Carb time.

Went to go ride last weekend and the bike was hesitating through first gear to where I thought I had to push the bike to get it going. It didn't stall just kept sputtering. Finally after getting it up to temp it still seemed very doggish but at least the RPM's would climb even if slowly. When idling it sounded like it was misfiring a bit. Got it to my friends hopuse just to see gas bubling from the side of the carbs where the little C pin is on the right side of the bike. Upon closer observation I found that the PO used sylicone for one of the carb gaskets and now the carbs are flooding even at idle.

So to sum things up: I get to do my first complete Motorcycle Multi Carb rebuild 8O

Hopefully I will have the kits before this weekend. I hate not being able to ride

 

One step at a time and you'll be riding on rebuilt carbs before you know it!

Keep us Posted on the process as you start them and make your way through them.
We'll be here to root you on and give you some tips along the way.

 

I have rebuilt automotive carbs before but never worked with more than one to a vehicle. Should be fun and the best part is this will be one more check mark on my things to perform on the bike list. I was originally planning it for my winter worklist.

By the way was someone selling the Yics tools online? I have the Man-o-meter and almost everything else I could need.

 

Here they are:


c5) Yamaha YICS Port Clean-Out Tool----the YICS chamber runs side-to-side in the back of the cylinder head, and is accessed via a 12mm bolt on either end (this is the same chamber that the HCP93 synch passage-block-off tool fits into). This chamber has four tiny passages in the top, one for each cylinder. These passages can accumulate soot and other material over time, effectively clogging or reducing their capability to pass the fuel-air mixture through them, and thus compromising their function. This YICS port probe & clean-out tool has a spear point that can punch through the toughest accumulation of carbon build-up, and has marked notches on the extension rod to indicate exactly how deep into the chamber the tool must be inserted to easily locate the passages. Convenient dowel handle allows for ease of use. A very handle tool to have around!

HCP1282 YICS chamber Port Clean-Out Tool:
$ 14.95


vv7) Reproduction YICS Port Blanking "Block-Off" Tool---this is the tool you'll need to perform a proper carb synchronization on any YICS motor......without it, you're just wasting time. This block-off tool is used to isolate each cylinder from the others while perfoming a carb synch. Updated version of the factory #90890-04068-00 tool. Some people claim that this tool is NOT needed to perform a proper synch; we disagree, and so do the Yamaha engineers who designed the YICS system. Quality aluminum tool features a snap-open and shut trunnion handle design like the original. This is NOT a cheap home-made tool and has all the proper seals, dimensions, and high-temp insulators as an original factory tool. IN STOCK!

HCP93 reproduction YICS port blanking tool, each:
$ 37.00

 

If you have a vacuum gauge ... that's all you need.

We'll deal with that after you get your Carbs rebuilt!

 

Well, things did not go as well as planned. I got the carbs out, took them appart 1 at a time (found a peice of what looked like grass in the diafram of carb 4). Cleaned all the components and bench synced the carbs. after reinstalling them the bike seemed to run better than before but was poping at idle (not bad though). Attached the Sync tool and performed the carb syncrionization per the Man-o-meter instructions provided by the tool. seemed to be running better yet. Took it out for a test ride and thats when everything took a bad turn. When excelerating it seemed like it was starving for gas, I took it up to about 65mph and when I pulled in the clutch the bike just stalled. It stalled any time I pulled the clutch when I was slowing down or came to a stop but would idle at a complete stop if in nuetral only, put it in 1st with the clutch in and it would hesitate and die.
Took it back to the garage and checked the sync and it states it is dead on. Definately does not have the exceleration it used to.

One other thing I noticed which may be electrical in nature is if you compress the front forks (need to compress allot for this to happen) the engine idle speed slows down and almost stalls out. You have to compress them about 3/4 of the travel at a fairly fast rate for this to happen like coming to a quick stop.

Any Ideas?

 

the last item seems cable related.
what do your plugs look like? (not the shape) color.

 

Last time I checked they were a beige color, I have not checked them since the last ride. I will check and update when I get home. Didn't feel like it was a good idea to ride it 60 miles round trip to work and back with the way its running.

 

Finally had a chance to look at the bike yesterday. Turns out it was the pilot screws were set wrong. I have the bike running better and hopefully will be able to get it fine tuned this weekend. I have it to where it idles good, accelerates ok (still hesitates some of the time but can at least get highway speeds again without opening it up) and is not getting very good gas milage (about 20mpg). It hasn't stalled yet either

 

Finnaly got some time to perform more work on the bike. Rebuilt the carbs again (this time the floats are not upside down). I have got the gas milage up from (measured) 16mpg to 42mpg The downside is that it still does not accelerate properly. It idles and starts great. When I go to leave from a dead stop it hesitates (almost like its loading up) and kind of chugs until I get to about 3500 RPMs when it feels like someone hit the nitro button and the front tire almost leaves the ground. I think it may be something in the carbs but am not sure. I have to give it another oil change today due to gas in the oil (got gas in the oil when the floats were flipped). I have it drained and waiting for now. Any ideas or advice would be a great help.

 

The other good news was when you compress the front forks (need to compress allot for this to happen) the engine idle speed slows down and almost stalls out, it was a cable issue. Removed the hoke cable from the cover on the back of the handlebars and it works fine now.

Good call Wizard!

 

You can permanently work-out the hesitation by adding a teenie-tiny bit of Richness to the Pilot Mixtures.

Just a nudge. Keep it within the width of a Dime each time until the Pilot Mixtures add the supplemental Richness needed to sustain power until the Main Jet Supply kicks-in.

Be patient making the adjustment. Since you are close to having them zeroed-in, the reward will be finding the spot that allows the bike to Idle strong and accelerate from Idle right on up without a moments delay.

 

Thanks Rick, I will be trying to work on a bit in the morning when I get off of work (maybe even a quick turn or 2 at work). It is a great feeling coming this close to being finished with the tuning. Then I get to turn to the customizations >

 

Not a TURN!
Not a Fraction -- like a quarter or a half!

A "Hair". A degree or two.
Barely move the Screw.

You have found the AREA where the Air~Fuel Mixture will be dramatically altered if adjusted beyond more than a couple of degrees.