wr 450 09 power loss
Posted October 13, 2011 - 02:52 PM
Can anyone help
Posted October 13, 2011 - 03:22 PM
hi i am having a problem with my wr 450 2009. The big starts fine and runs great at low speed. Once i hit mid range it starts to bog down really bad. Just kind of has power surges. Bike was working great but i had to replace cyclinder and rings also adjusted exhaust valves to spec. I had factory jetting and tried going to 48 pilot and 168 main bike won't start so went back to 42 pilot and it starts fine, went for ride and power loss happened. went back to factory jetting and put restrictions back on still a little better but still has a bog
Can anyone help
Not sure I understand what you repaired and why; Cylinder and rings, but no piston, wristpin, etc?
You have to describe your problem by throttle position and by rpm: like this:
" 1/4 throttle is fine in any rpm, but at 1/2 throttle the power goes away as the rpms rise..."
Then we can give advice without guessing.
Posted October 13, 2011 - 06:50 PM
Took it out for test ride and bike started good can rev it up to full trottle in neutral. @ 1/4" Still runs good. But @ 1/2 Trottle and up the bike starts to spit and sputter and won't increase in speed. This happens in 1 st and 2 nd gear didn't get any higher in gears.
I had a 168 main jet and went back to a 162 main
Posted October 13, 2011 - 07:53 PM
Sounds like you have a major obstruction in the carb, a loose needle, or a vapor lock (gas cap not venting).
Is it possible you put the slide plate in upside down? The hole goes on the bottom....
Posted October 15, 2011 - 04:28 AM
Posted October 15, 2011 - 10:15 AM
Posted October 15, 2011 - 02:11 PM
just wondering can it be a problem with the rings. Went i rebuild the engine i done a leak down test and at top dead center air was coming up around the timing chain. It wouldn't hold pressure at all. Took it of top dead center slightly and held the crank and it pressure up.
Are you serious? You felt compelled not to mention that your top end won't hold pressure, but you still wondered why it ran poorly??
Posted October 16, 2011 - 05:33 AM
Tdc should have both valves closed fully and therefore hold pressure. No pressure at TDC means rings or open valves, neither are right.
Posted October 16, 2011 - 07:16 AM
Posted October 16, 2011 - 09:20 AM
i replaced the cyclinder piston and put 4 sets of new rings in it trying to get a leak test to hold. Everytime it is the same went by manual and everything sees good until i do a leak down test. Dots are lined up with cycinder head at top dead center. Valves don't leak on leak test it is just coming up around timing chain. Guess the rings are no good. It will hold a leak down test if i take it slightly off top dead center.
Sounds like you did not mic the cylinder and piston to see if they are a match.
Posted October 16, 2011 - 10:55 AM
Posted October 16, 2011 - 11:41 AM