Why you SHOULDN’T Re-jet your (AUS SPEC) DR650 carburettor & hack air-box : Vince Strang’s opinion 

Great video. Vince knows his stuff. My DR 650 is the only bike I've ever had the brains to hold onto and I've been through a lot of bikes in the last 30 years. I really like these no crap videos because you and Vince are not trying to sell me sh£$e that doesn't work or I really don't need. Keep it up, men.

Allways great to hear what Vince The Wise says. Great vid ,keep them coming.👍

Great advice from Vince.

All makes sense to me. I have experience on many types of engines/ carbies and have to agree with your reasoning. I have had my stock engined DR in the exreme outback in Australia on long trips. I have shipped my DR to New Zealand for a private tour and did a few thousand km. Mountain roads and low lands. No trouble. My opinion - leave it alone- you are likely to just chase your tail. Just enjoy the ride on this great motorcycle.

Mark victor from biker bits sent me here . Interesting watching your journey and your learnings from scratch . Hope you get a bit more knowledge before you set off - lots to learn still - good luck on the journey - subbed

Vince is correct, I have high comp piston and cleaned the ports up with no rejeting but the rest of the carby mods with open full FMF. The thing is a monster everywhere throughout the rev range with slight better economy. From down Under.

Thanks for weighing up on the other side of the argument. I have ignored the advise and cut up my air box though 😋 but I like to tinker. And thanks more so for showcasing the pilot jet! before and after doing the 'power mods' sometimes it would bog down when giving it a tiny bit of throttle. Definitely going to look into what's going on there. Cheers, enjoy the ride!

I totally agree, My stock std 650 with factory carby and a Delkevic pipe is trouble free, starts straight away and in a race is always level with or in front of a carby modded bike :-) and as Vince stated I get better fuel economy

You can tell this guy knows his shit in the first 15 seconds. So glad I saw this video.

I took Vince's advice about 6 years ago when I just acquired my DR, no issues, great economy. Notably, he differentiates less restrictive jetting in Australian models compared to elsewhere.

Interesting theories from Vince. I've found my DR has alot of popping on deaccel with an open pipe. Have a jet kit on order - Barry from cross training enduro seems to think otherwise. If an engine is running lean out of the factory, and you put bigger jets in it you can get better fuel economy as the engine is running more efficiently. I have a 2012 model DR and will post up my results :)

In the U.S. the bike is just toooo restricted and must be opened up. Even if you don’t need the power going one size on the jets will make the engine run much cooler which adds to the longevity of the engine. I do agree it is a great bike with a great factory set in some countries just not the U.S.

I agree 100% with this guy. I’m in Canada and the stock carb is very good. I was just riding with my buddy and he has the opened up air box. My stock 2020 was faster and used less fuel.

I’ve never heard of oil dilution problems with the DR. That should only occur if the rings weren’t bedded in correctly. I fitted the Procycle 790 kit and it transforms the bike on the road, much better acceleration for overtaking and uphill. Really hurts the fuel consumption but I don’t cross the Simpson, and fitted a 25 L tank. Worst standard suspension of any bike I’ve owned, life threatening to be blunt. They won’t be sold soon, due to new rules re ABS.

