HELP!!! losing power/rpms only on climbs

[ullose272]

went out and tried doing some climbs this weekend and about 100ft or so up the hill and at 7500-8000rpm it just starts kinda popping and loses power and rpms but as soon as i level back out its fine? i was thinkin maybe fuel pickup in the tank? what do you think?

 

[theultrarider]

Is this sled new to you? Have you made any changes to it lately? Has it run perfect and this just started all of a sudden? Riding than same temps and elevation you normally ride?

Sorry if these questions sound stupid, but sure helps to eliminate alot of things right of the bat.

 

[ullose272]

ive only ridden it this year, first time ive done climbs because i was taking it easy on the new motor. mods are: slp 6-9k head, slp single, vforce reeds, 19/43 gearing, 159 track, team red 140/320 primary spring, 10-62 polaris weights, 420 jets with '02 needle, slp airbox kit. i run 25% 110 octane for the head because i run between 4500-7000ft. the sled runs great the bottom ~50 ft, and then peters out

 

[theultrarider]

Did you look at your plugs when it was "popping"? I am guessing that you may be lean. I had slp singles on 3 of those. We generally run 470-490 mains in those here around @ 2000'. The 02's need to run about 4-5 sizes larger mains than the 03 and newer due to the needles and the timing in the 02's. Try going up about 4 sizes on your mains, and then do a long pull up a hill and kill the motor while still at wot. Then read your plugs and piston wash. You sound lean to me.

 

[skis_n_skid]

Could be lean jetting as theultrarider sated, could also be a fuel flow problem. Were you closer to 4500 or 7000 when you had this problem?

If there is a fuel flow problem it makes sense that it would first present itself while pulling a hill since that is when fuel demand is the highest. The pickup in the tank could be clogged or it could be in inline filter. Could also be the fuel pump. You can test both the pressure and the flow rate from the fuel pump.

After it happened, did you check the clutch/belt to see if they were hot?

 

[devilrmk]

I ran 390's at 4000ft with my slp single

420's with slp twins

02 needles.

I don't think you are lean but check your plugs.

 

[ullose272]

im thinking fuel flow, where is the inline filter? i dont think ive ever seen it and ive had this thing completely apart. i just dont really see it being lean as it was still doing it at ~6000ft AND about 30 degrees. it was happening at about 8000 rpms and would drop to about 7000rpms, i did notice that if i would go from climb to side hill it would go away within a second or so.

 

[Mtn Escape]

I had an issue a couple years ago with similiar problems ran great, on flat, hills it would die, engine stalls. Ran out of fuel. Found the pulse line pinched by the air box. Rotated the fuel pump never had that problem since.

 

[cowboysedge]

Ves? If it is a Ves. Exhaust Valve bellows. Check for small pin holes in the rubber around the shaft. Take them off and check from the back. If they are blue, replace them with the new orange ones.

 

[devilrmk]

There isn't a filter. Well, inside the tank but its really just a screen.

 

[ullose272]

Pickup in tank is good. Pulse line looks good. Ive never replaced the ves bellows and they look black?

 

[ullose272]

Well i replaced the bellows. And it didnt fix it. But the problem got worse. And actually it started idleing low. Im thinkin the fuel pump its on its way out. Can u rebuild these pumps?

 

[stretch]

try cleaning the wiring connection to the temp sensor - could be the det system actting up when under heavy load

 

[ullose272]

'02 no det system, but i may replace the temp sensor too, its pretty folded over

 

[devilrmk]

Yes you can rebuild them. Its just a diaphram.

 

[ullose272]

Plugs are chocolate in color. Could it be my stator crappin out? Somebody said maybe a voltage reg?

 

[slash]

POPING OUT THE PIPE/ritch OR INTAKE/lean

 

[devilrmk]

Voltage reg won't make a difference on the way it runs. It can have 0 voltage and still run fine. The motor electrical is seperate.

 

[ullose272]

hmm that makes sense, the more i think about it, its seem more like a bog, its hard to tell with my pipe.

 

[ullose272]

Anybody? I dont want another wasted trip