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timing issue on RT I think

PostPosted: Sun Mar 19, 2017 3:36 pm
by swissdean
rsz_resized_pistion_crown.jpg
Hi, just whipped head off Rt195 to suss size to order new meteor type and noted this pitting on piston crown..this kit has circa 500-700 miles on it and at first was running super lean..first 100 or so miles and then with some carb mods seem to be pulling clean and fine..i suspect this may be a timing issue ( i have a varitronic set to max retard)..any other thoughts from what you see?

Re: timing issue on RT I think

PostPosted: Mon Mar 20, 2017 8:13 pm
by a-teamlambretta
cant see owt with all that carbon, give it a clean up and then some more pics ;)

Re: timing issue on RT I think

PostPosted: Tue Mar 21, 2017 4:05 am
by Fast n Furious
Something not right with that squish band. :(

Re: timing issue on RT I think

PostPosted: Tue Mar 21, 2017 8:38 am
by MickYork
The marks on the piston head don't appear to be from pinking. It looks more like physical damage ?

Re: timing issue on RT I think

PostPosted: Tue Mar 21, 2017 9:25 am
by Adam_Winstone
^... agreed, the symmetry makes me think that the central line of markings, if that's what we're talking about, are manufacturer's markings or something else. To me I do not see any marks on piston crown that look like pinking / detonation damage.

Adam

Re: timing issue on RT I think

PostPosted: Tue Mar 21, 2017 2:03 pm
by swissdean
Fast n Furious wrote:Something not right with that squish band. :(
you have me worried now... I admit to being a novice and had placed some solder through the plug hole to the side of the head and then measured and it seemed spot on.. what do you see?

Re: timing issue on RT I think

PostPosted: Tue Mar 21, 2017 2:04 pm
by swissdean
MickYork wrote:The marks on the piston head don't appear to be from pinking. It looks more like physical damage ?
yep on strip down found one gudgeon pin wire clip missing so suspect this was the cause of the marks

Re: timing issue on RT I think

PostPosted: Sat Mar 25, 2017 12:21 pm
by Fast n Furious
swissdean wrote:
Fast n Furious wrote:Something not right with that squish band. :(
you have me worried now... I admit to being a novice and had placed some solder through the plug hole to the side of the head and then measured and it seemed spot on.. what do you see?

Putting solder down the plug hole method isn't a good way of doing it. This can cause the piston to rock over on one side and give you misleading measurements.
When you rebuild it, I recommend you refer to the method statements in sticky's manual on this.
Also, check to see that the squish profile matches with the dome profile of the piston.