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Rebuilding a XP 720 Motor

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Hi guys,

Just a little update.
The jet ski is running great. Like a dream:p. Only little thing is sometimes the starter doesn't start right away when you pres the start button. It sometimes takes a few second or sometimes needs to be pressed a few times.

Also just wanted to ask how often i should service it and what does a service consist of? I read/heard only to replace the plugs and change the oil in the pump with a new seal. Is that all?
Also one main thing i'm scared is the oil pump. How can i keep and eye on this and make sure it doesn't fail. As id hate to kill my $2500 engine!!!!!


http://www.youtube.com/watch?v=Xc-jHfjvMXs
 
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Great looking ski, nice job.
I like the sticker on the hood about the "A$$ whooping" and the pic of you??? flying in mid-air.
 
Thx.
I'm doing another vid that i'll post soon. My first time filming with a Gopro Hero 2:)

It's the beginning of winter but i'm having so much fun with this ski. every chance i get i'm out on the river with friends:p
I often compare it to the newer 155+hp ski's but i still like mine better. Ok they go much much faster but when you see them doing skids or 180 or 360's it looks like the are on a Bentley and are having a smooth ride. Mine i've got to hold on for dear life!!! Now when we do the trick at two on the ski its so unstable and even more demanding. I also sometimes like in that mid air pic, like to gun it prepare myself and do a hard turn followed by a launch of a couple of meter. Lol. good fun and great pics:p

Anyone have any tips on whats involved for the service, how often and procedure?
Thx
 
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I never have used one but from what I've read, it doesn't help much.
Wait and see what other members have to say about this item....or do a search for it.
 
Some more pics:)

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Me and a mate
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And another of my falls:p
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So would anyone be able to tell how often i should service it and what does a service consist of? I read/heard only to replace the plugs and change the oil in the pump with a new seal. Is that all?
Also one main thing i'm scared is the oil pump. How can i keep and eye on this and make sure it doesn't fail. As id hate to kill my $2500 engine!!!!!

Much appreciated:)
 
So no one can give me some advice on the above??

For now the ski has been sitting as we are in winter. Was going to take it out with Macgyver that was going to test his ski but the shaft bearings sized!!!! got to get that replaced now:(
 
well...as i have the same ski as you i was worried about the pump too since my first engine had a melt down..after talking with DR. HONDA i have realized exactly how reliable these ol pumps are..just replce the filter every once in a while and be sure to change the lines on it abd you should be ok.... replace them with CLEAR lines so you can see the oil flowind and just look at it every once in a while
 
i think you guys are getting a bit confused, the Jet pump has the oil and seal you need to change in a 'pump service', the Oil pump (front of the mag housing) has a small inline filter before it in the line from the tank (Brendon would have put a new one in when he rebuilt it)
 
Hi Guys, Its been a while. So little update, The ski has been in storage most of winter. Have braved the elements a couple of times but finally got the complete wetsuit, boots and gloves gear. Lol!!
Only issue that came up in the middle of winter when i started it now and again, is one day it started this whine that got louder and louder and turned out the shaft bearing had seized!! Good thing i didn't run it for more than a few mins when that happened.
It went to the shop and got a new set of bearings. Also serviced the oil injection system with a new filter and new oil in the pump.

Also finally ordered blacktip wishbone mats and a seat cover for it that are soon to arrive:) This weekend is going to be around 34deg so with a go-pro and a reliable ski, i'm sure to enjoy myself:)

Also, I'm a bit undecided if i need to start modifying the ski with high comp heads, exhaust, carbs, etc or just run it as is and keep an eye out for a 1999+ Xp similar to Macgyver's one. Man that thing is fast!!!! What would you guys suggest?
Thx
 
Hi Guys, Its been a while. So little update, The ski has been in storage most of winter. Have braved the elements a couple of times but finally got the complete wetsuit, boots and gloves gear. Lol!!
Only issue that came up in the middle of winter when i started it now and again, is one day it started this whine that got louder and louder and turned out the shaft bearing had seized!! Good thing i didn't run it for more than a few mins when that happened.
It went to the shop and got a new set of bearings. Also serviced the oil injection system with a new filter and new oil in the pump.

Also finally ordered blacktip wishbone mats and a seat cover for it that are soon to arrive:) This weekend is going to be around 34deg so with a go-pro and a reliable ski, i'm sure to enjoy myself:)

Also, I'm a bit undecided if i need to start modifying the ski with high comp heads, exhaust, carbs, etc or just run it as is and keep an eye out for a 1999+ Xp similar to Macgyver's one. Man that thing is fast!!!! What would you guys suggest?
Thx

Leave the thing alone
It will become less reliable and to go fast = a lot of money.
 
Had an awesome day today, Made a little circuit with some weights and floats to race around with the ski's. Also went on a little cruise up the river and even a few jumps from wakes caused by a big ferry boat:D. My 720 is as fast as the 787 3D., but gets eaten by the 99XP :)
Can't wait to do it all again tomorrow....

5 Doo's and a broken Yami at the end Lol!!!
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The fleet:)
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Ok so for this summer i started to mod the ski, a bit late but i started. Firstly so far i've done some easy and cheap mods.
I Ripped my purple molding off and thx to MacGyver, I was able to get some black side guard strips and yellow inserts for free :)

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Also made my own rear hull extensions out of alu plate i had laying around from my transom build for my explorer.

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Also started to make my own sponsons. First thoughts were, "i hope i don't run over and chop anyone in pieces"

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Got rid of the checker plate effect by grinding it down with a sand paper disk surprisingly fast. Now trying to get a alu block or a hard plastic to make the spacer between the hull and fin


More pics and mods to come:)
 
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Ok so Got a bit more done on the ski today.

First was the sponsons. Shopped around and got those plastic off cuts bits at a shop. Not sure what exactly they are called but i'll find out.

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So made the spacer. With the measurements from MacGyver HX, I cut them to shape. The spacer has a taper but also a slight curve to match the hull. Easily achieved with a sand grinder disk.

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And this is how it looks:) Also sanded the bottom of the fins to give it a blade effect:) I replace the small 15mm dia washer with a 40mm dia one inside the hull. Also the factory sponson had three holes, but i added a fourth one to help distribute the load on the hull. Didn't want to put washers on the sponson side as i much rather pull through the $10 plastic than make rip open the hull.

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Once it was all nearly installed, had two bolts left, i had to pull both off as i had forgotten to add silicone to make it water tight!!!!! Lol

Total cost for my sponsons incl 316 marine grade bolts nuts washers etc was $52.36 (not counting time, elec power, sand disk, drill bit and equipment as thats was already there:) )


Also got a set of used moto renthal handle bars for $25. They are a bit wider so i had to cut them. Glued on my grips and use the billet finger throttle from my kawasaki (engine still not built. Anyone has an extra finger throttle for sale?? )

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Thats it for now.
Next is the black tip wish bone mat and the seat cover that are coming in the mail:)

Then a factory pipe:D!!!
 
WOW when i began reading this i was like .... this guys is opening a can of worms. But u did a real nice job getting ski back to life..... GREAT JOB , im impressed
 
Thx, I'm really happy and enjoy myself taking a peice of shit and turning it into something... You should read my seadoo Explorer custom build thread:) I wonder what's worst than worms???? That explorer build was all done by myself and started off way worst than this one:) LOL

http://www.seadooforum.com/showthread.php?47230-Jet-Boat-conversion-Ideas

Ouuuuuu and the kawa build thats still in progress:p hehe, I must say, I love those worm cans:p
 
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