800 Jetting with NON hooded carbs ?, HELP !

[lasse]

Hello


Last winter I brought a brand new leftover ( ZX ) 800 and all was fine except the jetting ...
All winter I had big trouble to dial in my carbs on my 800 sled with the NON hooded carbs....
...and the troubles continues this winter

A couple of guys here on SnoWest & DooTalk recomended me to put in some other BRP needles, Yamaha E-clip shim and a slightly stronger RAVE spring.

Now I have put that stuff in my sled but it still not running right

The engine is running sluggish and not so responsive as it should and is a pig on gas

I also have checked the oil injection and the pump arm is aligning against the dot in the housing at idle


My OLD ( OEM ) carb set up :
Main jet : 520N
Pilot jet : 20
Fuel screw : 1,0 turn out
Needle : 404 162 027 ( 9XDY01-59 )
Needle shim : OEM

Reeds : OEM "W" style.
Rave spring : OEM "Black" 420 239 942



My NEW carb set up :
Main jet : 520N
Pilot jet : 17,5
Fuel screw : 1,0 turn out
Needle : 404 161 942 ( 9HIY01-52 )
Needle shim : OEM + Yammi shim

Rave spring : OEM "Blue" 420 239 941
Reeds : Boyesen RAD reed cage


Riding height : 350 - 900 Meter , ( 1148 - 3000 Feet )


Anyone having some suggestions to point me in the right direction ?

HELP !!


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[hymark860]

Your sled sounds like a 02 model. That year had some updates to the MPEM. Did you get those done?

 

[lasse]

Your sled sounds like a 02 model.
That year had some updates to the MPEM.
Did you get those done ?

My sled is an 2005 !
..but with the non hooded carbs that all
800 ZX sleds had except the 2003 800 HO Summit-X


Last winter my dealer checked the MPEM box and changed the DPM module to a sligtly bigger type
..After that It run sligtly better but not good

During this summer I also got a new set of Boyesen RAD reed cage from the dealer instead of the crapy OEM reed cage.
And then I put in the other things I had been recomended...
But the engine still runs awful bad




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[bigjb]

Try checking your chokes. They may be stuck open from road grime or just mis adjusted. If they are not closed all the way it will suck the fuel and run like crap. I had a similar problem u are having.

 

[HAROLD]

get rid of the 520N main jet and put in a 500. I got a 2002 with the non hooded jet and it was way fat. I have not had any problems running a 500 jet in Michigan or in Wyoming.

Could it run a little cleaner? sure, but plugs are cheaper than pistons. I ran all last year on one set of plugs, sometimes they were kinda wet and crusty but it always started and never left me stranded. I am running the BR9EYA plugs this year, not the expensive BR9ECS. I have ran the standard BR9ES in the past also.

I did put in a set of Cudney pistons and rings in it because the rings were starting to flake apart. This was done 3 years ago. I had the exhaust and carbs off this fall and looked at the cyl walls, look good and compression checked out good also. 135-140 @ 900 ft elevation.

2002 summit 800, 159" x 2", ceramic coated pipe and y pipe because it was cheaper to get done than replace the fatigued and broken heatshield.

 

[lasse]

Try checking your chokes.
They may be stuck open from road grime or just mis adjusted.
If they are not closed all the way it will suck the fuel and run like crap.
I had a similar problem u are having.

I have checked that, but with no luck

 

[Ox]

You may have had better luck at first had you mentioned that it was a Lynx and not a Doo.

We have not had the Zx here since '03 and non-hooded carbs here since '02, so here is what I did on my '02:

480 Main with 942 (?) needle. It is the 2001 800 SUMMIT needle. Run in middle if not one leaner...

Retarded the timing 2*

There were a cpl of MPEM updates for the '02, but I would hafta assume that you had that right outta the gate...

Sled went from 7 US miles/gallon to 10 (on trail comparison) however I don't think it was ever all that "crisp".

 

[lasse]

We have not had the ZX here since '03 , and non-hooded carbs here since '02, so here is what I did on my '02:

480 Main with 942 (?) needle. It is the 2001 800 SUMMIT needle. Run in middle if not one leaner...

Retarded the timing 2*

There were a cpl of MPEM updates for the '02, but I would hafta assume that you had that right outta the gate...

Sled went from 7 US miles/gallon to 10 (on trail comparison) however I don't think it was ever all that "crisp".

All 2003's ZX also had the non hooded carbs.
( Except the Summit 800 HO )

Yes, I have the 942 needle in the sled now.

My MPEM is checked of the dealer, and it is OK

The engine is burbling all over the revs and is not at all responsive, hesitates and so on....


Driks a lot of gas --> 5,0 Litre/10 Km





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