waterline restrictor placement for cold water riding

Hi there, new to the X so I apologize in advance if this post format is incorrect.

Basically the title sums it up but to get to the meat of it I'm new to the sport and bought a XFT with a 701 and some extra goodies. I've done a fair bit of reading but I cant seem to find a cooling line setup anything like mine and where I live the sport is rare so good luck asking other builders, this is where I have finally given in and asked the internet for help. I've included a crude diagram of my cooling setup but basically it goes like this-

cold water inlet-Y fitting-manifold-head-pissers
-RRP pipe

cold water inlet-Y fitting-manifold-head-pissers
-RRP waterbox

From what I have read on the form I need 2mm reducers for where I ride (BC, Canada). problem is I'm not sure if I should put them between the pissers and the head as most suggest, or before the Y fitting that send water to either my pipe or waterbox. my only concern with putting it before the pissers is causing more water to be sent to my pipe/waterbox and flooding it.

Any help or advice would be greatly appreciated and who knows, maybe some day this will help some other new rider. thankyou
 

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Location
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Your water line going to your to your spray bar,
(that’s the line you’ve drawn to your pipe chamber) normally is in the outlet of the exhaust manifold, should already have a 70 to 100 carb jet in the spray bar for chamber cooling and pipe tuning and a filter right before it with a different jet screwed into it ?
These jets will regulate your water to your pipe chamber.

Now on the cooling system restriction, I run 3 restricters, one @ the water box and 2 @ the pissers over board…

I didn’t notice an engine temp change until I went below 2mm restricters in 55 ish degree water, riding freestyle type riding (practicing set up wakes) was hard to get the engine above 105 degrees… 2mm is a good starting point though

Make sure your hose clamps are tight, carry a couple extra clamps with you and a tool for clamps and small needle nose pliers..

Keep an eye on your pisser flow while riding to catch a partially plugged restricter.. plant particles or Debris in water can get trapped at the restricter slightly disrupting the outlet flow.. easy to fix on the fly if you have those 2 tools…
 
I rounded up all my cheap 1/4" drive sockets and used the ones with the smallest thru holes as restrictors. I put them right at the pissers for full pressure and flow into the motor, pipe and waterbox. Pipe and waterbox use their own mikuni main jets. The motor itself is supposed to be about 150 degreese
 
Your water line going to your to your spray bar,
(that’s the line you’ve drawn to your pipe chamber) normally is in the outlet of the exhaust manifold, should already have a 70 to 100 carb jet in the spray bar for chamber cooling and pipe tuning and a filter right before it with a different jet screwed into it ?
These jets will regulate your water to your pipe chamber.

Now on the cooling system restriction, I run 3 restricters, one @ the water box and 2 @ the pissers over board…

I didn’t notice an engine temp change until I went below 2mm restricters in 55 ish degree water, riding freestyle type riding (practicing set up wakes) was hard to get the engine above 105 degrees… 2mm is a good starting point though

Make sure your hose clamps are tight, carry a couple extra clamps with you and a tool for clamps and small needle nose pliers..

Keep an eye on your pisser flow while riding to catch a partially plugged restricter.. plant particles or Debris in water can get trapped at the restricter slightly disrupting the outlet flow.. easy to fix on the fly if you have those 2 tools…
You sir are a saint. Thankyou so much for the fast response, and incredibly informative considering my terrible drawing haha.

Do you run the same kind of restrictor, and size, before your waterbox that you do before your pissers?
Is your
 
Location
Stockton
You sir are a saint. Thankyou so much for the fast response, and incredibly informative considering my terrible drawing haha.

Do you run the same kind of restrictor, and size, before your waterbox that you do before your pissers?
Is your

Welcome! Yes same size in those locations. I use old carb seats like mentioned above ^^ and drill them out to different sizes to get the temp I want…
Install them so the part the needle sits in, is the out flow direction, so it doesn’t capture debri
 
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I like these quick connectors with a built in restrictor. They have several different restrictors to adjust for your desired water temps. One of my buddies has them on his ski and they are pretty sweet. I plan on running them on my superfreak when I get it finished. Always put the restrictors on your bypass lines going to the pissers. You'll put one on each bypass. My buddy also uses these on the inlets with no restrictor for easy quick disconnect for pulling the engine or pipe for service.
 

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Welcome! Yes same size in those locations. I use old carb seats like mentioned above ^^ and drill them out to different sizes to get the temp I want…
Install them so the part the needle sits in, is the out flow direction, so it doesn’t capture debri
is their any risk to parts running those 3 2mm restrictors? you would think the waterbox would overheat, and a blown water hose is nothing but a blown gasket could be troublesome where i live. although i guess running too cold could also be costly
 
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Location
Stockton
is their any risk to parts running those 3 2mm restrictors? you would think the waterbox would overheat, and a blown water hose is nothing but a blown gasket could be troublesome where i live. although i guess running too cold could also be costly

Yeah there is some risk with restricters, hoses can pop off with increased pressure if the clamps get loose.. remember to check if a readjust is needed in summer water temps. Etc..

When are you planning to install the restricters ?
Reason I ask is I use decimal sizes and can’t 100% recall how small iam going.. I also went out of town and will be traveling back on Wednesday. I just converted 2mm to decimal and got .078 and 3mm was .118 about. .078 seems like it’s in range but I think I was going smaller ?
I’d like to refresh my memory by checking my restricter sizes…. And msg you back…

“From memory, I recall experiencing 2mm is still large and I didn’t get a lot of temp change at that size in 53 degree water, engine was like 105 degrees, freestyle type riding “riding in circles, blipping the throttle.

