Author Topic: No start...its spring...PD Carb (Read 21402 times)

Sdsbassist · « **Reply #50 on:** April 14, 2014, 04:41:41 PM »

...or, before keep taking them on amd off, is there a decent way to test thay the pump is functioning before I put it on the bike?

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750K · « **Reply #51 on:** April 14, 2014, 04:43:30 PM »

If your not sure what its actually doing or not doing, cutting holes etc is probably not going to help. The accelerator pump circuit is pretty basic, if its not clean its not going to work properly. If the check valve is toast that's another issue.

750K · « **Reply #52 on:** April 14, 2014, 04:49:02 PM »

Make a wooden rack that holds the carb bank, put it in a bench vise. Get it working with it on the bench after you know it's spotlessly clean and floats are set, fast idle cam set. Then visually verify the accelerator pump is working properly, once you know it's all set up and working put it back on the bike. If the bike still won't start you most likely have a different problem, spark, timing, electrical...

Sdsbassist · « **Reply #53 on:** April 14, 2014, 05:43:14 PM »

How would I prime it without the cables connected?

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harisuluv · « **Reply #54 on:** April 14, 2014, 05:59:28 PM »

I really don't know why all your problems seem to lead to the accelerator pump. Bikes without it can start just fine.

I really think you should do some reading, research, familiarize yourself with terminology, and then reassess afterwards.

I don't even know what you mean by "made a bigger hole." That doesn't sound good though.

Sdsbassist · « **Reply #55 on:** April 14, 2014, 06:04:08 PM »

In the mickey mouse ears.

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Sdsbassist · « **Reply #56 on:** April 14, 2014, 06:05:12 PM »

Agreed. Im going to set the yiming tonight and make sure the points are behaving as they should.

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harisuluv · « **Reply #57 on:** April 14, 2014, 06:25:31 PM »

There is a 3000 mile tune up check list that you can do a search on the forum and find it easily. You should probably do that before you mess with the carbs more. Often times though, people do one or two things, and call it good.

750K · « **Reply #58 on:** April 14, 2014, 06:51:38 PM »

Quote from: Sdsbassist on April 14, 2014, 05:43:14 PM

How would I prime it without the cables connected?

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In the middle of the carb bank, theres the wheel the throttle cables attach to. You can twist it by hand, follow the shaft it's on to the number 4 carb. There's a plate that the idle adjust screw hits. Pull the plate repeatedly, it's got a big spring the throttle shaft is attached to it. Either by the plate at the idle screw or by the wheel the cables attach to, twist it a few times to get gas into the pump circuit. Once it's primed you should see all four nozzles squirting gas into the carb throat, you will need to hook up an external gas supply or run a long fuel line from your tank. However you run a fuel source have it higher than the bank of carbs, gravity feed. Just like it would be on your bike, doing this on a bench saves you so much of the on and off on and off you do if its on your bike.

Sdsbassist · « **Reply #59 on:** April 14, 2014, 08:17:51 PM »

Cool. I adjusted points tonight, but now ive got gas pissing out of three of my carb bottoms.

Float height should be 14.5mm correct? 78cb750

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flybox1 · « **Reply #60 on:** April 14, 2014, 08:31:50 PM »

Yes. 14.5mm, which turns out to be the same as the top of the pilot jet. Just use a straight edge across the tip of the pilot jet.

Be sure your bowl drain screws are seated.
Gently tapping the end of the bank of carbs works wonders in sticking floats...use something soft, like wood or a rubber mallet.

Sdsbassist · « **Reply #61 on:** April 14, 2014, 09:38:24 PM »

Got it and done. Lined the. Up with the top of the jets and whammo. No more leaks.

Still cant get my accel pump working. I know it works cause I put some gas in the bowl, actuated it and gas shot out of the hole with the o ring in a noce healthy squirt. When I look at the plunger rod when I actuate the throttle, the plunger doesnt hardle move at all. Is there a way to adjust that? That could be the issue.

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AintNoEasyWay · « **Reply #62 on:** April 15, 2014, 05:36:36 AM »

The diaphragm doesn't need to move that much. It's got a spring & pressure built up in the tubes that will force fuel through the nozzles.

