DRZ FCR Fine tuning

Recently installed an FCR on my DRZ. After initial dramas it seems to be running fairly well.

I just want to get it idling a bit nicer.

I pulled the carb apart on the weekend and installed new jets (second hand carb, unknown jetting) and a extended fuel screw.

Despite the new jets being the same as the old ones and the only other new part being the fuel screw, it now seems to run a lot better than it was. During this process I noticed I had put the manifold boot on around the wrong way, perhaps that would explain a bit too as the intake path now seems a lot smoother/ straighter.

However, I would still like it to idle a bit better and not have that slight cough when the throttle is first cracked.

When I first tested it after I put it all back together I had the fuel screw set at 2 turns. I got the idle not too bad, sounded a little low to me but it idled. When I rode it it was like a wild animal, plenty of grunt, but popping and backfiring like crazy.

I went home after 10-15 mins, readjusted the fuel screw to 2 and 1/4 turns, adjusted the idle to what I tought sounded a touch better and went for another ride.

This time it didn't feel as wild, still an improvement on how it was prior to changing the jets, yet it didn't pop and backfire as much.

With it idling I tried adjusting the fuel screw in both directions and a 1/4 turn either direction will make it stall. I cut my losses and left it alone.

This morning it was a bit of a pig on take off but came good. Still an improvement over how it was before the jet change. It's mainly when putting the choke back in after warm up, it coughs and splutters up my steep driveway.

Any suggestions on what it may need to just smooth out this last 5%?


Heaps more grunt but!

what is the current jetting?

- 200 Main Air Jet

- 160 Main Jet

- 45 Pilot Jet

- 100 Pilot Air Jet

- EMN needle


Did you ensure the AP is working correctly? Not lugging it, right?

Your post was a bit convoluted, so I assume you are talking about sluggish acceleration.

Thanks for the reply

Ap works fine. When I was pulling it apart I accidentally moved the throttle wheel and received a healthy face full of fuel.

Sorry if I was unclear, I just mean that when you crack the throttle it coughs slightly and then is fine. I'm talking <5% throttle. When moving the thing goes great it's just that slight cough and a temperamental idle are the only remaining issues.

Oh and a hatred of tube tires...

Help please anyone

TT store FCR or where did it come from?

Did you oring the AP linkage or wire it or do nothing?

No idea where it came from. I made the mistake of buying second hand. After all the initial drama I had the only remaining issues are the slightly off idle.

AP is o ringed and mini zip tied

Does the cough occur just off of idle or when you are cruising along at mid throttle and if you gve it the gas, it balks?

There is a little bot of that at low revs when it's cold, it's fine at cruising speed, the issue is mainly from idle.

The stock carb idled really smoothand held constant revs, is it unrealistic to expect the FCR to do the same? It just seems to idle a bit rough and have this slight cough I mentioned

Try raising your idle speed slightly. Assuming you can grab a handful of throttle from idle, well, just is not going to work.

What is not going to work?

Nailing the throttle from idle or close to idle.

Sorry, just to make sure I understand you, your saying that that is something I will never be able to fully eliminate? It will always do that when stomped on from idle or close to idle?


your AP is shooting to much fuel at a low rpm for your motor to handle. your motor rpm is going to slow to burn the shot of fuel. it can't handle it so it falls.

once you get going, the shot of fuel from the AP is not bogging because the rpm of the motor can handle the extra shot of fuel

Ok that makes sense.

However it give a bit of a cough even when the throttle is rolled on slowly.

Sorry, just to make sure I understand you, your saying that that is something I will never be able to fully eliminate? It will always do that when stomped on from idle or close to idle?


Yes. No one normally rides at idle that goes WOT. You might reduce it somewhat if the idle speed is raised (assuming you have it less than the rec. 1,850 rpm.)

I increased the idle speed as someone suggested to help cure my idle issues.

This afternoon i was sitting at a set of lights and noticed the idle was unusually high. I reved it a few times and the idle dropped, then stalled. Got it restarted, rode home. When I got home it dropped idle speed and stalled again. Restarted it, did it again. Then I noticed a puddle of fuel under the bike that had come out through one of the breather lines.

What's going on? I really just want this sorted out. First it idles like a pig, now this. Getting frustrated.

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