Hi everybody. As of today my bike is still in the shop with the same problem, oil puking outta the rear breather. Here is the link to the original thread for reference.
https://www.hdforums.com/forum/sport...lp-needed.html

The shop has been communicating with Dan at Zipper's on this and have checked and rechecked everything that Dan suggested. They checked oild drains, tried to add a washer to the tit on the butterfly valve, and replaced the oil pump only to have the same issue occur. They admitted they have no clue what to do next. They are thinking of pulling the engine and sending it to Zipper's for inspection to see if they can figure it out.

This seems to be a total mistery that no one can solve. Any new thoughts on this? I don't know what they are going to do but I just wish I could be enjoying the nice weather and riding. Getting bummed out.

 

I've only had oil blow by once and it was on a dr400 I got for my dad for a project bike to work on together. It was the piston ring gaps were lined up in a row, lol. Hope you can get back on your bike soon.

 

Did they take jugs off & check the rings? Sounds like some ring gaps may be close to each other & causing the blow by.

 

One thing that seems odd to me in all this is that it's just the rear breather. If there was excessive crankcase pressure/blowby it should be puking out both breathers.
Have you checked that you do have some air coming out the front breather when it's running? just thinking that if the front breather was obstructed all the air would have to come out the rear breather and with that much air rushing out of just one breather it might not have time to shed the liquid oil suspended in it.

 

I thought if it's coming from the rear breather, it's coming from the head of a single cylinder and wouldn't be effected or effect the front cylinder.

 

Good point, I was thinking of bottom end pressure but if compression was leaking UP thru the valve guides and seals it would just pressurize the one head breather. Oh well...I'll have another beer and think about it some more

 

Crispie Nubbins, they said they did and everything checked fine.

HOTLAP, I did check this before I took it to the shop. I rubberbanded sandwich bags on each of the breather hoses and both inflated immediately and stayed inflated. Air is venting out of both breathers.

I have spoke with the shop manager in more detail and he said it looks like the drain holes in the rear head look smaller than the front but didn't say if they measured them to confirm or not. They asked Zipper's about it and it was not addressed.

I'm wondering if Zipper's did replace the head when it was sent back for repairs and didn't bore out the drain holes or something? If so I really wonder why the shop doesn't measure the drains to compare and just drill the rear ones to match the front if they do find a difference? Would the rear head having smaller drain holes cause the oil to build up and dump out at high RPM's or prolonged riding? Thanks

 

Well the bike is still down and out in the shop. The top end has been sent back to Zipper's so they can run tests and measurements of everything they can to try to pinpoint the cause of the oil building up in the rear head. Before having the parts shipped, they had the shop do every test and check they could think of and even replaced the oil pump with no luck.

Hopefully Zipper's will be able to figure this out. If not I really hope they do something to the effect of either replacing the kit or upgrading it somehow so it will work as intended. I will keep everyone posted on what they find and do to fix the issue.

 

Wow another month goes by, how frustrating!

 

Gets on your nerves stuff like that doesn't it, get the number of the shop and give them daily calls, till the get fed up and spend quality time on the bike.

I wanted to throttle the owner of a shop, when I KNEW they were lying to me about how much work the were doing, I just played along stupid till the got fed up and gave me the bike back fixed with the SAME problem.

Till I fixed it myself.