CRF150RB Carb setup help

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11/8/2020 11:29 AM

So I got it new, it's a 2020, and it's been a pain to start, idle, and keep running from the first day. I've done some reading and went withthr JD carb kit and jetted for my elevation. But it's still hard to start, doesnt really idle, and today the fuel screw backed out. I guess that was probaly from my constant adjusting. This is my first four stroke, so maybe I'm missing something, but I've spent way more time just trying to get it running correctly, than actually riding. Anyone have any tips on the setup for this bike?

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11/8/2020 11:34 AM

Airick wrote:

So I got it new, it's a 2020, and it's been a pain to start, idle, and keep running from the first day. I've done some reading ...more

We had a 2008 that we bought brand new that acted very similar to what you describe. I ended up finding out that the valves were out of adjustment as soon as we adjusted the valves it started and ran great

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11/8/2020 11:46 AM

Airick wrote:

So I got it new, it's a 2020, and it's been a pain to start, idle, and keep running from the first day. I've done some reading ...more

walent215 wrote:

We had a 2008 that we bought brand new that acted very similar to what you describe. I ended up finding out that the valves ...more

X2

Paw Paw

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11/8/2020 12:14 PM

Thanks, I'll give that shot. I was hoping 13 yrs. in without many changes small things like this would have been addressed in production, but what do I know...

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11/8/2020 4:25 PM

It's highly unlikely your brand new bike has valve clearance out of spec.

Starting on carb'd 4-strokes is all about the pilot jet and the fuel screw adjustment. When those 2 are right, the bike will fire up easily every time. If either of those 2 are off, you'll kick until your blue in the face.

Since you've been messing with the fuel screw to the point that it's falling out, I am going to suggest you start there. Get an EZ-adjust aftermarket fuel screw (it's a crime they don't come with these stock) and reset it to the stock setting. Make sure you get the o-ring, washer and spring on correctly and make sure the stock o-ring is not stuck up inside there.

Also, remove the plug on the bottom of the float bowl, loosen the carb clamps, rotate the carb and get the pilot jet out and clean it. Make sure no small bits of dirt or debris are laying in the bottom of the float bowl plug.

Also, since this is your first 4-stroke, you have to know that starting technique is very important and much different than a 2-stroke. Keep your hand off the throttle when kicking!

When cold - engage the choke, kick through slowly until you feel the hard compression of top dead center (TDC), rotate the throttle twice so the accelerator pump squirts some fuel in, reset the kicker and give it a solid kick all the way through.

When warm - no choke and no hot-start, slow kick until TDC, then reset and solid kick all the way through.

When hot - same as warm except hold the hot start lever while kicking.

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Powerband in every gear !

11/8/2020 5:46 PM

FGR01 wrote:

It's highly unlikely your brand new bike has valve clearance out of spec.

Starting on carb'd 4-strokes is all about the pilot ...more

X2 except I have seen a few new bike come out of the crate with valve clearance issues. Not many but a few over the years I was the service department manager at a very large multi brand bike dealership.

Paw Paw

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11/8/2020 6:10 PM

My wife had one of these 150's, very finicky to set up at elevation.
For cold starting I would follow FGR suggestions but another critical step is take your hand OFF the throttle when cold starting and place it on the throttle housing. On our bike, even the slightest bit of throttle and you could kick that thing all day long and it would not start.

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