DR650 pipe, main jet and airbox mods

[Farp]

The bike is a 2009 DR650SE. I recently installed an FMF Q4 muffler on it; increased the main jet size to 160; and lifted the needle 0.035 inches by using an small washer as a shim (no adjustment notches on the needle). I also drilled out the brass plug under the slow speed air/fuel mix screw and turned the screw out 2 full turns from all-the-way in.

The dealer (Vancouver Supermoto, located on Powell St near Clark) recommended that a hole be cut in the top of the air box but I was reluctant to do this so I made all the mods but left the airbox in stock condition except for removing the snorkle.

After completing the mods I tested the bike on the Deltaport causeway - a long, flat, straight section of hwy with very little traffic on it. The bike ran extremely rough on the top end; the surging and missing was intolerable so after the first run I removed the airbox cover and made a second run and the improvement was amazing - the bike was still accelerating at over 165 kph when I chickened out and shut it down.

I took the bike home and holesawed a 3 inch dia hole in the top of the airbox on the other side from the snorkle hole and then cut out the section between the two holes with a box cutter razor.

The improvement in performance was well worth the effort. The bike pulls much stronger throughout the entire range from bottom to top. I put a couple of hundred miles on it this afternoon and based on the first two tank fills the mileage has improved from about 60mpg to 70 miles per gallon - mostly paved back roads with the average speed being 50 to 60 mph. I attribute this to the bike operating more efficiently with improved air-flow and carburation.

The pipe is a little louder than stock but not much. There is a noticeable increase in deceleration popping, but that could be due to the FMF muffler being less effective as a silencer than the stock one. However the FMF is about 10 pounds lighter than the stock muffler and this is weight that is situated quite high on the bike so picking it up on a steep slope (or anywhere for that matter) is going to be noticeably easier. All in all these are mods that I would recommend for anybody interested in getting more performance out of the DR650, and I'm really glad I did it.

 

[Buck]

imported post

imported post

Excellent report. :clap:

Congratulations on finding out what we all knew since 1996 Enjoy the ride and newly found power, performance and economygains! :tup:

 

[mineice]

imported post

imported post

I have also done these mods... I also put the head pipe on... I was wondering is there suppose to be a exhaust donut between pipe and head? As I am also getting a little popping on deceleration...

Thanks....

 

[Farp]

imported post

imported post

As far as I know there is no exhaust donut. There have been reports that the header pipe weld restricts the exhaust flow and should be ground away, but the weldment on my bike was almost flush with the pipe wall so any restriction would have been mimimal. I felt that grinding the weld would not improve exhaust flow enough to make up for the risk of weakening the joint so I left it alone.

Deceleration popping is an inherent trait for big singles. I have read comments that if your DR650 pops while decelerating it's an indication that you've modified the carb jetting and the exhaust correctly. In our case, I don't think the popping is caused by air being sucked into the exhaust at the header pipe joint - big thumpers just pop on deceleration.

One thing is certain - the factory set-up has the bike running too lean. This lean set-up is apparently done to comply with stringent emission regulations, but running a bike too lean will cause it to run too hot and in the long term can damage your piston, so there's another reason to set your bike up correctly.

 

[BE EF]

imported post

imported post

Hey Farp, where did you buy the muffler and jetting kit? what did it set you back? I'm looking to do the same to my bike but am looking for the best deal I can find. Thanks

 

[Farp]

imported post

imported post

I got it at Vancouver Supermoto on Powell St, near Clarke (google Vancouver Supermoto). The guy who runs the place is named Mark and his assistant is named Annie. She's a knowledgeable biker and they're both really good people to deal with.

I'm not sure what the exact cost of the tailpipe/muffler was. I put the bike in Supermotard trim for when I ride it on the street so the pipe was part of the bill that included 17" wheels front and rear, and Super Maxxis street tires - but the cost was around $500, for the FMF Q4. I think they included the jet for free.

I've put over 500 miles on the street with the bike in motard trim and it is a total blast to ride on the asphalt. When I want to take it off the asphalt it takes me less than an hour to swap the wheels.

