Old Phazer 2stroke woes-butterfly carbs, bogging

[rogerz1000]

Hi everyone, I hope this is the correct place to post this. I have 2 old Yamaha Phazer sleds. One is a 1999 and one is a 2000. They are 500cc with the non rebuildable triangle fuel pumps. They bog and seem to be looking for more fuel.

Things I have done to both machines-
I have purchased brand new fuel pumps and installed them this past summer. I checked the flow on them before hooking them to the carbs. They were flowing plenty of gas.
New fuel line, but not the vacuum line from the motor.
Cleaned carbs thoroughly, and synched the best I could without a sync tool. I'm pretty good at this.
set fuel/air screws to recommended setting. I have tinkered with these and found the best spot, but it doesn't solve the issues.
Checked spark, and installed new plugs.
installed new read valves.
checked boots for cracks.

I have not cleaned the throttle position switches. Not sure this would cause the bogging issues on both sleds though.

Has anyone had these issues and knows what could be going on, or are there different carbs that may work? I heard that these butterfly carbs are just junk. Is there anything I can do?

Thanks!
Roger

 

[Macheater]

Check that your TORS is connected and that there isn't excessive slack in the throttle cable. If the TORS is not connected, the machine will NOT accept throttle.

 

[VX1R]

Roger....I just dug out one of my old Phazer's last weekend to take on a vintage ride this weekend. It sounds like you pretty much covered all of your bases in your post trying to get everything running to spec that you did.

I had a very similar problem with mine a few days ago....did everything that you mentioned. The sled started great. I took it around the field for a few laps and once it warmed up I noticed that it seemed like it was starving for fuel in the mid range. Depending on how well you've cleaned out the carbs the first thing that I would look at is are the pilot jets clean. The tiny orifices in the pilots are well known to get clogged which causes a lean condition that you encountered. I found on of the pilot jets to be partially clogged so I ran the carbs through the ultra sonic cleaner.

Once cleaned everything looked good. Started it up again and it idled great. Took it out again and after it warmed up it still had a mid range bog. Not as bad but was very noticeable. I had the air screw set at the recommended setting of 1.5 turns from fully seated. I adjusted them to 2.0 which seemed to help. 2.25 turns out was spot on. I'm sure that this cold weather here in the mid west has effected the carb settings. I might install the next richest pilot jet next week to see how the motor reacts.

IMHO these old butterfly carbs still work great. They just need to be clean and fine tuned.

You might want to take a look at this manual. It's got a wealth of tuning information that might help you: http://www.mikuni.com/pdf/vmmanual.pdf

 

[VX1R]

Check that your TORS is connected and that there isn't excessive slack in the throttle cable. If the TORS is not connected, the machine will NOT accept throttle.

^ ^ ^ ^ ^ ^ ^ ^
Good info.

 

[rogerz1000]

The cables are pretty tight on both sleds. They do take throttle but then bog pretty early on. Sometimes they take throttle and rip. It's odd.

 

[rogerz1000]

Maybe I should check the carbs again but I cleaned them good last year. This has gotten old. Not riding with my son and fixing too much is just crazy. The pilots were perfect. These machines have always had these issues from when I got them. They were better a bit after the fuel pump and carb cleans last year, but now the issues returned. I treat the fuel well with startron and mystery oil which works really well in everything else I have.

 

[maim]

bog can come from sticky clutches as well. do you know when the primary spring was last replaced? i chased a bogging issue on my et410 that turned out to be a weak primary spring. i can tell it is starting to get weak again from how it performs in powder.

 

[MrSled]

This should be posted in the Totallyamaha.net forums!

 

[blueironranger]

Still sounds like something it plugged. I've had to soak my Phazer II carbs in seafoam overnight to get all the gunk out of the tiny passages. A normal quick clean didn't get everything which resulted in a bad bog going from idle to WOT and it didn't run right in the mid range.

 

[TPAY243]

especially the piolet and main jets, also make sure you clean out all the air holes in the face of the carb they will plug up with belt dust. If you're not useing compressed air to blow air through everything you probably have some carp stuck in there some where. Make sure you have fresh gas also it doesn't take long now days for that carp gas to go bad. The butterfly carb only has one adjustment screw and it is right on top of the carb. I'm telling you if don't have these carbs clean they will bog on the bottom end like a m f er

 

[rogerz1000]

Thanks everyone for the help. Sorry about the post in the wrong place. I really am not on the computer a lot so I don't go on or post at all as I have a lot going on and would rather be riding as well, and not on the computer unless I need to be. I am really thorough at cleaning. I use a can of carb clean and hit everything. Good pressure in those cans! All passages, and then some! I take the jets out and have cleaned every passage on them, and the passages that they are in. These carbs weren't really gummed up at all. They are super clean now! I use Startron to treat the gas and it's fresh for sure! I had them both going ok yesterday am and as the day went on they got worse again so I'm not sure what to chase now again. I guess I will take another set out and look again but this is the 4th time doing this on both. Not sure it's the issue.

I know I had a TORS issue on one of them. Is there a quick way to bypas that for testing?

 

[TPAY243]

Un plug the connection by the carb and plug the wires back in to each other that will bypass it.

 

[maim]

did you check the fuel filter was intact? sounds like it might be coming apart. had it happen on my vk when i tried to get it going after sitting a long time.

 

[rogerz1000]

Yes, thanks! The filter did fall off one of them and it was wreaking havoc. I added an in line filter outside of the tank and took care of the issue on that machine. The other one is still having wide open throttle issues breaking up even after installing a filter, cleaning everything, and new plugs.[/QUOTE]