Carb problems with my 2nd Gen?

That would be my guess. Normally when one head pipe is colder like that the problem is that carb is closed off more than the others. Since the carbs have been off and on a couple of times (from what I can tell) a sync is probably in order anyway.

 

I did watch the butterfly valves open and as far as I could see they opened at the same time.

I'm confused as to why I'm being told not to touch the Pilot screws when the Service manual says they should be adjusted, and other people say you should also.

 

The caps are drilled out: someone did that because they wanted to adjust away from the factory setting, so chances are that they are.

Your mechanic doesn't want to touch them, so since you have bought the bike no one has verified that they are all set the same.

Those that are saying don't touch are likely saying so because the problems you describe may not be symptomatic of maladjusted screws.

You need to make sure they are all set the same. There is no risk in doing this. Mark your screwdriver or pay attention to the label on the driver handle and count the number of turns it takes to gently seat in each screw. They should all be the same. Screw them all back to where they were or to the factory setting. I recommend the latter.

I agree with Donald too about double checking the valve clearances. What spec reference did the mechanic use? Since he was messed up about the stator cover could he have also used Gen 2 specs (I don't know if they are different, but worth checking).

 

...and I suggest you do the bench sync as Dukiedook suggests: align the valves with the small holes. One carb does not change. You need to adjust all other carbs to it. Examine closely where the valve is relative to the small holes and make the other three carbs valves sit identical. This will get you pretty close, at least close enough for decent running and or to eliminate carb sync problems as a cause if it still doesn't.

That's lots of work though. Might as well replace the float needles, etc. while you have the carbs off.

 

Must differ here as mixture screws are set up at factory to meet lean EPA standards, and the bike will run better at the low to mid speeds slowbird mentions., but carbs on '86/'87 VFR must be removed the first time screws are adjusted. Switching the float bowls left to right will free up the screws--which have a tab that limits their motion--for easy screwdriver adjustment later.

I'd start with 1/2 turn ccw and see if yiou notice improvement at low speed.

 

I must reply in the interest of accuracy : stator cover never needs removal to adjust the valves, not on a VFR and probably not on a VF as there is a small access cover at end of crank.

Turning carbs upside down won't foul anything up or clog float needles.

Carbs must be removed to access float bowls, and bowls must be removed to change float needles, obviously.

Carbs do not need to be re-synched after a simple removal if adjustment screws were not moved or screws loosened that hold carbs to airbox base.

Michael E (usually well informed) has also provided info that needs explanation: initial screw settings (2 1/2 turns) should start out all the same, but it's very likely that after proper adjustments doing the "idle drop" proceedure outlined in the service manual are completed that screws will need individual tweeking and not end up being all the same due to small variations in individual screw shapes.

Ask your "mechanic" if he removed the float needle seats as there is a small filter attached above that could be clogged and limiting fuel flow.

 

You know WAY more than I do. I stand corrected and thank you sir.

Lot's of good info here Slowbird!

 

In fact, this is not the case. Anyone who has done it can tell you that the removal and reassembly procedure takes quite a bit of effort. During this process the carb rack can be tweaked slightly. It doesn't take much at all to throw off the sync of the set. I suggest doing a sync every time the carbs are removed. I can personally attest to the fact that a sync adjustment will probably be necessary.

 

I think the confusion about when to sync and when not to sync, and when you are supposed to mess with the pilot screws is part of the reason this guy who worked on my bike is doing such a poor job. I've been given the impression that he didn't touch the pilot screws or synch the carbs. He just cleaned the carbs a little and checked that all 4 float bowls had the same amount of fuel coming out of them. (he said it was close).

He attaches a tube to the float bowl drain and drains each bowl into a measuring cup and makes sure they are all the same. ???

When I had the carbs out I cleaned everything. I removed the jets and made sure they were clean. yes, I did clean the little filters in the float valve guide area.

I went out to the bike this morning and the carbs were wet with gas again. They seem to seep fuel after sitting overnight.
I run my finger along the seem where the float bowl meets the carb body (front left carb) and it comes back wet with gas. I guess I need new float bowl o-rings?

I pulled the front two plugs:

The front left plug looked like this:


^^ This is the cylinder that the header pipe doesn't heat up as much or as fast as the others.


The front right plug looked like this:


I cleaned and re-installed them both. Started up the bike. It didn't idle great. A little black smoke came out of the exhaust when I revved it.

Took it for a spin and it still suffering low to mid range. Idle feels rough.

:frown:

 

Every time you adjust the valves and/or pull the carburetors you'll need to re-synch them.

Bench synchronization (adjusting the position of the throttle butterflies so they look similar to the eye) will get you close but to dial things in you will need take your bike to a motorcycle shop or purchase a synchronization tool.

On this note, you should also re-adjust the idle mixture screws (AKA pilot screws) though you don't need to follow the Idle Drop procedure (leaning the mixture until the idle drops) - as this has more to do with the politics of emissions requirements than the engine's performance.

 

I would start with replacing the plugs if you have a cyln not lighting up

 

I'm reading this mess and thinking the same. Your plugs are fouled. It doesn't take much to do that. 1st replace plugs. You don't need to bench sync carbs. Get a set of gauges for syncing. Then adjust the 3 adjustable carbs to the non adjustable one. 1st gen is #4 is the non adjustable. 2nd gen could be #2 as you stated. You will have to adjust each carb several times. One will effect the other by raising or lowering the rpms which changes vac on each carb. Until all are so close the rpms really don't change much. They need to be within 2hg of each other at worst case.

