300sx build

[2006superjet]

its a good ski

i have has 440 650sx and 750sxi blaster and now super the 300sx it a decent ski i can load it up easy its only like 200 lbs empty and 2 buy no prob throw it in a big pool or somthing.

the 300 has a lil more power like 3 hp more than the 440 and is more stable. i am 180 and know how to ride and balance so its no problem just hold it full and slowly get up from your knees after its plaining and ur good to go it suck with you get air cause the prop needs to get full again and it is sluggish but its still melow.
i got it for 400 and its clean and runs great i can prob sell it for 400 so im renting it, wish i could say the same for my super. moneypit

 

[Polish jet pilot]

Cool project...I'd 80hp in that hull would work miracles! Only if the pumps had a larger diameter....

 

[WFO Speedracer]

Defoaming time,the foam in this thing must have weighed 20 or 30 lbs.While I was in there I also removed the scupper and exhaust tube and ran the exhaust out the hole where the scupper was.I also added a larger bilge tube and glassed up the holes in the bottom,everything protruding through the hull has been sealed with 5200 fast cure.I have already poured the foam and cut it off,its now ready for reglassing .:wiggle:

Look D B PURPLE TURF,don't get excited its coming off.

 

[afcblink]

So, is this thing on the water yet?

 

[djkorn1]

I want IT!!!

 

[SKItarist750]

can a stock one even get like a 200lbs guy on plane?

yes it can! as a matter of fact i rode a 300 stocker a few years back when my 750 was blown up and i was waiting on a crank. i'm about 230 lbs and it got me on plane...it took about 20 secs at full throttle though. :rocketwhore: whenever i would bunny hop it would lose so much momentum in the air that when it came back down, that single cylinder just couldn't keep me on plane. easy to sub though cuz it's so lightweight.

 

[WFO Speedracer]

Yeah its on the water,not running to well at present,some kind of weird total loss problem,I have to pull the engine and see whats up with it.Been riding the 650sx conversion ski lately.

 

[WFO Speedracer]

Yep the weird total loss problem turned out to be resistor spark plug caps,that combined with resistor plugs was cutting my spark big time,also it has a setup similar to a Rad cover,you loosen four allen head screws and turn a knob and that turns the stator plate to adjust the timing,thing is the allen bolts were tight but the plate was not locking down.So when I pulled the engine I disassembled the stator plate and took some material off the stator locking plate ,now when you tighten it all down it stays where you put it.This setup is kinda neat because it has no switch,it has an auto switch that senses movement of the crank and turns the ignition on,when the rpms drop below a certain range it cuts itself off.Now I have an air leak at the intake manifold that I tracked down yesterday.its time for some more compression and maybe some more exhaust porting for more bottom end,also the impeller pitch is too high,I have a 15 pitch Skat on the way for it and some reed gaskets.

 

[WFO Speedracer]

I got the gaskets in today to fix the air leak,so I decided to pull it apart and do the deed.I have been looking for the reed boosters I had to put back in the cages when I take this apart,I looked for quite a while and gave up.When I got it apart I found the reed boosters,they were in the reed cages in the engine duh huh! At any rate I decided to put the bad bones reeds back in and try them again since I had gotten the other problems worked out,I also replaced the hodge podge of bolts holding the intake on with stainless studs and USB nuts,much ,much nicer setup now.Maybe it will get warm enough tomorrow t try it out again.:fingersx:

 

[WFO Speedracer]

I just got back from riding today,it still did not want to dial in right,I finally decided to disconnect the on and reserve hoses and run them directly to each carb,my bog disappeared as soon as I did that. I started dialing in the high speed adjusters,and got it dead on the money.I still need to install some non resister plugs and open up the plug gap to .050 .It freaking rocks now,I need more compression and a lower pitch prop but its right in there,finally I have the ski I always knew it could be,this thing is so short and light that its a blast to ride,not really squirrelly at all just totally badass! :woot:

 

[afcblink]

want.

 

[WFO Speedracer]

Did a few mods to the handlepole today,I shortened the steering up by 1 inch,going to test it out now and see how I like it.The aluminum on the top is just a laminate so I can replace it with something else at a later date,I am looking at carbon fiber sheet and at thin diamond plate,the diamond plate would be cool looking but kind of rough though.The chin pad is just sitting there,its off the thunderjet,I think I will pull a mold and mod one up to fit this pole exactly.

 

[WFO Speedracer]

Next mod up d -cut ride plate,I think you can do without pics on this one,back to the lake I go yeeeeeeeeeeeeehhhhhhhhaaaaaa!!!!

 

[WFO Speedracer]

The D-cut works pretty much the same on this as on anything else,nose pops up quicker,maybe a little too quick.At least I have some more leverage on the pole now to keep the nose down,all in all I am pretty happy with it.

 

[JoeD]

Cool build, I have a 701 going in my 300sx hull sometime this winter. Haven't decided what to do with the pump yet though?

 

[WFO Speedracer]

Cool build, I have a 701 going in my 300sx hull sometime this winter. Haven't decided what to do with the pump yet though?

I was thinking about that today,the 650-750 pump would mount lower in the hull but,the shaft is much smaller so there is working room inside the driveshaft tube and the engine is mounted on aluminum plates on top of the stock mounts.Seems to me you would just get plates of the right thickness to make up the difference in driveshaft height.Then its just a matter of mounting a 650-750 style bearing carrier to the bulkhead,finding the appropriate length shaft and modding the pump tunnel for a bigger pump,shouldn't really be that hard.I think I have found two more of these locally and I may pass this one onto my son and start on one with a bigger engine and pump.

 

[Polish jet pilot]

Great project - action photos?

 

[WFO Speedracer]

Great project - action photos?

post#40 :twak:

 

[WFO Speedracer]

This ski has now become my sons ski,he really likes my 650SX flatdeck and he likes his 300SX so you guessed it why not combine the two.The plan is to make a semi flat deck with a 650 engine and to mod the pump tunnel to accept the 650 pump.I will also be shortening the handlepole about three inches to get the weight transfer further forward.Here is the progress so far today,more to follow soon as time permits

 

[WFO Speedracer]

Going a little different route here,I peeled away the SMC from the foam and using some contact cement recycled some of the pieces,they will be glassed at the seams and then glassed over on the back,this gives me somethin nice and flat to lay up against and it should be very strong.I like the way its looking so far.