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New Member with XR650l would appreciate Jetting Advice

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Hi to everyone, there is some great information on this forum, I've been reading it prior to my purchase and even more since. Thanks to all for their contributions.

I bought a 2007 XR650l on Saturday completely stock and with only 1400 miles. I live at just over 5,000 feet above sea level. I was amazed how gutless the bike was - do they take a while to loosen up? the previous owner was even older than me and a bit of a "steady eddie"

Having read up on all the info I decided to make some changes, I'll run through them in order with the hope that someone will be able to understand where I'm coming from.

Firstly the original air filter was pretty dirty, at higher revs it was hesitating which I took to be running to rich. I replaced the filter with a unifilter and removed the snorkel. This got rid of the hesitation and it ran well if a little anaemic on the bottom end - too lean.

I thought I'd try some new jets, while at it I gave the bike a once over and adjusted the valve clearences etc. To my frustration I haven't been able to remove the spark plug yet, since the 07's don't have a tool kit and none of my large collection of plug sockets or box wrenches will work. I can get one from Honda for $28 bucks but not for a week :banana:. I got a 55 pilot and a 155 main to try. The 55 seems to make it run much better on the bottom end, a lot more torque off idle. The 155 main jet made the hesitation return but it was more powerful when not hesitating and surging. Today I decided to do the "Dave Mods", I'd been holding back a little, it just seemed an extreme thing to have to do to an almost new bike. So I drilled the slide holes to 5/32, and put about a 0.022" washer under the needle. I left the 55/155 jets in place and set the mixture screw to 2 turns out. The bike had a lot more power and much faster response but under load - 3rd, 4th, and 5th gears there was hesitation and then she'd really take off, then hesitate again. It was at its worst in 5th gear under acceleration. Based on my experience with the original dirty filter I read this behavior to be too rich a mixture. Looking at the end of the muffler after 20 miles also gave that impression. I removed the carb again, and swapped back in the 152 jet leaving the 55 pilot in, I set the mixture screw at 1.5 turns. On testing this it ran powerfully and pretty well other than when under load in 5th or one time snapping the throttle open very quickly in 3rd going up a steep hill where the hesitations started again. The bike starts easily cold or hot and idles great.

I'm not sure which way to go now, I think I'll ride it some more and look at the plug, when I can get the right tool. I'm also wondering if the plug gap and condition are OK. I'm thinking maybe drop the pilot jet to a 52?. I'm still getting some popping on the over run but still have the smog kit, If my understanding is correct, this doesn't effect the actual running of the motor, I've been avoiding changing too many things at once, so I can clearly see the effect of the individual changes. I'm going to stay with the stock muffler, I don't want too much noise and all my cash went into buying the bike. Is there an aftermarket baffle that's still available?

These jet sizes seem small to what others are running. Anyone have any thoughts. My apologies for such a lengthy first thread, but I wanted to try and get all the info down.

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Well i`runnin 55/158 jets.......and the exhaust is a really nice brown color,plug looks perfect.:banana:..but my engine isn`t stock,,,and i`m at sea level.......i`m thinking you need to go at least one size smaller than 55/158 to start with,,check the plug and go from there...

I`d wait,save up and get the FMF Q4 🤣

B

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How much do you think raising the needle with the .022 washer effects the mixture? This should make it richer than the stock setting assuming the same main jet. I'm not necessarily looking for ultimate power but want the mixture to be correct to keep engine temps down with summer coming, I don't want to run lean.

How loud is an FMF Q4 compared to stock?

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How much do you think raising the needle with the .022 washer effects the mixture? This should make it richer than the stock setting assuming the same main jet. I'm not necessarily looking for ultimate power but want the mixture to be correct to keep engine temps down with summer coming, I don't want to run lean.

How loud is an FMF Q4 compared to stock?

Raising the needle will richen it up earlier as the needle starts out a tad higher.

Depending on where in Utah you are, your jetting is hard to call as your altitude could be anywhere! 58/160 here in the Boise area is a tad rich, but she runs great. Well she RAN great... motor's sitting on the bench right now🤣

The Q4 is not a lot louder than stock... it just sounds deeper... better :banana:

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I'm at 5,000 feet plus, pretty soon I'll be back to stock jets, that's what makes me think there's something else at play because everyone else seems to be running much bigger jets, even at altitude. A plug chop seems to be in order to see if firstly it's OK and secondly what color it is. Boise is only about 2600 feet, 58/160 is way bigger than I'm running.

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A couple of things... Did your bike begin life at sea level? What size are the "stock" jets (Realizing that a dealer may have rejetted the bike)?

The stock pipe may be a big part of the problem. I have had several thumpers over the years... replaced the stock exhaust on every one of them and ALWAYS ended up lean when I did. If you replace the pipe and it doesnt stumble and pop, I'll be surprised.

