going to reroute the breather hose's on my 2015 and want to run a couple questions by you guys. do you think 7/32 vacuum line is big enough ? and do you think it can hold up to the heat running between the cyls ? going to run it from the back of the fliter backing plate between the jugs and then down between motor and inner primary case. won't see it from the right side and you will only aee a very small section of it from the left. i just don't know if it can take laying on the cyls. or if it's big enough for the volume of air going though it.

 

anything that's rated for fuel/vacuum line will do.

those of us with carbs have same type line carrying gasoline between our cylinders.

Mike

 

You need to use line rated for fuel/oil since there will be oil vapors inside the line. I'd go with 5/16" since it will be easier to find the 5/16" x 1/8" NPT hose barb fittings.

Here is the write up I did on this modification.
https://www.hdforums.com/forum/touri...ification.html

 

I've used 7/32 vacuum hose for the past 6 months on my FM Pro-billet stage 1 a/c set up with stock a/c cover without issue, but I don't run it the way you plan. I routed mine off the breather bolts down to a "T" and then behind the backplate to a breather filter from the local parts store. Although I may be modifying that set up soon by getting rid of the breather filter and going with a vented canister as a catch can that I found online. The whole set up hides inside and behind the stock a/c cover. I would think if you're going to run a hose anywhere close to the engine, a thicker fuel line (rather than a vacuum line)...maybe 3/8...might be better. But 7/32 hose definitely fits snug to my breather bolts.

 

This is what I did, 1/4 inch line. Runs along the frame on other side. My new pistons had alot of carbon in just a few hundred miles. So went with this, had in back before but didn't like the looks there. No filter on them, but they are pointed straight back on the frame. I cut the hoses in the box & barbed them to the new line so wouldn't have a kink.

 

this is exactly what iam going to do, except just continue the line between the jugs and then dropping down between the engine case and inner primary. long run for 7/32 line. kinda like trying to breath threw a straw.

 

I'm running the same set up you want to do. Use some wire zip ties on both sides of the cylinders to keep the hose from making contact with the heads. There are places on both sides to accomplish this. Been using it for several years and no burn thru's yet.....