Author Topic: completely F&*K%$G puzzled, PLease help (Read 4953 times)

cafe2be · « **on:** April 22, 2009, 08:37:24 PM »

Bike is a 77 750f. Ran fine before taking apart and puting back together.
Carbs fully rebuilt and cleaned, check accel pump. 125 mains, currently running 2 turns out on A/F screw
Mods: pods and a supertrapp muffler, kingkustom wiring diagram (eliminated signals and markers also removed diode). NOT running a choke cable or a push throttle cable.
Motor was not taken apart, OEM ignition system, new battery, starter solenoid and rectifier are good

Problem: Bike idles fine but falls flat on its face after releasing clutch when the bike is on the ground.
when the bike is off the ground it runs through all the gears fine.
Also when I have the butterflies on the carbs shut the bike runs better. when the butterflies are wide open on full throttle pull the bike chokes and stalls out

Pulled the plugs, the bike is running rich

PLEASE HELP!

ev0lution7 · « **Reply #1 on:** April 22, 2009, 08:48:47 PM »

first off why did you remove the diode\"

? uh do you know what a diode does??? if you say to remove weight i'm going to reach though the computer and hit you over the head with my laptop keyboard

anyways ...

ALWAYS start with STOCK jetting even b4 your mods and after... then ride the bike and check the plugs.... a good tuning trick is to use champion plugs for tuning then go back to your NGK's... serious 1 step at a time you dont learn wot walk by running??? you take baby steps!!!

cafe2be · « **Reply #2 on:** April 22, 2009, 08:53:34 PM »

evolution. I started with the oem jets, when I had a yoshi pipe and pods. The bike did not run well at all.

As for removing the diode, definately not to lighten up with the 1/110 of an ounce. I followed kingkustoms diagram and did not see a diode. So i removed it. Should be hit over the head, could use it.

Do you think the chain is too tight??? Would that bog down a bike on accel?

ev0lution7 · « **Reply #3 on:** April 22, 2009, 08:58:37 PM »

good diagnostic tech.... (this is mine and has always worked for me dont let the secret out ok...

)

start from b4 your made your mods....

then see what you did 1 step at a time ...

jet sizes are realllllllly funny... what works for my bike doesnt work for yours get it??

so step up 1 size it RUNS WORSE then step down?? or go half sizes... its kinda a science.... now as far as chains go use a 2nd person sitting on the BACK side of the bike (2up) and check chain slack it should be barley loose with a heavyier person on the back seat....

cafe2be · « **Reply #4 on:** April 22, 2009, 09:02:57 PM »

would the bike stall do to the chain being too tight and not being able to drive.

mlinder · « **Reply #5 on:** April 22, 2009, 09:32:46 PM »

Quote from: cafe2be on April 22, 2009, 09:02:57 PM

would the bike stall do to the chain being too tight and not being able to drive.

No.

Sporkfly · « **Reply #6 on:** April 22, 2009, 09:54:58 PM »

Carb tuning. Do it right. Basically. Plug chops (using Champion plugs, they're cheaper) for WOT and find your main jet. Or start with idle, both are decent starting points in my book. Once you have WOT (main jet) dialed in, then start with your mid range to adjust for the needle setting. Again, idle if you didn't do that first. Plug chops for all throttle positions and tune your carbs from there. I promise you'll have the carbs off and apart a number of times to get it right.

Did you not have the stock air box or was it incomplete? What made you decide on pods? I ask because you say you have a stock engine...

cafe2be · « **Reply #7 on:** April 23, 2009, 02:51:20 AM »

went with pods for the look. The thing that is puzzling me if when the rear tire is lifted off the ground the bike will go through every gear and not stall out. When the tire is on the ground it sounds like its sucking in air and then dies.
also with the current carb set-up (125s) the bike ran last season before taking it apart. Problem with the wiring?
I am going to order a bunch of different size main jets. I was told with pods and a aftermarket pipe to jump to 125 jets. Stock are 105s

cafe2be · « **Reply #8 on:** April 23, 2009, 02:57:42 AM »

also noticed with plug chop that the bike has to be able to drive. Can it be done in a stationary position?
The accelerator pump diaphram is in great shape as well.

aussie · « **Reply #9 on:** April 23, 2009, 02:59:21 AM »

Quote from: cafe2be on April 23, 2009, 02:51:20 AM

went with pods for the look. The thing that is puzzling me if when the rear tire is lifted off the ground the bike will go through every gear and not stall out. When the tire is on the ground it sounds like its sucking in air and then dies.
also with the current carb set-up (125s) the bike ran last season before taking it apart. Problem with the wiring?
I am going to order a bunch of different size main jets. I was told with pods and a aftermarket pipe to jump to 125 jets. Stock are 105s

20 sizes up, is a massive jump in jetting

aussie · « **Reply #10 on:** April 23, 2009, 03:01:34 AM »

Quote from: cafe2be on April 23, 2009, 02:57:42 AM

also noticed with plug chop that the bike has to be able to drive. Can it be done in a stationary position?
The accelerator pump diaphram is in great shape as well.

