SGX 91RS

[BigChuck]

David

Good idea. The RSVO motor will have more torque that you can think of. But you will need to have a handle on the head numbers and know were to start and were to set the head so the motor will live.

 

[Tom Foley]

Yes Ray .010" is fine on a 91. Tom, I knew his head volume must have been a communication error.

Yes the pipe needs to be .470" all the way David. As I recall the 80 stinger is s only about .420" I would stick with the 80 pipe. The 90 pipe will only give you more torque that you don't need.

6.3 cup is too much for a 90 SGX unless your looking to go 100 mph. 5.8" cup on that H-50 will put you in the low 90's and the boat will handle better. Just shorten the pipe and let it breath (stinger) and you will go fast with little effort.

Thanks Andy. Will be fun trying to open up the inner stinger. Your memory is real good .420 it is. Got to scratch my head a little on this one.

Ya I did bend it a little to much at the pond. But it sure did go. Think I will hold off on propping it up till I get the hang of it.

The fancy button and all the whittling on the P/S it sure seams to like the cup. the stock 1667 made it jump out of the water at launch.

Just want to keep up with the new twins. :lol:

David

It worked!!!

The RPM's were over the top. Way over the top blew the guts out of the plug seal and all. Could not catch up with the needle and burn a pin hole in the piston. :angry:

Time to start over.

I guess I should have mentioned to be sure to start with a richer needle setting....always a good idea when making changes to the engine/pipe.

I put the Boris flow meter on it and started at 40. Just got away from me. The link on the needle fell off and that was all see wrote. It wants to rev to the moon though. I just have to learn better needle management. I am very bad at it when it starts to sing and my heart starts pumping. Didn't stick the piston any way. The mods work on the 91 the same as on my 45. I'll get it next time. Maybe?

Got a 1.00 EVO P/S to use just need the button. Think I'll wait till I get the hang of it before I go there.

Hope Stu gives me the volume discount. :lol:

Andy you have any headers for a 91RS in the SGX?

David

Lose the 3rd channel needle deal ..when you have real power ..DONT NEED IT !!!!

 

[dwilfong]

Yes Ray .010" is fine on a 91. Tom, I knew his head volume must have been a communication error.

Yes the pipe needs to be .470" all the way David. As I recall the 80 stinger is s only about .420" I would stick with the 80 pipe. The 90 pipe will only give you more torque that you don't need.

6.3 cup is too much for a 90 SGX unless your looking to go 100 mph. 5.8" cup on that H-50 will put you in the low 90's and the boat will handle better. Just shorten the pipe and let it breath (stinger) and you will go fast with little effort.

Thanks Andy. Will be fun trying to open up the inner stinger. Your memory is real good .420 it is. Got to scratch my head a little on this one.

Ya I did bend it a little to much at the pond. But it sure did go. Think I will hold off on propping it up till I get the hang of it.

The fancy button and all the whittling on the P/S it sure seams to like the cup. the stock 1667 made it jump out of the water at launch.

Just want to keep up with the new twins. :lol:

David

It worked!!!

The RPM's were over the top. Way over the top blew the guts out of the plug seal and all. Could not catch up with the needle and burn a pin hole in the piston. :angry:

Time to start over.

I guess I should have mentioned to be sure to start with a richer needle setting....always a good idea when making changes to the engine/pipe.

I put the Boris flow meter on it and started at 40. Just got away from me. The link on the needle fell off and that was all see wrote. It wants to rev to the moon though. I just have to learn better needle management. I am very bad at it when it starts to sing and my heart starts pumping. Didn't stick the piston any way. The mods work on the 91 the same as on my 45. I'll get it next time. Maybe?

Got a 1.00 EVO P/S to use just need the button. Think I'll wait till I get the hang of it before I go there.

Hope Stu gives me the volume discount. :lol:

Andy you have any headers for a 91RS in the SGX?

David

Lose the 3rd channel needle deal ..when you have real power ..DONT NEED IT !!!!

Tom

You know I think that would be the best thing I could ever do. Can't mess with the needle if I don't have a button to push.

David

 

[Andy Brown]

Yes Ray .010" is fine on a 91. Tom, I knew his head volume must have been a communication error.

Yes the pipe needs to be .470" all the way David. As I recall the 80 stinger is s only about .420" I would stick with the 80 pipe. The 90 pipe will only give you more torque that you don't need.

