brute force 750 carb vents

07galaxy650 · October 23rd, 2008, 12:04 AM

So I have ran the coolant reservoir up, and the carb canister thing done. I hear that i need to run the crankcase to the pod as well, but need to know how and what to buy. Anything else i am missing? Its a 07 650I. Thanks.

shawn3806 · October 23rd, 2008, 01:05 AM

Front and rear diff breathers for sure.* Did you plug up the duckbill on the bottom of the airbox?* Have you made a fip seal for the airbox lid yet?

07galaxy650 · October 23rd, 2008, 08:58 AM

Arent the diff on the 07 and up already ran? What is a duckbill and fip seal for the airbox? Thanks man.

NMKAWIERIDER · October 23rd, 2008, 11:08 AM

N.P, can the duckbill actualy leak? Just put a little silicone over the end maybe?

07galaxy650, A lot of people do run the crankcase vent to the pod, but doing that destroys positive crankcase venting (PCV for short). More and more people are putting catch cans or oil traps inline. VTprairie and many others (including me soon) are using the catch can used by the Yamaha YFZ 450. A smart design that works. Its only about 9 bucks from Babbits. As is, the crankcast vent is not in danger of getting water in in unless your airbox gets water in it, people run it up and use catch cans to keep the oil out of the box on long wheelies and steep hill climbing. A bad habbit the Brutes have.

Here's a pic of the YFZ 450 catch can.

http://i483.photobucket.com/albums/rr196/B...YFZCatchCan.jpg

07galaxy650 · October 23rd, 2008, 12:47 PM

Ok well on hl site, one guy said he just spliced in a pcv valve and left it attached to the air box? Would it work? I think it would except it might still puke oil on long wheelies. Is the only way to keep it from puking oil the catch can method? Thanks.

NMKAWIERIDER · October 23rd, 2008, 01:14 PM

Well, I thought of a PCV valve, but they are used on cars that have that vent tied into the intake manifold where the loss of vacuum would cause some problems. The spring that regulates the check valve is too strong for the lower vacuum level on the airbox. So, my take is that although it might help, probably not the answer. I was just thinking that the problem is the location of the vent on the block, behind the rear cylender, and when the front of the engine rotates up, the oil runs back and some covers the vent hole, getting sucked up to the airbox. Why haven't they fixed that yet? Yamaha never had the problem because they always had somthing to deal with it. If it was on the front of the engine, I don't think you could be going down hill steep enough to be a problem...without doing some endos, and you probably wouldn't be on the gas making extra vacuum in the airbox...like you are doing wheelies or hill climbing. It's more likely you would be on the engine brake . I just had a thought of getting a tappit cover from Babbits, drill and tap it for a fitting, put a small baffle on the inside like a car's valve cover does to deflect oil from splashing off the tappits, replace one of the front tappit covers with it and run the line back to the original place on the air box. What would be wrong with that? Well, if that chamber is sealed off from the rest of the engine except for some oil drains, that could be a problem. I'll have to study the casting design...but for now, a well placed catch can in my opinion is the way to go.

Just a thought...

07galaxy650 · October 30th, 2008, 11:34 PM

Ok so here is the update. I am waiting on my shims to come in, so i have just been tinkering with small things. I vented the coolant reservoir, fan, diffs, crankcase, carb drains, carb vents, gas tank vent, sealed the duckbill on the air box as well as sealing the air box itself, and thats it for now. I am going to run the water pump up tommarrow as well, flynt from HL said to. Other than that, I think i have her covered. The only thing I found that wasnt vented is a 3/8id hose coming off a box thing on side of the carbs. It is only about a 3 inch long tube and runs down by the backside of the front head. I dont have a clue what it is. Any of you know what I am talking about here? It is labeled in the pick as G. It just says rubber hose in description and doesnt say anything about what it comes off of.
http://partsfinder.onlinemicrofiche.com/cy...;A=196&B=18

07galaxy650 · October 30th, 2008, 11:48 PM

Ok so I think it is the throttle link case. Does it need to be vented also? I might go ahead and vent it anyways, just to be safe.

NMKAWIERIDER · October 31st, 2008, 11:24 AM

<div class='quotetop'>QUOTE (07galaxy650 @ Oct 31 2008, 03:48 AM) <{POST_SNAPBACK}></div>

Quote:

Ok so I think it is the throttle link case. Does it need to be vented also? I might go ahead and vent it anyways, just to be safe.[/b]

I believe that's just a drain for the throttle case, and it will get water in it through the cover and the cable input. If you run that drain up, water will have no way to completely get out and some will sit in the box, covering part or all of the linkages, and do what water does best, rust. Plus water can be sucked into the carbs through the butterfly shafts if its high enough, and if the seals & shafts are warn a bit. Better leave that one alone. There is a check valve thing you can put on the end that will slow or stop water from entering that tube but will allow it to drain. I believe the carb bowl overflow tube had somthing like that on the end down by the bottom of the engine where it dumps. Sence you ran those up, maybe you don't need it and can put it on that tube. By the way, so where will the bowl overflow (slosh-over) go after it fills the tubes as high as it can? Just a thought. If you are ever doing some crazy stuff or running a realy rough road for a long period, and you loose a cylender, pull the plug and find its fowled with gas, you will know why. Some conditions can cause the fluid levels in the bowls to increase faster then the engine can use it, causing overfueling...like the choke being on. That's what the overflows are for, to not allow the level to exceed a fixed level. Long rough roads can bounce the floats enough to keep letting fuel in or high angles like wheelstands or extreem nose-downs or way-off cambers can take the carbs outside their designed operating range. Or just plain worn-out needles or seats. When the bowls are overfilled, it does need somewhere to go. You might have smelled gas sometimes after doing something extreem. That's the overflows working...usualy.

Just my take.