Jetting help '04 RM 250

Chris_sopjes
Needing help with jetting issues.. Currently riding a 2004 RM250, and I recently installed a Pc Works pipe with an R304 Shorty Running on 91 mixed at 40:1 using Castor 927. For elevation I'm at 5,000+ ft. Issue I'm having is the bike tends to bog On hill climbs, wide open, etc. I know changing jetting is crutial when changing out pipes but I don't know where to start
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RussB
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RussB 5/24/2017 12:14am
5/24/2017 12:14am
Open up your carb and tell us your current settings.

Sounds like you may be a little lean
Alex71
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Alex71 5/24/2017 5:31am
5/24/2017 5:31am
first of the pc system the bike run well? i don't think that the only exhaust system can cause this symptoms...
Chris_sopjes 5/24/2017 8:45am
5/24/2017 8:45am Edited Date/Time 5/24/2017 8:49am
I'll be tearing into it this afternoon.. Before the system I had a stock expansion with an FMF muffler and it ran fine no problems, idle was a little low but that was it really. Also note, when I noticed the problem I changed the plug and new air filter but that didn't change anything

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Chris_sopjes 5/24/2017 11:27am
5/24/2017 11:27am Edited Date/Time 5/24/2017 3:54pm
RussB wrote:
Open up your carb and tell us your current settings.

Sounds like you may be a little lean
Main Jet: 165
Pilot jet: 48
Needle: NECJ, Clip 2

Also reinstalled factory pipe and fmf muffler, same bog
Paw Paw
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Paw Paw 5/24/2017 4:22pm
5/24/2017 4:22pm
If you r float level is not set correctly it will lean out on uphills.

Paw Paw
Chris_sopjes 5/24/2017 4:48pm
5/24/2017 4:48pm Edited Date/Time 5/24/2017 5:58pm
Paw Paw wrote:
If you r float level is not set correctly it will lean out on uphills.

Paw Paw
How do you adjust the float level? Even just riding around on flat ground it bogs out. Pulled reeds and checked them, there's a little gap. Tried flipping the and still a gap, would this cause my issue?
RussB
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RussB 5/24/2017 11:55pm
5/24/2017 11:55pm
Chris_sopjes wrote:
Main Jet: 165
Pilot jet: 48
Needle: NECJ, Clip 2

Also reinstalled factory pipe and fmf muffler, same bog
An NECJ in clip 2 is a touch on the lean side.
There would be no harm in going to the middle 3rd clip and seeing how it runs.
Your main is also a touch lean. I ran 168/170 in my RM, but then I am in a different country with different fuel etc to you so hard to say.

But as above, I would start with your float level. Use your manual for instructions and the correct measurement to set it too.
Chris_sopjes 5/26/2017 2:16pm
5/26/2017 2:16pm
Chris_sopjes wrote:
Main Jet: 165
Pilot jet: 48
Needle: NECJ, Clip 2

Also reinstalled factory pipe and fmf muffler, same bog
RussB wrote:
An NECJ in clip 2 is a touch on the lean side. There would be no harm in going to the middle 3rd clip and seeing...
An NECJ in clip 2 is a touch on the lean side.
There would be no harm in going to the middle 3rd clip and seeing how it runs.
Your main is also a touch lean. I ran 168/170 in my RM, but then I am in a different country with different fuel etc to you so hard to say.

But as above, I would start with your float level. Use your manual for instructions and the correct measurement to set it too.
Well I pulled the Carb apart, cleaned everything, and played with the floats a little bit and they were hardly out. Adjusted them a little not much change. Ordered a 168 main and a 45 pilot so I can play with it a little and see if there's a difference.. thank you for the help and advice, I will keep updated when I get everything changed
YZ125H1
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YZ125H1 5/27/2017 5:37am
5/27/2017 5:37am
I have the same year bike and pipe bolted up right now. The bike ran noticeably different after bolting up the PC system from the OEM system (Wouldn't idle and loaded up). I'm in the NE about 500ft mixing at 40:1 running 93 pump gas. My only other mod is vforce 3 reeds. The issue I am having right now is the bike acts like it hits a wall in the upper rpm's and doesn't seem to go anymore. I ended up buying two richer and two leaner main jets. Last weekend I swapped out the 168 for a 172. Whenever I get the time to take the bike out I'll see if I went the right direction.

My current jetting is (stock just 1 clip leaner):

168 Main
48 Pilot
NECJ Needle
Clip position 2

I did notice my bottom end is a quite a bit less reponsive than before with the stock system. Not sure if this is from the 10oz FWW, turn my idle up, or drop my pilot jet 1 size.
RussB
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RussB 5/29/2017 5:07am
5/29/2017 5:07am
YZ125H1 wrote:
I have the same year bike and pipe bolted up right now. The bike ran noticeably different after bolting up the PC system from the OEM...
I have the same year bike and pipe bolted up right now. The bike ran noticeably different after bolting up the PC system from the OEM system (Wouldn't idle and loaded up). I'm in the NE about 500ft mixing at 40:1 running 93 pump gas. My only other mod is vforce 3 reeds. The issue I am having right now is the bike acts like it hits a wall in the upper rpm's and doesn't seem to go anymore. I ended up buying two richer and two leaner main jets. Last weekend I swapped out the 168 for a 172. Whenever I get the time to take the bike out I'll see if I went the right direction.

My current jetting is (stock just 1 clip leaner):

168 Main
48 Pilot
NECJ Needle
Clip position 2

I did notice my bottom end is a quite a bit less reponsive than before with the stock system. Not sure if this is from the 10oz FWW, turn my idle up, or drop my pilot jet 1 size.
The R304 silencer will reduce top end. A shorty adds mid/bottom at the expense of top end.

You will need to make jetting changes to suit the Pro Circuit system, I went 2 main jets leaner when running a shorty silencer as opposed to the long stocker.

I'd definitely recommend trying a 45 pilot
NorcalVet
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NorcalVet 5/29/2017 5:43pm
5/29/2017 5:43pm
I'm at sea level

165 and 45 as recommended in the kit

05 rm 250

Pc pipe, v3 , non shorty pc
110 purple and 927 @ 32-1
Runs perfect no spooge
Fresh plugs, buy extra for your tool box







Chris_sopjes 6/10/2017 3:43pm
6/10/2017 3:43pm
Update
Checked my float level and it was in spec. Dropped in a 162 main, a 45 Pilot, and needle on P. 2 Bike is running alot better. Thanks for all the help and input
RockyMtnMX
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RockyMtnMX 6/12/2017 8:42pm
6/12/2017 8:42pm
You are at 5,000 feet so there will be a decent size difference between sea level jetting and what you run. I am at 5,000 feet in Colorado and have a 2006 RM 250 and vary between a 158 to 162 main jet depending on time of year and temp. I am using the NECJ needle second clip from top and a 46 Pilot.

Hope that helps.

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