What are the "best bang for the buck" sl 750 mods

[Technical Support]

Re: What are the "best bang for the buck" sl 750 mods

Correct.

[Skexies]

Re: What are the "best bang for the buck" sl 750 mods

Been eons since I've been online... *waving* Glad to see someone interested in the SL's still :) Most phun ski I own.



I've got a 95 SL750, I purchased from an owner who just installed a new SBT engine. I tore it down an modded it from there. 2 seasons later I've only had slight detonation drop a bit of compression on the rear piston. Replaced that and ready to go more. Wonderful ski, super fast (for the years), light and nimble, you should be able to get about ~60mph.

Best bang for the bucks mods:
1: Check out www.groupk.com, use their porting work and head work(93 octane). They did a lot of research to get the setup right, why re-invent the wheel? (Yeah I play with porting as well, but didn't need to jack with theirs)

2: Either use groupk's bored & rejetted carb factory carbs (better bang for the buck) or swap out the lower intake manifold & carbs from the PRO786 that are 46mm mikunis with dual fuel pumps on the bodies (what I did)

3: Reed cage spacers

4: V-Force reeds & cages or carbon tech reeds (I use carbon tech on this one and v-force on my race skis)

5: I stick with the 1mm over from SBT, at 2mm over you get funky heat build up on the 750 that requires race gas to avoid detonation.

6: o-ring the heads and cyls. Makes piston inspections easier.

7: Polaris has an intake update kit for skis that offers essentially an R&D intake. If you can find one floating around, go for it. If you choose the PRO 785 carbs, you'll have to watch out for clearance. I went with the actual R&D setup there, but had to grind and re-epoxy stuff to move the fuel lines, etc out of the way. It fits exactly against the wall.

8: If you can find one... switch ignition computers to 1997 slx pro cdi. The timing down low is more advanced and it is a bit more retarded up top. Helps acceleration and heat mangement. Incidentally I still have one spare in the shop, if you are interested and the price is right.

9: (Hotseat) Hardened drive shaft 4" extended - less likely to snap, bend and throw a prop and the longer drive shaft is required for the new pump. OEM is not hardened, but will more than likely work fine in the 750.

10: Polaris offered a solid drive shaft / prop shaft coupler for the pro785 or pro1200?, but stopped manufacture. If you can still find one, if it much lighter and stronger. I'm out of them.

11: 4" extended pump. You'll need a kit, talk to Randy @ watcon.com, he usually has the parts floating around. You'll need an extended cooling tube, different trim rod, pump extention(wear ring), bolts & washers.

12: Polaris offered an R&D intake grate for the pro 1200, if you can still get the OEM part. It works well. I'm fairly sure I have one? in inventory still here.

13: Prop, I use the skat swirl, don't go too big.

14: Polaris updated the stator sections in later models (like the 2001 genesis) to a stainless steel 6 vein. Pick up one with new bearings & seals installed and an aftermarket (hotseat or randy) hardened stub shaft. Much more economical than buying the skat 6,8,12 vein.

15: Pick up a ride plate for the sl750 from randy at watcon. Best plate for speed I've found.

16: Polaris offered a sponson kit for the SL750, if you can find the kit, you can use it. I picked up pro758 race sponsons from randy @ watcon and mounted those. Regardless you'll be cutting the foam from the inside back walls, drilling holes and mounting plates with silicone adhesive. ;)

17: Polaris provides a plastic factory 4 degree pump wedge on the 2001 Virage. Best bang for the buck there. Keep the factory trim installed as well, it'll help.

18: sl750 has a dual siphon pump nossle. (I've also added an electric bilge inside) You can swap to either the 2001 virage nossle body & add a duckbill drain(no siphons & best performance but duckbills are tempermental) or the 2001 Genesis nossle body (1 siphon, best compromise) and plug up the other openings on the hull.

19: Finger throtle. Randy @ watcon has a cool billet one that is very comfy & trick.

20: I updated to the pro786 handlebars & electric controls, gives me bilge control and molded in grips.

21: Pro 785 seat? I built mine up custom and lightened, but used the pro 785 hydroturf cover.

22: Hydroturf footwell pads and traction mats, I hate flinging off.

23: Pick your waterbox, I use hotseat and a custom one.

24: Eliminate the petcock or replace with new. They get old and starve the engine of fuel.

