Is this head done for? Pitted dome

[panama]

Hey all,
I don't have a lot of experience with 2 strokes so I'm not sure what to do here.

I just received my GT185 case, cylinders and head back from the blaster. Before sending it off it was loaded with carbon so I hadn't noticed the pitting in the dome.

The right side is perfect but it seems the left has had some damage done to it at some stage in the bikes life.

Is this head still usable and are those pits likely to cause performance issues or cause overheating? If so, is this repairable or am I better of sourcing another head.

Any help would be much appreciated.

Thanks.

head1.jpg

head2.jpg

[CBWELLS]

Just an opinion, but you asked!

I wouldn't worry about it. As long as it seals at the plug & around the top of the jug it'll be alright. Apparently it was working before took it apart, right? Otherwise how did it get carbon deposits?!? I would probably try to smooth out any of those gouges that are raised above the surrounding surfaces. Maybe some sandpaper on an inflated (tennis?) ball of the approximate curvature as the dome. In any case, it's easy to replace if you should ever think it is a problem.

Good luck.

[panama]

Good point, It is very easy to replace. My only real concern was preignition caused by hot spots but as you say if I shave down some of the high spots it should be alright.

I'd really hate to have to source another head after I just had this one blasted.

[Alan H]

+1 on CBW. I've run heads worse that that 'back in the day'.
Just get rid of any high spots to avoid short term problems.
As soon as a bit of carbon goes in the holes it'll be great.

[panama]

Oh good, thanks for the advice.

As far as cleaning up the high points, would a dremel with a grinding stone suffice? My mate said I should start with some 600 wet/dry and then jump up to 1000.

[Craig380]

+1 on the above, my 380 had a head like that for 5+ years with no problems. I didn't even know about it until I'd had the bike for a year, and lifted the top end to replace the wrist pin bearings. It was also running 1mm oversize on the left cylinder, and standard bore on the other two. These bikes are tough.

I just used a fine file then wet & dry to remove the big high spots. Don't worry about the pits, as mentioned, they will fill with carbon pretty quick. You could use a Dremel but be very careful not to remove too much metal -- just skim off the high spots.

[Coyote]

That baby looks like it shucked a ring as what you call pits are actually dings. Doesn't matter though. Don't go to any extremes. Just grind any ridges that are standing proud. Button it up and don't look back. No need to source another head.
TIP: Next time you have a head blasted, put some old spark plugs in it to protect the threads. Snug fitting rubber plugs work just as well.

[CBWELLS]

Panama,
As for using a DREMEL or other grinding tool,....I'd be very cautious. They can be hard to control & might make the situation worse. I'd try manually with the ball & sandpaper as I mentioned earlier, & I'd start with a fairly course grit.... 180 or 200, then maybe go finer, but your not trying to make a mirror here, & it doesn't have to be "PERFECT"! The aluminum is pretty soft & the hi-points should come off easily. If ya find it's not working to your liking, you can always use the grinder after.

Just curious; Did the piston show similar damage? Are you re-using or replacing it?

[Suzsmokeyallan]

In such a case as that place the head in your lap and use a flat face drift and hammer to tap the high spots back down into the material. Once you've gotten the high material as flat as possible then use a dremel to lightly clean the areas around the section to level it all up.

[tz375]

That's a good idea Allan. Just gently hammer the high spots down.


Do not go looking for perfection - it's not necessary. All you need is no high spots. Dings are not important.