Engine Cuts Out Under Power

[paulwilliamaskew]

Hey folks,

Just attempted to start my DR650 (2015)......having a few problems

She idles fine but as soon as I put 1/3 -1/2 throttle the engine starts spluttering and if you put more power on after this she will cut out

Can anybody advise me what to check before I start taking the bike to bits? I just put some new fuel in the tank and it made no difference

I will attach two videos of the problems (apologies about the exhaust noise!)

First video is of me opening full throttle.

https://www.youtube.com/watch?v=cwZ76J9J8yo

Second video is of me opening it to when it starts spluttering for a while, then opening all the way until cut out.

https://www.youtube.com/watch?v=2bQZL3y6t34

Any help would be greatly appreciated!

[Warin]

Check fuel flow into carby float bowel .. remove float bowel, put a container under the carby and open the fuel tap ... if it does not flow but dribbles you have a blockage .. possibly in the plastic filter fitted to the carby inlet.

[teevee]

clogged jet(s). this has happened to me several times as my DR sits for extended periods in between uses.

[Warin]

Originally Posted by teevee

clogged jet(s). this has happened to me several times as my DR sits for extended periods in between uses.

Turn off the fuel .. and then let the engine run - pulls most of the fuel out of the jets.

This responce is to teevee and is prevent blocked jets ... not to fix the original problem!!!!!!!!!!!!!!!!!!!!!!!

[paulwilliamaskew]

Originally Posted by teevee

clogged jet(s). this has happened to me several times as my DR sits for extended periods in between uses.

Mr DR650 has just been sat for 7 weeks while I was away at work

I will try turning off the fuel and running her for a bit

Thanks so much Back in a while!

[paulwilliamaskew]

I tried running her for a bit.......no luck

Could somebody tell me what I need to do from the following diagram? Not too familiar with these things to be honest

http://www.vincestrangmotorcycles.com.au/carby.pdf

[Nigel Marx]

I'd start with taking the float bowl off the bottom of the carby, and then taking the main jet (14) out. Look to see if there's anything blocking the jet hole, and blow it out. If you can't see it clear after blowing, poke something soft, like a piece of grass stem into it, or a blast of compressed air. Never use anything that is tougher than brass. The jet is a precise size.

Cheers

Nigel

[paulwilliamaskew]

Well.........I took the whole carburetor out to inspect.

The bolts on the carb must be some of the worst ever made! Jesus I ended up grinding them into flat blades to get them off! They are replaced now anyway.

The float bowl had quite a lot of gunk in it. It was a sort of clear jelly substance which I removed. The crappy Suzuki white 'filter' on the fuel line was full of stuff as well. Think I will replace that tomorrow also.

Result: She works perfectly now Thanks everyone always appreciated!

Does anybody know how I can reduce the exhaust 'popping' noise when I come off the throttle? I fitted a Barratt exhaust a while back

[Warin]

Originally Posted by paulwilliamaskew

I tried running her for a bit.

That is to prevent teevees problem! And possibly you should use it too to prevent future occurrences. Works on lawnmowers too.

Originally Posted by paulwilliamaskew

Could somebody tell me what I need to do from the following diagram? Not too familiar with these things to be honest

Remove the float bowel. Turn the fuel off first.

To do that there are two screws on the bottom of the carby - screw #36 shown in your pdf diagram ... only one screw shown but there are two.
The flow bowel is not numbered in your diagram ... but screw #24 is fixed to it.

Now turn on the fuel and check that it flows out on to your boots. It should run out freely .. not dribble. If you want to avoid wasting fuel then put a container under the carby. If it does not flow out freely ... then check its flow out freely from the black rubber tube that runs from the fuel tank to the carby. Item #23 is the plastic filter that can get blocked .. remove it and clean it if required.

If it runs freely then do as Nigel suggests ... I'd use a nylon fishing line as the
probe, item #14 is what you want to clear ... it is brass so yellow coloured and has a small hole in its centre.

Good luck.

-----------------
Ar .. see you have done the deed .. fairly easy to follow your nose. Harder to type it up.

First thing I did was to replace those carby bolts with stainless steel allen cap heads ... past experience say those bolts will seize and be impossible to remove. I'd even be tempted to put torqueX bolts in there! Put some 'never size' on the thread of these bolts .. no matter what you put in there (and I'd not use the bolts with damaged head here).

[teevee]

Originally Posted by Warin

Turn off the fuel .. and then let the engine run - pulls most of the fuel out of the jets.