25: I updated my front fuel tank to the new style sending unit. This has an integral fuel sender that doesn't F'up. and is more sturdy. You can either mod the current tank or replace it along with the new sender/pickup. (this is not best bang for the buck, it isn't cheap, but works great and allows me to block off the old sender location and use fuel tank foam)

26: Front fuel cap. OEM one cracks and leaks water into the tank. there was a recall & update kit or you can just buy a billet one. Always inspect the cap gasket regularly... if it cracks you bring in water and jack the engine.


Hope ya have a great time, it is tons of fun!

[beerdart]

Re: What are the "best bang for the buck" sl 750 mods

Now that last post was "Bang For The Buck"

[1fastxc]

Re: What are the "best bang for the buck" sl 750 mods

Thanks Skexies, that's by far the best response so far. That's what i was looking for. Here's an update of what i'm working on. I've got the crank back. I bought wiseco pistons(stock bore), that i'll be setting the bore clearance on myself to prevent cold seizure. I have a line on some v-force reeds and spacers that i'm going to buy. I already ordered an Ocean pro ride plate. I have the 3 outlet fuel pump and OP vortex FA's and i'll be using the stock carbs for now. I'll be getting a Skat-trak 13/18 swirl impeller. I also have an aftermarket waterbox(i don't remember the brand since i ordered it 4 years ago). I'll also be getting the 4 degree pump wedge you mentioned. I found out that little secret too. It only costs $20 vs.$80 aftermarket. I have a new filler neck kit also. Now a couple questions for you. I'm getting a different intake grate for sure, and i'm leaning toward the R&D ones. I see they offer a different one for the sl 750 compared to all the other models. What's the difference between them, and which is better? Just by looking at the two, the 750 one looks like the wing might be taller. Also the extended pump setup you are talking about, is that the stock setup they used on later models? Thanks.

[1fastxc]

Re: What are the "best bang for the buck" sl 750 mods

Also, would you be willing to give up any of the porting and head specs from the group k setup? I also play around with porting, and i would send out my cylinders to group k, but my budget won't allow it at this time. I could do the work myself, but would like some proven specs.

[Skexies]

Re: What are the "best bang for the buck" sl 750 mods

Sounds like you are having fun!

I don't know the dif between the R&D grates, sorry.

Sorry, I don't have the head specs or porting specs and the cyls are on the engine. Also, I hope you understand that I respect the huge investment in time and money Group-K puts into R&D and would not, if I had them, give that information out unless it was no longer a service still offered by them. I will say that unfortunately the SBT heads on the remanufactured engine were definately NOT performance grinds and mine didn't have enough material left on them to mill it to where they needed to be. I'd recommend changing them asap. I waited until the engine broke in and I knew I wasn't going to have to use the SBT kick-azz warenty, then tore it down and kicked the cyls to group K with another set of used heads.

Yes, the extended pump is the factory pump used on most later models. Be careful, as a few of the older skis [like the pro 785] don't all use the correct 4" extended pump/shaft and some didn't offer the stainless stator.

Essentially you just need the wear ring from a later model, drive shaft & bolts.

You can extended the steering cable by buying a 4" length of aluminum rod [1/2" diameter will work] drilling and taping it to extended the old steering cable.

You can extend the coolant pipe by cutting it and extending it with some textile reenforced (auto) hose and a couple of clamps. This also allows you to use pump wedges without issue. Later models also used larger ports from the pump nossle [behind the screen] to the coolant pipe connecting area. I often grind that area out to increase flow.

You can make your own extended trim rod or buy a used one.. ;)


I suggest the following as a cheap mod as well;
I use similar varients (although a bit more elaborate) on all my performance modded Polaris skis. Some I've had to make spacers to kick the rail up and clear things others the rail works with a few minor grinds on it.

Buy an aluminum bar .5" x 2" x 13" (I use online metals... love those guys as much as SBT http://www.onlinemetals.com/merchant...owunits=inches)

Have or buy a 3/8" NPT pipe tap & proper size drill bit.

Buy (3) 90 degree 3/8" NPT right angle brass adapters from Home Depot, Lowes or Ace Hardware. One side Female, one side Male.

Buy (3) 3/8" NPT to 1/4" barb straight brass adapters from Home Depot, Lowes or Ace Hardware. One side male, one side barbbed.

Buy (3) 90 degree 1/4" pissers from your favorite PWC performance shop. I get mine from Randy @ watcon, they are made by UMI.

