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Post by rcq92130 on Feb 21, 2015 10:59:57 GMT -5
Concur with above. At OP: When you installed the BBK, was there any silicone or other sealant(s) used? Reason why I ask is because I just installed a 72cc BBK on a rescue moped w/5000 mi. When I removed original jug I noticed that whoever had worked on it before had used a sealer about the gaskets (which is another issue in itself) and when torqued down had oozed into the oil path; thereby stopping the flow of oil completely. When I pulled the wrist-pin from the piston, it had some.... Well, here's a pic (been enhaced to show stuff) The main blockage was in the engine case itself = DANGER....BOOM! LOL  I had a similar wrist pin overheat and thought the oil was not getting there --- but --- Alley explained this is a "splash" system --- the oil passage you pointed to is only for oil to the valves in the head. oil for the wrist pin and piston skirt is provided only by the crank cycling down into the oil pool and splashing some up. Not a pressure system (except for the valves). |
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Post by JerryScript on Feb 21, 2015 11:12:31 GMT -5
There is an oil pathway cut into the engine block and jug that goes through the guide pins. If you run your engine with the valve cover off, you'll see the oil coming up through the rocker arm assembly following the dowel rod path. Notice the picture posted above, the lower arrow he is pointing to the oil path that I'm speaking of. Here's a very good explanation of the oil system with detailed pictures: scooterdoc.proboards.com/post/50522/threadSo if you have gasket goop squeezing into these paths when you torque down your head, you will have issues! |
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Sophomore Rider
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Post by mopojo on Feb 21, 2015 11:15:19 GMT -5
@ rcq92130:
Gotcha. The cam was burned the same color as the wrist-pin as well as the cam-to-head-seats.
Simply stated: it was overheated and abused.
The main point was to make one aware of a possible error when installing a head....(with pic showing possible outcome).
I am sure it wasn't the first time sealant has caused overheating.
Those passages are there for a reason, eh?
Thanks
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Post by JoeyBee on Feb 21, 2015 13:11:57 GMT -5
mopojo, that a great tip. So the recommendation is using the paper gasket instead of RTV? And if a silicon sealant is used, it should be very sparingly.
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Post by xyshannen on Feb 21, 2015 13:32:19 GMT -5
If you torque the head bolts to the proper specs, it shouldn't need any silicone sealant at all.
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Post by xyshannen on Feb 21, 2015 19:57:03 GMT -5
I think you guys need to lighten up a tad. The guy has already made one of the biggest mistakes one can make when rebuilding an engine. It's a lesson he probably will never have to be taught again. At least now he is here and in the future can ask us questions when he isn't sure about something. Seriously guys, these little motors are so simple a well trained monkey can work on them...Just look at all Geh has accomplished.  |
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Post by JoeyBee on Feb 21, 2015 20:59:05 GMT -5
I think you guys need to lighten up a tad. The guy has already made one of the biggest mistakes one can make when rebuilding an engine. It's a lesson he probably will never have to be taught again. At least now he is here and in the future can ask us questions when he isn't sure about something. Seriously guys, these little motors are so simple a well trained monkey can work on them...Just look at all Geh has accomplished. Agreed. Ill say I learned from his mistake also. |
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Post by JerryScript on Feb 21, 2015 21:24:42 GMT -5
This is your only warning guys, stop the personal attacks, offer help, or suffer the consequences!
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