-
This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.
The X4 Thread
- Thread starter purple_people_eater
- Start date
- Status
Austrian Rotax
Active Member
How is the stability of a 951 x4 at 65mph? Also any info on possible hour ratings for a 951 with a hot rods crank? Or even wsm crank?
seadooaddiction
Active Member
Once I get mine buttoned up and I get some seat time ill let ya know!
doomann88
New Member
Couldn't be happier with it right now, held up great all summer. Only had to replace the brushes in the starter at one point. Otherwise it's just gas and go.
I don't want to start a shit storm but here's my opinion on the 951. Under engineered. Now with that said, if you can keep water out of it and properly build it and maintain it, they can last a long time.
I have heard that a while back hot rods got bought out and then started having them built overseas...and that it's on the level of a SBT or wsm equivalent these days. Way back when... They were awesome. Now... Not so. I personally had a 951 here with a new hotrods crank that came from ses with a boat a friend bought. It literally lasted 10 hours before it locked up, broke a rod, and destroyed everything.
To ses credit, he did take care of it including the cases. He tried to blame it on lack of oil, which we confirmed was not the case. Not really sure how that it is even possible seeing as the piston hardly had a scratch on it.
I think the only way to go is oem crank on a 951, oem fully if the budget permits. Then make dang sure there isnt leakage from the pipe. Use the diaper, use the deflectors, I think the old mani and paper gasket are better.
In closing if you do this conversion, do not just buy a used 951 and drop it in. Rebuild it top to bottom.
Sent from my SM-G920V using Tapatalk
I have heard that a while back hot rods got bought out and then started having them built overseas...and that it's on the level of a SBT or wsm equivalent these days. Way back when... They were awesome. Now... Not so. I personally had a 951 here with a new hotrods crank that came from ses with a boat a friend bought. It literally lasted 10 hours before it locked up, broke a rod, and destroyed everything.
To ses credit, he did take care of it including the cases. He tried to blame it on lack of oil, which we confirmed was not the case. Not really sure how that it is even possible seeing as the piston hardly had a scratch on it.
I think the only way to go is oem crank on a 951, oem fully if the budget permits. Then make dang sure there isnt leakage from the pipe. Use the diaper, use the deflectors, I think the old mani and paper gasket are better.
In closing if you do this conversion, do not just buy a used 951 and drop it in. Rebuild it top to bottom.
Sent from my SM-G920V using Tapatalk
Last edited by a moderator:
Seadoodoc
Active Member
65 is fine. I can turn hard WOT at that speed . 68 to 70 range it chine walks and wont set up for hard corners untill you scrub speed. My Xpl could turn hard at 69 mph. No throttle burp. On crank shafts.... dont spin these mtrs beyond 7k rpm and they live. Failures at 7200 rpm are bad. Failures at 7500 rpm are mutually exclusive to buying a new Tesla.
Sent from my SM-G920V using Tapatalk
Seadoodoc
Active Member
Total weight of 951 over 787 is about 25 lbs. 100 vs 125) Interesting note the stock 951 pipe alone weighs a mamouth 20 lbs of entire engine weight. I suspect aftermarket pipes weigh 5 or 6lbs. Fitment is issue. Stock OEM is built to fit. Does it lean a little to one side? Yes. Undetectable riding it. What ever conversion weight gains, easy to loose in other areas.. battery...minus 10lbs.. Bottom line on 951 x4 conversion... you want race boat fast on a budget? Throw 787 in the trash
Sent from my SM-G920V using Tapatalk
seadooaddiction
Active Member
Seadoodoc, your running an oem black exhaust pipe setup on your conversion, correct? I decided to forgo the white pipe install for sake of riding this season and requires lest clearancing of the hull. The white pipe is just too darn snug at the moment.