love your vid, tough one coz as you intimated it ain't so simple an issue. The stirrer in me cant help but poke a bit of fun as well as thoughts (no offence, I actually do run stock carb / snorkel in, but with a straight through muffler. I would only ever adjust jets if the range of conditions i'm likely to encounter / FAR warranted it, not because someone told me what the right jet size is). Best leave stock? Sure, why not, trust the Suzuki experts; after all they based the DR engine on the Otto cycle! Those in the know may remember Toyota's famous "Otto cycle" / "O2 advantage" campaign of the 1990's and how good those engines performed in motorsports! But why not modify it (IF YOU KNOW WHAT YOU'RE DOING. Even something simple isn't: Is a richer pilot jet preferable to a standard size with a tweak to the mixture screw??? ). And there's more chance of oil dilution from a conservative one size fits all stock bike setup than an individually calibrated modified setup. The DR's carb has been designed and built to a set of priorities and targets of the whole system (reliable, quiet, smooth, safe, inexpensive, compact, warrantiable motor). Unfortunately, it doesn't match what some riders want so it's understandable getting the throttle to open quicker without bogging, and not having the overall airflow overly baffled (restricted), will be sought; but lets face it even the stock settings / setup are only a touch more conservative a compromise of exactly the same things anyway and the mods are hardly radical by comparison. And sure, the mods can't provide miracles but extra air / fuel at proper FAR is still extra power; I'm sure anyone that understands the fluid mechanics and thermodynamics of it all could correctly explain why compression ratios, valve size/lift/duration etc ultimately determine the potential pumping capacity / power whilst someone who knows their mechanical engineering could point out the longevity limitations of the 40+ year old mechanical / material/cooling design. Hmmm, come to think of it, more valve duration means more power less fuel efficiency ; is that a good mod??? I'm looking forward to catching up with your why you shouldn't revalve your DR650 suspension. And if anyone actually reads this and has revalved their shock and it works well, please message me the shim stack so i can give it a try.

I am in California and I did the Procycle jet kit and It made a huge difference, better low speed and smoother throttle response along with more power.

I really enjoy your videos. I have a stock DR 2022 I’m in the US .My question is are the DR sold in the US the same as the ones sold in Australia as far as the carburetor and jetting?thank you.

Great content men 👏. I'm in cen cal valley. I've ported the exhaust pipe at the weld,and put on a dominator slip on. But after seeing this vid...I think I'll skip on cutting holes/rejetting. So should I leave snorkel off or put it back on? If there's no advantages to having it off... then I'd rather put it back on to . Any advice is greatly appreciated. Ty u for your time and knowledge Sirs.

Agree 100%. Only adjustments needed are to turn the fuel screw out 1.25 to 1.50 turns from fully seated and shim the fuel needle .030 inches to fix the factory lean pollution control tune. The shim removes the mid range surging and the enriched fuel screw adjustment removes the inconsistent fall to idle when rolling off throttle on different temperature days. It removes the ultra lean factory tune.

Mine has the air box mod already done when I bought it. However ive put a stocking over it to stop crap getting in. Its really fine but still lets it breath.

I bought a new dr last year then started doing mods to suspension, sprocket gearing, pipe and procycle jet kit. The jet kit made a big difference to throttle response and revs much quicker. Would never go back to stock.

I did fmf slip on, 2 inch hole saw out of stock airbox, 155 dyno main jet with needle shimmed on 2 not 4. A/f screw two turns out. It’s running like a dream super responsive and climbs to 100 much faster than before with a little throttle left still. When the K&n air filter arrives it might make it too lean but for now it’s perfect

What exactly would a person in the US need to do to get their DR650 carb to Australian stock specs? What are the stock jet sizes?

I don't cut my airbox. At sea level, I just pulled the snorkel, installed upgraded filters, installed an extended idle-mix screw, and installed adjustable overseas/KTM needles. At higher altitudes, I can pull the sidecover off of the airbox and adjust the idle-mix screw. For extreme altitude changes, I could adjust the needle by clip position or shim. A GSXR muff is in my shed, awaiting install.

So Vince says to only replace the pilot(size?) jet for ez cold starts? Ok .Will it help a 1990 DR Kickstart model? Everything I've done to this bike has to be custom DIY. no aftermarket parts for my 90. Thnx men.

Like the video and anyone like me that rips a dr 650 there great bikes and I have been trashing bikes for 40 years in northen ont Canada and the dr has been my best one over the years and outlast all others even my honda wasnt as tough .

