starter has no problems starting even when hot.

[jhbietz]

Keep us posted. I have no ida if its going to hold long term on a 150. I have had excellent results using copper cote though so who knows it may be ok.

[rscotth]

After my ride toay I am feeling real good about it. Don't the 50cc engines run fairly high compression ratios? I have seen literature stating they are in the range of 11.5 - 1 so maybe I'll luck out.

I wish ARP made head studs for the GY6.............................

Regards
RSH

[rscotth]

Update: everything is back together and I adjusted the valves and put about 100 miles on it. It accelerates ok... goes right to 6500 rpm which is in the sweet spot BUT once it gets to 7K it takes a LONG LONG time to almost but not quite get to 8K. I'm talking like a mile in a full ninja tuck and if there is a head wind give it up.
So.........................is this sounding like the head gasket? My gasket set is still on backorder so i still can't change it but it sure is suspect. Especially since I should be about a whole point hight on compression.

Any other ideas- maybe valves?

[jhbietz]

Did you put a new head on or just reinstall the original one? Sure wouldn't be a bad ida to check the valve clearance. On a new head I like to lap the valves just to be safe.

[rscotth]

It is a new head and I also lapped the valves as well! I like the way you think. Also cleaned up the bowl area and port flashing and had .025" decked off.

I was real busy today but I'm gonna go back in and check valve clearance again since I have about 100 miles on it.

Ever heard of valve regression? Kinda a new concept for me but it does make sense. Especially on a new unseasoned head.

[jhbietz]

It can sure happen. When I do a big bore kit for a customer I always end up adjusting the valves again after breaking in the engine. They all seam to tighten up for some reason.

[rscotth]

Exhaust valve measured .003 so I opened it up to .005 for comparison. Intake was still at .004 so I didn't touch it. No difference, seems to rev fine to 6500 rpm and idles well and starts good but won't hardly rev past 7K. Even switched out the cdi box to eliminate that.

I can hit 7K a little over 3/4 throttle the last bit seems to do nothing with a max speed of 56.9 mph (Garmin 60CSX).

Sound like fuel delivery- carb?