951 Cylinder Bore

[Sportster-2001-951C-Stock]

That's a wicked cool boat. You should look into Copart for the drive and maybe the engine. They sell insurance cars, boats' sleds, bikes and skis that are considered totaled or not fixable. Most boats you don't need a license for so you should be able to find a good deal.

Rear deck reminds me of a Mach 1 mustang or something. Hope I don't have to cut it out, it's gonna be tight. Transom isn't very tall either, might be hard to keep the drive from being too deep. Ugh... Just finished grinding out a crack in one sponson, looks like they had some issues before and used the wrong resin, the repair was sloppy, very brittle, probably used polyester resin and/or didn't mix it right, I could strike it with a wrench and it was chipping right off, was split open and they didn't stitch it back first, just tried filling in the open gap. Why's it split in the first place, Looks like they were grinding it thinner or trying to change the shape, bizarre.

You mean a Copart license right? Good idea on snagging wrecked boats from them, hadn't thought of trying that.

 

[funsummerahead]

That's my guess, maybe 52 MPH. We call it the "FATSO" and also the "Pink Menace" as it's 4 feet wide and 9 feet long and weighs 500# or close to it dry. The 787 has about the same size jet pump and the 951 jet pump is larger and I have no interest in cutting that out and glassing one in. Makes no sense to try the 951 which I don't think will fit with the exhaust anyways. The 787 may fit. The original Kawi 650 did about 32 MPH with 50 HP. So a 787 is 110 HP so I would think it would do 50 or a little more. The jet pump on these old Kawi's is old school too. Silicone everything, slide it on the driveshaft, bolt it in and then silicone it again and press the silicone in again with an old credit card. Then wait 24 hours for it to cure when you could be riding... No fancy seals or O rings, just silicone the heck out of it and wait a day..,.

 

[funsummerahead]

Rear deck reminds me of a Mach 1 mustang or something. Hope I don't have to cut it out, it's gonna be tight. Transom isn't very tall either, might be hard to keep the drive from being too deep. Ugh... Just finished grinding out a crack in one sponson, looks like they had some issues before and used the wrong resin, the repair was sloppy, very brittle, probably used polyester resin and/or didn't mix it right, I could strike it with a wrench and it was chipping right off, was split open and they didn't stitch it back first, just tried filling in the open gap. Why's it split in the first place, Looks like they were grinding it thinner or trying to change the shape, bizarre.

You mean a Copart license right? Good idea on snagging wrecked boats from them, hadn't thought of trying that.

Copart is technically free, kind of. Most but NOT ALL boats on there you don't need a license to buy from them. For most cars you need a business license to buy a junker to rebuild. If you need a broker it's about another $400. There's a lot of goofy fees besides that. Bidding fee for how much you bid so the more you bid the more it is UNLESS you bid at a kiosk when you're there, that's free in most areas. Administration or paperwork fee $40. Gate fee is $60. Like I said MOST of the boats are NO LICENSE REQUIRED so in your case you could get a great deal. You're not going to rebuild it so if there isn't a title you're good. You will have to do some homework and Due Diligence but I'm sure you can pick up a good deal if you only need the drive and or the engine too.

 

[mikidymac]

The 787 vs. 951 is a pretty good debate and one I have had with a lot of friends.
These are actual radar numbers on smooth water for the two engines.
787
SPEED & RPM INFO -----95/96XP(97/98 SPX)-------97 XP -----------------GSX ------------- GTX

A)* Stock (10 hrs)---------- 57.2mph/6750---------56.5 mph/6780 ------56.8 mph/6820 ------ 52.2 mph/6820

951
I998 XPL 61-62 mph
1999 GSX 60-61 mph
1999 GTX 57-58 mph
1999 LRV 50-51 mph
1999 RX 58-59 mph

As you can see it's more than just 2 mph that the 951 has on the 787, it's more like 5 mph on average. What you don't see is where the 951 makes it's power advantage. If you have ever ridden one on mid to top they pull way harder than the 787 but on the bottom they are pretty similar.