Shop manuals claim that you can adjust the actuating plate (the "pump arm") for the rod, but it's pretty solid metal & I don't think you need to start tampering with anything else like that. Very unlikely that it's causing any issue.

Sdsbassist · « **Reply #63 on:** April 15, 2014, 08:03:20 AM »

its a reason I thought of because of of the fact that when I activate the plunger with the bowl full of gas (but off the carb) I get a good steady stream.

When I put an air compressor to the carb body and spray through the bottom nozzle hole, air comes out all 4 nozzles.

How many times after filling the carbs should you have to twist the throttle to see results? I also received my new diaphragm yesterday and plan on putting it on there tonight to see if that will pull more fuel out.

Also adjusted the timing so hoping she will pop today.

TwoTired · « **Reply #64 on:** April 15, 2014, 09:10:30 AM »

Did you compare the new pump's actuator rod length with that of the old one?

flybox1 · « **Reply #65 on:** April 15, 2014, 09:15:08 AM »

Quote from: Sdsbassist on April 15, 2014, 08:03:20 AM

How many times after filling the carbs should you have to twist the throttle to see results? I also received my new diaphragm yesterday and plan on putting it on there tonight to see if that will pull more fuel out.

10-15
I'm able to see it fill the clear connector tubes first, then it starts to spray.
twist slowly, as the pump bowl takes a second to refill. its only gravity fed.

750K · « **Reply #66 on:** April 15, 2014, 10:38:47 AM »

From what I remember there are two lengths of diaphram rods, I was ordering carb parts last summer for the carbs on a cb650 I'm rebuilding for my wife. I had to check my 650 service manual for the length, Sirius has a long and a short. If you have a short rod Bahahaha you won't get enough of a pump, lol.

AintNoEasyWay · « **Reply #67 on:** April 15, 2014, 10:49:47 AM »

Didn't think to suggest checking rod length.

flybox1 · « **Reply #68 on:** April 15, 2014, 10:54:19 AM »

size does matter

Sdsbassist · « **Reply #69 on:** April 15, 2014, 12:15:31 PM »

well, knowing me, I should have a big rod.

If I have a small rod, it would explain why i cant squirt.

I will compare the sizes and make sure that there is no difference. I will also take out the good used one that's in there and try the brand new one tonight. Hopefully that, along with timing should give me a runner so I can test out the other systems.

martin99 · « **Reply #70 on:** April 15, 2014, 01:49:01 PM »

Just a thought - have you used the correct size o ring for the check valve on #2 float bowl? I think I'm right in saying that if you use one that's too fat it's possible for it to compress and block fuel flow when bolted up to the carb body.

flybox1 · « **Reply #71 on:** April 15, 2014, 01:55:15 PM »

Quote from: oldskoolnuts on April 15, 2014, 01:49:01 PM

Just a thought - have you used the correct size o ring for the check valve on #2 float bowl? I think I'm right in saying that if you use one that's too fat it's possible for it to compress and block fuel flow when bolted up to the carb body.

+1. Forgot about that.
The buna-n o-ring I purchased at the auto parts store caused this when the bowl was fully tightened down.
I carefully modded the o-ring to have a larger ID. Now it works fine.

Sdsbassist · « **Reply #72 on:** April 15, 2014, 02:53:13 PM »

Good point. I did buy a generic one from the hardware store....i will make it smaller today.

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Sdsbassist · « **Reply #73 on:** April 15, 2014, 05:31:38 PM »

So anyone have suggestions on where I can get this oring. That one was way too fat.

I tried putting carbs on again and am still having issues starting. I adjusted valves, adjusted points and will static time tomorrow. Its damn frustrating because it was running a couole days ago, then the next day, nothing...

BAH

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harisuluv · « **Reply #74 on:** April 15, 2014, 07:10:46 PM »

Well, I think I already said a couple times the accerlator pump is not going to help your start and idling. Did you clean your pilot jets? and if so how, exactly. Detailed.

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Author Topic: No start...its spring...PD Carb (Read 21402 times)