Author Topic: Vacuum value at idle (rough idle problem).  (Read 6203 times)

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#20

Offline rarch

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Re: Vacuum value at idle (rough idle problem).
Reply #20 on: 05 May, 2016, 10:05:52 PM
Well done.

I've heard of pumps with internal strainer/filter getting clogged up which reduced the fuel flow, symptoms were lack of high speed but bike could maintain a constant lower speed.

Do you have any idea what would cause a pump to deliver at a higher pressure, could it be a blocked pressure relief valve within the pump?  Maybe it can be cleaned...

#21

Offline J-man

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Re: Vacuum value at idle (rough idle problem).
Reply #21 on: 05 May, 2016, 10:49:09 PM
Edit: so it must give 3.5 bar no matter rpm? Or is that just 1 point of reference?
Last Edit: 05 May, 2016, 10:57:32 PM by J-man

#22

Offline Marudny

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Re: Vacuum value at idle (rough idle problem).
Reply #22 on: 05 May, 2016, 11:44:29 PM
*Originally Posted by rarch [+]
Well done.

I've heard of pumps with internal strainer/filter getting clogged up which reduced the fuel flow, symptoms were lack of high speed but bike could maintain a constant lower speed.

Do you have any idea what would cause a pump to deliver at a higher pressure, could it be a blocked pressure relief valve within the pump?  Maybe it can be cleaned...

All constructions I've met are designed with external fuel pressure regulator (which is vacuum operated - to increase fuel pressure). Relief valve is only a kind of safety valve. It's my first time with return less fuel system.

In CBF fuel pressure regulator is in the pump assembly, probably relief valve does FPR function. If not, there should be fuel pressure regulator. Pump always deliver higher pressure (typically 5 bar). After pump is FPR which regulates pressure. It's very simple construction - spring and diaphgram. Spring weakens with time and FPR delivers higher pressure than set.

I'll check at the weekend :)

*Originally Posted by J-man [+]
Edit: so it must give 3.5 bar no matter rpm? Or is that just 1 point of reference?

Service manual says 50 psi at idle. It's very hard to measure fuel pressure while riding :) But pressure is constant in all conditions, flow is higher while riding (injectors have longer opening time).
Last Edit: 06 May, 2016, 12:29:05 AM by Marudny

#23

Offline Mark91

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Re: Vacuum value at idle (rough idle problem).
Reply #23 on: 21 May, 2020, 10:31:43 PM
Hello,

Yes, I know, the Honda does not recommend the throttle body sync, but has anybody tried to do it?
What is it the correct method ?

Thanks.

#24

Offline liamF

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Re: Vacuum value at idle (rough idle problem).
Reply #24 on: 05 February, 2021, 11:24:59 PM
Hi Mark91
sorry for late reply but just wondering if you got info on throttle body sync and why you wish to do it?

#25

Offline Mark91

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Re: Vacuum value at idle (rough idle problem).
Reply #25 on: 06 February, 2021, 02:51:08 PM
Hi,

No problem, I did it with the bypass screws.
I would like to do it, because the cylinders during the kms starts to wearing in every engine. And with the throttle body sync you can balance this wearing.

#26

Offline liamF

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Re: Vacuum value at idle (rough idle problem).
Reply #26 on: 06 February, 2021, 04:33:24 PM
Hi Mark,
That's all you can do as I see it, as the butterfly plates are on one solid shaft with no spring loaded adjusters as with many other bikes. I've been playing with a rough running bike for awhile now, which I've solved with a valve adj as I found all exhaust tight and 3 inlets tight and setting TB vacuum at 240mmHg MAP discon. This is best its run in 3 years, bike is 08 with 32000mls on it

#27

Offline Mark91

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Re: Vacuum value at idle (rough idle problem).
Reply #27 on: 06 February, 2021, 07:45:32 PM
Hello,

Me too is the same. I also did a valve clearance adj. The only problem is when I connected the sync. tester I have to remove the map sensor's pipe.
So we have to the the bypass screw adjustment very slightly, otherwise you will increase/decrease the idle speed.

#28

Offline liamF

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Re: Vacuum value at idle (rough idle problem).
Reply #28 on: 06 February, 2021, 11:07:56 PM
Hi Mark,
MAP needs to be discon inorder to get individual reading from each throttle body, just wondering if many valves were out, mileage, and reading on gauge you used, as getting mine to run correctly has being a long love/hate saga.

#29

Offline Mark91

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Re: Vacuum value at idle (rough idle problem).
Reply #29 on: 07 February, 2021, 07:09:45 AM
Hi,

Sorry I can not remember for the values on the sync tester.
1 exhasut and 1 intake valve was out of the tolerance. I have 64.000 km in the bike (2011) and I am the first owner.

 


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