Topic: Idle issue

[BlueRidgeHonda]

Hey Guys,
I can't believe my build is so close to being finished! But I have just one more issue/question for ya'll.
When the bike is running, it's misfiring on cylinder number 1 when trying to idle.
At times it idles well, but then spits back through the number 1 carb.

I have:
-checked valve clearance and I'm fairly certain there is enough (.002in), even though I did not use a feeler gauge.
-replaced the #1 spark plug with a new one.
-briefly checked the pilot jet and seems to be clear. The carbs were cleaned last year and havent been installed until now.

The 1&4 ignition coil seems to be alright because #4 is firing just fine. Again, all of this is being tested in the shop and not after riding it on the open road.

I'm thinking it may be a valve seal issue or something in the carb itself? Just thought I'd ask the pros!

Thanks!!

[BlueRidgeHonda]

Oh, And the cam chain tensioner has been adjusted while at TDC.

[ekpent]

 What bike for starters. I would definitely use a feeler gauge to check the valves and the cam chain is not set at TDC at least for a 750 but the valve are .

[Yamahawk]

I'm with ekpent, use a feeler gauge. You really can't 'check' valve clearance without one. .002" is a very small measurement, and you can't check that by 'feel'. Your cam chain has to be set ATDC, I believe about 14 degrees... you turn the crank past the 1-4T line, making sure that it is on the COMPRESSION stroke on the #1 cylinder, i.e. both valve rockers are loose... hence, checking the valve clearance first, setting it to your .002 or .003 intake clearance. The exhaust clearance is .003 or .004 btw. I am going to set mine to the looser setting of .003" intake and .004" exhaust, as I want to make sure it has adequate clearance as I am not sure if it has a performance cam yet. Hope you get it sorted, check for intake leaks on the #1 manifold also.
Charlie

[rotortiller]

Maybe richen up the idle circuit?

[DaveBarbier]

You said you briefly checked the pilot jets in the carbs and that you're fairly certain the valve clearance is good. Be certain on these. Remove the carbs and remove the pilot jets and clean them perfectly once. Can't tell you how many posts people go back and forth in the carbs cleaning them because they weren't sure they were thorough enough the first time.

Also, check the spark plug cap resistance, might as well check all 4.

I'd also remove the spark plug on #1 after idling and see if it's wet with fuel or carbon fouled. I'd probably do this test first.

Edit: also what are your mixture screws set at?