DRZ-400s losing power

[Patak]

I have a problem with DRZ-400s :(, 2004, 7800 km.

Losing power at a high speed 120-130 km/h and the engine begins to extinguish and shut down . It can only light up after 10-15s.

I cleaned the carburetor - put a new spark plug - changed the oil before the 300 km - the new battery, I cleaned the air filter - cleaned the fuel tank and put a new fuel. No jetting just slip on exhaust that, I put in before 500 km.

Edited June 17, 2017 by Patak

[cowpie]

soooo .. jet it ... my opinion is the engine continues to break in for the first several thousand developing more compression ect and can use more fuel so symptoms like that seem to 'get worse' as time goes on with stock lean jetting .. ..

[Patak]

6 minutes ago, cowpie said:

soooo .. jet it ... my opinion is the engine continues to break in for the first several thousand developing more compression ect and can use more fuel so symptoms like that seem to 'get worse' as time goes on with stock lean jetting .. ..

jd jet kit is on the way ?

 

Suspected problem with stator ?!

[cowpie]

3 minutes ago, Patak said:

jd jet kit is on the way ?

 

Suspected problem with stator ?!

i doubt it .. jet it and then worry if the problem persists ..

[jjktmrider]

If it was stickly a jetting issue it would do it always and not take 10-15 sec. to restart . Could be as simple as fuel level running low due to poor flow or a heating up issue . To clarify , it will run up to 120km/h but then start to bog/loose power? ,or shut off completely? so 10-15s(seconds?) to restart ?  or bogs for 10-15s and then will rev back up to 120km/h ? So at a slower speed it will run fine with no issues ?

With stock jetting and even just a slip-on it definitely needs improved jetting either way.

 

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Edited June 17, 2017 by jjktmrider

[Patak]

3 hours ago, cowpie said:

i doubt it .. jet it and then worry if the problem persists ..

I cleaned the fuel tank, the fuel valves (petcok) are correct. At 120-130 when the engine stops, there are fuel in the carburettor. I checked the bowels - Fuel runs.  

The engine starts with 1-2s with delay. I noticed a lot of shooting from the exhaust when I release the throttle.

The engine loses power only at high speeds, I have never had any such symptoms at 1-2-3-4 speed. Maybe in 2-3-4 a little sense of gas breakdown 

Sorry for my bad english.

Edited June 17, 2017 by Patak

[jjktmrider]

Ya, I know english isn't everyone 1st language and translators don't always convert correctly so that's why I was just confirming .

It's running lean no doubt , you need a bigger main jet for starters . To check for proper fuel flow , you need to open the float bowl drain and let it run for 10-20s steady , watching the flow for any signs of slowing down ,to verify it is actually getting refilled with full flow . It's obviously getting some fuel so if you just crack open the drain screw and quickly close it you'll miss the loss in flow .  In lower gears your only hitting high rpms (using the most fuel) for short periods then changing gears so you won't notice it , but in high gear your running longer at the higher rpm ,so it will show up then only after a certain amount of time . I'm just bringing this possibility up because your saying it comes back after 10-15s , with just lean jetting it would always have the issue ,not just after a length of time at a certain speed running fine and then not .

 

 

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Edited June 18, 2017 by jjktmrider

[Beta300REcat]

There is an obstruction in your fuel supply somewhere. Maybe try running high speed with the petcock on 'prime' and see how it runs.

[Patak]

I have a gravity petcock and the are new one. Petcock have ON/OFF/RES. 

I checked the stator yesterday, looks who's new :). When the engine is running voltage on all three phases is 35V, when I give gas climbs to 80-95V. Let's move on...

[Patak]

Stator pic. 

 Ignition Coils maybe? I have a lot of backfire?

[Patak]

Thanks to everyone on the advice.

I have a question, my R/R shows in both directions about 500 om? Y1, Y2, Y3 to red and black to Y1, Y2, Y3 the same result . Is this normal?

I did the free power mode ? and the bike behaves better. Not be extinguished so easily.

Edited June 23, 2017 by Patak

[GuyGraham]

Stator looks good

Sounds very much fuel starvation

either block petrol tank cap vent, fuel filter on the tap or the fuel filter above the float valve needle which is item 18 on the diagram below

 

and this is what it looks like (the item on the left) which is basically another fuel filter but it doesn't take much for it to become clogged

 

 

[Patak]

I know what you mean ;). I cleaned that filter before 1000km and i put na new o-ring...

Edited June 23, 2017 by Patak

[jjktmrider]

That's about the ugliest one I've seen in a loooooooonnnnggggggg time . A lot of red'ish tint on all the jets , was the gas tank rusting ?

 

 

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[Patak]

47 minutes ago, jjktmrider said:

That's about the ugliest one I've seen in a loooooooonnnnggggggg time . A lot of red'ish tint on all the jets , was the gas tank rusting ?

 

So it looked like when I bought it. The first owner is only 5000km in 12 years ?. Now it's all clear;).

Edited June 23, 2017 by Patak

[Patak]

I think I found the cause of the problem 

Edited June 30, 2017 by Patak

[Patak]

I found a new problem  I took it apart and inspected the diaphragm to find one of the 4 clips holding the needle in the center of the diaphragm has broken off and there is no o-ring just lot of silicone . So we removed the broken piece...

[jjktmrider]

There is no o-ring around the perimeter of the diaphragm , there is a built in ring of material in the diaphragm itself that fits into that groove on the carb that does the sealing . It's important to watch that when putting the cap on so that ring is in the groove all the way around .

 

Unless your talking the o-ring down on the needle holder . I'm pretty sure mine didn't have one either back when I had taken the stock carb apart , but the holder wasn't broken , but it has been a few years.

 

 

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Edited July 1, 2017 by jjktmrider