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HELP!!!!!!PAIR MOD on a 99F4
I would like to do the PAIR mod on my F4, I'm somewhat mechanical but I can't figure out all the hoses there is one that runs from beside the right ram air duct then into a canister that has a line that comes out off the can and goes under the bike ( I assume that is just a moister trap) then the 5/8 line comes out the canister and goes to a valve that has a vacuum line that runs to the far right carb, the 5/8 line then continues onto the air box, then there is a valve that has a electric wire hooked into it.
Well what I'm asking I have 4 vacuum lines coming from my Carbs, two that come from either side and joins in a T and then goes to the air box. Then I have two that comes from the inner two Carbs and joins in a t that goes to the air box I believe. I have three lines that come from the Valve cover. Sorry if this is confusing! What I'm trying to figure out is what lines I plug. What lines I connect and where. |
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Here is what I have.
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The air box
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The four small vacuum tubes which are attached to the airbox are only used for synchronizing.
They're mounted to the airbox which acts as a stopper. Meaning, air does not enter the vacuum lines when properly attached to the airbox. https://cbrforum.com/forum/attachmen...2&d=1255055877 I believe these are your fuel lines. https://cbrforum.com/forum/attachmen...1&d=1255055755 This is your crankcase breather tube. It should be left attached to the airbox, imo. https://cbrforum.com/forum/attachmen...0&d=1255055612 These two tubes lead to the exhaust ports. Flow is controlled by means of the pair control valve and the pair check valves. There are smog block-off plates which you can buy that effectively replace the pair check valves, thus sealing off these openings. https://cbrforum.com/forum/attachmen...9&d=1255055571 If you're removing the evaporative canister, you're going to have three lines; one from the evaporative purge control solenoid valve, one from the tank (breather hose), and one to the air filter (clean air supply). If it's not needed, you should remove the breather hose from the tank at the evaporative canister, and remove the hose from the airbox at the airbox itself. Obviously, cap off all unused ports at the airbox. As for the evaporative purge control solenoid valve, I don't know how unplugging it will affect the engine. I'm pretty sure that's how to do it. In the first picture I posted, they connected the crankcase breather tube directly to the exhaust ports with a three way connector. I don't think that's a good way of doing it. If anyone sees anything wrong with this, chime in. |
Here's a good crankcase "clean air mod": LINK.
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Thanks for the help. on the first pic I know what the small one are Ive synchronized the carbs before I was just wondering what holes to block off that the red arrows are pointing to. as far as the lines inbetween carbs I blew in them and gas run out of the carbs, and the lines on the outside of the carbs I blew in them and it made my slides move in the carbs. all of those I leave hooked up to the air box right??????________________________
I can put the crank case vent to the two pair valve lines as seen on the F4i pic?_________ Agian thanks for the help! |
Basically all you’re doing with a clean air mod is diverting the crankcase gases somewhere else other than the airbox, and disconnecting the fresh air from the exhaust port. Racers do it simply to loose unwanted weight, and rid the motor of clutter. There's no real gain to be had from it, besides creating more pollution.
I wouldn't feel comfortable attaching the crankcase breather hose to the exhaust port, but apparently it's a common practice among stunters. The main concept being that if the bike falls over, the engine doesn't become hydro-locked as quickly. My concern with this would be that perhaps some of the exhaust gases would actually be able to make their way into the crankcase, but I could be wrong. I’d rather attach an external filter and re-route the crankcase breather hose elsewhere. With the hoses, the only one’s you’ll be concerned with are the big ones. The two in the middle are your fuel lines, and the ones on the outside of the carburetors, I haven’t a clue (so leave them attached). |
Thanks for the help. I going to put it back together.
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The hoses in between the carburetors are float bowl vents, I thought they were just vents so I connected a hose from them and run it up high so it wouldn't siphon the gas out of the float bowls.
As for the Crank case vent I did connect it to the Pair valves, as long as the reeds are still in the valves exhaust gasses have no way of getting into the crank case. |
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