GS vs XP Which should be faster?

[motogotro]

Hi again....newbie here.

I recently bought a 2000 GS and a 1997 XP. I had some issues with the GS but it is running great now and in fact, even though it has the smaller engine it seems to be noticeably quicker than the XP and may be faster as well. It hooks up better and pulls significantly harder out of the hole for sure but without a speedo I can't really tell top speed and I haven't had a chance to run them side by side yet. The best indicated top speed I've seen on the XP is about 48 but remember that is using the stock speedo and not GPS. The real disappointment with the XP is coming out of the hole. It feels like it might be cavitating until it gets on plane and then it hooks up better. You can actually hear and feel the engine pull down just a bit once it gets on plane. I found a piece of vegetation caught in the intake grate yesterday. I cleaned that out and took it out again this morning and while it was better it still doesn't feel right. The impeller looks good in that it doesn't have any nicks, dings or bent blades. It appears to be stainless steel and has a pronounced swirl finish to it so I'm assuming that is aftermarket but I have no idea what make/model/pitch it might be. The edges of the blades are rounded rather than straight. Looking at the stock intake grate on ebay it appears that I have an aftermarket intake grate as well. I just read up on checking the wear ring this morning but have not checked that yet.

So the questions are:

Would you expect a 720 GS to pull harder than a 782 XP out of the hole or am I chasing my tail here?
What is the best intake grate and impeller combo for a 97 XP or should I go back to stock and start from there?
On the off chance that the intake grate is a POS design, is there any value in taking it off completely for a test run to see if that helps the cavitation?
Are there any other tricks to help with cavitation or anything else I can or should test on the water?
How hard is it to replace the carbon seal? Does the engine have to come out?

If I have to pull the pump I'd rather fix all of the possibilities at once rather than work on it every weekend for the rest of the year. I'm willing to spend the money to make it right but at this point I'm not even sure my ski has a problem. It may be not be any different than every other 97 XP!

 

[speedbuggy67]

787 97 xp's are notorious for feeling underpowered and a one year only ski. a gs with 85hp moves pretty good, but not like a 787 GSX. You might not be going crazy.... I ride my 96gsx787 vs my best friends 99xpl 951 and when my buddy had a grounding issue and was losing his gauges and raves weren't opening correctly my gsx blew it away in every aspect. From a standstill my gsx (although has proks and jetted ) pulls right away and he only gets me past 55mph gps... the parabolic hull XP with that heavy nose is great in chop but doesn't help acceration at all...

Scott

 

[motogotro]

I looked at my wear ring through the nozzle and it looks pretty bad. It looks like some of the rubber? parts around the edges are breaking up and flaking off. I think I'm going to order a ring and see if that helps at all.

 

[AdamXP800]

Yep replace the wear ring and it will feel like a different ski



96 XP800!
Keep the 2 strokes alive!

 

[motogotro]

I pulled the pump today and it looks pretty bad in there. Whatever the coating is that is supposed to be on the wear ring is almost completely gone. I ordered a new ring, rebuild kit pump oil and impeller tool. The impeller looks pretty good but has a few small dings in it that I will clean up when I get it out. I have my fingers crossed that this is going to make a significant difference.

 

[motogotro]

When I pulled the cone off the back of the pump there wasn't any spring or any other parts in there. I see online that some of the cones have some anti-rattle parts. Should my cone have those as well?

 

[bajaman123]

http://partsfinder.onlinemicrofiche...a=53&b=19&c=0&d=-PROPULSION-SYSTEM---INTERNAL

Yeah...you're missing parts...see the diagram.

 

[JJinSC]

48 mph on that 97xp is about 10mph slower that it is capable. Typically the stock speedometer reads high. It sounds like you found a big issue though with the wear ring.


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[XP 787]

48 mph on that 97xp is about 10mph slower that it is capable. Typically the stock speedometer reads high. It sounds like you found a big issue though with the wear ring.


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True, I've GPS'd mine at 58 on glass nozzle up.

 

[motogotro]

I got all my parts in Friday and everything went together smoothly until I was ready to reinstall the impeller and noticed a crack in one of the blades. So that one stays on the trailer this weekend. Hopefully I'll get a chance to try it out next weekend.

 

[motogotro]

Impeller came in today and I put it all back together so new wear ring, reconditioned stock impeller, new shaft and bearings. I's definitely better than it was but still underwhelming. Coming out of the hole I think the GS still feels stronger. I picked up a couple of miles an hour up to 50, maybe 51 if I hold it long enough but not as good as I was hoping for based on some of the comments I've read about the expected top speed of an XP. The ski just generally feels heavy and sluggish compared to the GS. The engine sounds good, no missing or bogging, starts easily, idles perfectly. I'm stilling running both injection and premix so that may be costing me a little? At this point I think I would trade the XP for another GS and probably be happier. If I didn't have the GS I'd probably be happy with the XP but comparing them side by side the GS takes the cake.

