From recently perfectly running to barely at all now

I can't beleive I'm asking this question but something very strange happened. the bike was running perfectly, all cleaned, synced and tuned, at about 75 degrees.

since the heat wave started and we've been in the high 90's the bike progressively runs like crap. only 2 rides since the ill symptoms. can't rev up, all good over 2500. on the way home on the 2nd ride it got Real hard to tease it to 2500.

I always thought my Colortune mixture adjustment was too many turns out at 3.5 - 4.5 but it ran So Mint I just said oh well. so could that temp change the mixture since there's less air in one space since air expands in heat? if not, what the hell else should I look at. It really only has around 220 miles since it was done being tuned.

 

hey yama, what do your plugs look like?

increased ambient temperature could definitely change your mixture. generally it's not enough to run that badly but if you were already on the rich side (depends on the circumstances during the colortune - temp, humidity, altitude, etc. - for example if you colortuned before the engine was fully warmed up or at night when the ambient air is cooler, you may already be running rich under normal conditions), the extra heat could potentially be enough to make it overly rich. go for a ride and keep it at the problem rpm for a minute or so, do a plug chop and check the plugs...

also does it get better or worse as you ride? worse generally indicates a rich condition, better = lean (because the mixture gets richer as things heat up).

or maybe some grunge from the tank is clogging the pilots?

cheers,

Trev

 

thanks tibor. so I pulled the plugs and they are tan n perfect, soot on ring on bottom of thread only with a tan insulator. So I guess it's off with the carbs. guess I could do the clear tube method for consistansisy from one to the other while they're on the bike. this sux

 

I think you might have gotten a bad tank of gas, or your vent is partially plugged. Try running with the gas cap unlatched for a short period.

The heat wave might be a coincidence or it's revealed an unusual circumstance.

 

Check the Inline Fuel Filter if you have one.

Two years ago I was running great and suddenly I lost power and started limping along like I was out of gas.
I checked the Inline Filter and it was FULL of crap. Ugly stuff.

Whatever the sediment was got through the Filter and it cost me a Carb Cleaning to recover.

On another occasion ... I came to a stop and had to get a rife home in a Pickup Truck.
I checked the Inline Filter and it looked Brand New. Clear.
But,, there was NO gas getting to the Carbs ... on PRIME!

I pulled-of the Filter and blew-through it.
CLOGGED!!!
Cheap filter ... made in China. NON-Porous material.

Don't Break the Glass and Pull-Down the Lever until you check Fuel Supply Issues:
Clogged Filter
Failed Petcock Vacuum Valve
Air-Bound Filter

 

so the filter is flowing, the jets are open, and I replaced the gas. I actually thought it was bad gas cause when I did the clear tube method the fuel was clear and a little cloudy, no color at all. I checked 1 cylinder w/ the colortune and the mixture screw was right where it needed to be. But I Still Can't rev, she stumbles pretty bad, stalls too. the Choke will take it up and it'll rev from there...

 

When were the valves last checked?

Just checking; I am more likely to believe you've picked up a hunk o'crud in the carbs somewhere, or something has come loose and you've got a vacuum leak.

 

thanks Ftiz, valves were done recently, few hundred miles ago. I actually see some stuff floating around in the fuel filter... but the jets were clear yesterday when I checked

 

Test your Inline Fuel Filter for FLOW.
Not a sight Test.
Blow through it.

Investigate the problem that had you running poorly, ... previously.

Vacuum Bottle Test the Passages.
Hook-up a Vacuum Bottle and place the Vacuum Tube over the EMPTY Pilot Mixture Screw Hole with the Air Jet Hole Plugged with a Q-Tip.
Mark how much Gas you get from each Mix Hole in a times test.

Pull the Diaphragm Pistons.
Vacuum Test the E-Tubes with the Air Jet OPEN.
Do a Timed Test on each one.
Significant variations in FUEL Supply indicate PLUGGED Jets or a Stuffed-up Passage.