I'm 5'10" tall and I found the bike was too high for me so I lowered the rear end. With the 17 inch front wheel the front end of the bike is lowered 2 inches so that combined with the lower setting on the rear makes the steering geometry just about perfect, and when I take it off road with the 21 inch front wheel I just loosen the triple tree clamps and slide the fork tubes up. The front wheel can make contact with the fender when you do this so you don't want to ride too aggressively - but it's not a motocrosser so accept it for what it is.

I can't believe the improvement the lower seat/footpeg height makes. I've dropped the bike a couple of times with the original seat height because when I went to plant my foot there was nothing there and by the time my foot made contact with the ground the bike was on it's way down and I couldn't overcome the momentum. Since I've lowered it I had a couple of similar occurances only I was able to plant my foot and reef the bike up and keep going. With the higher seat height I wouldn't have been able to do that. It's also a hell of a lot easier to put both feet on the ground and duck walk the bike through the really rough stuff.

 

[BE EF]

imported post

imported post

thanks farp. there's alot of info there... glad your happy with the ride.

 

[tobster]

imported post

imported post

Hi Farp,

Sounds like youve got everything sorted now, hows about a picture or two?Im still waiting for my kit n exhaust to arrive, should be in next week, cant wait, have fun.

 

[Farp]

imported post

imported post

Hi Toby,

Here's a photo I took yesterday in the parking lot at the top of Mt Baker. The Mt Baker road is full of twisty hairpins and the bike stuck to the asphalt like a roller-coaster, man it was fun. I bought a sheepskin horse saddle cover and stuck a piece of foam rubber under it - big improvement for long road rides. Numbutt be gone .

I've finally got my dirt wheels done so I'll be putting them on this afternoon and I'll see you (hopefully) at Bruce's tomorrow around 9 - 9:30.

 

[tobster]

imported post

imported post

BE EF, I just picked up a aluminum Hindle muffler and mid pipe for $299 from Modern motorcycles (commercial drive, Van) and a Dyno jet kit for $65. It doesnt look as fancy as the FMF but hopefully the results will be the same, Im going to install it this sat so will let you know how it turns out........

 

[BE EF]

imported post

imported post

right on tobs, let me know how it works out.... I'm not big on the fancy but the more practical and price friendly the better!! hopefully your able to get out for a rip this weekeend. Cheers.

 

[tobster]

imported post

imported post

hmmm, my DR650 jetting story isnt so happy. I installed a Hindle full flow pipe, a 170 jet and opened up the box, 2.7 turns out on the fuel screw, 4th notch on the Dynojet needle (as per instructions). Better power but not huge, more noise, but thats OK, bad mileage, not good, I now get 180 to a 13ltank (including reserve). Im going to try the 160 now. Also discovered that the Hindle pipe hits the brake hose that runs on top of the swingarm when the bikes rear bottoms out. Ive nowgot a melted clip and some damaged sheathing. Im speaking to Hindle cos this is a design fault. On the upside, the bike is definately faster, runs a little cooler, 9lb lighter, 50% sharper throttle response, and sounds like a motorbike instead of a popcorn maker

 

[franhoser]

imported post

imported post

Tobster your problem is not the jetting it's the carb. the problem is that you have a Mikuni BST40(I think) carb. Same astheDRZ S and SMmodels. One of the worst carbs because I they are cheap. Jetting that carb won't yield much and don't waist your time and money unless you want a slightly better throttle response. I've mentioned this on another thread on this sitesomewhere before (I can't remember where).

If you want to gain horsepower and significant upgrade then you have to do the FCR carb conversion. $1000 will get you an extra 10-15 ponies. Go to thumpertalk and there is tons of discussion and instruction on this, mainly in the DRZ section.

I found buying a bike with an FCR carb standard is the cheapest solution specifically over the DR650 cause you also gain in suspension and weight and few other things.

I've had the DR650 and left the carb alone cause I knew the outcome. The best thing you can do on that bike is change out the stock muffler to a aftermarket free flowing muffler.

