Ear shaved, carbs acting wierd now. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 19 (permalink) Old 05-29-2013, 03:44 PM Thread Starter
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Question Ear shaved, carbs acting wierd now.

Ok, so I did the ear shave last week while I was waiting for my final drive to arrive. I got out on it yesterday after getting the FD installed and the bike would flat line at around 4-5K RPMs.

Took some time today to look things over. Needed to remove carbs again due to rear jug boot not aligned correctly. Fixed that. My only concern after reinstall is that the rear carb does not want to seat as deeply into the boot as the front carb does. I pulled pilot jet covers off the top of carbs, reseated diaphragm and put them back together. Noticed better sucking sound from plunger. Took it out again and it did climb through the RPM ranges completely, just not very fast.

So, I've been spraying carb cleaner around various areas of the carbs and seems no matter where I spray, it bogs the engine down. I dunno if the spray is altering the air going into the intake or if the spray is getting into the cylinders. I can do it on both carbs and achieve the same results.

Really, the bike doesn't feel much different than when I still had the ears on, aside from the lack of proper acceleration. I do notice decal popping coming from front jug exhaust, even though I have reed valves blocked. I can smell gas from rear exhaust, but the front does not have a gassy smell at idle. Prolly need to mess with A/F screws a bit.

So, what's going here? I'm stumped. Thanks!

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post #2 of 19 (permalink) Old 05-29-2013, 04:37 PM
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One thing, with open filters so close, the spray can get pulled into the intake through the filters, it doesn't take much to cause change in idle and you may not be able to see it.

Where are you on jetting and shims?

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post #3 of 19 (permalink) Old 05-29-2013, 04:40 PM Thread Starter
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Quote:
Originally Posted by Spockster View Post
One thing, with open filters so close, the spray can get pulled into the intake through the filters, it doesn't take much to cause change in idle and you may not be able to see it.

Where are you on jetting and shims?

*******
*******
142/42 +2 shims (#4 radioshack washers)

My thing is I expected better accel response, but it seems to take longer to climb thru the rpms than before. I dunno, maybe being off the bike for a couple weeks had me forget the before and after? Or, the pilot jet diaphragms are being a pain still?

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Last edited by blazblu82; 05-29-2013 at 04:42 PM.
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post #4 of 19 (permalink) Old 05-29-2013, 04:55 PM
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I was having a similar issue running out of steam at 6k. Narrowed it down to the screen in the petcock.
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post #5 of 19 (permalink) Old 05-29-2013, 04:59 PM Thread Starter
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Quote:
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I was having a similar issue running out of steam at 6k. Narrowed it down to the screen in the petcock.
Mine was due to the pilot jet diaphragms not sealing right. the plungers were not moving when I blipped the throttle. They do now. Just have an acceleration issue, I think.

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post #6 of 19 (permalink) Old 05-29-2013, 05:15 PM
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Which filters are you running? If they are the Emgo pods try switching to the K&n's I had a similar issue and switching the filters fixed the top end issue.

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post #7 of 19 (permalink) Old 05-29-2013, 05:26 PM Thread Starter
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Quote:
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Which filters are you running? If they are the Emgo pods try switching to the K&n's I had a similar issue and switching the filters fixed the top end issue.
Using Uni PK92's for air filters. Maybe I'll do a short run w/o filters on and see if there is a difference in performance. To me, the bike seems to have had better power when the stock pods were on. If it happens to be the air filters, I may save some $$$ and buy a pair of velocity stacks, that ought to look cool.

BTW, I did back the A/F screws out 3 turns and noticed a bit of gas smell from both pipes now.

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Last edited by blazblu82; 05-29-2013 at 05:38 PM.
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post #8 of 19 (permalink) Old 05-29-2013, 06:09 PM Thread Starter
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Test run w/o air filters didn't change anything. I think the left side carb has a vacuum leak. When I reseated the diaphragms earlier, the plunger moved readily with the throttle. Now, it doesn't. The right side carb is working fine. So, I think my issue here is lack of air getting into the left carb causing acceleration issues. The only difference I had running w/o filters was the bike acting like it was out of gas. The tank is low, but I can hear gas sloshing around still.

Any other ideas? I'm half tempted to buy a carb rebuild kit soon from PJ Motorsports.

When I get back to reseating the pilot jet diaphragms, is their a specific way of doing it so the rubber stays in the groove while I put the cap back on? It always wants to slip out and sit on top of the groove ring. Thanks.

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Last edited by blazblu82; 05-29-2013 at 06:18 PM.
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post #9 of 19 (permalink) Old 05-29-2013, 11:17 PM Thread Starter
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Oh, come on. Where are the carb guru's at? Nearly 100 views and no one has had an issue with their pilot needle diaphragm not holding vacuum as it should?

I am simply looking for some tips on how to get the diaphragm to stay in it's groove while putting the cap back on. I feel this is the only thing preventing the bike from running as it should.

Anyone?

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post #10 of 19 (permalink) Old 05-30-2013, 01:28 AM
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Is the plastic needle holder against the top of the needle? Sometimes it will not go all the way down and the needle has room to move up and down.

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