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S65 carb woes
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<blockquote data-quote="Sams65" data-source="post: 188396" data-attributes="member: 12820"><p>Finally got around to spinning some wrenches on this again but unfortunately no eureka moments. I took the old parts off and tried to take some measurements but lacking accurate tools, I had to make do with a digital caliper. Readings were inconsistent to say the least...</p><p></p><p>I even threw the old parts back on the bike (this included original head w/valves/guides/springs, original cylinder, piston and rings) and still got the exact same results with <u>massive rich condition</u>. Was hoping it would at least lead to low compression and oil burning instead. I'd take anything else... But it's like nothing's changed.</p><p></p><p>**Note: one thing I did notice when trying to fit the<u> old piston</u> with <u>new rings</u> into the <u>old bore</u>, I couldn't compress the rings enough with my fingers. And I don't have a ring compressor small enough for these teacup pistons (tried a hose clamp but no luck) So just ended up using the old rings. With the new parts I was able to do it easily with my hands, using the bevel on the underside of the cylinder to drive everything in. I measured the end gaps of the new rings and everything's within spec. So this is potentially something I might investigate again.</p><p></p><p>Attached pics of old and new parts in case any of you more eagle eyed might notice anything way off.</p><p></p><p>New combustion chamber:</p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1227.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1227.jpg</a></p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1212.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1212.jpg</a></p><p></p><p>New on left, old on right:</p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1229.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1229.jpg</a></p><p></p><p>Cylinders - new on left, old on right:</p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1233.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1233.jpg</a></p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1235.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1235.jpg</a></p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1234.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1234.jpg</a></p><p></p><p>Pistons - new on left, old on right</p><p><a href="https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1221.jpg" target="_blank">https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1221.jpg</a></p><p></p><p></p><p>To recap so far: Have now tried 3 different carbs, 2 different heads, 2 different cylinders, 2 different pistons and rings, 2 different air filters (and no air filter) and all result in the same pig-rich running condition.</p><p></p><p>At this point I might see if I can get my hands on some bore gauges/micrometers and do proper measurements. Any other thoughts or opinions?</p><p></p><p>Question - could the exhaust system factor in to this in some way?</p></blockquote><p></p>
[QUOTE="Sams65, post: 188396, member: 12820"] Finally got around to spinning some wrenches on this again but unfortunately no eureka moments. I took the old parts off and tried to take some measurements but lacking accurate tools, I had to make do with a digital caliper. Readings were inconsistent to say the least... I even threw the old parts back on the bike (this included original head w/valves/guides/springs, original cylinder, piston and rings) and still got the exact same results with [U]massive rich condition[/U]. Was hoping it would at least lead to low compression and oil burning instead. I'd take anything else... But it's like nothing's changed. **Note: one thing I did notice when trying to fit the[U] old piston[/U] with [U]new rings[/U] into the [U]old bore[/U], I couldn't compress the rings enough with my fingers. And I don't have a ring compressor small enough for these teacup pistons (tried a hose clamp but no luck) So just ended up using the old rings. With the new parts I was able to do it easily with my hands, using the bevel on the underside of the cylinder to drive everything in. I measured the end gaps of the new rings and everything's within spec. So this is potentially something I might investigate again. Attached pics of old and new parts in case any of you more eagle eyed might notice anything way off. New combustion chamber: [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1227.jpg[/URL] [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1212.jpg[/URL] New on left, old on right: [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1229.jpg[/URL] Cylinders - new on left, old on right: [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1233.jpg[/URL] [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1235.jpg[/URL] [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1234.jpg[/URL] Pistons - new on left, old on right [URL]https://i1257.photobucket.com/albums/ii510/sam84i/IMG_1221.jpg[/URL] To recap so far: Have now tried 3 different carbs, 2 different heads, 2 different cylinders, 2 different pistons and rings, 2 different air filters (and no air filter) and all result in the same pig-rich running condition. At this point I might see if I can get my hands on some bore gauges/micrometers and do proper measurements. Any other thoughts or opinions? Question - could the exhaust system factor in to this in some way? [/QUOTE]
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