2012 DR650...BONE STOCK, help me fix that

[EvanNaculum]

first post here in the DR forum. i ride a DRZ400 and my girlfriend just gave me the green light to start modding her 2012 dr650

it is 100% stock and its slower then my bike. we are on a budget, and she doesnt want her bike to be "loud" so the stock exhaust must remain. i want to change the gearing, cut the airbox hole, and put in a jet kit. i was hoping i could get some feedback on my choices.

Gearing: want to change both the front and rear sprockets. with its stock gearing (i believe its 15/42) you dont really hit 5th gear until the bike is going 75mph, which is unnecessary because the fastest she rides it is 70 on the highway. want to give it more power for around town. does 14/45 sound like too much?

Airbox: havnt taken a look in there yet, but i am assuming there is a snorkle similar to the DRZ400. i am familiar with the 3x3 mod for the DRZ, is the 3x3 mod common on the DR650?

Jetting: can anybody hit me with the jets i need to get. it would be stock exhaust, probably gunna fit a Twin Air foam filter in this weekend, and the bigger airbox hole. Pretty sure it is a Mikuni BST40 carb. sea level, between 50-75 degrees F are the average temps for this area.

side note, this is a street only bike...no trails in our area, so i doubt this bike will every see dirt.

Thanks!

[TN2Wheeler]

Way more than you want to know about DR650 carbs is here:

http://www.mxrob.com/mxrob_004.htm

The short of it:

Stage one: remove the snorkel, shim the needle ~.030, drill out the idle mixture plug and adjust, do NOT cut the airbox. Results in better midrange power, slight improvement in top end, minimal effect on fuel mileage

Stage 2: cut the airbox re Keintech template, install DynoJet needle, remove weld from inside of headpipe, optimize mainjet and needle height, adjust idle mixture. Results in stronger midrange and lots more at the top. Supposedly, the bike will do roll-on wheelies in 1st but this will likely drop your mileage into the 40's

Rob concluded the exhaust flows surprisingly well, particularly after deburring the weld at the flange. Not a lot of payback in an expensive aftermarket pipe.

[EvanNaculum]

wow. started reading that BST carb bible thread. in depth and great directions. thanks for posting that sure will help.

[Eazy-E]

I'm surprised your DR is slower than the DRZ. I'm guessing the DRZ has been modified. I think you've hit the nail on the head with changing the gearing afterall the DR is geared for over 100mph. Gearing down the bike will make a big difference in performance so I'd go this route first. You may find there's no need to change anything else. BTW I run an FMF exhaust and have to say I'm glad the main reason I bought it for the weight savings because it does zero for increasing performance. Sounds good though.

[EvanNaculum]

I'm surprised your DR is slower than the DRZ. I'm guessing the DRZ has been modified. I think you've hit the nail on the head with changing the gearing afterall the DR is geared for over 100mph. Gearing down the bike will make a big difference in performance so I'd go this route first. You may find there's no need to change anything else. BTW I run an FMF exhaust and have to say I'm glad the main reason I bought it for the weight savings because it does zero for increasing performance. Sounds good though.

Yea, she doesn't want her bike to be loud, and she weighs 100lbs soaking wet, so weight reduction/exhaust is not something I am too concerned about. The new sprockets will defenetly show her what her bike is made of.

What gearing are the DR folks running around here. The gear ratios on the DR seem to be much wider then on my DRZ, would 14/47 be ok for 75mph highway crusing?

[TN2Wheeler]

Yea, she doesn't want her bike to be loud, and she weighs 100lbs soaking wet, so weight reduction/exhaust is not something I am too concerned about. The new sprockets will defenetly show her what her bike is made of.

What gearing are the DR folks running around here. The gear ratios on the DR seem to be much wider then on my DRZ, would 14/47 be ok for 75mph highway crusing?

IMO that would be way low for a street bike. If I only rode on the street I'd leave the gearing alone. However I do some off-pavement tho so I'm running a 14 CS sprocket which is plenty low enough for all but the harriest single track. If I were you is start with just the 14 before spending more. You may need a new chain to go up to a 47 rear.