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The bike began life in Denver CO. Original Jets were 50/152 which is stock for the bike. I think the stock pipe could be the cause of the issue in that it's restrictive enough to stop you going past a certain point with regards to the mixture despite the intake mods, although I've seen others are running much bigger jets with the stock muffler successfully.

One thing I'm going to check today is the slosh baffle?, that plastic bit around the main jet, I have a feeling that that might not be staying in place, it seems it had fallen of already when I took the bowl off yesterday, whereas the first time I took it apart it was in place and I had to pull it off. If it's dropped down and loose it might be causing a problem.

Does the size of the pilot jet have much effect on mixture at faster engine speeds? I'm tempted to try a 52 pilot while I have it apart again and then use the 155 main as this combination would only be a small increase on each jet over stock i.e. 52/155 vs 50/152.

I've found a source for a plug socket locally so hope to get that and a 52 jet today. I'd still like to check the look of the plug and change it out for a new one with the correct gap just to eliminate that from the equation. I had a brand new NGK plug go out once on an RD350 I had back in 1980. I thought I'd holed a piston when it went on one cylinder during a spirited ride, I was relieved to find it idled perfectly when I pulled over, but as soon as you touched the gas it went on one cylinder again. Put the old plug back in and it ran perfectly.

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the 55/158 with drilled slide and shimmed needle per dave's mods is almost always a sure bet...though jets could require a tweak based on your elevation - the washer should be around .13x.278x.029 (IDxODxThickness)...Dubro SS #4

I'm around 2 1/4 turns out, another quarter turn and it had a lil bog spot in the throttle response around 1/3 rolled on, but generally 2-2.5 turns is the range - uni filter and an aftermarket pipe are ideal for sure, I think fmf has their pipes on sale the rest of this month...so if you have the dough check out the Q4

for the plug, I had to get a motion pro 18mm socket for around $23

http://www.motionpro.com/motorcycle/partno/08-0175/

it works fine but the rubber nub that covers the terminal end of the plug fell out so I just use it without the rubber - the socket works great though and the xrl is one of the specific models for which this socket was made

if you end up ordering from motion pro, they also sell the valve tappets, plug gap gauges, and miscellaneous items that are good to have on hand for the xrl for future jobs...like a throttle sleeve for bar replacements etc - so I'd have a look around the site if you place an order, just to see if there's anything else you might need - they sell pretty decent stuff

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Rocky Mountain ATV-MC is about 20 miles down the road in Payson, they have the motion pro socket in stock and some other goodies including jets. It's good to know the socket is working for you, I wasn't 100% sure it was right for the XR650l, I will definitely get one today.

I think an aftermarket pipe must make a big difference on flow, I couldn't get close to a 55/158 combo working with my setup and altitude. I think an FMF Q4 has to be on the cards here in a couple of months when finances recover.

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Excellent point Dave, I was just thinking about that myself, I'd noticed there is quite a bit more restriction on the air box with the seat and side cover on than when I've fired it up to make sure it will run after working on the carb, before putting these back. I was thinking about taking it for a run minus the side cover to see what difference will make.

I'm off to get the plug wrench etc. so I'll check that out and then try a run. Thanks to all for there assistance.

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OK didn't get quite as much time today as I hoped, but I did manage to get the plug out with the new socket. The gap was a little on the small side but color wise the tip was a little too white and the edges of the plug black. This would indicate to me it's a little lean on the top end and too rich at idle. Any thoughts from anyone else?

I rode it with the new plug installed, it runs pretty well until you give it a lot of gas and then it still hesitates under load.

Tomorrow the carb comes off again, I intend to check everything over and try a 52 pilot with a 155 main. Logically this gives me a little more fuel than the stock 50/152 combination and with the freer flowing unifilter and snorkel removal ought to work. We'll see, if it hesitates I'm going to run it with the side cover off as Dave suggests and see if that helps at all.

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OK, today I triumphed. Put in a 52 pilot with the 155 main back in. Ran perfectly, no hesitation and the front was getting really light in 2nd (not even in 1st stock). Third gear really gave great acceleration on steep uphill 👍 The plug was a light gray/brown after a run.

So what did I learn from all this other than the carburetor and spark plug are time consuming to remove for a single cylinder? (Carb removal and replacement, certainly gets a lot quicker with intensive practice)

The important thing I learned was that the pilot jet effects the mixture significantly at much higher rpm's than anticipated (by me anyway). Yesterday with a 55 pilot and 152 main I was experiencing hesitation due to over rich mixture nearly as bad as with the 55/155 combination, dropping the pilot jet to a 52 really made the difference. Something to bare in mind for the future projects.