I run temp strips, one on each cylinder and one one the water box, one on the pipe and check all my temps…

I start with equal size restricters, ride and check temps of my cyl, water box and pipe… adj pisser and box restricters until I get an engine temp iam ok with,

Then I adjust the pipes spray bar jet until I like the performance for my ride style and verify iam not over heating the pipe…

Then I adjust the water box flow… less water makes the box hotter and more noisy and the amount of water effects noise/throttle response some…

I use equal size restricters to start with to keep the pressure and flow the same at each point..

Have you rode your ski yet ? The RRP lay down pipe and tiny water box with nearly equal inlet and outlet water box pipes is susceptible to water back flow into your rear cylinder… I found out the hard way, deep water rebosrding the ski from the back of the tray..belly in tray, arms stretched out to the bars, azz of ski low in water from my weight…water in rear cylinder lol..

I’ve since raised my water box 3 inches or so and redid the outlet pipe..

Deep water, tilt bars so start stop switch is nearly in the water and start the engine, then reboard lol

Edit: I actually have my jet ski tool bags with me lol….restricters might be in them… I look in the morning lol

Edit: ok I had these sizes on me, see pic..2.0 are on far right, and I have 1.77 as well at home…I can see what others I have next week…

If the water is cold there like 53 or less.. I’d ride the ski and check your temps first…. With temp strips or a temp gun… you have to read them quickly so you need to ride close to shore and pop the hood fast and read it… then pop in the 2.0 and repeat…I found it hard with my engine set up to get above 135 degrees engine temp in winter… iam ok with 125 to 135 in winter…. I try to stay 135 ish in summer….140/150 is what I was shooting for lol….

My after market hull has non barbed cooling lines at the bulkhead so hoses can slip off more easily… my engine vibrates a lot and clamps on the those lines like to loosen….. turned out my cylinder to case bolts were failing so the cylinder chattered some… bolts were Titanium…..

I should add all those bigger sizes in that pic didn’t do Anything to the temp in winter

3.53
3.77
2.77
2.37
2.0
1.77
1.37 @ home I believe
 

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Yeah there is some risk with restricters, hoses can pop off with increased pressure if the clamps get loose.. remember to check if a readjust is needed in summer water temps. Etc..

When are you planning to install the restricters ?
Reason I ask is I use decimal sizes and can’t 100% recall how small iam going.. I also went out of town and will be traveling back on Wednesday. I just converted 2mm to decimal and got .078 and 3mm was .118 about. .078 seems like it’s in range but I think I was going smaller ?
I’d like to refresh my memory by checking my restricter sizes…. And msg you back…

“From memory, I recall experiencing 2mm is still large and I didn’t get a lot of temp change at that size in 53 degree water, engine was like 105 degrees, freestyle type riding “riding in circles, blipping the throttle.

I run temp strips, one on each cylinder and one one the water box, one on the pipe and check all my temps…

I start with equal size restricters, ride and check temps of my cyl, water box and pipe… adj pisser and box restricters until I get an engine temp iam ok with,

Then I adjust the pipes spray bar jet until I like the performance for my ride style and verify iam not over heating the pipe…

Then I adjust the water box flow… less water makes the box hotter and more noisy and the amount of water effects noise/throttle response some…

I use equal size restricters to start with to keep the pressure and flow the same at each point..

Have you rode your ski yet ? The RRP lay down pipe and tiny water box with nearly equal inlet and outlet water box pipes is susceptible to water back flow into your rear cylinder… I found out the hard way, deep water rebosrding the ski from the back of the tray..belly in tray, arms stretched out to the bars, azz of ski low in water from my weight…water in rear cylinder lol..

I’ve since raised my water box 3 inches or so and redid the outlet pipe..

Deep water, tilt bars so start stop switch is nearly in the water and start the engine, then reboard lol

Edit: I actually have my jet ski tool bags with me lol….restricters might be in them… I look in the morning lol

Edit: ok I had these sizes on me, see pic..2.0 are on far right, and I have 1.77 as well at home…I can see what others I have next week…

If the water is cold there like 53 or less.. I’d ride the ski and check your temps first…. With temp strips or a temp gun… you have to read them quickly so you need to ride close to shore and pop the hood fast and read it… then pop in the 2.0 and repeat…I found it hard with my engine set up to get above 135 degrees engine temp in winter… iam ok with 125 to 135 in winter…. I try to stay 135 ish in summer….140/150 is what I was shooting for lol….

My after market hull has non barbed cooling lines at the bulkhead so hoses can slip off more easily… my engine vibrates a lot and clamps on the those lines like to loosen….. turned out my cylinder to case bolts were failing so the cylinder chattered some… bolts were Titanium…..

I should add all those bigger sizes in that pic didn’t do Anything to the temp in winter

3.53
3.77
2.77
2.37
2.0
1.77
1.37 @ home I believe

I guess you could call what i do freeride? sometimes small circles practicing stuff, othertimes cruising at a decent speed chasing boats or buoys.

I plan to install the restrictors before I ride this season, probably to keep things simple ill end up getting those blowsion quick disconnects with included restrictors. I just got the ski last year and was so excited to finally ride I didn't bother researching the finer details. Ended up riding the whole season with no restrictors and I guess I got lucky because the first ride was in 43 degree water. Don't know if I need a flow control valve just yet, pretty happy with how the ski performs and the restrictor at the waterbox will probably help anyway right?


Its funny you mention the RRP backflow problem because that's how I ended up learning about restrictors. Got lucky there too as I was reboarding the normal way from the back and starting it, and like the complete noob I was I crashed many times but never ended up having water backflow down the pipe... or at least to my knowledge i didn't. It has a nice big block of foam under the waterbox so that's probably why.
This year I'm definitely doing to start reboarding from the side like you suggest, better safe than sorry.
 
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