XR650R JETTING with Baja Baffle???

I need jetting help please!!

My 2001 BRP has the full Honda Power Up Kit and runs awesome. But it is too loud for events up here in Ontario so I use the Baja Baffle insert when I need to quiet it down.

How should I adjust my jetting to get some of the performance back when the Baja Baffle is installed?? I am always under 5000'. The bottom end is very weak and I am getting the odd high hanging idle with the baffle. Mid range and top end are o'kay, but nothing compared to the open tip.

Any comments would be greatly appreciated.


If you plug up the pipe with a quiet baffle, you'll need to lean down the jetting some. For example, with the 40mm open tip I run a 175 main, but up in Colorado, above 8000', I run a modified stock tip (34mm), which is quiet, and use a 160 main.

This helps, but there's no way it's going to run as strong as with the open tip. It's just too plugged up with a quiet tip. But sometimes a quieter tip is needed, at the loss of some power, usually more at low rpms than at higher rpms. But it's usually worth the trade-off to avoid annoying people or getting a ticket. As far as I know, there is no way to get maximum power from a quiet exhaust on a four stroke engine.

Fortunately, here in Texas there are no noise laws, so anything goes.

got a question, this high hanging idle, is it only after you have warmed up completely, like getting borderline hot? my bike does this alot and i cant for the life of me figure out what it is. If you figure it out, please let me know, JR

i went down 1 size on the main per baja designs 172 instead of a 175 - the bike is super quiet with the baffle - its great for the trail rides near where i live that are close to houses - but its not as responsive - i take it out in the dez

jeff :)

I had a 96 600, which the two mechanics at my shop both rode. When I wanted to do dual sport rides he suggested a baffle from one of the quads or trikes of that time. It was much more open than the stocker, yet quieter than most aftermarket. Ran great too and the best part was it looked totally stock. Didn't have to go through sound checks, though it WAS lounder than stock :)

Thanks fellow BRP owners.

I did try the 172 main as per Baja Designs but found NO difference on my bottom end or mid range, but did find less top end. I guess I will just continue to mess around with a 165 and maybe a 160 and try the needle in the middle position instead of the 4th.

If anyone out here runs the power up kit and uses the Baja Baffle from time to time, I would be very interested to hear how you set up your carb to get the most out of it with the baffle in.

Happy Trails,


What temperature and altitude are you mainly riding at?

At 5,000 ft & 50F temperatures with the baffle installed, I'd probably start from a 165 main with the needle in the 2nd or 3rd clip from the top and use the stock 65S pilot.

At 3,000 ft & 50F temperatures, I'd probably start from a 168 main with the needle in the 3rd clip from the top and use the stock 65S pilot jet.

At 1,000 ft & 50F temperatures, I'd probably start from a 172 main with the needle in the 3rd clip from the top and use a 68S pilot jet.

At sea level & 50F temperatures, I'd probably start from a 175 main with the needle in the 3rd clip from the top and use a 70 pilot jet.

For every 10F change in temperature from the 50F, increase or decrease the main jet by about 2 sizes. For every +10F above the 50F, decrease the main jet by 2 sizes from the ones I listed. For each -10F decrement below 50F, add about 2 sizes to the main jets I listed. As for the pilot jet, add or subtract about .75 from the sizes I listed for every 10F change in temp. Add .75 for each -10F decrement in temperature and subtract .75 for each +10F increase in temperature. I hope I got that right cause I'm on my way out for a few hours and I'm typing this as quick as I can. It's rough advice, but it should get you somewhat close to a starting point.


Much appreciated. Looking at your suggestions backs up what I've been thinking. It has likely been running too rich, given the restriction of the baffle. It would seem logical that being too rich would flood the system at low rpms, but still burn o'kay at higher revs.

Thanks again,


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