My set up is now 52/155 at 5,000 feet with stock muffler, Unifilter, snorkel removed and Dave's mods with with a 0.022" washer under the needle, mixture screw at 1 1/2 turns out. Next job is to remove the smog octupus to get rid of the popping and some surplus pipework and weight. Not to far down the line, hopefully I'll be messing with the carb again when I get an FMF Q4 muffler and need to rejet again. For now I'm very happy with the improvement over the gutless stock setup I had last Saturday when I bought the bike.

Thanks to all on the forum for their participation, it's a really fantastic resource.

Edited by redhawk4

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So I am having similar problems. I was having a high speed miss and I did Dave's carb mods and it got worse, then I went down to a 52 pilot jet. It got better, but I am still having high rpm missing problems.

It has been de-snorkeled/smog pump and I have a unifilter. I live at about 6700ft above sea level.

Edited by kili

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So I am having similar problems. I was having a high speed miss and I did Dave's carb mods and it got worse, then I went down to a 52 pilot jet. It got better, but I am still having high rpm missing problems.

It has been de-snorkeled/smog pump and I have a unifilter. I live at about 6700ft above sea level.

The pilot jet affects low speed operation. You could put just about anything in for the pilot jet and it won't affect the high rpm running.

You want to change the main jet to tune high rpm, full throttle behavior.

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Sorry, I meant 152 mainjet not 52 pilot jet.

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Hi to everyone, there is some great information on this forum, I've been reading it prior to my purchase and even more since. Thanks to all for their contributions.

I bought a 2007 XR650l on Saturday completely stock and with only 1400 miles. I live at just over 5,000 feet above sea level. I was amazed how gutless the bike was - do they take a while to loosen up? the previous owner was even older than me and a bit of a "steady eddie"

Having read up on all the info I decided to make some changes, I'll run through them in order with the hope that someone will be able to understand where I'm coming from.

Firstly the original air filter was pretty dirty, at higher revs it was hesitating which I took to be running to rich. I replaced the filter with a unifilter and removed the snorkel. This got rid of the hesitation and it ran well if a little anaemic on the bottom end - too lean.

I thought I'd try some new jets, while at it I gave the bike a once over and adjusted the valve clearences etc. To my frustration I haven't been able to remove the spark plug yet, since the 07's don't have a tool kit and none of my large collection of plug sockets or box wrenches will work. I can get one from Honda for $28 bucks but not for a week :D. I got a 55 pilot and a 155 main to try. The 55 seems to make it run much better on the bottom end, a lot more torque off idle. The 155 main jet made the hesitation return but it was more powerful when not hesitating and surging. Today I decided to do the "Dave Mods", I'd been holding back a little, it just seemed an extreme thing to have to do to an almost new bike. So I drilled the slide holes to 5/32, and put about a 0.022" washer under the needle. I left the 55/155 jets in place and set the mixture screw to 2 turns out. The bike had a lot more power and much faster response but under load - 3rd, 4th, and 5th gears there was hesitation and then she'd really take off, then hesitate again. It was at its worst in 5th gear under acceleration. Based on my experience with the original dirty filter I read this behavior to be too rich a mixture. Looking at the end of the muffler after 20 miles also gave that impression. I removed the carb again, and swapped back in the 152 jet leaving the 55 pilot in, I set the mixture screw at 1.5 turns. On testing this it ran powerfully and pretty well other than when under load in 5th or one time snapping the throttle open very quickly in 3rd going up a steep hill where the hesitations started again. The bike starts easily cold or hot and idles great.

I'm not sure which way to go now, I think I'll ride it some more and look at the plug, when I can get the right tool. I'm also wondering if the plug gap and condition are OK. I'm thinking maybe drop the pilot jet to a 52?. I'm still getting some popping on the over run but still have the smog kit, If my understanding is correct, this doesn't effect the actual running of the motor, I've been avoiding changing too many things at once, so I can clearly see the effect of the individual changes. I'm going to stay with the stock muffler, I don't want too much noise and all my cash went into buying the bike. Is there an aftermarket baffle that's still available?

These jet sizes seem small to what others are running. Anyone have any thoughts. My apologies for such a lengthy first thread, but I wanted to try and get all the info down.

I also live at 5000ft up, and just picked up an 04 xr650l with Daves mod already done, as well as de-snorkeled, de-smogged, a uni filter, and a straight-through xr400 muffler on it. It has the crispest, snappiest throttle response I've ever felt on a thumper, accidental wheelies are the norm so far, and it pulls VERY hard from idle all the way up...with stock gearing. Done right those simple mods make a HUGE diff in the bikes running. I wish I had the jetting sizes for you, but the previous owner is now out of touch :D

I can say that when you get it right you're going to LOVE it 🙂

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