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R&D Flex screw on flat CR carbs. Problems? Lack of info all around

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I’ve heard a lot of good things about the R&D flex fuel screw so I decided to give it a try.  After doing the research on my own because of the SEVERE lack of information on the manufacturers website, I found that its suppose to work on all Keihin flat cr carbs.   Now this is where things get fuzzy.... the threads cut on, not one but TWO, screws so far have been completely different than the ones on my stock AND "T" handle needle.  The screw simply will not thread into my carb.  I honestly thought a few websites made a mistake by stating that it fits ALL FCR carbs, but even the track maint guy at the local shop is shocked that 2 have not fit so far!  Just a couple incorrectly cut threads? I would like to think NOT, but the QC at R1 Dean has to be TERRIBLE considering the simple SPELLING mistake right on their packaging!!!  (I mean how the hell do you miss that!!!!)

 

2008 YZ450F, Keihin Flat CR carb, 2 screws haven’t fit. The threads are not cut as fine as the stock screws. Has anyone managed to install this on a Yami in the same model years as mine??

 

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AFAIK, all FCR fuel screws are the same from the threads to the tip. The only variations are the lenth of the shaft from the threads to the point of driver connection and the type of connection, slotted or the 'D' cup.

 

If both your screws came from the same source, it is quite possible they are from the same faulty batch. Did you contact R&D?

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They shop guy is waiting for my call at 9am this morning and were going to go from there.  After checking it looks like the thread size is 5mm by 0.5 pitch.  I dont have a die for that size but the tap I have definitely shows threading problems on the screw when set side by side.

 

Very good info William, its pretty odd that 2 havent worked, but Im more so VERY shocked by the lack of info on the r1dean website!  We'll definitely make sure to get some info there way on the problem.

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Stock carb.. again confirmed by the guys at the shop.  Threads wont even fall in place with each other on 3 of the R&Ds that had on the shelf.

 

QC...whhhhaaaaaaat ha

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Again, it's your carb that is the issue.

 

I think your 'mechanics' are clueless. They are the weak link in this equation.

 

The old spring is probably still inside the carb, or a piece of the old oring, preventing them from installing it.

 

What city are you in?

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Stick with stock idk how many bikes I've ran into that run like shit because of those screws

 

that would be zero. it's just a fuel screw, with the same profile and length as the stock fuel screw....

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Im in LA.. The shop guys are not the ones installing it, that would be me.  Ive taken out the T handle screw about 5 times now and it comes out and goes back in perfectly every time.  The spring is not still inside, nor is the o-ring an issue.  The T handle screw is awesome, its just a little hard to adjust compared to the neat flex screw.

I wish I had a camera capable of taking a close enough picture to show the differences in threads on the R&D vs the T handle.  The threads on the R&D are simply NOT cut all the way, period.  No questions about it, even an idiot could tell by looking at both side by side that there is a difference.  Confirmed by numerous mechanical engineers in the machine shop within the company I work for as well, threads are just no good. 

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Im in LA.. The shop guys are not the ones installing it, that would be me.  Ive taken out the T handle screw about 5 times now and it comes out and goes back in perfectly every time.  The spring is not still inside, nor is the o-ring an issue.  The T handle screw is awesome, its just a little hard to adjust compared to the neat flex screw.

I wish I had a camera capable of taking a close enough picture to show the differences in threads on the R&D vs the T handle.  The threads on the R&D are simply NOT cut all the way, period.  No questions about it, even an idiot could tell by looking at both side by side that there is a difference.  Confirmed by numerous mechanical engineers in the machine shop within the company I work for as well, threads are just no good. 

Sorry, didn't mean to be a dick.

 

Call up Dean at R&D and ask him what's up. He's a cool guy. I bought a powerbowl 2, with a stuck check valve, and he had me drive over to his machine shop where he tested it and replaced it.

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that would be zero. it's just a fuel screw, with the same profile and length as the stock fuel screw....

now way the threads are so loose they leak and a super lean condition leaving you trying to adjust everyday till if falls off in the trails haha

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I doubt its all of them of course, most lilkely just the recent batches sent out.  Like I said Ive bought them from a couple different dealers now, quite a few of them, none of them worked.

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