The Igniter you got that made you run good might have sheet the bed.
Find a Spare.
See how she runs on a KNOWN Good Box.

 

I'm going to try everything Now but I don't know how to do the vacume tests. Rick please explain to me the vacume bottle for the empty mixture holes and vacume test on the E tubes. What's a vacume bottle? obviouslt the carbs are on the bench for this. I have all the stuff to do the test I'm sure just don't understand the method. the flow is good cause I just watched the bowls fill up with fuel. and the new/bad coil i replaced must be good cause I seen it work w/ the colortuune and all the pipes are getting hot at the same time

 

the carbs are apart on the bench (didn't break the rack) and I don't see any problems. I still for the life of me don't understand the methodology behind Ricks vacume tests. with the jets removed I have strong forced air flow through both corresponding fuel and air jets, emulsion tubes are perfectly clear. and I blew through the fuel filter and it was fine too. it must be carb related since the idle picks up w/ the choke.

and oh by the way, this new gas is clear too! not in bulk but in the clear tube method. I have Photos of fuel in the clear tube months ago where the fuel has color to it.

 

hey yamaman, have you checked the hats/diaphragms for air leakage? maybe the sealing edge of the diaphragm slipped out of the groove under the hat or something? hold the diaphragms up to a bright light, if you see light through any part of the rubber, they are probably leaking air. some say you can repair the rubber with a sealant...

let us know what you find.

cheers,

Trev

 

No.
The Carbs are on the Bike.

A Vacuum Bottle is a Tool that you use to Vacuum Chemicals and other liquids that you do NOT want introduced into the Vacuum Cleaner.

The Bottle has two hoses through the Lid,
Hose (A) goes down close to the Bottom of the Jar.
Hose (B) is short. Just inside the Lid.

You cab Hook-up a Vacuum to Hose A.
The Vacuum pulls a Vacuum in the Jar.
Hose B Vacuums the Liquid Passage.

As any Liquid gets sucked into the Bottle it falls away from Hose B and collects in the Jar.
Hose A stays clear of the Fluids and the Fluiids are not introduced into the Vacuum machine.

 

Thanks Tibor

Rick, oh I have that

So, block the Pilot Air Jet with a Qtip and put the carb top back together and run the bike? (then vacume the vacant mixture hole)

testing the Emulsion tubes, this can't be done with the bike running right/carbs mounted?

 

Guess what, I found a small rip in one of the diaphrams. the size is 8/32's or 6mm, very close the the mounting ring area. the other 3 are ok

would that little rip in one carb really cause it to not rev up?????? I would have thought 3 other strong cyinders could have compensated for that until the piston eventually moved.

anyway, I have red RTV gasket sealer on both sides of the rip now

 

it sure would, especially a tear that big, even the tiniest of pinholes have an impact. without vacuum the piston would never rise and you would never get the extra fuel to the engine over idle.

i'm glad you found the problem and can get back to riding!

cheers,

Trev

 

aaaaaaaaaaaahhhahahahahaha Thanks. so they just appear like that ey. after my RJ being more of a 'school' than a 'motorcycle' I don't know if this is a sign of good things to come, now that 'school' has been out and she's been running Great it seems school will Always be in session with this bike. Out of the 8 bikes I have, my RJ may not be my primary concern any longer. I'm stopping here, waiting, and going for a ride tonight (when the RTV is sure to be dry). Thanks again everyone

 

No.

The Lids are OFF the Carbs.
The Diaphragm Pistons OUT
The Pilot Mixture Screw OUT

You BLOCK the Pilot AIR Jet.
Vacuum the Pilot Mix Screw HOLE.
Look for Gas to make the trip from the Pilot Fuel Jet.

Do the Emulsion Tube and Main AIR Jet BOTH Ways.
Plug the MAIN AIR Jet and Vacuum the Emulsion Tube.
You should collect FUEL
Block the Emulsion Tube ... Vacuum the Air Jet and you should get some Fuel UP the AIR Passage, too.