Author Topic: brandEn's K4 (Read 176897 times)

brandEn · « **Reply #675 on:** October 28, 2013, 06:41:05 pm »

Good info Chef. I'm gonna swap em out for the originals tomorrow.
Thanks for the kind words. I hope your feeling better!

seanbarney41 · « **Reply #676 on:** October 28, 2013, 07:24:03 pm »

ignition advancer a little sticky?

brandEn · « **Reply #677 on:** October 28, 2013, 07:26:14 pm »

No it's been completely taken apart , cleaned, and lubed.

seanbarney41 · « **Reply #678 on:** October 28, 2013, 07:45:40 pm »

I would have been surprised if it hadn't...maybe try the clear tube float bowl level check to see what those needles are really doing.

Stev-o · « **Reply #679 on:** October 28, 2013, 08:10:20 pm »

Wow, it really sounds awesome. Glad I hounded you to buy that pipe.

Godffery · « **Reply #680 on:** October 28, 2013, 08:14:17 pm »

What your describing is typically a result of a Lean condition?

brandEn · « **Reply #681 on:** October 28, 2013, 10:41:10 pm »

Well some forum searching has gave me a plan of attack. I think I have been "Keystered" as others have put it. The carb rebuild kit I got was a cheapie from Ebay (cruzinimage). The float valve has much stiffer springs and does not compress at all under the weight of the float. I had to really adjust the float tang a lot to get the 26mm measurement. Apparently the Keyster kits have stiffer springs like mine and should be set lower around 23 mm so it very well could be a lean condition by not getting enough fuel in the bowls. I will pull the carbs tomorrow and put my old valves in and readjust the floats.

Second, I am going to put on different carb boots. I have two new ones and two that are in great shape. The ones I am using now I bought new but modified to use with my CR29 carbs by installing brass nipples as sync ports. I don't think they are causing any vacuum leaks but at least it will eliminate that variable and will be easy enough to do since the carbs will be off.

Third, I am thinking that it's possible the way I have the tee fitting in my auxiliary fuel tank installed could be giving me low flow to one side of the carbs. I will tinker with that a bit to see if that helps.

The bike starts great and revs real nice. Sounds fantastic. The issue is I can't get a consistent idle and it just idles poorly. Holding the throttle higher than around 2-3 grand it seems fine.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #682 on:** October 28, 2013, 11:41:45 pm »

I'm thinking it just wants to go for a ride!!

MCRider · « **Reply #683 on:** October 29, 2013, 04:48:25 am »

I know you say it snaps to the idle stop. But humor me. Loosen the A cable adjuster to where you have a good free play n the twist grip.

Let us know.
R

brandEn · « **Reply #684 on:** October 29, 2013, 07:19:10 am »

Actually Ron that was the first thing I looked at. I had it to where the cable had little tension on it. Thanks for all the tips. I will get things figured out ...... Eventually.

MCRider · « **Reply #685 on:** October 29, 2013, 07:31:32 am »

Quote from: brandEn on October 29, 2013, 07:19:10 am

Actually Ron that was the first thing I looked at. I had it to where the cable had little tension on it. Thanks for all the tips. I will get things figured out ...... Eventually.

Back to the air leaks. Good luck. I may have missed it, are your rubber boots/manifolds cracked?

brandEn · « **Reply #686 on:** October 29, 2013, 08:13:46 am »

No they are new but modified with sync ports for use with CR carbs and have seen a little use in TAO.

MCRider · « **Reply #687 on:** October 29, 2013, 08:20:09 am »

Quote from: brandEn on October 29, 2013, 08:13:46 am

No they are new but modified with sync ports for use with CR carbs and have seen a little use in TAO.

That's all from me, oops, just remembered. (Maybe its covered in the thread already and I've missed it.)

A sticky spark advancer can cause this too. You can often see if the springs on the advance weight have been sacked, it won't return to idle quickly or consistently. IIRC, The coils should be laying right on each other at rest. If there is any space between them you've got an issue..maybe.

They may not actually touch at rest, but they may be of different spacing, some small, some or one coil has a large space.

PS: I see seanbarney mentions this.

flybox1 · « **Reply #688 on:** October 29, 2013, 08:26:19 am »

SWEET!