Now the big issue is reliability. I am not even going to consider the 951 DI, just the carb models, I think the 787 is more reliable for the average owner Buth the 951 isn't that bad, it is much more maintenance intensive. It is not an engine you can just feed oil and gas and expect it to last like a 787. The 787 is pretty much bulletproof. Now the 951 you have to feed it only 100% API-TC full synthetic oil, make sure the fuel system and carbs are perfect all the time and fog it after every ride. The 951 was a very lean engine due to emissions that came out at that time so it needs all the lubrication and fuel it can get or they go boom. Because it is so high strung they also can't handle any water ingestion or condensation or they go boom.

For all my friends that just like to ride a ski, do basic maintenance and add gas and oil I always tell them to get a 787 and stay away from the 951. I just don't think they will give it the attention it needs.

I have no problem doing the extra maintenance the 951 requires, never let it ingest water and I fog it in the parking lot after every ride even when my friends and family are making fun of me. To me it is worth the extra performance over the 787. I only own this in my 2001 XP and there is no comparison between my two friends that have 1997 XP's, the 951 pulls way harder from mid to top. I did have a Group K Sleeper 1997 XP that was pretty close but we are talking stock vs. stock.

 

[Sportster-2001-951C-Stock]

As mentioned above and not to be overlooked, the pump is larger as well. It's important to match pump with the power plant. Sure, you can re-pitch impellers but that doesn't mean you'll be able to compensate for a smaller tunnel.

My guess is, Seadoo redesigned the pump to match the power plant.

LRV should have no problem doing 50MPH any day of the week except maybe for the worst conditions.

Agree, my 951 was way too lean, that's why I went up 2 sizes on the LS jet. Maybe 1 size woulda been enough, I'll try that someday maybe but I always make the 2x move 1st and it stuck. Also went with the weaker pop spring, don't think that made much difference. Easy starts cold or hot and runs like a top now. Probably this extra fuel does cause earlier fouling, went up one plug heat range and it's now what I'd call normal (ie: can make it through an entire season). Might be also, I turned up the oil to the rich side of the calibration line but you never see any smoke except fogging oil so I don't think so.

And I really do like the way those Rotax rotary valve motors run, my old XP was old reliable for more than a decade but in the end, I'm a reed motor guy.

 

[mikidymac]

As mentioned above and not to be overlooked, the pump is larger as well. It's important to match pump with the power plant. Sure, you can re-pitch impellers but that doesn't mean you'll be able to compensate for a smaller tunnel.

My guess is, Seadoo redesigned the pump to match the power plant.
.

Agreed but I think Seadoo got lazy towards the end, my 2003 GTI 720 has the 155mm pump so go figure, LOL.

 

[Sportster-2001-951C-Stock]

Agreed but I think Seadoo got lazy towards the end, my 2003 GTI 720 has the 155mm pump so go figure, LOL.

They can always pitch down in a larger tunnel. For Berkeley pumps the smaller wheels are for smaller displacements, I've seen as small as V6, could probably go 4cyl with the right cut.

Speaking of that, someone mentioned they were building or had the idea of building a surface drive Seadoo, wonder if they ever tried?

 

[etemplet]

It's IMO if you know what's good for you, you won't put her on a ski that's slower then the one you're riding!

I'm fixing up an RX for me. Azz whippin time for Bille Rae. LOL

 

[funsummerahead]

From what I've read anything with an accelerator pump runs a little too lean and that's why it's there in the first place - to clear the emissions and the accelerator pump is just a squirt gun for fuel to counteract a lean condition. It was on the internet so?

 

[funsummerahead]

As mentioned above and not to be overlooked, the pump is larger as well. It's important to match pump with the power plant. Sure, you can re-pitch impellers but that doesn't mean you'll be able to compensate for a smaller tunnel.

My guess is, Seadoo redesigned the pump to match the power plant.

LRV should have no problem doing 50MPH any day of the week except maybe for the worst conditions.

Agree, my 951 was way too lean, that's why I went up 2 sizes on the LS jet. Maybe 1 size woulda been enough, I'll try that someday maybe but I always make the 2x move 1st and it stuck. Also went with the weaker pop spring, don't think that made much difference. Easy starts cold or hot and runs like a top now. Probably this extra fuel does cause earlier fouling, went up one plug heat range and it's now what I'd call normal (ie: can make it through an entire season). Might be also, I turned up the oil to the rich side of the calibration line but you never see any smoke except fogging oil so I don't think so.

