I just rebuilt the 701 61x that was in it ran half way decent last year when I bought it but I new it could be much better found rear seal leaking so I rebuilt the thing from the bottom up trued and welded crank ported cases and cylinder 83 mm wiseco ada head with 35cc domes and 33 domes the thing won't turn more than 5900 according to a tiny tach but hits 53 on gps any day of the week on smooth water.Has a 15/19 solas should I go 14/18 I am running 5000' feet and up the motor should pull that except for elevation also has a jetinetics lightened flywheel.Could the tiny tach be off it reads good at idle? I only have about an hour on the new motor so I haven't pushe it real hard yet full throttle for a couple of seconds just to get a reading but it also looks like I am getting a light seizing kinda like a four corner seize but it was warmed up plenty before I gave it any gas I have a 145 main and 125 pilot with 28 psi pop off figured that was plenty rich to break in at 32:1 amsoil any help with any of these problems would be appreciated tremendously [B][/B]

15/19 is way overpropped for 5000ft. a 14/18 or 14/17 let let that motor wind out a little bit. You might be able to use the big prop if you bore the nozzle. do you have any other props hanging around.

What pistons are you running.? You cant trust the rpm if it isnt broken in yet, after a cou-le tanks, the pistons loosen up and performance increases. If you are running forged pistons, they require a really good warmup period, and lots of piston to cylinder clearance to work well.

I am running forged. I tied it to the trailer and let it run for a good 5-10 minutes before running it I set the clearances at .0065 when I had it bored I will try a 14/18 an see what it does.

I put a new impeller in yesterday and the tiny tach still only reads 6200 I went down to a 12/17 swirl the motor is not getting as hot as it was. I rechecked timing and it is correct,where are the rest of my rev's or is this as good as it gets at these elevations I know the motor is still breaking in and it is running way rich,still no carbon on the domes and plugs are dark brown and slightly wet.

Sounds like you are too rich on high circuits.
What are your jetting specs and turns on the screws?

I know I am slightly rich because I am trying to play it safe with the new motor I am also running 9's instead of 8's right now with the ada head to keep temp's down a little but I can't imagine it running as good as it is and missing almost 1000 rrr's from being rich I now I will get a few rrr's when the motor loosens up.currently at 120 pilot 1 1/4 out and 140 main 2 1/2 out haven't set the main yet I was going to wait till I go to regular mix before trying to set it.

A couple things.
What is the compression reading???? Safe comp for pump gas is about 180 max. [sea level]

I have a friend who is Head of the local Yamaha cycle service shop and has had years of tuning and race experience in 125cc street race bikes and PWC. Here is the stats for his Blaster:

RPM with stock prop, factory pipe, cdi and Group K pump gas porting is 73-7400 running about 54-55 mph. tried nujet and a few solas but nothing else delivered as good bottom to top as stock. Hope this helps.

I keep forgetting to take guage to lake with me at my house 135lbs but that is at 9000'feet which should be about 180ish at sea level I am going to try a 14/18 solas or skat I think the swirl is still laoding the pump and motor to much for this elevation.

Play with hi speed screw, you will be suprised how many rpm's you lose when very rich.