Seadoodoc
Active Member
We come from opposite ends of Country Nick! Literally. You are just now tinkering with motors we perfected in 2005 making 200 hp at 7500 rpm. Here,is,a summary. If your sloppy at attention detail and assembly , stick with 657x , 717 , 787 or whatever lawnmower engine your building. Start spinning twin 3 inch pistons @1000 cc hard and your margain of error goes away .. morale of story is stay within knowledge and capabilities. And dooooo not ever jump start your SD !
Sent from my SM-G920V using Tapatalk
We come from opposite ends of Country Nick! Literally. You are just now tinkering with motors we perfected in 2005 making 200 hp at 7500 rpm. Here,is,a summary. If your sloppy at attention detail and assembly , stick with 657x , 717 , 787 or whatever lawnmower engine your building. Start spinning twin 3 inch pistons @1000 cc hard and your margain of error goes away .. morale of story is stay within knowledge and capabilities. And dooooo not ever jump start your SD !
Sent from my SM-G920V using Tapatalk
See the problem you have Brian is most people do not have the superior/expert/guru level of knowledge that you have accumulated over your years of racing. Also most engine builders do not give anywhere close to a level of detail that you seem to have as far as margin of error. Although you have had that 951 apart a few times this summer....some of which was your sons error...but still. I know that wasnt the only issue this summer.
Many people never even take a seat off their machine. They expect it to run a long time with minimal effort. The 951 to many is not that motor.
Again....as we have talked about before...my opinions take in mind the average weekend warrior....not YOU.
You can keep your clapped out 951 Ill stick to my lawnmower engines....dick.
Last edited by a moderator:
Seadoodoc
Active Member
Seadoodoc
Active Member
Customer once came into my stereo shop and argued how much better vinyl records are than CD's . Years later he is back arguing how much better CD's are over Mp3 files. Im expecting any time he figures out that FLAC ultra high resolution files are the new generation. So Nick... within that intellectual evolutionary chart relative to watercraft, where do u stand ?. Vinyl records, 8 track.... cassette, CD.???. running out of crayons and napkins to explain further options. I must be dense trying to explain. 951 mtr is a dream until you meet 4Tec ..carry on Minnetonka with your minnie mouse mtr dreams
Sent from my SM-G920V using Tapatalk
seadooaddiction
Active Member
It looks like i may have tried asking a question at the wrong time...
The 951 is a "dream" for experienced people with mechanical ability and a big pocket book. Period.
I'm just stating my opinion and my 14 years of seadoo experience dealing with your average weekend warriors.
Nothing wrong with stating your opinion but when you think your opinion is the only way to go... Then feel the need to put down others opinions, That makes you a closed minded fool.
Sent from my SM-G920V using Tapatalk
I'm just stating my opinion and my 14 years of seadoo experience dealing with your average weekend warriors.
Nothing wrong with stating your opinion but when you think your opinion is the only way to go... Then feel the need to put down others opinions, That makes you a closed minded fool.
Sent from my SM-G920V using Tapatalk
Seadoodoc
Active Member
Send me your mtr.. I will assemble free to race spec .. no charge. Just to prove,a point.
Sent from my SM-G920V using Tapatalk
Austrian Rotax
Active Member
Total noob in this stuff but arent we all in regards to a quality motor rebuild at the mercy of who actually rebuilds the crankshaft and bores, hones and chamfers our cylinders? depending on the tolerances they find acceptable is the question, or the experience of the machinist doing the work; assembly as long as you do a leak down check, squish and follow service manuel to the T is there anything else you can do? As for assembly quality, I say all this assuming you have perfectly rebuilt carbs and clean fuel system, no vacuum leaks, properly maintained oil pump, etc. . . So are Hot Rods cranks any good still or no? My questions are stupid probly so please go easy on me
There are choices to make on your base gasket thickness for the squish measurement. It's also important to port match things. You must keep flow in mind. So many times I see gaskets that partially block areas. There are choices in rotary valve timing as well. There is right and there is righter. I think things like this are why some stock engines turn around 6800rpm and others hit 7K (with all other conditions equal of course).
- Status