The plus side to the XP is the lean-in turning, that can be a real hoot.

 

[JJinSC]

Mine will take a GS all day everyday. Something still isn't right.


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[speedbuggy67]

a 787 XP vs a 717 GS... the 787 xp weighs 525lbs vs 478 on the GS... 85 vs 110.... plus the nose heavy 97 xp... its def closer then you think. My gsx weighs 500lbs.... and will run away from the 97xp 787 with ease... I too agree i'll chose the GS hull whether 717 or 787. my best friends 99 XPL weighs 550 vs my gsx is very very close except for top end 55 GPS vs 60GPS, is when things get choppy the XPL starts to shine with that heavy front and cushy seat... I'll even get gutsy enough to say my GSX with beach house sponsons tears apart the XPL in handling..

Scott

 

[motogotro]

Thats 5.6lb per hp for the GS and 4.7lb per hp for the XP so on paper it would seem that the XP should feel stronger than the GS. I'm not really sure where to go from here. I'll read up on RAVE valve adjustments maybe and see if there is anything there. I'm watching the oil tanks on both skis and the oil is going down but not very fast so I'm not 100% sure the oil injection is working correctly or adjusted correctly. I'd really like to stop premixing but I don't want to fry an engine in the process!

 

[mikidymac]

I small tachometer like theTinyTach will help to see what rpm's you are turning on top end so we can see where you have lost some performance.

 

[JJinSC]

a 787 XP vs a 717 GS... the 787 xp weighs 525lbs vs 478 on the GS... 85 vs 110.... plus the nose heavy 97 xp... its def closer then you think.
Scott

I think you got the hoarse power backwards. The XP has 110, the GS has 85.

I small tachometer like theTinyTach will help to see what rpm's you are turning on top end so we can see where you have lost some performance.

This is a good idea!

 

[motogotro]

I hit an indicated 55mph on the XP last night in really smooth water. I also found that it feels better coming out of the hole with the VTS up about 1/4 but anything close to 1/2 and it will cavitate so it's a fine line. The RAVE valves are flush with the top and from what I've read they should be all the way down. I've ordered some RAVE gaskets and will pull them off and give them a good cleaning and see how it feels with them screwed down.

 

[mikidymac]

The RAVE adjustment could be some of your issue. I think the 97' XP might have been adjusted a little differently due to the drag of the larger hull.

I bought a brand new 1997 XP in 1998 and loved it but like yours it was lacking out of the hole. Top speed was fine but out of a hard turn it needed more. I don't want to pipe it because I like all of my stuff to look stock and be reliable so at the time I bit the bullet and sprang for a Group K sleeper kit. It was exactly what it needed. It was much faster out of the hole and I could walk all over my friends stock 97' XP. It was so much fun to roost him then run away. He could never catch me. It was the best money I spent on that ski.

I still check the registration numbers whenever I see one in the area for sale. Would love to buy it back.

 

[motogotro]

This an old thread but I though I would share the difference a summer can make.

If you've read the thread you know I bought a 2000 GS and a 1997 XP at the start of summer but to my disappointment, the GS was a stronger faster ski in almost every regard. After a summer of learning and tinkering the tables have finally turned.

After a few trips to the lake, the GS developed a wrist pin knock so I fully rebuilt the engine including a new crank and a bore to 1.0mm oversize so it's now something like a 736. That ski runs awesome, pulls very hard out of the hole and is quite fast on top end for what it is. All in all I am very happy with that ski and my 13 year old son loves it.

I've done so much work on the XP it's hard to even remember it all, wear ring, impeller, carb kits, RAVE valves......you get the picture. I was never quite happy with it until I went from 1.5 turns out on the low adj screws to .75 out. What a difference that has made. The ski now pulls much much harder coming out of the hole and he throttle response is night and day different. In a head to head competition the GS use to smoke the XP coming out of the hole and match it on top end. Now the GS will still pull about a half to 1 ski length on the XP coming out of the hole but the XP will catch and pass easily. I've seen an indicated 60mph on the XP in full trim smooth water where I could barely break 45 when I first got it. The 1997 is a much disparaged ski and it is definitely heavy but once it's tuned right it is still a fun ski to ride. I've since bought a pair of 96 XPs that I'm working on for next year so we'll have to see which ones I end up keeping.

 

[96spxpos]

Glad you worked the bugs out on the 97XP, I love the way they look.