04 800 rev PROBLEM CHILD

Van Epps · Jan 3, 2010

Thanks for the set up info!! :beer;

I have not solved it yet, the sled is in the shop to have the dpm and mpem tested. Hope to have word by Tuesday...... hoping for a definitive diagnosis of the problem.

I will update as I know more.

winter brew · Jan 3, 2010

sent you a PM.

Van Epps · Jan 5, 2010

Daaaaammmmmmmit,

I took it to the dealer to have them hook it up on their diagnostic computer and test the dpm and mpem. They can not even get a reading?! They don't know how to bypass?????? Can anyone help with this? Why can't they just temporarily put a different mpem on the sled to diagnose the DPM? Could also run the sled with new MPEM to see if this fixes my issues, right?

Also found a damaged tether (where it plugs into the sled). No way to install a new tether due to not having computer access to the mpem in order to reprogram new tether.
Any help?

This thing is killing me!

Mac-Daddy-Racing-212 · Jan 6, 2010

Why can't they pull the tether wire from the dash to the MPEM and install a temporary cord. Heck take one from another sled and test it out. Can't be that much black magic in there.

Van Epps · Jan 9, 2010

!!! DPM solenoid is bad. New one on the way. !!! Here's hoping it's the problem / cure.

brutecamo · Jan 10, 2010

Did it cure the problem Van Epps?
I checked mine with the 9 volt battery and it clicks, so I'm assuming all is good. Also ziptied all my DPM vacumn lines thinking maybe they were leaking. Changed my clutching setup and the problem is still there. Is there a way to check fuel pressure from the pump? I'm starting to wonder if maybe I have a pinched/kinked fuel line, dirty filter or sticky carb slide? RAVE valves should not affect WOT? Running out of ideas real quick. HELP

Van Epps · Jan 11, 2010

Brutecamo, not sure yet. Parts will be here next week. I'll post the results. You can buy a dpm solenoid only for $40.... I have heard they can be bad even when hearing them click.... may be worth the $40 to try.

Joe Mama · Jan 11, 2010

I would guess DPM also. I run a 2.5" 151 on my 04 800 with no issues pulling it. Gearing is 19/45. Sorry no help on the clutching not even sure at this point what I'm running, i would need to check my notes.

Van Epps · Jan 13, 2010

Installed new DPM and it's still doing the same thing!

Danzick · Jan 13, 2010

Holy cow. and i thought my 04 hated me. this pry wont do anything but try when your riding to move the teather around a little. mine sometimes does weird things and i have to move the teather around a little to get it to stop. just a thought.

Van Epps · Jan 14, 2010

Here's what I have tried so far to clear up the problem:

Carbs cleaned
New spring tower cap, new rollers, new buttons, new primary and secondary spring (BJ set up)
New belt.
Cleaned rave guillitones
checked bellows
Installed new DPM assembly

been thinking ...... possibly pipe surge. Throwing more weight at it and will test tomorrow. Added 4.4 grams for a total of 19.8. sounds crazy to me, adding weight to raise rpm but I'll try anything at this point.

xpspenziv · Jan 14, 2010

no weight

throwing weight at it will drop rpms

add weight looze rpm
delete weight gain rpm

you said you plugged the holes in the air box,and put panty hose on the air box.how big are the holes?is any of the filtering plugged?

the plugs will tell you if its fat or lean.
you didnt say anything about new plugs! .02

xpspenziv · Jan 14, 2010

long shot

had a friends cat do similar,the can had come apart internaly.
would run fine untill alot of throttle was applied.
plus the mouse nest but it finally burned out

Van Epps · Jan 14, 2010

Van Epps said:
Here's what I have tried so far to clear up the problem:

Carbs cleaned
New spring tower cap, new rollers, new buttons, new primary and secondary spring (BJ set up)
New belt.
Cleaned rave guillitones
checked bellows
Installed new DPM assembly

been thinking ...... possibly pipe surge. Throwing more weight at it and will test tomorrow. Added 4.4 grams for a total of 19.8. sounds crazy to me, adding weight to raise rpm but I'll try anything at this point.

Ran it today with 19.8 grams. Same problem. The only difference is the RPMs are now surging between 7600-7900 vs 7700-8000.

lancelarue · Jan 14, 2010

Pull your secondary apart and check ,
worn bushing
buttons
Sounds like it's binding up under full load, beaking loose, binding etc.

brutecamo · Jan 15, 2010

The holes I plugged on the airbox are maybe 1/4"-3/8" round openings on the back off the sidepanel airbox.(keep the belt dust out)
Plugs look good.
Everybody I talk to tells me to check my clutches. Had them apart multiple times and all looks good. Going to install new buttons(existing ones still look good) just to rule out the last clutching possibility.
Mine does run good 90% of the time, but when rpms fall off to 7000 in a climb things can get sketchy real quick!
I'm going to get another tether programmed as sometimes mine does need to be adjusted to get rid of the beeps.
Just thought of one other possibility. My fuel tank always seems to be under pressure, is this normal? Whenever I take the cap off it depressurizes. Should the "Y" vent tubes off the top of the tank allow this?
I'm wondering if my tank is air locking.

Van Epps · Jan 15, 2010

Brute, I have heard recently that these Revs have occasional problems with tank venting. I don't know what this would cause as far as the problems you are experiencing but......... if you go to DOOTALK forums and look in the

"REV Chassis / Mountain sled" section of the forum and go into the "TTabs Modshop" thread (sticky, right on top) In here you will find great instructions on how to enlarge the tank vent to ensure venting.

hope this helps!

live2beel · Jan 15, 2010

You probably dont want to hear what I think it is

I think the crank might be on its way out. Maybe a bearing. Mine did the same thing. How many miles?

live2beel · Jan 15, 2010

Also another thought. Maybe a cracked pipe.

Danzick · Jan 15, 2010

I was having this problem. check the tourque stopper behind the left cylinder. that thing was wore out and it cased the engine to tourque too much and the clutches would go in and out of alignment casuing to surge

04 800 rev PROBLEM CHILD

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