2016 800 Low RPM Problem

[Bowhunter]

I have a 2016 800 Pro 163 2.6 track with pro gears. Last year while it was completely stock I could only get 8050 RPM. I new I was going to go with a pipe this season so I did the SLP Magna force weights. Same thing RPM was only 8050. Over the summer I added an SLP stage 3 kit, Heads and pipe. This year I still average 8000 to 8050. 900 miles on sled. SLP recommends 8300 - 8400. I ride at 6K - 9K altitude.

Things I've done to improve this,
New Belt
New plugs and wires
New Motor mounts
New blue pink primary spring and new black purple in secondary.
Sent primary off to Indy Specialties and had balanced and any parts replaced if needed
New Relay's (all 3)
New gauge (Not the PID, regular gauge pod)
Had dealer relearn power valves and check compression, all good according the them

As a test I did try the factory 10-64 weights - same RPM's, I did try taking weights out of the Magna Force. It doesn't seem to pull as hard and will act like it's over reving motor will start cutting out. Sled pulls great with 3 weights in the magna force. I do weigh about 250 lbs dressed for riding. I had a buddy who weighs about 30 lbs less ride it - same thing. Last weekend riding down the groomed trail I could get to 8000 rpm at 2/3 throttle. Lots of throttle left, smash to bars - no additional go. Maybe I'm pulling correct RPM and the gauge is not showing properly except I'm on my second gauge and getting same results.


Any ideas on what the heck I have going on????

 

[nosman4]

This may not be your problem, but after going through everything and even more than you did I ended up replacing the top end. My compression tested fine, but with a borescope you could see scuffing on the cylinder wall. I tore it down and it had literally worn the rings flat along the cylinder where it lines up with the divider for the exhaust ports. Nothing else was found, I had Indy Dan Torque Plate hone the cylinders and and get me new pistons. I also forgot to mention this was the case on both mine and my wifes sleds... Now they both run amazing! I was pulling 8350 with spikes to 8450 all this last weekend. Borrow a borescope and take a look, you might be surprised, I sure was.... Both our sleds were damaged on the mag side of the PTO Cylinder. Both 16's Good luck

 

[WAsledder]

IMO compression tests don't always tell you what you need to know...a leak down test will. I just replaced a top end on a 16 axys that compression tested perfect but was only pulling 8100 rpms. After a rebuild I'm pulling 8500

 

[Madtown]

This may not be your problem, but after going through everything and even more than you did I ended up replacing the top end. My compression tested fine, but with a borescope you could see scuffing on the cylinder wall. I tore it down and it had literally worn the rings flat along the cylinder where it lines up with the divider for the exhaust ports. Nothing else was found, I had Indy Dan Torque Plate hone the cylinders and and get me new pistons. I also forgot to mention this was the case on both mine and my wifes sleds... Now they both run amazing! I was pulling 8350 with spikes to 8450 all this last weekend. Borrow a borescope and take a look, you might be surprised, I sure was.... Both our sleds were damaged on the mag side of the PTO Cylinder. Both 16's Good luck

Mileage on sleds?

 

[Bowhunter]

Only 900 miles on my sled. So if I need a top end I'll be very disappointed. I have never had to do a new top end with such little mileage.

 

[Griff]

Interesting as I have been relying on compression tests.... guess a bore scope will be going into my tool box now.