Completed 650SX Build - From 50Hp to 60+

Yes sir. I polished it and re-shaped the leading edges so they are consistent. I have a nice Solas 16 pitch and I like it but I noticed that it would quite often hit the rev limiter off of the holeshot. The stocker is a 15 pitch, has much less vibration...actually almost none, and seems to really hook up well through the whole range.
 
Hey, no problem Prodigy. I'll tell ya, this is probably the most fun I've had with modifying anything. I've done some small mods to my truck but it's just not the same. And when get to see how these mods actually improve your ski, it makes it that much more satisfying. I've mentioned it in the past and I can't help but mention it again, just the extra 4.5" of expansion chamber to the exhaust makes the most difference and should be the number one mod on everyone's list. I did this mod for a buddy of mine just recently and he thoroughly loves the performance improvement. He said it makes the ski what it should be and agreed that hands down it is the single most important mod he has experienced yet. The piece of tubing I used is very rare and can become very expensive to order just in that small of a size, but if you can buy up a used stock pipe, cut that straight portion of the stinger off, get as close to 4.5 inches as you can and either weld it onto the stinger you use, or couple it together with a 4" to 4" plumbing coupler from Home Depot for about 10 bucks. You will have to cut the rubber exhaust tube down to about 5 inches long or so, you should measure it first because it could be 5.5", and bear in mind that there is an anti-collapse spring inside that hose that you will have to snip through with side cutters. But also keep this in mind because it just happened to me last weekend. That spring will get brittle, mine broke about 5 times without me knowing it and it made a little ball of springs inside the hose, then the one broken end eventually poked through the hose and I ended up having a torn hose from it. If you have this happen to you, the next best thing you can is either buy a 1.75" ID heater hose to replace that old exhaust hose, or cut the old one to have a pair of 3" long couplers, buy a 2" ID stainless exhaust tip for a few bucks, cut the rolled over end off and the end with the securing bolts to get about 4.75" of solid, polished stainless tubing and couple that together using the 3" couplers made from the stock hose. If you wanted to, you could also go to Home Depot and buy a couple of 2" rubber plumbing couplers if they sell it. Oh yeah, one thing to bear in mind too, when you use the 4" to 4" rubber coupler, you do need to double clamp each end. The coupler comes with a groove for one clamp to sit in, but you need a second clamp per side right before the edge of each pipe that you are bridging. If not, the pipe will flex inside the coupler and will cut it. The extra clamps really solidify the pipe and almost eliminate the movement so the coupler stays intact. Hope that helps if I haven't mentioned it before. There are more mods to come but now it's mainly buy and bolt parts, the poorman mods are slowly coming to a finish. I'll post the new parts as they get installed.
 
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Whats going to be the compression difference between a milled stock head and an aftermarket head? Ive been considering sending my top end to groupk for porting and I would also send the head for them to mill. And then I was going to do some of these upgrades...especially the exhaust. All to be done after my fall semester is over.
 
what domes? and are you able to send me a link to any page that has the same head? and what octane do you have to run? 105, cause idk if i'd want to go over 93
 
I am not sure what size the domes are, I just happened to see it on a ski and asked if it was for sale. He told me it was good for pump gas but only because it had a thick green gasket under it when he used it. I used the stock head gasket so I assume that is what brought the compression up. I use pump fuel with it but I also add in NOS premium octane booster. It bumps the octane rating up a full 6 points by the pump rating. So right now, I have 91 octane with the NOS giving me about 97 as long as it gets mixed properly. It definitely smells like AV fuel when you smell the exhaust and the ski seems to really like it. I found that my fuel economy has improved a little bit and the engine seems to stay relatively cool, if there was a detonation issue the engine would heat up a lot more than what it is when I run it. Plus it would not last very long before burning a hole in the center of the piston. So far, I have logged about 5 hours of run time with no issues. The NOS octane booster seems to be good stuff and although it is an added 20 dollar expense, it will treat about 15.8 U.S. gallons so you are still saving about 30 bucks by using that instead of buying 101 LL AV fuel at about $6.20 a gallon. As for links, I don't have any info on it. I'll just post up a pic of it and you can research it. I'll do what I can to find you some info but right now a pic is all I can offer.
 