6.3 cup is too much for a 90 SGX unless your looking to go 100 mph. 5.8" cup on that H-50 will put you in the low 90's and the boat will handle better. Just shorten the pipe and let it breath (stinger) and you will go fast with little effort.

Thanks Andy. Will be fun trying to open up the inner stinger. Your memory is real good .420 it is. Got to scratch my head a little on this one.

Ya I did bend it a little to much at the pond. But it sure did go. Think I will hold off on propping it up till I get the hang of it.

The fancy button and all the whittling on the P/S it sure seams to like the cup. the stock 1667 made it jump out of the water at launch.

Just want to keep up with the new twins. :lol:

David

It worked!!!

The RPM's were over the top. Way over the top blew the guts out of the plug seal and all. Could not catch up with the needle and burn a pin hole in the piston. :angry:

Time to start over.

I guess I should have mentioned to be sure to start with a richer needle setting....always a good idea when making changes to the engine/pipe.

I put the Boris flow meter on it and started at 40. Just got away from me. The link on the needle fell off and that was all see wrote. It wants to rev to the moon though. I just have to learn better needle management. I am very bad at it when it starts to sing and my heart starts pumping. Didn't stick the piston any way. The mods work on the 91 the same as on my 45. I'll get it next time. Maybe?

Got a 1.00 EVO P/S to use just need the button. Think I'll wait till I get the hang of it before I go there.

Hope Stu gives me the volume discount. :lol:

Andy you have any headers for a 91RS in the SGX?

David

Lose the 3rd channel needle deal ..when you have real power ..DONT NEED IT !!!!

Tom

You know I think that would be the best thing I could ever do. Can't mess with the needle if I don't have a button to push.

David

The third channel is great, BUT one must be disciplined to use it.

 

[julianconde]

Yup engine go from hauling the mail to junk if you don't Control your mixture. I run 3rd ch on everything I have except Twins

 

[Joern Markset]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

 

[Marty Davis]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

25% NITRO..............

 

[Chris Wood]

isn't that stuff used to kill weeds marty? don't they call that weed be gone LOL!!

 

[Tom Foley]

Sure would be cheaper than pissing all this unused nitro out the ehaust port on these 91's and 101's !!!!!!!

 

[BigChuck]

Not Really :blink: :blink: Big blocks are just going to THROW that fuel out the window

no matter WHAT the %%% numbers are.................... :lol: :lol: B)

 

[Tom Foley]

Not Really :blink: :blink: Big blocks are just going to THROW that fuel out the window

no matter WHAT the %%% numbers are.................... :lol: :lol: B)

:lol: :lol: :lol: :lol:

 

[dwilfong]

You should here the gas guys at the pond wine when thy have to launch it. The launch handle in the back gets covered with fuel and it get all over there precious hands. :lol: :lol: :lol: :lol: :lol:

Wayne got Castor sickness form it and miss work for a few days.

New P/S on the way round 2 ding ding.and a fancy new header from Tom.

Thanks Tom

David

 

[Rudi Arnesen]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

25% NITRO..............

You all might find this strange, but remember Jørn Markset became the world champion with his SGX90/CMB 91 RS this summer in Hungry.

I beat none of you could beat him on the race course even if you run allot of nitro.

I totally agree with Jørn, and besides this the speed is not only in the amount of nitro you are running.

 

[dwilfong]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

Joern

The carb is a modified OS 8AA. There is a pic of it in the thread.

I am very interested in your set up. What plug do you run. Also what carb do you run. I know that the sound level needs to be low at your races what pipe are you running.

I am always open to new Ideas.

David

 

[Andy Brown]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

25% NITRO..............

You all might find this strange, but remember Jørn Markset became the world champion with his SGX90/CMB 91 RS this summer in Hungry.

I beat none of you could beat him on the race course even if you run allot of nitro.

I totally agree with Jørn, and besides this the speed is not only in the amount of nitro you are running.

Some years ago I was sitting in 1st place after 3 rounds of racing at the Orlando Winternats in F hydro. The boat was clearly the fastest at the event. After the 3rd round Joe Ingrao walked up to me and said "I want to buy your boat" (Joe didn't race slow boats).

That result was on 20% Nitro!

