Ok so im having a build off with my buddy, X2 vs SX... The only rule is a 65o motor must be used in both... What im looking for is if anyone knows of a stroker kit for a 650 and if anyone does quality porting and polishing?... Im starting with a 650 motor that already needs rebuilt (130 psi in both cyl)... if anyone can help it would be great! thanks
650/X-2 650 stroker
- Thread starter blown
- Start date
- Location
- Washington
Not sure if there are stroker kits for them. But WB1994 on pwctoday has a 650 X2 that out runs a SXR. Theres a video on youtube
Joker
...chaos? Its Fair!
- Location
- La Porte, Indiana
groupk.com is your best bet.
- Location
- Washington
Id stay away from group K for the 650 motor. Group K doesn't do any work to the cases. They skip half the work. The Rad Dudes engine builder is suppose to be top notch, same guy that did the motor mentioned above. Ive also heard great things about Art chambers. Another guy is Chris Newmiller from Newmiller machine
Joker
...chaos? Its Fair!
- Location
- La Porte, Indiana
Ya I didn't know all of them dealt with 650's I just knew of group k who messed with them.
The X2 wont go as fast as a standup. It is not at all difficult to make a 650 go fast with high ports, a good pipe, and race gas. The groupK cylinder and head mod is a very good for power and longevety. A stock SXI/SXR ignition is a cheap way around the 650s rev limit. You will need a tach and the abillity to tune the pump because a high port 650 will not tolerate too much load.
- Location
- Washington
The X2 WILL go faster than a standup. Heres the video of the 650 x2 beating a SXR
http://www.youtube.com/watch?v=7L-rMGcaoq4
- Location
- Washington
:doh:
Damn how did I manage to miss the mag pumps
Damn how did I manage to miss the mag pumps
- Location
- Washington
I need to learn these secrets
Vumad
Super Hero, with a cape!
- Location
- St. Pete, FL
The X2 will almost always beat a standup off the line. Like a drag car without wheelie bars having to stay light on the throttle, the stand up has much more weight further back. I know it is possible to get a good holeshot with a stand up, but many times the weight of the rider on the back at low speeds makes the nose ride high. The ski jumps out of the water when hitting the throttle hard just off idle. The standup drives up instead of forward. The rider must ease into the throttle or risk driving the pump right out of the water, which causes a repeat of the problem. (Edit: Just look at the 1st holeshot in the linked video. The SXR jumps up as the X2 is immediately on plain pulling away. SXR is always playing catch up which it could do in a bouy race.)
On the contrary, the forward weight of the X2 and it's rider keeps the nose down, even at idle. The X2 can hit plain right off the line at full throttle. Rider skill can over come this problem on a stand up, and perhaps mods like an extended ride plate, but the X2 requires no mods at all and little skill to win off the line. That video of the X2 winning a drag race off idle isn't all that impressive considering the above. A much less powerful X2 can easily win the holeshot and lose the race. My X2 pulls 5-10 mph faster than my stock superjet on the top, but really isn't faster than my stock SJ until the X2 really gets on pipe at about 20mph. You wouldn't be able to tell this by the 100 yards the X2 puts on the SJ in the first 5 seconds as the X2 takes off on plain and the SJ struggles to get the nose down.
My X2 (previously) with a 750 motor, no porting, stock electronics, 9/17 prop, westcoast 650 pipe and a very poorly tuned set of 38mm keihens (fuel and oil pouring out of the exhaust) bored half over lost a drag race to a SXR by about 2 or 3 MPH. My 650sx had a stock motor with a single 44mm mikuni and a straight 15 prop. It pulled pretty solid into the mid 40's. I was very unimpressed by the speed and power of the stock SXR. compared to a lightly modified 650 or 750.
The X2 hull design is pretty poor. It wants to just fall over at about 40-45 mph. It's a big handicap in a race. However, the SX begins to porpose and handle poorly over 45 in a different way. The X2 gains a lot in the holeshot. Handling is different on the X2 than the SX, but I don't think I can say one is that much better than the other, except the holeshot, where the X2 has a clear advantage.
Not dogging either set up. The X2 has some definate strengths over the SX hull, but it's not without it's weaknesses. Same story for the SX.
On the contrary, the forward weight of the X2 and it's rider keeps the nose down, even at idle. The X2 can hit plain right off the line at full throttle. Rider skill can over come this problem on a stand up, and perhaps mods like an extended ride plate, but the X2 requires no mods at all and little skill to win off the line. That video of the X2 winning a drag race off idle isn't all that impressive considering the above. A much less powerful X2 can easily win the holeshot and lose the race. My X2 pulls 5-10 mph faster than my stock superjet on the top, but really isn't faster than my stock SJ until the X2 really gets on pipe at about 20mph. You wouldn't be able to tell this by the 100 yards the X2 puts on the SJ in the first 5 seconds as the X2 takes off on plain and the SJ struggles to get the nose down.
My X2 (previously) with a 750 motor, no porting, stock electronics, 9/17 prop, westcoast 650 pipe and a very poorly tuned set of 38mm keihens (fuel and oil pouring out of the exhaust) bored half over lost a drag race to a SXR by about 2 or 3 MPH. My 650sx had a stock motor with a single 44mm mikuni and a straight 15 prop. It pulled pretty solid into the mid 40's. I was very unimpressed by the speed and power of the stock SXR. compared to a lightly modified 650 or 750.
The X2 hull design is pretty poor. It wants to just fall over at about 40-45 mph. It's a big handicap in a race. However, the SX begins to porpose and handle poorly over 45 in a different way. The X2 gains a lot in the holeshot. Handling is different on the X2 than the SX, but I don't think I can say one is that much better than the other, except the holeshot, where the X2 has a clear advantage.
Not dogging either set up. The X2 has some definate strengths over the SX hull, but it's not without it's weaknesses. Same story for the SX.
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Their Hammer is set up for race gas, the Sleeper for pump gas. GroupK setups are made to survive long full throttle runs. Hot freestyle setups have too much compression for that without a programable ignition.
N2 H2O
Previously Tbone550
- Location
- Charlotte, NC
I wouldn't use group k. There are a variety of widely used and respected engine builders. Erik Brigham has built some sweet motors for the RAD DUDES. That 650 in the x2 in the video that outran the sxr was built by Erik Brigham. Another way you could get an easy stroker setup for your 650 is to use a 750 small pin bottom end. You would need to have 650 pistons made to work with the 750 rods, though. The 750 crank is 4mm longer, so it would be a 4mm stroker. The 650 cylinder would bolt right up to the 750 bottom end with a 4mm spacer plate for the longer stroke. I would just talk to Erik and see what he suggests...
- Location
- Nashua,NH
stay away from group k. i have ridden wb's ski and the brigham ported motor performs really well through out the power band, and is super reliable. porting alone will make a big difference but what it really comes down to is having a complete package of the right parts.
- Location
- Cruising Around
My dealings with Harry at Group K have been great. Great power, very linear delivery of power, and longevity of crankshaft. Motor he built for my 750sx (800 hammer 96) made the boat almost unridable. Harry is very meticulous and wants your motor to last.
