Floats, Pitot and bov location

[TT]

I have finally got some seat time on MPI/Bender stage 2 kit. It runs very strong - and I'm crancking up the boost in baby steps.

I was out riding yesterday with my friends. We had a blast in a bowl - even though it is spring time.

During one of the first shuts the sled scared the crap out of me. Almost at the top of a long shut sled flooded and died. The sled was wheeling and slamed down hard when it happened. Not funny - I barely saved my sled from rolling down the hill. It does this every time if I let it hard down after wheelies or if I hit moguls hard going uphill. It never happens driving on the trail - even driving crazy and chopping the throttle.

So I ended up just doing small stuff, when all the other guys (none of them with a turbo) was having a blast going up things I did dare to because of the flooding issue. You can have a big guess how was crowned "the chicken" - LOL

I'm pretty sure it's the floats that have to be adjusted a little more. I have them at 15mm (11-15mm is Yamaha specs). I have read that people has gone as low as 17mm. It kind of scares me going that low - with benders known lean spot. Any inputs?

I will check that my fuel pressure is between 4,5-5 psi before adjusting the floats.

I have been thinking if it would be smart of me to either add an extra bov or move it. I have my bov located in the charge tube between the ic and pitot. I have read some of Dave/powderlites answers (old posts) concerning this issue. It sounds logical to have it before the pressure signal to the float bowls. What are your feelings move the bov, add on or just leave it?

 

[Ted Jannetty]

I have finally got some seat time on MPI/Bender stage 2 kit. Runs very strong - taking up the boost in baby steps.

I was out riding yesterday with my friends. We had a blast in a bowl - even though it is spring time.

During one of the first shuts the sled scared the crap out of me. Almost at the top of a long shut sled flooded and died. Not funny - I barely saved my sled from rolling down the hill. It does this every time if I let it hard down after wheelies or if I hit hard packed snow going uphill. It never happens driving on the trail - even driving crazy and chopping the throttle.

So I ended up just doing small stuff, when all the other guys (none of them with a turbo) was having a blast going up things I did dare to because of the flooding issue. You can have a big guess how was crowned "the chicken" - LOL

I'm pretty sure it's the floats that have to be adjusted a little more. I have them at 15mm (11-15mm is Yamaha specs). I have read that people has gone as low as 17mm. It kind of scares me going that low - with benders known lean spot. Any inputs?

I will check that my fuel pressure is between 4,5-5 psi before adjusting the floats.

I have been thinking if it would be smart of me to either add an extra bov or move it. I have my bov located in the charge tube between the ic and pitot. I have read some of dave/powderlites answers (old posts) concerning this issue. It sounds logical to have it before the pressure signal to the float bowls. What are your feelings move the bov, add on or just leave it?

So, You have an MPI supercharger combined with a Bender Rear mount?????

You must have an 03 model with the old float bowls, you need to upgrade the float bowls and jet extensions.

4 psi is fine and 15 mm is fine.

BOV is your Friend when tuned right.

Ted.

 

[HURRICANE]

If your rx1 is an o3,there is an updated float bowl to solve your problem. Call One Stop Jim. He stocks the bowls

 

[TT]

No - MPI sold Bender stage 2 kits under their name. The difference was that the MPI kits had charge tubes and exhausts made of titanium instead of stainless steel.


I have a mountain version with the upgraded float bowls and jet ext. - the o-rings are new.

Link to pics of kit and bov location:


http://ty4stroke.com/viewtopic.php?t=57938

 

[Ted Jannetty]

Are you absoultely sure it is flooding and not running out of fuel???

 

[TT]

I have learned on thing in life - never be absolutely sure.

But I have to hold the throttle at wot position and crank it for some time to get it started again.

If I'm really quick and pump the throttle after I slam the sled down after a wheelie I can keep it running. I burbles and start running good after you get the revs up. So I'm pretty sure it's flooding. No popping - just burbles.

 

[HURRICANE]

Check that the boost signal to your fuel regulator is taken from the carb boots

 

[TT]

I have the signal from the plenum chamber.

I was thinking that taking the pressure signal from the carb boots would make the regulator react faster - correct?

Dumb question - wouldn't I have the same problem when chopping the throttle going down the trails. Then it's no problem. As stated it only happens when I'm slamming the sled down from a wheelie or going fast uphill a hit something hard.

 

[HURRICANE]

thats your problem. Your pressure is staying high to long. Just switch your hose to the carb boots.It will be fine

 

[TT]

Thanks - I will give it a try! It's not funny doing the small stuff when all the N/A is having all the fun on the hill - LOL

 

[TT]

A new bypass valve is on the shopping list this summer – I was hoping the vortech bypass valve Ted sells would fit somewhere on the charge tube on the Bender stage 2 kit. Ted have you installed any Vortech bypass valves on the Bender kits?

Anyone that has any thoughts on location on the bypass valve – before or after the pitot since it is pressurizing the float bowls?

 

[Ted Jannetty]

A new bypass valve is on the shopping list this summer – I was hoping the vortech bypass valve Ted sells would fit somewhere on the charge tube on the Bender stage 2 kit. Ted have you installed any Vortech bypass valves on the Bender kits?

Anyone that has any thoughts on location on the bypass valve – before or after the pitot since it is pressurizing the float bowls?

Yes we mount them in the charge pipe by the chain case, we also move the Pitot tube more forward to make room.

Watch your A/F very carefully with the Fuel pressure Regulator signal on the carb boots, This can create a serious lean condtion at part throttle.

Here is why, Your cruising down the trail at part throttle, your carb boots are seeing vacuum, This Lowers Fuel Pressure, and your intercooler is charged with boost raising float bowl pressure which works against fuel pressure entering the bowl.

You could empty the bowl and not get any fuel past the needle and seat.

To run your Fuel Pressure regulator signal to the boots you MUST have a Blow off valve capable of flowing enough air during part throttle cruise to Prevent the above situation.

Call me if this does not make sense to you.

203-753-7223

 

[TT]

No problem Ted - it make perfect sense. Do you by any chance have any pics of the Vortech bypass valve installed on a Bender kit?

We only have two weeks left of riding so this will be on the "summer to do list"

Conclusion before the Vortech is installed: pressure signal to the fuel regulator from carb boots and WOT all the time - LOL

 

[HURRICANE]

We have turbo springs on are web site to correct a rich condition as the boost is building. You may experience this as you get things closer to being dialed in

 

[TT]

Wouldn't adding a second bov to the plenum chamber and keeping the pressure signal to the fuel regulator in the plenum be the best solution?