 

[aaron alberico]

I have close buddy of mine running a cmb101 in a mono

and is one of the fastest mono's in OZ

and he only run's 25% nitro.

regards Aaron

 

[dwilfong]

I think I might try this 25% nitro setup. Can just swap heads at the pond and see what it's all about.

The local speed shop sells 50% vp in 5 gal. cans for $91. with the oil and extra methanol $15 a gallon fuel would be real nice not to mention the wear and tear on the $180 P/S.

The way I see it the case is the same whether you run a 1.01 or a .91 P/S. You can only move so much air thew the ports no matter which way you go. Makes sense that a smaller displacement will rev higher with the same amount of air flow. Like what was said were are not pulling stumps. I think RPM's are the ticket.

David

 

[Terry Keeley]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

Joern

The carb is a modified OS 8AA. There is a pic of it in the thread.

I am very interested in your set up. What plug do you run. Also what carb do you run. I know that the sound level needs to be low at your races what pipe are you running.

I am always open to new Ideas.

David

Been looking for a big bore OS for my 80, Tower says the I/D is:

Inner Diameter of Air Inlet (narrowest point): 11.85mm (0.47")

(widest point): 15.75mm (0.62")

Is it really oval shaped?

 

[dwilfong]

What kind of carb are you using?

Put on a turbo head at 0,45 mm squish band, fill up with 25% nitro and you will make it a lot easier for your self

Joern

The carb is a modified OS 8AA. There is a pic of it in the thread.

I am very interested in your set up. What plug do you run. Also what carb do you run. I know that the sound level needs to be low at your races what pipe are you running.

I am always open to new Ideas.

David

Been looking for a big bore OS for my 80, Tower says the I/D is:

Inner Diameter of Air Inlet (narrowest point): 11.85mm (0.47")

(widest point): 15.75mm (0.62")

Is it really oval shaped?

Terry

The 8AA that I have was not oval bore when I got it. This carb has the same part # for the barrel as the 9B. The body is bigger with a wider spacing on the bolt pattern. It also dose not have the idle stop screw.

I modified it to make it oval bore. The measurement are referring to the tapper of the inlet Ventura. With the body being larger you have room to grind the body and barrel on the low speed needle side of the bore.

It is much less expensive also.

David

 

[153stars]

Yes Ray .010" is fine on a 91. Tom, I knew his head volume must have been a communication error.

Yes the pipe needs to be .470" all the way David. As I recall the 80 stinger is s only about .420" I would stick with the 80 pipe. The 90 pipe will only give you more torque that you don't need.

6.3 cup is too much for a 90 SGX unless your looking to go 100 mph. 5.8" cup on that H-50 will put you in the low 90's and the boat will handle better. Just shorten the pipe and let it breath (stinger) and you will go fast with little effort.

Thanks Andy. Will be fun trying to open up the inner stinger. Your memory is real good .420 it is. Got to scratch my head a little on this one.

Ya I did bend it a little to much at the pond. But it sure did go. Think I will hold off on propping it up till I get the hang of it.

The fancy button and all the whittling on the P/S it sure seams to like the cup. the stock 1667 made it jump out of the water at launch.

Just want to keep up with the new twins. :lol:

David

It worked!!!

The RPM's were over the top. Way over the top blew the guts out of the plug seal and all. Could not catch up with the needle and burn a pin hole in the piston. :angry:

Time to start over.

I guess I should have mentioned to be sure to start with a richer needle setting....always a good idea when making changes to the engine/pipe.

I put the Boris flow meter on it and started at 40. Just got away from me. The link on the needle fell off and that was all see wrote. It wants to rev to the moon though. I just have to learn better needle management. I am very bad at it when it starts to sing and my heart starts pumping. Didn't stick the piston any way. The mods work on the 91 the same as on my 45. I'll get it next time. Maybe?

Got a 1.00 EVO P/S to use just need the button. Think I'll wait till I get the hang of it before I go there.

Hope Stu gives me the volume discount. :lol:

Andy you have any headers for a 91RS in the SGX?

David

Lose the 3rd channel needle deal ..when you have real power ..DONT NEED IT !!!!

Tom

You know I think that would be the best thing I could ever do. Can't mess with the needle if I don't have a button to push.

David

Can set EPA on radio so as not to over lean ,fine line as it is , but the needle probably had way too much room for leaning left in it.