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New but never ridden 07 150RB runs terrible


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I just bought an 2007 150RB for my son. The bike is brand new, never ridden, with only 1 original hr of ride time on it. It was a project pit bike for the guy I bought it from that did not happen. The bike was never stored with gas in the tank or the carb. As far as I understand the bike has only had gas in it since the past October.

My son rode it today for the 1st time. The bike died all day and was very hard to keep it running. He had to be very diligent about keeping it running. Starting was very difficult as well.

Current jetting is 145 MJ 45 PJ clip is on the 4th position not sure about the fuel screw yet. Need to replace stock one with one you can actually get to. All new jets installed by the guy I bought it from, stock jetting would not make the bike run either.

I have not done any work on it yet, picked it up yesterday.

If the bike was never stored with gas in it. It has only had gas in it since this past October dose it sound like I need to clean the carb?

Is the jetting right? We're in so Cal at about 900 ft.

Any input?

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The pilot circuit is not right, but everything is on the rich side according to Honda jetting chart, which, at 40-60 degrees, calls for 135, 40, and 3rd clip with pilot screw at 2 1/4. Try cleaning the carb, and pay especial attention to blowing out the pilot passages, not just the jet.

 

As I noted on your other thread, '08+ jetting specs, and especially the needle, work better in the '07 carb. That would be 138, 38, NMQS needle 3rd clip and 2 turns pilot screw. But others have had success with different combinations. You have some homework to do. Did you google: "jetting crf150r thumper talk"? Google search is better than TT search, and as noted before, there is a wealth of information on jetting to be found. 

 

Start here for help specific to '07 issues: https://thumpertalk.com/topic/1061864-2007-crf150r-carbidle-issues/

 

P.S. Don't overlook the possibility that the valve clearances might be out of spec. as that can make pilot jetting impossible to get right.

Edited by Old Plonker
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Thanks for the input. The current jetting was done buy the guy I bought the bike from and was recommend to him by a company called Sigma jet kit out of Arizona. I was surprised how off the changes from stock are, they are off the chart!

Just to clarify. So are you saying I should focus on the 08 chart and forget about the 07 specs?

Could it really be valve clearance on a brand new never ridden bike? I'll check it when I pop the carb out for cleaning. I'm also having a difficult time believing the carb is dirty on a bike that's never been used, stored with out gas in it, under a tarp in the garage, with new jets in it that were just put In a couple days ago. I guess anything is possible and all it takes is one grain of sand right.

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Thanks for the input. The current jetting was done buy the guy I bought the bike from and was recommend to him by a company called Sigma jet kit out of Arizona. I was surprised how off the changes from stock are, they are off the chart!

Just to clarify. So are you saying I should focus on the 08 chart and forget about the 07 specs?

Could it really be valve clearance on a brand new never ridden bike? I'll check it when I pop the carb out for cleaning. I'm also having a difficult time believing the carb is dirty on a bike that's never been used, stored with out gas in it, under a tarp in the garage, with new jets in it that were just put In a couple days ago. I guess anything is possible and all it takes is one grain of sand right.

 

It sounds like the typical '07 voodoo, trying to make things work with the '07 needle. It would only be a valve clearance problem if there were over 30 hrs or so on the engine. And, yes, go straight to the '08 specs, starting with the NMQS needle. Do the a/p mod too, since it is easy and cheap. All the information is on the thread I sent you. 

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We have over 80 hours with no valve movement on ours. I wouldn't worry about jetting right now. The carb is probably dirty. My sons yz sat for a few months and the needle stuck that quickly. I couldn't believe it.

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I pulled the carb tonight and will clean it tomorrow. I did notice a white kind of chalky residue on the float bowl float.

 

Remove the main and pilot jets and use a can of carb cleaner with the straw attached to spray up the passages to remove any possible deposits blocking the full flow.

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I wanted to see if just cleaning the carb would be the fix to this dilemma. Well not so lucky!

Cleaned the carb really good, all the passages inside the carb as well as the jets them self, installed a fuel filter. Dumped all the old gas and flushed the tank with new gas, then put new gas in tank. Set the fuel screw to 21/2 turns out.

Tried to start the bike and it probably took me 10 or more kicks to get the bike to fire up ran for a bit but soon died. Need to keep on the gas and finesse the throttle to keep it running. Seams the problem is unchanged by only cleaning the carb.

So I ordered the 2008 needle as well as a 138 MJ & 38 PJ. I will keep you posted thanks for the input.

Can someone explain what a hanging idle means, reading that a lot but not sure what it means.

Edited by Bill_B
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Hanging idle means the revs stay higher than than idle when the throttle is released. It's usually caused by an air leak in the carb or intake

The 07 150r has a removable pilot air jet on the carb ('08+ is a fixed orifice)... It's a slotted jet located at the 7 -8 o'clock position looking at the intake bell mouth. Ensure that jet is present and property tightened.

Edited by mjruopp
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  • 2 weeks later...

Finally getting back to this thread. So I ordered the new jets and needle oldplonker suggested but did not get them in time before we went riding this past Saturday. The night before I figured I would see of I could get the bike running a bit better. Adjusted the fuel and idle screw and managed to get the bike to start and run pretty decent. The bike ran well all day with out stalling for flame outs. My son said he felt the bike was running good and had no problems running and starting. Yesterday I took it for a test ride to see for myself. It starts pretty easily BUT you need to give it about a 1/2 a twist when starting it. I notice it dose not want to start to easily with out giving it some gas, "not normal". After the bike is warm it stars very easily without gas and with out hot start, and best with the hot start. When on the gas hard and steady the bike feels very good, just like it should. It seams to flutter a bit and some popping when letting off the gas here and there. Overall the bike seams to run pretty good but it's not perfect. The starting with gas on and a bit of fluttering and slight popping are really the only issues.

So I'm questioning weather or not I should make changes or not.

Current jetting is all 2007 settings.

MJ: 145

PJ: 45

Needle is: NHNT 3rd clip position.

Fule screw: 21/2

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  • 3 weeks later...
Finally getting back to this thread. So I ordered the new jets and needle oldplonker suggested but did not get them in time before we went riding this past Saturday. The night before I figured I would see of I could get the bike running a bit better. Adjusted the fuel and idle screw and managed to get the bike to start and run pretty decent. The bike ran well all day with out stalling for flame outs. My son said he felt the bike was running good and had no problems running and starting. Yesterday I took it for a test ride to see for myself. It starts pretty easily BUT you need to give it about a 1/2 a twist when starting it. I notice it dose not want to start to easily with out giving it some gas, "not normal". After the bike is warm it stars very easily without gas and with out hot start, and best with the hot start. When on the gas hard and steady the bike feels very good, just like it should. It seams to flutter a bit and some popping when letting off the gas here and there. Overall the bike seams to run pretty good but it's not perfect. The starting with gas on and a bit of fluttering and slight popping are really the only issues.

So I'm questioning weather or not I should make changes or not.

Current jetting is all 2007 settings.

MJ: 145

PJ: 45

Needle is: NHNT 3rd clip position.

Fule screw: 21/2

 

 

Sounds like your float may be out of adjustment.  Did you verify it was set properly when you had the carb apart?

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