Buy 1 roll (50' or 25') of blue 1/4" air hose from Home Depot, Lowes or Ace Hardware. (normally used for air-compressor tools.)

Buy 1 package of JB weld

Buy (6) stainless hose clamps for the 1/4" lines

6 screws of proper length to bolt the bar down... Measure, I'm not sure the proper size off the top of my head.

Some zipties to keep it all together

(optional line restrictors for the 1/4" line of various sizes)

1:
Mark, and drill the bar exactly where the factory coolant bar mates to the screw holes on the heads. Allow some room for play as the heads rarely go back perfectly the same unless you are anal with indexing. You may have to grind or drill strategic places to clear objects and the bar will mate up flat. [you can use the old coolant rail as a template]

2:
Drill and TAP for 3/8" NPT the bar in proper places to allow the coolant holes to align as well.

3:
Mix some JB weld and use to seal threads of barbs to 90 degree NPT adapters [don't get messy ;) ]

4: Determine what angle you want to points the 3 individual coolant hoses to, so they are easy to route with other internals and don't conflict with other things like sparkplugs or exhaust pieces. Use JB weld on the threads here as well as you screw them into the rail and stop at the correct angles for all 3. (I usually have the angles so the hoses all layer up along side one another, it makes it easier to zip tie.

5:
Figure out where you will have enough room for hose to come off the wall and snake back to the coolant heads and drill holes to fit the pissers through. Mount them in the hull with adhesive RTV. I always use the front deck where you normally see triple pipe pissers and make them point down and back @ 45 degree angles. (my post-modded craft have 3 or 6 pissers each depending on whether single pipe or triple pipe respectively)

6: Cut the threaded ends off the 1/4" hose (not needed). Then cut proper lengths to feed from the rail's barbs to the pissers in the hull. Mount them with screw clamps and bundle together with zip-ties.



For best performance you want to slightly restrict a line or two so that all the cyl temps are even when running at WOT for a while. The Fujis have a tendancy for the front cyl to get less coolant flow than the rear. (You can test temps by finding someone who has a I.R. thermometer to borrow for a bit) Even without balancing the temps, you'll still be better than the factory. HOWEVER, you will have to be MORE careful at warming up the engine before getting crazy from idle/low speed to full, as there is no more spring/thermostat in this config to keep the water from flowing.

If you get nasty cool, you can make another bar to cap the entire line of 3 cyl heads down. This would help prevent the cyls from torquing around under load as much, and looks very kew.



For your fuel, I assume you know to T into the factory supply lines between the carbs. But in case not, you want to supply fuel between the carbs.. as under high demand the last carb often starves out from the first two. The pro 785 mikunis have two pumps to stop this issue, one feeds the front and one feeds the rear and then they both feed the middle. The middle then feeds the return restrictor & line.


One last thing, the hull of the polaris is noted to crack from time to time back where the pump mounts. You can build a 90 degree bracket, cut to the radius of the pump nozzle and drilled to allow the trim rod through... To connect the two top nozzle bolts to two new bolts you would run thruogh the top deck, at the back of the ski by the tow hole. This will support the back of the nozzle and keep it from flexing up/down/left/right when under load.


Steven Eric Fisher
Shade tree racer, fabricator, and dubbed "Good-azz baller"
"Tim Allen must be a long lost brother"

[ShowMePro1200]

Re: What are the "best bang for the buck" sl 750 mods

Welcome back, Skexies!

Ah, what a breath of fresh air - a thread about the old Polaris boats that doesn't start out, "well, unfortunately, you bought a Polaris..."

While we're on the topic of Polaris, SBT shouldn't you be telling folks that the 650/750/780 cranks are 'chemically bonded' and not actually welded? Should there be some form of disclosure here? I have never bought one but I always was of the impression the cranks were welded and would end that problem forever.

;) :D No flame intended :D ;)

[Wet Wolf]

Re: What are the "best bang for the buck" sl 750 mods

There are 2 R&D intake grates for the Polaris, the stock small wing which is found on the pros and the hurricane, and the large wing which has to be ordered aftermarket. When looking it up in a parts catalog, t will be listed as fitting sl650/sl750. It was originally designed back in 93 I think. The wing is larger and it sits a little bit lower than the stock type r&d. If yo can get one of the big wing grates, definatley go for it. It might slow you down .5mph on the glass, but will do much better in the chop.

