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I am stumped on what to do and looking for guidance.

i have a 2018 Drz400sm.

put it through the first service then went through with the 3x3 mod with JD jet and full FMF pipes.

followed everything the jet kit said and tuned for sea level with blue needle in 3rd position 160 main and 25 pilot and fuel screw 2 1/2 turns out. 

Took the bike for a spin and it ran like crap. 

Idle is fine . But the bike just has no power anywhere and feels like a 50cc machine. Top speed was 95kmph on the road. 

So following this a took the carb apart and tried more jetting combos thinking it was just running lean. No success. Still slow with no response. 

I put the bike back to complete stock jets and exhaust and taped over the 3x3 hole to replicate the snorkel back in. And even then it ran the exact same no power and weak response. 

So currently the bike is sitting back at full fmf exhaust , blue needle in 4th position, 160 main 25 pilot and 2 1/2 turns out with 3x3 airbox standard air filter. All to which it runs slow like the throttle doesn't work but every now and then it surges in power for a second and dies away. 

i looked into the  TPS ( throttle control sensor) and it is running the correct resistance of 5 at closed throttle and 3.9 open. 

What could be the problem?

help would be much appreciated.

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Hmm  - I'm no expert on these carbs - I fuel injected my SM....But check your carb for vacuum leaks. especially around the top cap and diaphragm. As there are two parts to restricting airflow (the butterfly - which is cable operated) and the slide (vacuum operated) you might find that the if you have a leak the slide may be preventing you from developing power by being fully closed.

 

I have just pulled mine out of the box of spares that I have for the bike to check and see where the vacuum hoses go.  It looks to me like there is a vacuum take off on the cable side - that should go to the vacuum operated petcock (fuel lever) and the PIRS valve (if you still have that fitted, if not then make sure you have blocked the tub off!) and a large spring covered tube that runs from the solenoid at the bottom to the back top cap (this restricts power in 1, 2 and 3 gears)

PS you might want to repost - or move this post to the DRZ section  - the members there will know 

As an aside - what part of NZ are you?

Cheers

John 

Edited by roleyrev

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Cheers for you insight mate.

first thing tomorrow I'll have a look at the top cover and ensuring the diaphragm is seated and I have no leaks.

yeah I have all those pipes linked up still. 

Interesting about the solenoid... do many take that out I wonder if it restricts power?

oh I get around nz haha but I would say my home bases are tauranga and auckland.

thanks for your advice.

 

 

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7 minutes ago, Cinnychai said:

Cheers for you insight mate.

first thing tomorrow I'll have a look at the top cover and ensuring the diaphragm is seated and I have no leaks.

yeah I have all those pipes linked up still. 

Interesting about the solenoid... do many take that out I wonder if it restricts power?

oh I get around nz haha but I would say my home bases are tauranga and auckland.

thanks for your advice.

 

 

Yeah it does restrict power, Check on you-tube for the how-to on removal.  

 

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Try the red needle clip 3.I presume you are running the Mikuni Bsr36? Standard pilot jet 22.5 will also work fine.I have the K9 SM and have exactly the same setup as yours but after speaking to James he said try the red needle and it did work out better.Admittedly though i have replaced the standard air filter with a foam unit.Performance was better with the foam unit.I suspect though something went wrong with the carb assembly.That needle on the Bsr is a pain to put back without breaking those plastic tabs.I broke one tab and because the needle was then offset the boney had problems just like yours.I removed the solenoid as well as the pair valve system.Also make sure that the little o-ring is also still there at the vacuum diaphragm.

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