2 lower engine mount bolts covered in dark oil gas upon removal

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JZ05220r
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2 lower engine mount bolts covered in dark oil gas upon removal

Post by JZ05220r »

So I got the engine out today and after removing the last 2 bottom engine mount bolts I noticed they are covered in dark oil. They have a faint gas smell as well. It would have been very hard to detect leaks in these locations with a leak down tester with the engine still in the bike. It seems I had some very sneaky leaks inside both ports where these bolts go through the crankcase. Is it possible to have had gas mix/air leaks within those 2 ports on the cases that these bolts go through? Pics of the bolts and locations in question below. Thanks
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2005 KDX220r 1991 KDX200 2022 KTM 500excf
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bufftester
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by bufftester »

Not without some cracks in the case. Those 2 locations are dead space, i.e.: they are not filled with transmission oil or part of the combustion/exhaust path. More likely is that it was splooge from the exhaust port that worked its way down the front of the engine.
JZ05220r
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by JZ05220r »

bufftester wrote: 03:53 pm Nov 16 2022 Not without some cracks in the case. Those 2 locations are dead space, i.e.: they are not filled with transmission oil or part of the combustion/exhaust path. More likely is that it was splooge from the exhaust port that worked its way down the front of the engine.
I never had a trail of wet oil coming from the exhaust port. This engine only had 12 hours on it. It got dirty but it was always fairly dry. It was just crusty with dirt if I didn’t clean it. Their was no oil on the threads or the outside portion of bolt head, completely dry. I don’t see how oil would have got to the inside of the engine mount bolts with both of them tight and in place. Very weird, I’m gonna do a quick leakdown test and sprays some soap water inside of each hole before sending it off again to be fixed by the original builder.
Last edited by JZ05220r on 07:12 pm Nov 16 2022, edited 1 time in total.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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bufftester
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by bufftester »

Yeah, that is odd. hopefully you don't find any more cracks
JZ05220r
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by JZ05220r »

bufftester wrote: 06:56 pm Nov 16 2022 Yeah, that is odd. hopefully you don't find any more cracks
Yea I hope this it it. No actual cracks, just poorly sealed areas. Thank you
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by Slick_Nick »

Likely a poor sealant job on the crankcase. Didnt you also have an air leak between the case halves? Or was that another guy?
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JZ05220r
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Re: 2 lower engine mount bolts covered in dark oil gas upon removal

Post by JZ05220r »

Slick_Nick wrote: 01:41 pm Nov 17 2022 Likely a poor sealant job on the crankcase. Didnt you also have an air leak between the case halves? Or was that another guy?
Yea I do have a leak there as well. What a disaster.
2005 KDX220r 1991 KDX200 2022 KTM 500excf
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