Donvito

My bike has been making a chirp sound from the exhaust for a while. Now that I have my more serious problems under control, I would like to know what it is. I am attaching a recording so if anyone can offer some advice I would appreciate it. Thanks.

Transmission fluid and no restrictors. The level in the tubes stays pretty steady.

First I filled the carbs with straight Techron per Gary's advice. Then I synced the carbs with my home made synchronizer. (picture included). This solved my problems except for a deceleration backfire which is probably due to an exhaust leak which I am not too concerned about. If anyone lives in my area, Palm Harbor, FL, and wants to stop by to sync their carbs just give me a call at 727-504-7028 or send me a private message and I'll be happy to help. Just want to repay all the help I've gotten from you guys. My side cover vent finally bit the dust. Has anyone done a cheap and easy fix? I just want to keep it covered and don't care about opening it. Thanks again. [ATTACH]77033[/ATTACH] [ATTACH]77034[/ATTACH]

The slide move freely. I have a question about the needle valve. I am including pictures. there is a gap between the lock washer (not sure of the correct name) and the spacer. I never removed this so I assume it is correct. There is a small tab on the spacer which I know goes into the corresponding hole in the slide. Then there is a spring and a washer. I assume the spring goes against the spacer and the washer above the spring and before the screw but I'm not sure of this. Please let me know the correct set up. Thanks. [ATTACH]76899[/ATTACH] [ATTACH]76900[/ATTACH] [ATTACH]76901[/ATTACH]

Thanks. I switched the slide diaphragm assembly with the right rear carb and the problem moved also. So, it is a problem with that assembly. There is a small hole in the diaphragm so I guess I should repair that. I know there is a lot of info on repairing diaphragms and I've done it before but I can't remember what I used. Any help there? Also, what should I be looking at on the slide and needle valve? Someone mentioned "loose/leaking main jet/emulsifier tube" but I don't know what that is or how to check it. Thanks again.

Thanks for the advice. I've spoken to Gary and done the carb cleaning and it really helped. Started a new thread, carb slide problem.

Thanks to all for your help in my last post especially Gary who walked me through the carb cleaning process. I am happy to say the bike is running better but there is still a problem. The left rear carb, #1, slide doesn't move when observing it through the intake. The other 3 do. It also will spit gas out sometimes when I hit the throttle. I removed the diaphragm and slide and they are moving freely and the diaphragm looks good. The vacuum port plug is on and I don't see any obvious leaks. What should I do next. Thanks.

Thanks for the offer and I'll be in touch.

Mostly on decel but will pop back through the carb intake under load like going uphill. Believe only running on 3 cylinders but not sure how to check. Would really like to find a local who knows what he's doing but doesn't seem to exist. Not thrilled about the idea of pulling the carbs again and guessing at the problem.

Thanks for the offer. About 3 years ago I tried repairing it myself. Pulled the carbs and tried to rebuild them, changed the plugs, cleaned up the ignition system. It ran better but still didn't have the power it did previously, poor gas mileage, some backfiring. Never sure if it was firing on all 4 cylinders. Now it's worse again and I want to get it checked by someone with more ability then me but I don't know where to take it. There's a Yamaha dealer not far from me called Cycle Springs Powersports but I don't know if they're any good with these 1st generations. I've only been riding it occasionally mostly because of the way it runs but I want it to run good again. I may be expecting too much from a 26 year old bike but I'm very attached to it and don't want to give up on it. Before my son was born, my wife and I would ride all over the country. Having a child changed our vacations to family events. Well, he is off to college in the fall and I want to resume where we left off 18 years ago but I need to determine if it's repairable or if it's time to move on.

Hi, it's been a while since I've been here. I own an 87 and have decided to bite the bullet and seek professional help. No, not for my mental health although I can use that too. I live in the Clearwater Florida area and need some advice on a reputable mechanic in my area. I think it's carb related. So if anyone is from this area and can refer me to someone within 20 miles or so it would help me out. Or if someone lives in my area and has the knowledge and skill to fix it I am willing to compensate you. Thanks.

Thanks! That helps.

I need a jet block gasket. Don't know if replacements are available or if I can repair. Let me know how to repair or where to get a replacement. I'm including pics. Thanks.

Thanks. Couldn't find an air leak and vacuum on 3 and 4 are the same so I assumed the problem is in the carb so I pulled them off. Rubber intake boot looks real good. Posting pics of the boot and top and bottom of carb #4. Gonna try to separate the left and right banks. Couldn't loosen the screws last time so if you have any suggestions I would appreciate it. Should I replace the upper and lower clamps while I have them off and where can I find them? Checked auto parts and hardware stores last time but they only carried hose clamps. Will post again when I have something to report and let me know what pictures to post. Thanks for all you help.

I attached a hose to the carb drain hose, opened the drain screw and started the bike and I have good fuel flow. Also checked the fuel level again and it is good. Adjusted all idle mixture screws to 2 1/4 turns out. Removed the air box, started the bike and placed my hand over #4 carb opening which caused the cylinder to run. It will continue to run as long as I keep my hand over the opening and restrict the air flow. What would cause that? Getting ready to remove the TCI if you still think I should.

Thanks. Checked the fuel level and compared to #3 carb and levels are the same. Just to eliminate the ignition system, is there a way to test the voltage at the spark plug? Could it be a weak spark? What is the proper voltage? Before removing the carbs, is there anything else I should check? Should I do a compression test or is it unnecessary because the cylinder fires with carb cleaner? Thanks for your help.

Thanks for the advice. I have changed all the plugs and the fuel filter. When I remove the spark plug wire from #4, insert another plug and run the bike I do get a spark (and a shock) Should I try switching the spark plug wires between #2 and 4? As far as measuring resistance I'm not sure what that means but will try the other suggestions. The air box is back on the bike with the filter installed. Thanks.

I am a new member and would like to thank everyone for all the great information provided. I have an 87 with about 47k miles that I purchased new. Although, I am not a mechanic, I have always done all maintenance on the bike except for a valve adjustment done at 30k. The only repair it ever needed was a starter gear train replacement that I did myself. A couple of months ago, after sitting for a couple of months, the bike would only run with the choke on. Relying on info from the forums, I tried the Seafoam treatment with no luck so I removed and cleaned the carbs. After this, the bike runs without the choke but cylinder #4 won’t run. So far I have synced the carbs, changed the air and fuel filters, changed the spark plugs and switched cylinder 2 and 4 plugs, measured the carb fuel level, checked for vacuum leaks as best I could, tried adjusting the idle mixture screw and removed the carb vent hose. I have also switched the diaphragm and slide assembly between #3 and 4 carbs with no change. (I don’t know if this is recommended but I wanted to try it before buying a diaphragm) The cylinder will run if carb cleaner is sprayed directly into the carburetor. I am not completely sure this problem didn’t exist prior to working on the carbs. So, I am looking for other tests or possible fixes I can try. If I have to remove and disassemble the carbs again, where should I focus my attention? The bike has been trouble free for 22 years so I don’t have much experience in these matters. Thanks for any help provided.