Now for the gas leaking problem. Do the float needles have a nitril (rubber) tip or a metal tip? If rubber then I would suspect the floats are adjusted wrong-to high. If they are metal, then it could be either they and the seats are not sealing perfectly OR it's todays gas. Either way the float height needs to be checked. I could go on for hours about how many carbs will leak/drip because todays gas formula and how many people with carbs have that problem. Even with new needle and seats.

As was said before adjust all pilot screws to 2-2 1/2 turns out as a preset prior to final running adjustment HOT. Do this preset first! Then sync carbs.

Do you have a factory manual for your bike. If not get one!! Clymer, Hayes, Hanes or what ever are NOT reliable with specs. Next you either need to find someone who knows what they are doing!! Not one of your local "guru" people. It seems you don't know or have much experience or mechanical talent. It shows by spraying a flammable liquid on hot exhaust pipes.No offense intended. So someone who is a 4 on a scale of 1-10 may seem like a guru to you. You need some who understands carburation and how all circuits of carbs work and work on a running engine. Just because someone works on bikes for years doesn't mean they really understand what they are doing in all areas of an engine. Knowing how to take something apart is different that knowing why or the theory behind how it works. This place has a lot of good help. But everybody has a different view on what you are doing and different ways of find the problem. Some are close and others are not in the ball park. See if you can find one good person to work with that knows what they are doing and is willing to work with you by phone or what ever and stick with them until the problem is fixed if your going to do this yourself. To many chefs spoil the pot kind of thing. Plus you will get really confused stirring the pot different ways without/different results. Because one adjustment/procedure may/will effect another. There is logic to trouble shooting. At least to start with.

Good luck and PLEASE keep the flammable stuff away from hot surfaces!! Unless your wearing a fire suite and have insurance.

 

^ +1

Well noted Grey.

 

Bench synch to expose the small holes evenly THEN manometer synch, this will make your life much easier.

That is probably my problem with my leaky #1 currently, all that damn ethanol in the gas. Get yourself a new gasket and float needle.

Static head measurement method (with the clear tube hooked up to outlet) is the most accurate way to measure actual static head in the float bowl. Your guru had the right idea there at least.

 

Found a couple things that may be adding to my issues:

1. Fuel flow does not stop when you put the Petcock to OFF. Going from ON to RESERVE seems to work. (judging by me being able to switch to reserve when the bike gets low on fuel) But when I disconnect the fuel line from the fuel filter it just flows out and doesn't stop. I managed to plug the hose to prevent all the gas from the tank leaking out.

2. Float is getting gas in it somehow. It drops (sinks) lower than the rest.

They are Brand new plugs. Won't cleaning them and ensuring the gap is ok be sufficient?

Rubber tip.

I have a Factory service Manual. I know the others can have incorrect info in them.

Easier said than done. How do you know if someone knows what they are doing until they have either done a good job or done a poor one?

The "guru" I took the bike to was recommended by many. He did good work on my 1st gen and on the bike of another member of this forum.

It's easy to read a thread and state the obvious that bad work was done. It's harder to go out there and find someone who is actually reliable and affordable. (Not to mention within reasonable distance)

If you really meant no offense by the above statement, I think you should have chosen your words a bit more careful.

Again....easier said than done.

Unless people who know what they are doing wear badges or have tattoos on their foreheads it hard to find someone reliable. i have been through many mechanics who have done many shitty things to my old 1st gen and now this.

It's hard to find good people.

I heard that ethanol can be bad for some bikes. I have always run Shell 91 cause it contains zero ethanol.

 

brand new plugs or not if the header tube is not getting hot it is most likely fouled
best bet is to replace it and try again.

seems everyone is jumping on the carbs. you have noted he did the valves as well, maybe a compression test would help to see if any of the valves are adjusted wrong and are not fully seating.

Also how to the rubber boots look connecting the carbs to the engine?

 

I agree. That has been my experience.

 

It is hard to find a good MOTORCYCLE mechanic.
There are no standards.
In the auto world there is a standard now. ASE certifications.
But not in the motorcycle world.

I do feel sorry for the motorcycle consumer.
There are no apprenticeships-no organizations.
A good motorcycle mechanic can quit working on bikes, and work on cars
and can get much better wages, and get better benefits immediately.

The families that own these dealerships just have mechanics to honor warranties.
That is what they say, but the truth is that they make enough money off of the
profit on the mechanics to pay for all the lights to be on etc.,.
They charge $100 per hour to the customer, and pay the mechanic less than $20. phr.

 

The header pipe wasn't getting hot at first. As I said afterwards: I cleaned, checked the gap, and re-installed the Spark plugs and I was running on 4 cylinders again.

But....I checked the header pipes with a Thermometer and it said that 3 header pipes were in the low 200's (degrees F) while the one front Left header pipe was around mid 100's (degrees F).
But when I pulled the plugs again, that one Left front plug looked fine and it was the right front that was fouled.

Yes. Unfortunately, with all the other mistakes he made he very well could have bugger'd up the valve clearances. I don't have the necessary tools to check the compression. Another thing to add to the list of tools I require.

They are brand new boots I ordered from Honda a couple weeks ago. When I had the carbs out they looked fine.

 

But....I checked the header pipes with a Thermometer and it said that 3 header pipes were in the low 200's (degrees F) while the one front Left header pipe was around mid 100's (degrees F).
But when I pulled the plugs again, that one Left front plug looked fine and it was the right front that was fouled.

the one that reads 100 could be just picking up heat from the rest, or poss a valve is open ( not seated fully )
I would ck that cylnder to start with. best way to ck plug is to remove it pop it in the wire and ground it to the frame ans make sure it sparks. ( w/o getting shocked )

check and see if any local members near you have a comp tester. I think they are not that expensive if you have to buy one.