Hard start - 2002 Honda Reflex NSS250

TECH & HOW-TO
1

So I’ve had this scooter for a couple of years. Rebuilt the carb when I got it, use fuel stabilizer and Sea Foam on every fill up, and did a bunch of other things to it.

However when it is cold or sits for a few weeks I need to finagle the throttle to get it to start. Then it runs fine when warmed up, but that hard start has me scratching my head. Idles fine ones running, but in order to get it there, I need to rev it past 2k on the hard start ups.

I can’t find a vacuum leak anywhere, and it didn’t run before the rebuild so I have nothing to compare it to.

These don’t have a manual choke, they have a system that uses a wax substance that “closes” the auto choke system once it’s warmed up.

If anyone has a clue I’ve scoured the interwebs and can’t find a straight answer that isn’t fuel/air/spark related. Just seems like if I had a manual choke it would start fine but I can’t locate good info on the auto choke system these have.

Trying to save some gas since it gets 60-65 mpg :joy:

2

It’s an old carb, even with a rebuild there can be worn parts that would cause it to run erratic. There appears to be complete new aftermarket replacement carbs on Amazon for less than $40. They have generally favorable reviews too, that might be worth a try…

https://www.amazon.com/NICHE-Carburetor-Assembly-2004-2007-16100-KFR-842/dp/B09DDB9HP5/ref=sr_1_5?dib=eyJ2IjoiMSJ9.IBqcnFWi0NHQdbTRInDGfaOe5aLKH7k5v7IZuVjhL4a0wYuWoAThB3WEyMjte7_vk_-BSgZe6DIG7y-AlY7OcCwlFh_1vK3cFkXU-bNWazwWSA831kg_PgpGf5tg-JBJ8mlnxY1l7rbXBo3mvrbZIuPBGMIoj8Imx9s2cBApSvMMobufNWJKxA73YuSm1YKaKDPGWEFH63nXZbO0RErpSwjQ0GnsPkdtO7u_ZgCrP6PZ5UsVW2JnWfGXrLGUOkXFS-C_zRPyMiCXP_WjI2_5KxVWHvmPwsHRrcYAM9dOMmA.nsDnOJaCfU338FnnRwZm8a5uTs5B1kbey3NfURrWuxg&dib_tag=se&keywords=2005+honda+reflex+nss250+carb&qid=1774970273&sr=8-5

OR if the problem is just on start up the choke is controlled by an electric servo motor. ( I don’t see anything that is not mechanical/electro-mechanical in the choke circuit on this carb) Part #8. Maybe you can test it’s function by removing it from the carb and seeing if the plunger moves when the ignition and starter are activated. New part is $75

https://www.partzilla.com/product/honda/16046-KFG-000?ref=f7b2bbfcd7b975e280a2953d8d46fae6cdce96a4

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1 Like
3

I found a video where they tested that #8 part, guess I’ll need to re locate the video and test it. I remember they said it heats up and has a wax or something that loosens up and allows it to reseat when the engine is warm and not needing the choke.

I had it out yesterday and rode great, just when it was cold it fights start up.

Might also look into a new carb