[T30]

I've had both the DRZ and the DR and found them both to be comprable in power but different in feel. My modded DR pulls harder than my buddies similarly modded DRZ but the top end is slightly less on my DR. I use stock gearing and it works great on the road and on open dirt trails. I replaced my BST40 with a TM40 with 500 miles on the bike, so I can't help you much with your jetting. However I did run the modded airbox and stock exhaust (header weld removed) for a while with the pumper carb. With just those mods it would do roll on wheelees in first with stock gearing.

[ttsquirrel]

I've got 14/46 gearing on stock engine and pipe, Dunlop 606 front tire and and swap out rear rims whether I ride street or dirt. It works great on and off road. Cruise along @80 in the fast lane

[EvanNaculum]

I've got 14/46 gearing on stock engine and pipe, Dunlop 606 front tire and and swap out rear rims whether I ride street or dirt. It works great on and off road. Cruise along @80 in the fast lane

cool, what would you say your RPM's are doing 75mph with that gearing? (if you had to guess by engine sound, i assume you dont have a tach). 14/47 seems to be premium on the DRZ when running the ACT wide ratio gear set that is available for the DRZ. i do not have this gear set on my bike, but i assume it has to be pretty similar to the gear ratios on the DR, which are clearly wider then the DRZ.

[BDM]

I'm going with TN2Wheeler, stock gearing for all street (some even go to a 16T CS) or 14T for a little more snap. With a 14, cruise @ an honest 60 = good, 70 = OK and 80 = not so good. Note most of the speedos (including DRZ) are 5-10% optimistic.

The DR is a torque motor and the DRZ more mid and up. In a higher RPM race (1/4 mile, top speed) they are similar in power but when short shifting or in a roll-on the 650 will prevail over the 400. Real world everyday use the DR out powers the DRZ and does so with a wider ratio box and 35 lbs heaver then a DRZ.

If the bike is for her set it up for her not to meet your expectations.

Also not a fan of the Keintech cut the top out of the air-box setups as IMO overkill for stock bike tune, instead go to the local hardware store and find some plastic plugs 1-2" diameter then hole saw a couple holes and remove the snorkel. Doing it this way allows you to fine tune the intake noise and to some degree jetting with the plugs/caps and you will still be increasing the opening area X3 or X4 over stock. I hate doing mods which can not be reversed & you can still do the Keintech mod if you really think it needs more. My normal setup is snorkel removed + a 1 3/4" hole for sea level to about 7000' and open a 2nd 1 3/4" hole for high elevation rides.

Bruce

Edited April 3, 2013 by BDM

[TN2Wheeler]

... My normal setup is snorkel removed + a 1 3/4" hole for sea level to about 7000' and open a 2nd 1 3/4" hole for high elevation rides.

Bruce

Stock (140) main jet?

[BDM]

Stock (140) main jet?

It's been a while and my records are not great. I need something that will work from 0' to 10'k with minimal changes. We dual-sport from sea level in Baja to the high passes in CO. Last week was 0-9500 in Death Valley. My setup is an FMF Q4, snorkel removed and 2ea 1 3/4" holes with 1 usually plugged.

Jetting as I remember is;

Pilot; stock 42.4 with an extended fuel screw. Tried 45, to rich.

Needle; stock with 2ea #4 washers under the clip. Tried DJ & one from a Polaris quad.

Main; my notes say a 155 Dynojet main but not sure and besides the DJ numbers don't directly crossover to the Mikuni. Stock exhaust with modded air-box should be 140-150 range.

I was experimenting at the same time as MXRob with needles and such. Have DJ kit but always thought the needle was overly rich for high altitudes and high fuel consumption. I'm sure the DK kit works well with the pipe and air-box mods if you don't plan to go high.

Not a fan of the BST at all (have 2 KTMs with FCR) but hard to justify the money on the DR to swap. I have had plenty of issues with clogged Pilot jets, bad float "O" rings and fuel flooding the air-box as a result (What no separate float-bowl vent/overflow?) so remove the air-box drain cap (bottom front) & leave off, any air entering will be filtered.

Some people overthink this as any jetting setup is a compromise at best.

Bruce

Edited April 3, 2013 by BDM

[TN2Wheeler]

155 DJ is supposed to be about the same as a 145 Mikuni. That sounds about right for your setup.

[JRL305]

I know this is an old post but just in case somebody is watching, does anyone know how thick the round plastic spacer is the comes stock under the needle. And... is it uniform in shape?

Thanks,

John KD4FTA

2012 DR650