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Post by JerryScript on May 30, 2016 14:38:11 GMT -5
After 7500 miles, I finally had my first breakdown on my SSR Pacifica 150cc BN157QMJ-3. Blew the spark plug hole out. I just tore it down, and will be replacing the head with a new one from Scrappy's tomorrow (they are closed today for Memorial Day). Upon removing the head and inspecting it, I found it was a horrible casting job, lots of rough edges and a couple of voids, so I'm not surprised the plug blew out (no indication of cross threading, and I hadn't removed the plug in months). $40+ for a helicoil kit + tap vs $60 for a new head, no brainer to replace rather than repair. Another thing I noticed was the valves are very differently colored now, and I don't know if that's an indication of other issues, ( pistonguy what do you think?): i1232.photobucket.com/albums/ff362/JerryScript/Scooter/20160530_120446_zpsmbm4o19v.jpgI know I've been running rich, but that's on purpose since I do ride on the freeway for my work commute, and didn't want a lean condition causing damage. |
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Post by lain on May 30, 2016 14:53:08 GMT -5
Looks normal to me. Broke down a couple dozen engines in the past year, only seen this sort of thing on engines with vacuum leaks while running rich. Since you blew the spark hole out though you plan to replace the head anyways right? I'd check the intake for leaks, looks like the intake burned hotter than the exhaust somehow.
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Post by JerryScript on May 30, 2016 15:27:33 GMT -5
Could be lain, however I had zero issues before the plug blew out. I ride to work at 60-65mph for about 5 miles on my daily commute, and have never had any issues with performance (no surging, idle's fine, no backfiring, no bogging). I can post more pics of the head showing the rough casting, but now that I think of it, the casting has nothing to do with the plug threads, they are threaded by a tap after casting. I'm going to have to assume I did not torque the plug properly last time I checked it, and it slowly worked it's way loose over the months until it finally blew out. Now it will not even grab the threads. I could go the tap+insert route, but for $20 more I think a new head is a better solution, especially since I live less than 15 miles from Scrappy's and don't have to wait for a head to be shipped. |
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Post by pistonguy on May 30, 2016 15:30:13 GMT -5
After 7500 miles, I finally had my first breakdown on my SSR Pacifica 150cc BN157QMJ-3. Blew the spark plug hole out. I just tore it down, and will be replacing the head with a new one from Scrappy's tomorrow (they are closed today for Memorial Day). Upon removing the head and inspecting it, I found it was a horrible casting job, lots of rough edges and a couple of voids, so I'm not surprised the plug blew out (no indication of cross threading, and I hadn't removed the plug in months). $40+ for a helicoil kit + tap vs $60 for a new head, no brainer to replace rather than repair. Another thing I noticed was the valves are very differently colored now, and I don't know if that's an indication of other issues, ( pistonguy what do you think?): i1232.photobucket.com/albums/ff362/JerryScript/Scooter/20160530_120446_zpsmbm4o19v.jpgI know I've been running rich, but that's on purpose since I do ride on the freeway for my work commute, and didn't want a lean condition causing damage. Nah Brugh, your looking good, Normal Difference in Color and you have 7,500 on her. just fine Remember, the Exhaust (exaggerated) port is Blow Torch, we cool it with fuel and heat it with air. Bunsen burner is all. The Exhaust Valve will always be a Tan to White color and its just fine, There is allot to do in color with the fuel and oil your running. The Crp on the Intake Valve is "Coking" more than running to rich, very normal. Lucky I have a Big Block Chevy Open Chamber Heads on hand. This BBC has LOTS of miles on her, and the color difference you see is normal and just fine.   |
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Post by JerryScript on May 30, 2016 15:35:20 GMT -5
Thanks pistonguy, I appreciate you easing my worries! |
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Post by pistonguy on May 30, 2016 15:42:20 GMT -5
Looks normal to me. Broke down a couple dozen engines in the past year, only seen this sort of thing on engines with vacuum leaks while running rich. Since you blew the spark hole out though you plan to replace the head anyways right? I'd check the intake for leaks, looks like the intake burned hotter than the exhaust somehow. Ya got that backwards. he's lookin good for 7,500 miles The Intake Valve is Always the Larger Valve, Getting a Cooled (one source) intake Charge Hence the Darker Color. The Small Valve, the Exhaust Valve Get Hit by the Blow Torch and thats why its Tan to White. Very important is Both Valves also transfer there heat to the valve Seats for Cooling. This is much over looked in a proper valve job. |
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Post by JerryScript on May 31, 2016 18:27:22 GMT -5
Got the new head and gasket from Scrappy today. While I was there, I had them pull out a BBK jug to check, standard jugs do fit the BN157QMJ-3, 54mm stud spacing, the head is non-standard, it's taller. This means I should be able to use one of the drop in NCY 61mm BBKs!
Got her back together, took a test ride, all is good, back to smilin and ridin!
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Post by pistonguy on May 31, 2016 18:39:59 GMT -5
Got the new head and gasket from Scrappy today. While I was there, I had them pull out a BBK jug to check, standard jugs do fit the BN157QMJ-3, 54mm stud spacing, the head is non-standard, it's taller. This means I should be able to use one of the drop in NCY 61mm BBKs! Got her back together, took a test ride, all is good, back to smilin and ridin! Good Info Buyer beware of the NCY drop in 61mm kit, i dunno if there all that way but Mine is. I have one, and they cut the Skirt off the Piston to clear a stroker application. This Piston is Not usable. unreal they did this NCY piston is on right. Taida 61mm on left with skirt in tact showing the chopped off area in Red  |
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Post by JerryScript on May 31, 2016 20:07:04 GMT -5
Good Info Buyer beware of the NCY drop in 61mm kit, i dunno if there all that way but Mine is. I have one, and they cut the Skirt off the Piston to clear a stroker application. This Piston is Not usable. unreal they did this NCY piston is on right. Taida 61mm on left with skirt in tact showing the chopped off area in Red Thanks for the heads up, that's a pretty short skirt, I wouldn't even want it on a stroker, clamshell would be much better! With that little bit of info, I'm most likely going to get the Taida from Dan. With the type of riding I do, 65-70mph on freeway for about 5 miles each way to work, never passing 7500rpms, would you suggest the ceramic or the forged? |
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