Author Topic: help please??  (Read 1230 times)

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Offline schneider419

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help please??
« on: July 04, 2008, 11:53:00 AM »
i've put a new top end on my 350f, new pistons, rings, etc. i put on a head i got off of ebay, took .010'' off of the head, cleaned up good. lapped in the valves, put all valves and springs etc. back in the same places. i did some minor port work on the intake and exhaust ports, mostly grinding off some of the rough casting spots and rounding off the bottom edge where it turns into and out of the cylinders. i put in new points and condensers timed it to stock. they are spot on. now when it runs it will not idle at all. any thing below 2,000 rpm it dies like you turned off the key. it has a little miss or popping out no. 1 exhaust, like maybe the valve is not seating right. it pops once about every 4 or 5 seconds. it acts like it wants to ldle better when its cold. no. 1 plug looks to be a dark dry sort of black which seems to me to be the idle settings are i little off or ignition. the other plugs look good. i changed the coil that feeds  no. 1 cylinder but it's still there. i've had the carbs off to check the ldle circut about 7 or 8 times this year. i'm getting way to good at that. my brother inlaw says it is too lean at idle, but when i put in richer jets it is worse. i tried messing with the air screws but not much happens. i checked for an air leak at the intakes, they are okay. i have stock exhaust pipes on it but there are 8 holes drilled in the end of each one. i wonder if i am looking at more than one problem i guess thats about it any thoughts?? thank you.

martino1972

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Re: help please??
« Reply #1 on: July 04, 2008, 12:03:32 PM »
double check your timing chain,might be off 1 tooth...

Offline schneider419

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Re: help please??
« Reply #2 on: July 05, 2008, 06:07:45 AM »
timing chain    as in cam chain?????

Offline HondaMan

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Re: help please??
« Reply #3 on: July 05, 2008, 09:32:42 AM »
timing chain    as in cam chain?????

That's the one!

The 350F is very sensitive to idle screw settings, so if yours is not responding to those adjustments, something is amiss, mechanically speaking. It's easy to get that cam off by a tooth or two.

What are the float levels in the carbs?

Your pipe changes won't cause this problem.

A burned-out resistor in the sparkplug cap can cause plug fouling, but it will take 20 or 30 minutes to blacken a plug like this.
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Offline schneider419

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Re: help please??
« Reply #4 on: July 05, 2008, 01:08:39 PM »
the float levels are at 21mm as per the manual set with the float gauge. i wonder if by working on the ports i will have to tune this as four individual cylinders or engines. i made sure that the line on the cam was even with the top of the head but maybe it jumped when i put the cam chain on. darn four cycles, two strokes are so much easier.

Offline schneider419

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Re: help please??
« Reply #5 on: July 06, 2008, 12:00:31 PM »
thank you all for the suggestions, I'll give them a try.

Offline heffay

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Re: help please??
« Reply #6 on: July 06, 2008, 12:10:07 PM »
petcock.   8)

you don't have to pet it... but at least check it.   ;) 
moving the old tank around and disrupting all the crud can really make a difference.
Today: '73 cb350f, '96 Ducati 900 Supersport
Past Rides: '72 tc125, '94 cbr600f2, '76 rd400, '89 ex500, '93 KTM-125exc, '92 zx7r, '93 Banshee, '83 ATC250R, 77/75 cb400f