 

[old trials guy]

imported post

imported post

Like the man says, you can't get something for nuthin....otg

 

[tobster]

imported post

imported post

I agree the carb and a lot of other stock parts are *rap but it sounds likeyou aresuggesting I put a free flow pipe on the stock carb without a re-jet? Can you put a full flow exhaust on with just an airbox mod?In doing that arent you removing all the back pressure and just keeping an already lean fuel ratio, Ive never heard of that working before, but theres a very good chance im wrong..........I was going through this process not to gain huge power just to get things running a littlebetter and cooler. Im going through rear tires like no tomorrow at the moment and dont want to make it anyworse by adding another 15hp...I think you know exactly what I mean

 

[old trials guy]

imported post

imported post

Hi Tobster:

Everytime you change anything that influences air flow, exhaust flow, cam timing, etc you will likely require jet changes. A less restrictive exhaust system usually results in having to increase main jet, needle setting (or possibly a richer needle), possibly pilot jet (if it is replaceable as on some carbs it is fixed) and tweak the fuel/air mixture screw. Increasing the opening in the air box introduces even more air which in turn will call for more fuel.

If you are committed to a modified air box and replacement exhaust you will need to find the correct combination. Keep in mind that jets and needles do not work independent of one another. My approach is to determine the main jet size first as it has the greatest influence on the system. If you are tuning old school (no dyno) fit the jet recommended by the pipe manufacturer and find a road where you can run the bike for several seconds at full throttle in a higher gear (ideally top gear if possible). You will have to perform a "throttle chop" which means cutting the throttle, pulling in the clutch and killing the motor as close to simultaneous as possible (without killing yourself). Remove the plug and check the color of deposits on the inner porcelain insulator. There are reams of photos available regardin proper color but you are looking for a light tan color and no specks of aluminum.

Once you have established the main jet I would then tackle the pilot jet. If you cannot tune for smooth idle and you get poor off idle, slow speed throttle response or stalling it is likely lean and needs a richer pilot.

Finally, and the most challenging is getting the correct needle setting. Trial and error for smooth mid throttle running and good fast throttle response.

The mixture screw is important for idle smoothness and influences just off idle performance.

Throttle slide cutaway also influences fuel air but lack of alterate parts and cost versus the generally small effect usually results in just workingwith the stock one.

Keep in mind that every change you make will affect the balance of the system. Hence my smart A$$ comment you can't get something for nuthin.

I am surprised to hear that some folks get better mileage with an aftermarket pipe and air box mods but maybe they don't have to twist the throttle so hard to get the power they need. My experience is mileage deteriorates with most performance mods.

You probably knew all this and I am sure others have different approaches but this is how I would do it.

otg

 

[tobster]

imported post

imported post

Thanks OTGfor the detailed reply, Ireally hope Ive got a grip on the principles of combustion, as a gas fitter/plumber its daily business for me (my smart ass response!). Engines are of course different to furnaces but the principles are the same, pefect combustion (stoichiometric) is only possible in theory though and completely impossible with my dollar store carb. But theres no harm in trying to get as close as poss. I was really just recounting my jetting experience in relation to Farps, which seems to have been more successful in terms of MPG and power etc.Its a great topic though, Ive spoken to Modern, Vancouver supermoto, Farp, yourself, Franhoser, Ruskin rider, and everyone has a slightly different spin on things, basically its trial and error. Working on the carb itself is a relatively quick job so its no big deal to mess around. Things have got a little more complicated as since ive installed this hindle pipe, when the bike bottoms out the pipe hits the swing arm and the brake hose on top. So now I have to revert back to the stock pipe and jet whilst Hindle decide what they are going to do, so far they have suggested I post the pipe back to them in Calgary, it took4 weeks for them to send it to me so I think it would be faster for me to cut and weld a new mount for the pipe and just forget about the hassle its caused (not that I have any welding skills or equipment of course!), I did however genuinely want to let them know that this was a design flaw cos its potentialy dangerous having brake fluid gush onto your rear tire and I cant be the only DR with a hindle on Im sure, actuallyI think I saw you at Bruces the day after I installed the pipe abouta monthago, I did as you said and took it for a run on the saturday morning down airport way, only had the pipe on 5 mins, I was cracked wide open testing my new set up, when I saw a policeman pointing a radar gun at me, he wasnt very understanding and gave me a $483 fine for excessive speed...Im guessing by his reaction that maybe hes had a bad experience with bikes, maybe he came home early one day to find a DR in his driveway and his wife hurridly throwing her clothes on (pure speculation), guess Im lucky I wasnt tasserd, either way I will continue to tinker and annoy everyone with my banter until the moderator shuts me up! But you are absolutely right, the spark plugs hold the answer and I will take my biggest pliers to them asap and see whats going on......he he.......cheers:hb:

