Jnz

Im looking to get more from my 951 in my gtxl- I currently have a fresh rebuilt engine, and your jet kit installed. Looking at my options to get more out of it for the next season. What are my best options I ride this ski for rec. I was originally looking into the jetworks exhaust mod as it is supposed to give you better hole shot and they say 3-5 mph, but I doubt that. Some others were suggesting a miller head and new impeller or a white pipe? What would you recommend?

Mr. Bill

You can build more torque and horsepower if you do some minor mods along with the what you have now using my filters and rejetting kit. These additional mods, each one will add a very small amount in it's own way. The largest bolt-on gain without going to a more extreme cost like a big bore kit and expensive carbureators, and additional clyinder porting along with some expensive exhaust system, will come from Rinaldi reeds and the Miller carbureator spacers. That mod will yeild an additional 8 hp, and a slight bump in compression using a Miller head with his specially designed pump gas friendly inserts ( inserts is the technical term for domes in a head that uses interchangeable domes ) may really help the holeshot. We proved the 8 hp on stock motors when testing those parts on the dyno at Miller's place.
A smaller gain, yet a wothwhile one, is the 1997.5 GSXL white pipe, but you also need the white exhaust manifold that matches the pipe and the white pipe type '97.5 motor pipe bracket for the mag housing mount that completes the exhaust swap-over to see the gain, and you can add to that gain if you use the tapered cone that R&D made (they made two versions) in their second edition cone, a better working cone than their first attempt at it making cones for oem 947 pipes.
I do not know if they still have any though, so the used market may be the only option to get one. I may have one stashed in my shop somewhere, I cannot remember if I sold it or not. Anyway, even without a special cone on the white pipe, you may get an additional 100 rpm or so, which is is noticable as it means a bit more torque to turn the impellor.

I was the pioneer in developing pipe rejetting kits for oem Sea Doo pipes, starting with the 787 motors, but I soon stopped offering them as the buyers would not yield my warnings to keep the small jet openings clear of debris, and the gains were there, but minimal anyway over the oem water regulator system. I just cannot see a 3-5 mph gain in an oem pipe rejetting kit only, without some other mods too. 3-5 MPH is a big jump in speed on an otherwise oem motor. Less is most likely what you would get, but Art at Jetworks has always been a standup guy, so I will not go as far as saying he is quilty of false advertising. I know he was working with stinger sleeves too at the time, and I cannot recall if he was using his aftermarket carbs too. Maybe 3-5 with a bit of help from the other parts, and also, who knows what impellor was in the pump. Before my disability, he and I used to share a ramp at our local lake, him testing his stuff, and me testing mine. We shared ideas when one of us was hung up on a problem we were trying to work through and the other was present at the lake to bounce ideas off of. It was a two way street between us then, and probably would be today if I was into my old routine of testing 3-5 days a week at the lake, instead of talking about it here on the website with guys like you Mosly though, back then, he was out there alot with his Yamaha triples that his team was using at the local races, working on them. Occasionaly, he would show up with some customer's Sea Doo he needed to tune. His 951 pipe rejetting kits came along much later though as I remember it. Although guilty of it now and then, I try not to make a habit of commenting on other aftermarket suppliers claims, unless I have personally used it on one of my boats.

So, Rinaldi reeds, Miller carb spacers, my rejetting and filters kit with a Miller head and you will see a gain in speed. Add the white pipe and manifold, more, if it will fit into a GTXL hull, which I have not tried to do. It was made for GSXL hulls, and I have put one on an XPL a time or two also. But there is always a reason to change an OEM pipe design, and that may be they wanted only one pipe to fit all models, I do not know.

Some of the speed quotes you hear about different parts may not be as effective on a heavier, longer three seater hull, Whereas on a GSXL, or XPL, may be closer to the truth of the claims, so keep that in mind when listening to other people's stories about what made their boat go faster, and I do not put stock in speedo readings on Joe Blow's personal ride. You never know when their claims may have been a result of also replacing a wornout wear ring or a dinged up impellor that doesn't make it into the story.

strokersquid

I have a 1998 purple/red GSXL. does this mean I should be looking for a white pipe and manifold for better performance ?

Jnz

Thanks Bill, that is some great information you've given I currently have your jet/filter kit and it worked like a charm with a fresh carb rebuild. With the items you've suggested do these need to be done at one time or can I put one on at a time as I go?

And strokersquid from what I've gathered since owning is if you don't have it yet get Bill's jet/filter kit, you will notice a nice gain. probably more bang for the buck than anything else out there. And make sure your carbs are nice and clean.

Jnz

Where can I purchase Miller parts, I know it's Miller Racing, but does Mell have a website?