Quote from: brandEn on October 28, 2013, 04:32:49 pm

I adjusted my floats to 26mm before installing them. One thing I noticed is that the float valve springs would not compress under the weight of the float when it was resting on the tang. Not sure if that would cause problems or not.

you'd get fuel out the overflow if the float valve wasnt working properly

a stiff float valve spring will just shut off flow sooner than a worn or soft spring would.

cheftuskey121 · « **Reply #689 on:** October 29, 2013, 09:58:15 am »

Quote from: flybox1 on October 29, 2013, 08:26:19 am

SWEET!
Quote from: brandEn on October 28, 2013, 04:32:49 pm
I adjusted my floats to 26mm before installing them. One thing I noticed is that the float valve springs would not compress under the weight of the float when it was resting on the tang. Not sure if that would cause problems or not.
you'd get fuel out the overflow if the float valve wasnt working properly
a stiff float valve spring will just shut off flow sooner than a worn or soft spring would.

Which in turn could be causing the starvation allowing his idle to roam an his jets beg for fuel. Mine did the same thing until I made sure all 4 float heights were set proper and equal. No more rpm hunting for me. Hope it's as easy as that for you branden!

brandEn · « **Reply #690 on:** October 29, 2013, 12:05:32 pm »

I appreciate all the input everyone please keep it coming!

So I replaced the floats valves and verified the float levels were all even using the clear tube method. I took pictures of the 1 & 4 bowls with the marks I made indicating fuel level. The 2 & 3 bowls are the same. I adjusted my air screws out to 1 1/4 turns out. I put new carb boots on. I took the advancer springs out and they seemed weak so I took about 3/4 of a loop out to stiffen them up. I also fixed my aux tank. There is definitely an improvement but it still not perfect. The idle drops and raises before it settles down after blipping the throttle.

CB750 Idle Issues take 2
ignore the tach, its not working correctly

CB750 idle issues 2

Godffery · « **Reply #691 on:** October 29, 2013, 01:27:23 pm »

The more changes you make at one time, the harder it will be to determine what the true issue is.

You may want to replace the Advance springs now; shortening them is a bit like playing with Voodoo.

brandEn · « **Reply #692 on:** October 29, 2013, 02:02:17 pm »

Haha! Can new ones be had?

MCRider · « **Reply #693 on:** October 29, 2013, 04:58:49 pm »

Quote from: brandEn on October 29, 2013, 02:02:17 pm

Haha! Can new ones be had?

I don't think so, never were. OCICBW

You could buy a full advance, but now I think they are NLA.

Stev-o · « **Reply #694 on:** October 29, 2013, 05:24:18 pm »

I agree with Jerry, ride that thing! She doesnt want to idle in the garage....

brandEn · « **Reply #695 on:** October 29, 2013, 05:42:28 pm »

Got a couple things to button up with the brakes and headlight then she will be roadworthy.

seanbarney41 · « **Reply #696 on:** October 29, 2013, 05:52:20 pm »

float level should be 3 or 4 mm below the gasket...that looks too low

brandEn · « **Reply #697 on:** October 29, 2013, 08:00:24 pm »

Quote from: seanbarney41 on October 29, 2013, 05:52:20 pm

float level should be 3 or 4 mm below the gasket...that looks too low

Really? Hmmm, I though I had the 26mm set good. Maybe I measured from the wrong spot. I measured from the bottom of the little notch of the carb body casting.

cheftuskey121 · « **Reply #698 on:** October 29, 2013, 08:03:07 pm »

Quote from: brandEn on October 29, 2013, 08:00:24 pm

Quote from: seanbarney41 on October 29, 2013, 05:52:20 pm
float level should be 3 or 4 mm below the gasket...that looks too low

Really? Hmmm, I though I had the 26mm set good. Maybe I measured from the wrong spot. I measured from the bottom of the little notch of the carb body casting.

that's the measurement I've used too. sounds crazy but are your fuel lines from the aux tank getting fuel to the carbs properly? and what about your vent lines? up and over the airbox is convention. just trying to go through all the "dumb" stuff first

seanbarney41 · « **Reply #699 on:** October 29, 2013, 08:20:02 pm »

Quote from: brandEn on October 29, 2013, 08:00:24 pm

Quote from: seanbarney41 on October 29, 2013, 05:52:20 pm
float level should be 3 or 4 mm below the gasket...that looks too low

Really? Hmmm, I though I had the 26mm set good. Maybe I measured from the wrong spot. I measured from the bottom of the little notch of the carb body casting.

setting the float to 26mm is supposed to result in the fuel level being 3 or 4 mm below the gasket. I have found that it often does not. So much so, that I don't even measure the float position anymore. I just adjust the float until it results in the actual fuel level being 3 or 4 mm below the gasket. No idea how much of this really has to do with your idle problems, but it has worked for me.

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Author Topic: brandEn's K4 (Read 176897 times)