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No, it's not interchangeable domes. I like the concept of the O-ring heads but I prefer to know that I can use stock gaskets when needed instead of tracking down parts that may be NLA. I was surprised too with the results from the tester, I was expecting to be around 180, maybe 185. I did run 91 octane with it for the first tank because the tank was already full and I didn't want to get into draining it. It seemed to be alright with it but still, anything in the 200 range needs that extra few points or you will be always running the risk. Because premium doesn't sell quite as quickly as regular, more so these days with the price gouging they're doing to us, that premium could sit in their tanks for up to a month. Or well over that if the area isn't highly traveled, anything over 30 days old in the life of fuel with it being made out of the cheapest components they can get means that octane ratings will start to drop off after that 30 day mark, more so with ethanol blends in the 87 and 89 octane ratings. I'm not sure if they're mixing ethanol in the premium grades yet, I know Shell doesn't but it does stuff in a lot of nitrogen as a filler which in my opinion is useless. It's just an inert gas much like argon for MIG welding. I suppose it could help in slowing down the combustion rate but I doubt it. Inert gases just do not burn, that is their purpose. Fuel just isn't what it used to be. I've seen carburetors so clogged up with stale fuel that they were building a green film inside the carb, and that was only after 3 months. Has anyone noticed that back in the mid 90's, premium fuel used to have that blue tint to it, and now it all has that corn yellow/goldish tint to it. Plus it doesn't smell the same either. I used to like the smell of fuel when I worked on my old skis or 4-wheelers, now it gives me severe migraines if I'm around it for just a few minutes.
 
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Joker

...chaos? Its Fair!
Ok, so here are the last stages of my mod works until I either blow the ski up or get ahead a little over the course of the winter. So for this mod, I cut out the middle bar in the stock intake grate. I just used a tiny hack-saw for small area plumbing work that I had kicking around (it's about time it had a purpose) A little change of this mod from what I have read in the past is that I changed the angle of the curved portion at the back of the grate, to be a little more aggressive and I sharpened the edges to cut the water instead of jamming through it. Also I gave the curved area a bit more of an opening to allow the additional amount of water in and keep that pump loaded. Think of it as looking like the wide mouth beer cans, less glug and more chug lol. I'm not sure if this will help but it can't hurt. I also read recently that by just putting a stainless washer in between the ride plate and the hull only at the back two bolts (closest to the rear of the ski) it will help to reduce porpoising, I'm going to try it and see, for how cheap the washers are why not.
yes the washers do help to stop porpusing. i have 3 on my 300 and it helps significantly. it also helps with carving.
 
glad to see you modded up your 650sx some more. come next winter i will be making either an aluminum or all stailess steel pole as well. i will be doing your stock pipe mod too. i cant wait to start riding again!
 
I've only been off of the water for about a month now and I'm dying to get back out. I have to wait though until next summer now. The water temps up here are getting a touch too cold for my liking. I sent out my custom handlepole for black anodizing and will be setting it up next spring. It looks sweet being that flat black. I'll try to get a pic or two up in the near future.
 
nice i wish i had time money and skill to do that to mine haha its a 1990 same decals and its got a coffmans exhaust icean pro ride plate and grate and stainless prop(not sure what pitch but it needs a lower one and its roached from the previous owner) but its super clean and i got it for 650 bucks. i want to do some stuff like what you did to yours but for now i really just want a prop and foot wells
 
I had to replace my impeller this year because I had a tap chip when chasing out the threads. It totally trashed the threads inside the hub so I put a Skat-Trak 10/18 on in place of my old Solas 16 straight pitch. Very noticeable difference through the bottom end hook-up curve. Footholds are still on my list and now that the ski performs so well, they're becoming more of a priority to me. My stock turf finally let go this summer and is tore up pretty good now, so this is the perfect time to start putting a turf and foothold job on the front burner. I made my own custom moulds to fit my feet instead of the "one design fits most" that the manufacturers have to produce. Making the mould was pretty easy actually, it just takes a lot of time and about 40 bucks worth of materials. I'll try to post up a little info on what I used and how I did it but it was not my idea. I found it on pwct awhile back, bought the same materials and just put the time in to get the design I figure will work best for me. I gotta tell ya though rider, try to get that stinger extension B-pipe mod done. You might not be so worried about the impeller as a first priority after you feel the difference. I'm not kidding, it is like night and day difference.
 
Here are the pics of the handlepole I made after I had it sent out for black anodizing. I quite like the looks of it, makes me think of parts for a Stealth Bomber. This thing was a nice matching metallic blue but I just could not find any clear coats that would either not react with the paint and turn to mush, or be solid enough to resist chipping but soft enough to not wear off. So this was my better option and again, it did not cost me a cent.
 

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