Jnz

Ok, from searching the site I found that I actually am best to get the parts from you, So what I would need to know is if I can put each of the parts on separately or if its a combined thing. And what would the cost be for the parts that I would need (reeds, spacers, and head , gaskets)

Mr. Bill

No problem putting the parts on one at a time. There will be no need to change the jetting, maybe only a minor adjustement or two to the H&L needle adjusters.
Sorry I couldn't have answered sooner, you can order the parts from Chris at my shop, he usually comes in a little later, but if you miss him, leave a message. Be sure to mention you want to buy parts and you live in the USA. And please, speak slowly when leaving a phone number.
Chris @ 626 9149509 for parts.

Bill O'Neal
WCM

strokersquid

should i be looking for a white motor pipe ( PO did some carb work already but i'm not sure what. has individual filters at least )

Mr. Bill

I have no comments about whatever the PO did to your carbs as I do not know any details of what is inside them unless it has my kit in it.

White 947 pipes are fairly rare these days as Sea Doo only built a very limited number of gery deck, white motored GSXL's. It was only 6 months later they introduced the red deck, silver motored GSXL. Both are offically 1998 models per the VIN numbers, but most of us refer to them as the 1997.5 model, or "Grey Deck GSXL ". The two are very different in many ways.

White 947 exhaust manifolds and pipes only came on the '97.5 GSXL, all other 947's use the same black pipes that were to become the production model 947 tuned exhaust systems in the real production models of all 947 carbureated powered Sea Doo's from 1998 onward. Along about 2001, Sea Doo made a change to the exhaust manifold by cutting an oring groove in the Ex manifold's headpipe flange on the top of the exhaust manifold in an effort to get that joint to seal better. The problem is with the groove being brittle and we find many that are broken off when we dismantle the headpipe from the exhaust manifold. Repairing it is costly if you have it welded, then have a machinist re-cut the groove after resurfacing the warped flat surface after welding it.
It is about just as good and much easier on your pocket book to fill the whole groove up with special epoxy that is made to be used on bead blasted clean aluminum parts, then flat sand the total flange surface of both the manifold and headpipe, then use an oem gasket with orange High Temp silicone on both sides of the gasket and a light, even coat of orange silicone on both surfaces of the two parts. If you evenly torque the 3 bolts, and get the nut as tight as you can without breaking ithe stud, your pipe will not leak water at that joint.
No matter what model or year exhaust manifold and pipe you have, from 587 all the way up to 947, remove the 8mm or 10 mm stud from the manifold, then flat sand the two surfaces. Red Loc-Tite the stud fully back into the bottom of the threaded hole it came from after running a bottom tap through all four threaded holes to clean them, then blast out the residue in the holes with compressed air. Always torque the bolts or nut evenly in steps so as not to warp any flange surfaces. You must get the stud fully seated in the threaded hole, or you will find that you cannot get the nut back on if the pipe is fully seated on the manifold, and if you put the nut on the stud before fully seating the pipe to the exhaust manifold because you did not fully seat the stud, your box end wrench will not fit between the pipe and the top of the stud when the nut is fully tightened back down. Then you say "how am I going to get this wrench out of here " ? Or, "how am I susposed to get this box end wrench onto the nut, there is not enough space between the stud and the pipe ". So, you take it all back apart and start over, cleaning everything nice and clean again, tapping the holes so the studs and bolts can fully seat into them after blowing them clean, re-siliconing another new gasket. Not much fun to cut corners !

There are mods to the black pipes and silver manifolds that can result in extra power from the exhaust system, but they are not easy mods for a DIY guy that has no machinery. You can shorten the exhaust manifold surfaces where they meet the clyinder ports by as much as 8mm safely. You can open the ID of the manifold pipe flange by 2-3 mmm if you taper it down into the top of the manifold as far as to the split, and do the same to the headpipe to match the manifold, but go as deep into the pipe opening as far as a long porting tool will reach. Trim the Ex flange gasket to the larger I.D.
You can use a thin aluminum sleeve in the tail cone. It does not hurt to experment with different I.D. diameters of the sleeve, but do not exceed a sleeve wall thickness of more than a couple of mm. You can get it too small and burn pistons. You can also do like Jetworks and make up a water jetting kit for your pipe, or buy Art's kit. You can also add his water valve to reset the water flowing into the new stinger brass water fitting you just added to your tail cone. You will need to alter the mounts for the pipe, as nothing will realign after triming 8 mm from the manifold. There may be other interference problems too that you will need to solve also.

These changes will do alot for accelleration, and if you get the stinger sleeve and water-into-the mid-pipe jetting correct, you will see more rpm and top speed from your stock black pipe. Probably, no, surely, much better that buying a non modded white pipe and mainfold and just bolting it onto your silver motor.

Novi, R&D, and Hot Products at one time or another, sold sleeves for 947 tailcones. At least one may still have some.

We, like the German's say " VE HALF ARE VEYS " of making anything better.