limiter tabs

[letank]

Noob to the NH750, but not motorcycles...

I have acquired a 2003 NH750  (16Kmiles) but it is really lean here in Cal. I need the choke for about 5mins.
 are the limiter tabs simple caps that can be pulled down.You cannot view this attachment.

thank you, neat site with a lot of very tech details

[Bob H]

but it is really lean here in Cal. I need the choke for about 5mins.
 are the limiter tabs simple caps that can be pulled down.

No those tabs don't just pull off. But that's not your problem.
I have a CA 750 NH that did not require the choke to be on that long, when it was totally stock.
The owners manual says the choke can be fully shut off about "half a minute" after starting the bike.



Needing the choke on that long is "compensating" for something. One of the carb passageways is clogged... something is wrong.

Was your bike in storage? You may want to run a few tanks with Seafoam to see if things open up, before going to the hassle of pulling the carbs and rebuild.

Prior to my carb rebuild last year, my bike "ran fine" but not real happy above 5k RPM. It could go higher, but just sounded straining.
I followed Pete's advice and increased the jets per the carbjetkits.com recommendations and now it smoothly jumps up to redline with no flat spots.

The CA bikes ARE LEAN but those limiter tabs only adjust the very small flow of fuel at idle.

On those limiter tabs - You can't do much while they are on the bike. Even with the tabs off (mine were cut off) you can't really get to them even with special tools to do a proper adjustment - so you just make sure they are all the same.

I set mine at 3 turns out and believe it is a bit rich. Stock was around 2 or 2.5 turns out I believe.

If you do need to pull your carbs - you may want to review this thread for info on the emission stuff on your bike.
https://nighthawkforums.com/index.php?topic=214.msg1642#msg1642

[mollusc]

I'm going to disagree on the choke here.  I've never had a carbed bike where I could get rid of the choke anywhere near that quickly.  5-10 minutes has been pretty standard -- remember that your entire carb assembly has to warm up to its regular operating temperature before everything is optimal, and that takes some time.

[Pete in PA]

It's not too bad. Just pull the carbs, clean, and rejet.  Even brand new this bike, especially the Cali. version was too lean.  It's not normal to choke for 10 min.  It's just all Honda was allowed to do because of the EPA. Read old posts here, We've done it.

[Bob H]

I'm going to disagree on the choke here.  I've never had a carbed bike where I could get rid of the choke anywhere near that quickly.  5-10 minutes has been pretty standard -- remember that your entire carb assembly has to warm up to its regular operating temperature before everything is optimal, and that takes some time.

When my California (lean) bike was totally stock I could take the choke off within a minute.

With slightly bigger jets, if I DON'T take the choke off within a minute the bike begins to stutter until I take the choke off.

The Owners Manual (posted above) does mention that after you turn the choke off, if the idle is unstable to open the throttle slightly. I have a throttle lock and do adjust the throttle a bit to make sure there is no issue as I am putting my helmet and gear on.

If someone didn't have a throttle lock and was waiting for the bike to warm up enough to run perfect without any throttle adjustment - yeah that is going to take more than 30 seconds. Before my throttle lock I would at least cut the choke down to 1/2 as soon as the RPM started jumping up, which is usually 20 to 30 seconds after starting my bike.

[mollusc]

I can see bigger jets changing how you use the choke, of course.  Strictly speaking these carbs don't have a choke at all; rather, it's an enrichment circuit.  More fuel rather than less air.  If you're already adding more fuel through larger jets, some of the task is already done.
Really though, every single bike is going to be different.  Adjust and operate yours in the way that works for it.  I'm very surprised that the Owner's Manual would say something as specific as half a minute.  And going back to the OP, I don't think 5 minutes is too far out of the ordinary.

That said, the mix was apparently very lean from the factory, especially on the CA bikes.

[letank]

What has happened in the last 20 years, the gas is different with the 10% ethanol and before with whatever is added to gasoline, gas is leaner, I had to tweak the 30 year old carbureted Jeep a few times. When the MTBE was added to gas to make it cleaner my Jeep mileage dropped by 10%.

That 750 is really cold blooded, it runs fine but tend to stall at idle, hence my idea to first deal with the idle setting.

I have tweaked my other bike an 850 Yamaha triple, and it runs a bit richer, and starts without the choke, but yes the choke is used for the 1 min warm up.

Thank you for your replies. And I have used the search functions hence my specific question about the cap on the idle settings. Yes the TSM mentions the different turn for the Cal and 49 states being different.

[Bob H]

That 750 is really cold blooded, it runs fine but tend to stall at idle

Does it do that after fully warm? Could it "stall at idle" while waiting at a red light?
I would suspect a clogged passageway (like to the idle circuit) before an adjustment of the mixture screw if your bike ever stalls at idle (after warm).

On these older bikes, there is always SOME point in their history where they don't get ridden. Stuff dries up in passageways. Until you see that carb cleaner blow through each passage, it is a gamble.

A lot of times a prior owner will raise the idle speed to compensate for clogged idle passageways, which tends to manifest as low power at full throttle because not all jets are contributing to the mix.

I have tweaked my other bike an 850 Yamaha triple

I had a 1980 Yamaha 850 triple with the shaft drive, and still miss it.
Should never have sold it. I have ridden the MT-09, XSR-900 and the Tracer 900, they are all great bikes and faster than the old triple. But they lack the character. Mine was like a freight train.