And I really do like the way those Rotax rotary valve motors run, my old XP was old reliable for more than a decade but in the end, I'm a reed motor guy.

 

[funsummerahead]

A couple years ago I rebuilt a Yamaha SUV and my buddy bought a Sea Doo LRV. They're both about 13 feet long and 5 feet wide. Both about 110 HP - Sea Doo with the twin cylinder 951 and Yamaha with the triple 1200. Both did about 50 to 55 MPH but were completely different on the lake. The LRV was like a freight train and just plowed through the waves and the SUV would go over most of them and I suppose with the QSTS - Quick Shift Trim System that helped and you could get a little air. They're about the same size, weight, HP, but were completely different - I guess the hull design was the main factor.

 

[Sportster-2001-951C-Stock]

From what I've read anything with an accelerator pump runs a little too lean and that's why it's there in the first place - to clear the emissions and the accelerator pump is just a squirt gun for fuel to counteract a lean condition. It was on the internet so?

Yeah, you might expect that's a clue and there's some truth to it. My observation was the accelerator pump allows a leaner idle mixture so you don't get a flat spot coming off idle. My flat spot was much higher up, well after the acc pump cam travel had completed. Maybe if I'd been more aggressive with clearing the three pilot holes the original LS jet was big enough....

I hear with the 787, a larger low speed jet doesn't make much difference, as if the pilot holes play a larger role in that case.

At any rate, the pilot holes and passage to them MUST be whistle clean.

 

[funsummerahead]

I was thinking about a SD jet boat. Not easy to find one at a reasonable price in good condition. There's one for sale now with a single 720 in it but I can't go for that. That would be like my 4 Winns Fling with the 90 or 95 Merc sport jet in it. Maybe 35 mph. You know it's slow when your 10 year old says it's slow...

 

[mikidymac]

You are correct the accelerator pumps were for emissions. It allows leaner jetting for idle so less smoking and emissions when idling then gets to add fuel to get going.

 

[Sportster-2001-951C-Stock]

I was thinking about a SD jet boat. Not easy to find one at a reasonable price in good condition. There's one for sale now with a single 720 in it but I can't go for that. That would be like my 4 Winns Fling with the 90 or 95 Merc sport jet in it. Maybe 35 mph. You know it's slow when your 10 year old says it's slow...

I think you could pull a tube just fine but if you want to teach your son to ski it's not enough power IMO, maybe for 2 skis and that's being generous but not slalom. And yeah, it's no speed demon. There are a lot of underpowered boats out there, seems to be the case more for over 20ft The 4.3, V6 stern drive is one of my favorites in a lighter 19ft or so, they run surprisingly well, expect +50MPH. With the right prop, you can pull more than one skier with the 3.0, 4cyl.

One nice thing about the stern drives is if you take care of them they last forever.

 

[Sportster-2001-951C-Stock]

You are correct the accelerator pumps were for emissions. It allows leaner jetting for idle so less smoking and emissions when idling then gets to add fuel to get going.

Also, I like the option of being able to give the motor a prime shot by using the throttle. Often I can start mine stone-cold on warm days without using the choke. And when it fires off but still cold where it lean-stumbles a little for the first few seconds I can actuate the throttle quickly and give it a shot.

 

[Mekanix]

Cp can custom make any size piston you want so it might be that.

I once has a 1981 gs400 with 67mm pistons. I stoped at a conservative 78mm and could have went to 83mm with those sleeves.

The old pistons and sleeves fit into the new sleeve lol .

So it's possible to bore up to the bolt holes an resleeve but at some point the porting will get too small. There is a 1051 kit isn't there ?

 

[etemplet]

I'm gonna measure again and put this stuff up for sale. Cylinders and the R&D 46cc head. I've learned that for me stock builds are the way to go. I've done a good bit of motorcycle road racing and one thing is certain. If you are not wide open throttle you are not using all the horse power.