Author Topic: No power over half throttle (Read 2171 times)

jayowen · « **on:** May 24, 2015, 05:26:29 PM »

Just replaced spark plug caps and wires. Cleaned emulsion tubes. Still getting spark. Idles great just no power with a twist of the wrist. Just bogs down. It's a 76 cb550f any help would be awesome

flybox1 · « **Reply #1 on:** May 24, 2015, 06:01:02 PM »

Any exhaust or air intake modifications from stock?

jayowen · « **Reply #2 on:** May 25, 2015, 12:19:51 AM »

Has uni pod filters. Ran fine maybe a bit rich before I cleaned the emulsion tubes.

Whaleman · « **Reply #3 on:** May 25, 2015, 07:16:09 AM »

I assume you also made sure the main jets were clean.

jayowen · « **Reply #4 on:** May 25, 2015, 09:24:21 AM »

For sure. They were nice and open. Took them apart and sprayed with carb cleaner and compressed air

jayowen · « **Reply #5 on:** May 29, 2015, 10:48:40 AM »

So float height was way off. Set it to spec and not as much sputter but still sputters at 3/4 to full throttle

flybox1 · « **Reply #6 on:** May 29, 2015, 10:50:43 AM »

because of the pods, i suspect you are lean at WOT
only way to find out is to do a plug chop at 3/4 or higher throttle pos.

jayowen · « **Reply #7 on:** May 29, 2015, 12:02:30 PM »

Agree with you there. Gotta jet up a bit on the mains. Showing lean at wot with a plug chop

jayowen · « **Reply #8 on:** June 01, 2015, 02:57:48 PM »

bumped the 98 stock mains to 105's and running like a champ

jayowen · « **Reply #9 on:** June 05, 2015, 02:51:21 PM »

just kidding. after riding it around in traffic the plugs fouled on me. seems oil or carbon. so i moved the needle clip up on slot and running mad lean. backfiring out of the carbs. even wot shows no promise now. what happened......

Tews19 · « **Reply #10 on:** June 05, 2015, 04:04:27 PM »

Lets start with your actual carb settings....

jayowen · « **Reply #11 on:** June 05, 2015, 05:12:24 PM »

stock pilots. float level set at 22mm verified today. stock is 98 mains right now at 105. has uni pods. exhaust is 4 into 1 similar to the one that comes on the stock 550F. air screws at 1.5 turns out.

jayowen · « **Reply #12 on:** June 05, 2015, 05:31:51 PM »

needle clip is at 2nd from top which is the stock position.

flybox1 · « **Reply #13 on:** June 05, 2015, 05:47:53 PM »

Quote from: jayowen on June 05, 2015, 02:51:21 PM

just kidding. after riding it around in traffic the plugs fouled on me. seems oil or carbon. so i moved the needle clip up on slot and running mad lean. backfiring out of the carbs. even wot shows no promise now. what happened......

did you assume it was your needle clip that was the cause of the overly-rich condition? Or was it a WAG? Did you do a plug chop at WOT to see of those 105 jets were.right?

You seem to jump around without much thought as to how your change will effect the rest of your bike performance.
Wot main jet chop, first.
3/4 throttle for clip position, but only AFTER your main jet is dialed in.
Then...1/4 throttle chop, but only AFTER your clip position is correct.
Get the correct pilot jet ...finish with an idle.chop for mixture screw..
Be methodical.

jayowen · « **Reply #14 on:** June 05, 2015, 07:05:57 PM »

thanks for the explaination of that. gotta wait for some extra jets to come in and do some plug chops. how far do i typically need to go in WOT before i read plugs?

flybox1 · « **Reply #15 on:** June 05, 2015, 09:36:43 PM »

On a brand new set of plugs, under load, 3-5min.
I used 4th gear over 4 mile low grade incline. Easy place to kill it and coast over safely.

jayowen · « **Reply #16 on:** June 11, 2015, 03:11:49 PM »

so i bumped main up to 110 and it pulls like crazy at WOT now. but after about 10-15 mins of normal riding it starts to blubber in midrange up and have no power up top again. dang this is frustrating. pulled plugs and they look good to me

Duanob · « **Reply #17 on:** June 12, 2015, 09:57:54 AM »

How about finding a stock airbox / filter set up and be done with it. The pods or unifiters offer no performance upgrade on these bikes.

jayowen · « **Reply #18 on:** June 15, 2015, 04:03:38 PM »

working on that. should be here on wednesday. dang jetting......

turboed13b · « **Reply #19 on:** June 15, 2015, 07:32:14 PM »

Running better when cold and blubbering is a sign of a rich mixture. I have almost the exact setup as you running 110 and needle clip at the very top with 40 slows.

If I could find 108 that would probably be the best setup.

When I am jet tuning I use the choke to see if I am running to rich or lean.

For example if I can't give it full throttle with choke all the way open I slightly close it. Do another pull and if it runs to redline then a bigger main is needed.

The choke will have little to no affect if the bike is running too rich so I move to the petcock trick.

If my bike is blubbering and acting slugish you can turn off the petcock. If it runs smoother then you have a rich condition.

jayowen · « **Reply #20 on:** June 15, 2015, 09:05:49 PM »

cool tricks. should have some time to play with that tomorrow

jayowen · « **Reply #21 on:** June 19, 2015, 09:58:08 AM »

WHELP. She is running great and not fouling plugs anymore. I took her into a local dealer my fiancee dad uses. They did a compression test which came out fine and they recommended replacing the condensers. It looks like once they got hot they would create a dull spark. Swapped those out and she is running great and jetting is completely

evanphi · « **Reply #22 on:** June 19, 2015, 10:52:16 AM »

..................................?

Don't leave us hanging!

jayowen · « **Reply #23 on:** June 19, 2015, 11:52:30 AM »

completely done ahhaha whoops. forgot to finish typing. too busy riding it around now :-)

Deltarider · « **Reply #24 on:** June 19, 2015, 12:09:06 PM »

Always start with the simplest and check the ignition (all items) and doublecheck before you move to the carbs.

Left condensor (1+4) is bad, right condensor (2+3) is good.

Vinhead1957 · « **Reply #25 on:** June 19, 2015, 12:40:33 PM »

Great video to illustrate it.

News:

Author Topic: No power over half throttle (Read 2171 times)