This responce is to teevee and is prevent blocked jets ... not to fix the original problem!!!!!!!!!!!!!!!!!!!!!!!

been there done that and still got gunked. even ran it dead then drained float bowl using screw. seems as though the utterly horrific gas we have in nicaragua will kill just about anything that sits. it's gotten worse over the past several years as fuel quality has worsened.

since ethanol seems to be the culprit to a large extent, what i'm going to try this year is making up a few gallon batch of de-ethanoled fuel and run that through the system for storing after draining the pump gas from the last trip.

[Warin]

Originally Posted by teevee

since ethanol seems to be the culprit to a large extent,

At least some of the lawnmowers around here stipulate that ethanol based fuels are not to be used ...

[Gipper]

Glad you got the DR running again, sounds like an ethanol problem - its horrible stuff, I avoid using any fuel with it, in every petrol engine I own - if I have to use it and let the bike sit for any more than a few days then I use a fuel stabiliser (Sea Foam) which seems to help reduce crap building up in the carb.

Take that small white filter from the carb inlet and throw it in the bin, they have a tiny surface area and clog up quickly, instead use a proper inline fuel filter, they have 10x the surface area to filter the fuel and last a lot longer before having to clean them (backflush)

As for the decal popping on overrun, the DR is renowned for it, what setup do you have on the carb/airbox? its hard to tune it out with a performance can like the Barratt - or even the GSXR 1000 can, the only real way is to increase fuel flow, which will take the edge off it, but not much, if you do try that, increase the fuel in small stages and compare fuel consumption, but the fuel screw should not be out more ~2.5 turns.

Best way to clean the carb is to strip it down, remove all plastic and o rings and immerse it in Pine Sol for about 3 hours, this removes any varnish/gunk build-up.

[mollydog]

Originally Posted by paulwilliamaskew

Well.........I took the whole carburetor out to inspect.
The bolts on the carb must be some of the worst ever made! Jesus I ended up grinding them into flat blades to get them off! They are replaced now anyway.

The float bowl had quite a lot of gunk in it. It was a sort of clear jelly substance which I removed. The crappy Suzuki white 'filter' on the fuel line was full of stuff as well. Think I will replace that tomorrow also.

Result: She works perfectly now Thanks everyone always appreciated!

Does anybody know how I can reduce the exhaust 'popping' noise when I come off the throttle? I fitted a Barratt exhaust a while back

From symptoms you describe the DR's BST 40 Carb can often have a clogged Pilot Jet. The Main jet is hard to clog but can happen too. Crud in bowl is not good. When bike starts and idles but won't accept throttle, it's almost Always clogged Pilot jet or Water in fuel. (been there, done that!)

You may have had WATER in your fuel? The suggestion about of Sea Foam in the fuel along with STABIL can help if bike is stored. All good! Also good to crack float bowl drain screw and drain old fuel every month or so (if possible)

I use both the little white filter and an additional inline filter. Both are good for me as riding in Mexico can mean crud in fuel.

If you had done even a cursory search you would have learned about the stock float bowl screws. (Nightmare!) Why? Due to USA EPA rules Suzuki made float bowl screws PERMANENT. NON removable. They use RED lock Tite (Japanese version is White ... equally stubborn)

I used an IMPACT DRIVER tool with correct JIS bit (not Phillips bit). A good tap and screws broke loose. I did this with Carb OFF bike, held carefully in Vise. Some use a Dremel to cut slots but the Impact tool worked great, took seconds. I replaced all screws with Allen Head screws.

You can learn a TON about the DR650 from ProCycle in Bend, Oregon. A great source for DR650 Parts and knowledge. Or go to the DR Riders DR650 forum. drriders.com

[tremens]

Originally Posted by paulwilliamaskew

Does anybody know how I can reduce the exhaust 'popping' noise when I come off the throttle? I fitted a Barratt exhaust a while back

try blocking AIS.

[Tomkat]

Postscript: the original symptom was typical of a blocked main jet. The engine runs fine when pulling through pilot and needle jets but above half throttle the main jet starts to suck and if it's blocked the engine will run leaner and leaner and stall. Often the main jet blocks first, even though it's the largest, because it sticks down into the floatbowl so any debris that drops in there gets sucked into the main first.

Glad it's sorted.

Re popping back in the exhaust the usual cause is an air leak at the joint between the exhaust and the cylinder head. With a rattly engine you may not hear a slight gas leak on throttle, but on over-run it sucks air back into the pipe and any unburnt fuel ignites, hence the popping. I've also heard of this being caused by the idle mixture screw on the carb being set too lean (same effect, too much air on closed throttle). Take the exhaust off, check carefully for leaks or splits then refit and tighten down carefully with a new gasket. Set the idle mixture screw per the handbook and that should do the job.