Hmmm - I made a link pipe, swapped the silencer for a Hayabusa can and pulled the snorkel. It starts way easier, the drive snatch around 80kmh has gone - it holds 100k in top on a fraction of the throttle and is way faster on top gear acceleration over 100k.

check this out ,DR650 project: transforming the stock carburetor! (BST magic)︱Cross Training Adventure

So where can i get the Aus carb setup specs? I know it's a different needle but what jetting?

Agree. After swapping back and forth jets and springs, widening and then closing again the airbox I have found some modest gains and achieved >165km top speed, a few % better kpl and significantly better response with stock pipe. Although coming from a motocross background I enjoy riding and tinkering in equal degree the effort and cost involved negates the improvements, unless you are said tinkerer. It requires riding in varying conditions, noting and recording in a log and then diagnosing then changing and repeat. Any hardware mods will put you back a few steps again. Any significant power gains will also significantly reduce durability.

Do you need to do any mods after adding a pipe (screaming demon)?

100% Both our DR's on 100 000km each and both have been over 5000m altitude many times and still stock standard. He is not wrong. You can't push out enough more horses to make it a better bike. Leave it as is.

Did the jet kit and I hesitation in some rpm. Feels like going against sporadic gusts of head winds.

I should have listened to this guy spent my whole summer so far messing with this damn carburetor and still not running right

how does gas dilute oil in the engine?

Yes you can 'wash the bore' if jetted too rich. But the bike will be running like a dog well before that point.

Tell vince the jd jet kits mint I get 250km out of standard tank and go's alot better 🤙 runs good temps to oh yea cut spring to 😎

yah

yes M8

Pull the snorkel and call it a day. Been there done it. LOL thanks

I agree to disagree. My new DR650SE (Canada) has a very bad off idle stumble and very poor mid range power, especially when trying to hold a specific speed. Let alone the sketchy throttle control ability. Basically on and off. All this forces me to run at higher RPM and higher RPMS for taking off from a start. What does all this equal.... inefficiency and excessive fuel consumption, also all this aids developing bad habits. An off factory tune is required, at least in North America, especially for carburated bikes. In fact, he said it himself. Australia has more lax emission laws than North America..... so for us, proper tuning is a big deal.....

im not that technical incline so will just leave stock lol

I've got to totally disagree with Vince here. I've done the BST Magic to my last two Dr's and it made a huge difference especially for a maximum of $20 for a few jets. My filters aren't any dirtier and I've never heard of any oil dilution ever. My fuel consumption actually improved. Sorry but there's some dodgy misinformation in this episode mate. I'm thinking Mr Strang is looking after his own business here lol. I live in Australia too.

I completely disagree. If youu know what you are doing and have an intimate feeling for the BST40 you have baby jesus in your hajnds. Best bike in the world with a discerning carb mod and free flow exhaust.

There is so much just plain wrong information here: We HAVE ridden our DRs around the world - with stock jets, cut springs, drilled slides, ground needles and GSXR exhausts: the so-called BST Magic. The rest of the motors are stock. Immediately it was done, we noticed far better throttle response and had to turn the idle down. All three bikes easily topped 161 km/h on correctly-calibrated Vapor computers. The bikes are now on roughly 70,000km - stock pistons, cams, valves - even the clutches. Valve clearances have barely moved, if at all. Our fuel consumption went DOWN with these mods - loaded with all the gear we needed to live on the road for a year, we were routinely getting 23-24km/l even on questionable fuel, dirt roads and rough terrain; I cut 1" x 2" holes in the airbox on the shore of Lake Titicaca (between Peru and Bolivia, where we went 5200 metres ASL) to let in more air, and I put duct-tape over the holes below 4000m. I have never found any traces of so-called "Oil dilution" even when the oil temp soared in heavy traffic of plugging through jungles and landslides - but we do have manual fuel taps and know enough to routinely turn the fuel off overnight. Oil & filter changes at 6000km intervals. This misleading information is nothing more than an advert for a shameless self-promoting dealer and it ensures that I'll not being buying from that business again.

I call BS for US models anyway.