 

[tobster]

imported post

imported post

Thanks OTGfor the detailed reply, Ireally hope Ive got a grip on the principles of combustion, as a gas fitter/plumber its daily business for me (my smart ass response!). Engines are of course different to furnaces but the principles are the same, pefect combustion (stoichiometric) is only possible in theory though and completely impossible with my dollar store carb. But theres no harm in trying to get as close as poss. I was really just recounting my jetting experience in relation to Farps, which seems to have been more successful in terms of MPG and power etc.Its a great topic though, Ive spoken to Modern, Vancouver supermoto, Farp, yourself, Franhoser, Ruskin rider, and everyone has a slightly different spin on things, basically its trial and error. Working on the carb itself is a relatively quick job so its no big deal to mess around. Things have got a little more complicated as since ive installed this hindle pipe, when the bike bottoms out the pipe hits the swing arm and the brake hose on top. So now I have to revert back to the stock pipe and jet whilst Hindle decide what they are going to do, so far they have suggested I post the pipe back to them in Calgary, it took4 weeks for them to send it to me so I think it would be faster for me to cut and weld a new mount for the pipe and just forget about the hassle its caused (not that I have any welding skills or equipment of course!), I did however genuinely want to let them know that this was a design flaw cos its potentialy dangerous having brake fluid gush onto your rear tire and I cant be the only DR with a hindle on Im sure, actuallyI think I saw you at Bruces the day after I installed the pipe abouta monthago, I did as you said and took it for a run on the saturday morning down airport way, only had the pipe on 5 mins, I was cracked wide open testing my new set up, when I saw a policeman pointing a radar gun at me, he wasnt very understanding and gave me a $483 fine for excessive speed...Im guessing by his reaction that maybe hes had a bad experience with bikes, maybe he came home early one day to find a DR in his driveway and his wife hurridly throwing her clothes on (pure speculation), guess Im lucky I wasnt tasserd, either way I will continue to tinker and annoy everyone with my banter until the moderator shuts me up! But you are absolutely right, the spark plugs hold the answer and I will take my biggest pliers to them asap and see whats going on......he he.......cheers:hb:

 

[Steve&Sherry]

imported post

imported post

Hello I own a 2008 DR650 and despite what other people may say the DR is the best Dual Sport out there, if you want to jump table tops buy a YZ250 if you want to make it from Kamloops to Merritt on the coquihalla in 18 minutes but a Ducatti but if you want action on both sides keep what you have, and as far as carb modding this is what i did and if you do a bit of research you may save some money down the road, when i bought the bike new in Kamloops, I live in Merritt, i brought it home and i was on Fleabay looking to Farkle before it was unloaded out the back of my truck (pathetic) i bought an FMFQ2 and an oversize header for $350, and $150 i loved it bought a DJ jet kit for the carb ($50) opened up the airbox on top set the carb up drilled the second hole changed the airfilter to a twinair ($45) but as you will soon find out farkling is an addiction you won't be able to control yourself if you know there is something better, because that FMFQ4 you have will need to be repacked by this time next year so now that winter is coming and you could still sell your can as fairley new and get most of your money back write this stuff down: FCRMX 39 carb from a YFZ 450 yamaha quad from 2000 to 2007 i paid just under $100 for mine, A 2001 Titanium stock exhaust can for a GSXR 1000 Jesse at Keinteck in Oregon has a midpipe for the 2001 GSXR 1000 can that will allow you to bolt it right on $150 some excellent instructions to follow for both mods from MXrob over at thumpertalk.com and with these two mods alone my friend your bike will friggin kick rear end the bike will be new and sound like it is supposed to and the can even looks good i realize yours looks good to but when it needs repacking you will wish you went this way the GSXR can hasjust as much flow and is light and looks good and never needs to be repacked ever!!!!

 

[mineice2003]

imported post

imported post

Steve drop me a line. Marcel [email protected]maybe hook up for a ride

or have a look at your beast