Search results

Yes many times, the Keihin 42 is not oversized on a 750 so its easy to tune. There are leftover PJS single 750 manifolds for Keihin on ebay. These have smaller passages and make response and tuning better than the stock manifold. Theres not much to change with additional mods. Everything will...

The pilot should be 82 with stock spring. A 150 main should allow the top screw to run about 1 turn out, power tune the top screw for best performance.

Dont use polystyrene in an engine compartment!! EVA floor padding is much more suitable and very lightweight.

For cost savings find out how much methanol can be mixed with pump gas and cheap oil before it gets cloudy. A 25% mix would be easier to live with but an expensive castor/ester oil (like 927) may be needed. Make some $3/gal MS109.

The only way I have ever been able to get good response and power form a 650 is with compression, timing, and 112 octane gas. The ports cannot be lowered much without losing power, and theres not enough of that to begin with. The only good pump gas option is a 750 engine.

Just like scuppers, they are great if you can ride out of everything you do every time. Otherwise its a very bad idea. That never seems to get in the way of anyone sinking their skis of hydrolocking their engines.

You will need the weight up front if you are above average height/weight. If you are little then find a Mariner box and mount it on pads made of EVA floor foam, over 5lbs can be saved.

Maxima 927 was popular in racing 20 years ago but they were also running 440 pumps and spinning over 8500 rpm. A stock or limited 550 can live on cheap oil. Most old skis have rusty cranks that are time bombs so have fun while it lasts.

Mikuni I-body carbs have larger venturis than SBNs relative to the butterfly diameter. The I-38, I-40, and I-42 have the same bolt spacing and are easily adaptable with a protec 90 degree manifold and linkage, I never measured I-44 and 46. They wont pull fuel as well as an SBN with the same...

West has better advertisements and a better looking can. Thats about as technical as it gets here.

The universal theme of all motorsports enthusiast. Louder always "FEELS" faster even when its not.

I looked at two OEM cranks and two cases. The hole in the bearing is blocked and the case passage is ported to the front cavity.

The case oil ports dont line up with bearing ports very well. I always extend them so they do. The front weep hole is ported to outside cavity, make sure that passage is clear. Congrats, you are the only other person that ever noticed.

A modified 900ZXI ring and nozzle makes all the A/M stuff look weak.

There is no way to get perfectly smooth throttling with a tuned pipe, they are either on or off. A stock Superjet exhaust has no tuning and gives linear power delivery although less of it compared to a pipe. Try a stock exhaust and see if it makes enough power for you.

Yes, just like the pic. Pack grease in between.

The spring goes outside for this application.

You will have to see how it works for you. I know they can become difficult to plane for big riders . If you were over 200lbs the ski would likely be unrideable without some nose weight. A 750 nozzle wedge is 4 degrees.

You should be able to pull a 9-17 swirl or concord 12-18 with an 80mm+ nozzle. Your high port engine will not tolerate too much load so if it is slow to get on the pipe (assuming the carb tune is correct) then bend the blades. A bored nozzle is a must for more thrust.

How big are you? I know a stock length 650sx, stripped down and with a 2lb waterbox was difficult for a 180lb rider to ride out of a tail stand. If its too short try adding a nozzle wedge from a 750sx before adding weight to the front.