No, because you need to be able to load it up

cafe2be · « **Reply #11 on:** April 23, 2009, 03:08:15 AM »

going to buy a kit from sci 105,110,115,120

Hush · « **Reply #12 on:** April 23, 2009, 05:21:17 AM »

I don't think your problem is chain related Cafe2b but there should be about 3/4 of an inch of play right in the middle of the lower chain when the bike is on the main stand, when it comes off the stand it should still have a bit of play.
That's kind of guesswork but for most bikes that works, if your clutch works properly it shouldn't matter if you are on the stand of on the ground, the bike should not stall....is your clutch adjustment OK?

alltherightpills · « **Reply #13 on:** April 23, 2009, 06:02:04 AM »

I don't know how much those jets are at sci, but at cycle-re-cycle (http://www.crc2onlinecatalog.com/Index_Main_Frame.htm, under fuel system parts, then under misc carb parts) they are 3.25.

Put your stock mains back in (you don't need to pull the carbs off the bike to do this, put a hose on the drain spigot under each carb, drain the gas, and get an attachment to put a screwdriver bit in a socket wrench, and voila, bob's your uncle, you can change your main jets) and move up incrementally.

I did my plug chops for the main jets at WOT, up a hill through all 5 gears. Pull the clutch, kill the engine, and stop. Luckily the place where I was working on my bike was just over the crest of the hill so I could just coast back into the garage. Pull yer plugs and look at em.
Here is a good guide for what plugs should and shouldn't look like:
http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

Good luck.

Johnny5 · « **Reply #14 on:** April 23, 2009, 06:16:34 AM »

Even if it's running a little rich, it shouldnt just die after letting the clutch out unless your spark plugs are trashed. It'll run rough and boggy, but shouldnt stall out.

Is the clutch adjusted properly?

cafe2be · « **Reply #15 on:** April 23, 2009, 08:11:12 AM »

I am going to check out the clutch today. I noticed when putting it into first that it sounds very notchy and stiff. Makes a interesting noise too. Also very difficult to find neutral.

I am def going to do the plug chop once the bike runs.

I agree that even with the bike running rich as hell it should still run. I am thinking that the bike may not be fully engaged in gear when the load is on.

SCI sells a jet kit includes 105,110,115,120 for $49.99 + $5 shipping.

cafe2be · « **Reply #16 on:** April 23, 2009, 08:47:30 AM »

Bike makes a clunking noise when putting into gear, esp first. Could the clutch not be fully engaged and make the bike stall while rolling on gas and off throttle.

Need clutch alignment?

Johnny5 · « **Reply #17 on:** April 23, 2009, 09:36:41 AM »

How loud is the clunk? Most bike will "clunk" into first gear but a reasonable clunk is normal.

Does it grind into gear?

cafe2be · « **Reply #18 on:** April 23, 2009, 09:53:48 AM »

Sounds like a person who is learning to drive a standard car for the first time. Grind and Clunk.

Made the noise when the bike is on the ground, when the rear wheel was off the ground it did not make the clunking, grinding noise.

Johnny5 · « **Reply #19 on:** April 23, 2009, 10:26:41 AM »

Sounds like a fried clutch or bad cable adjustment. Especially if you're hearing that grinding noise.

SHORTROUND · « **Reply #20 on:** April 23, 2009, 10:32:38 AM »

bike sounds lean. need more fuel.

cafe2be · « **Reply #21 on:** April 23, 2009, 10:33:23 AM »

Thanks johnny. I am definately going to check out the clutch adgustment today.
Any chance it would be a clogged petcock filter??? It flows gas fine.

cafe2be · « **Reply #22 on:** April 23, 2009, 10:34:44 AM »

Bike is running rich, plugs are showing it and my eyes are tearing from the exhaust. Even when leaning it down get a little better.

Still BOGS hard when blasting the throttle wide open.

Johnny5 · « **Reply #23 on:** April 23, 2009, 10:37:49 AM »

Quote from: cafe2be on April 23, 2009, 10:33:23 AM

Thanks johnny. I am definately going to check out the clutch adgustment today.
Any chance it would be a clogged petcock filter??? It flows gas fine.

In my experience with clogged petcocks, the bike would start up fine and run about a mile or two until the float bowls would run out of gas. Then bog down and die. If you have gas in the bowls, when your problem is happening, it's not the fuel flow. Something's happening as soon as you put the bike in gear.

cafe2be · « **Reply #24 on:** April 23, 2009, 10:49:31 AM »

Great point johnny. Definately going to adjust the clutch today. Reading up on clutch dragging now.

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Author Topic: completely F&*K%$G puzzled, PLease help (Read 4953 times)

ev0lution7

ev0lution7