My crank guy up here has been glueing cranks for decades. In fact, i just had rod kits put on the hurricane and had the crank trued and glued. I have ever ad a problem with any of his glued cranks, and have installed hundreds of them.

[1fastxc]

Re: What are the "best bang for the buck" sl 750 mods

Thanks for the reply wet wolf. I've seen 3 different r&d intake grates so far for polaris. The shorter wing style(general polaris in the catalogs), the taller wing(sl 750/ hurricane 700) And the one that is standard equipment on the pro 1200 which has a bar in the middle of it according to the picture on partsland.com. Would you recommend the taller wing out of these three? Thanks.

[Polaris_Nut#1]

Re: What are the "best bang for the buck" sl 750 mods

Skexies, really knows his stuff!!!

Group K is the way to go! The other guys set me up for race fuel by mistake years ago. Their respones was double your head gaskets. They even tried telling me that polaris did that from the factory on some models.

Cheap 100 Rpm increase - Change the cooling orfice on your exhaust pipe with the screen to the smaller diameter one in the 780, from like 2.3mm to 1.0mm if I remember correctly. My manual is in the garage with my new SBT 780

If you get those extension pump parts indivdualy you also need the longer steering cable, I got a used slx pump off ebay way cheaper than dealer cost.

skat-trak makes those nice pumps for polaris, and they are cheaper at the deal, even cheaper if you can find one online, in which case I might be bidding against you, need one for the SLX and one for the Hurricane. The pump makes a big difference.

There was a recall on that petcock issue

The factory sponson kit comes with inserts and you don't need to take out the foam.

I'm running the big R&D grate, also the 6 degree wedge more lift.

I haven't found one cheap enough yet but the pro trim motor is suposed to be twice as fast.

Wolf gave me a good tip, besides his awesome invention. bore the exit nozzel cheap for the do it yourself-er

I can honestly say pro-series reeds, spacers, air cleaners and a primer kit made the most improvment, followed by the R&d grate

I love these old polaris ski's, the new one's cost too much

[1fastxc]

Re: What are the "best bang for the buck" sl 750 mods

Polaris nut, did you happen to see the pump that was on ebay last week? It was from a 96 1050. That was why i asked if the parts skexies was talking about was the same as a later model. They were asking $100 for it but there were no bids. I was skeptical since there were no bids, and it was from florida and i don't know what all the issues are with salt water, otherwise i was going to bid on it. I got a set of pro series reeds off ebay last week too. Impeller is on the way too. Thanks for the tip on the screen swap.

[Polaris_Nut#1]

Re: What are the "best bang for the buck" sl 750 mods

"Item number: 4546481289 This is from a 1996 SL 900. May also fit the 1050. It is in great condition. Bearings are great, spins freely."
If he relist it, you want it. Not a bad price either! You'll need to use that impeller you got coming. You'll need to modify that steering cable and trim rod or replace them, longer drive shaft too. I did a search of completed items, he has listed that at least twice. you might have to email him and ask him to relist it if you really want it.

you can look up the diferent models and compare parts here http://www.partsland.com/

I bought my 95 SL750 new and was ticked off when the 95 SLX came out shortly after. I went to the dealer, got out the micro fisch thing and ordered everthing I could afford. Waited on the expensive things like the pump, They wanted $400, YIKES!

Tip I got from Group K, keep your thermostat ditch the spring and plunger.

don't know if you can still get this? 2871560 intake grate from polaris $29.99 (cheap) any of the R&D grates are better than what come on the SL

2871466 sponson kit 28 inch $79.99 can find em on ebay for $25 now and then

Good luck parts hunting

[1fastxc]

Re: What are the "best bang for the buck" sl 750 mods

So that pump from ebay would do the trick? What is the difference between that one, and the type you are looking for? Also, would there be any major issues since that pump was used in salt water? Thanks.

[Polaris_Nut#1]

Re: What are the "best bang for the buck" sl 750 mods

I'm just looking for the stainless steel stators. They are way better than the cheap cast ones. They have different numbers of veins also. They provide better hook up. I got a 6 vein on my SL750. Gives it a lot more thrust. I was putting the cone back on my old pump set up and could see water squirting out of the cast one, it was craked and taking in water. Don't know about the salt water, Not any around these parts. Might have some corrosion.