Phazer won't rev beyond 5500RPM - Snowmobile Forum: Your #1 Snowmobile Forum

diverdown_5 · 12-18-2007, 10:07 AM

Hi All, I'm new to this forum and have a question about my daughter's 89 phazer... First I'll say it starts and idles like a champ. The problem is that it won't go beyond about 5500rpm.

Here's what's been done so far...
cleaned carbs (tors bypassed)
overhauled fuel pump
replaced coil with wires and boots
replaced plugs
replaced CDI
checked stator(not falling out)
replaced exhaust with known good exhaust
compression 125-130 both cylinders

I have too much time into this thing to give up now.

I've already read through the Yamaha posts and don't see anything resembling this so I thought I would ask.
Any help would be greatly appreciated.

Skligmund · 12-18-2007, 11:47 AM

Did you ever run through your clutches? Clean em up and see what that does. You might need to rebuild them though.

diverdown_5 · 12-18-2007, 11:52 AM

I've not looked into the clutches yet. I've never had clutches apart on any sled so I'm not sure what to look for. Is there a link that might explain what to look for or how to overhaul?

Thanks again for the suggestions.

SkiDooFormulaMX · 12-18-2007, 12:07 PM

carb boots arent dry rotted or cracked are they?

diverdown_5 · 12-18-2007, 12:41 PM

No. I've checked the carb boots and also sprayed brake cleaner on the crank seals to see if I pulled in a seal. The RPM's don't change with brake cleaner spray so there's no leaks there!

Gunner · 12-18-2007, 09:30 PM

This may be a dumb question because it sounds like you have your stuff together. But when you adjusted the throttle cable was it set so it would pull the carbs all the way open?

i.e. slack in the cable (be it stretched or too long)

Does it do it if you have the sled jacked up so the track can spin freely? I've heard rumors of bad bearings in the wheels, torn up hyfax or the track being to tight to cause problems..

Chain too tight? Lost a bolt in the drivetrain causing it to be at an angle? Clutch alignment?

I'm really just shooting in the dark here wondering if something is causing drag..

diverdown_5 · 12-19-2007, 04:26 PM

Thanks for the ideas but yes, I've checked all of those things including pull the suspension out to check and ensure no excessive drag.

This all started when the CDI went bad causing a misfire. The misfire would come and go and eventually got to the point that it wouldn't move. I swapped the CDI from another phazer and it went away. The muffler baffles were also loose so I cut the muffler open and removed the baffles and re-welded it back together. That's when the lack of power/bogging started. I was so sure it was the muffler causing the lack of power I bought another one... Still the same!

Skligmund · 12-19-2007, 06:03 PM

Wonder if the new CDI is compatable? Check grounds and such, you might have weak spark.

diverdown_5 · 12-20-2007, 09:22 AM

I don't see an excessive voltage drop on the ground circuit and the spark seems good.
I want to check the clutches tonight if possible and see if maybe the secondary is binding.

raiderx65 · 12-22-2007, 07:38 PM

wow!i thought you were onto something with muffler. And the throttle cable was a great suggestion. got me to thinking, you might want to just go back and check some of the simple things. Sometimes when we get in a hury we miss stuff. I know i have.

diverdown_5 · 12-28-2007, 08:59 AM

I've now replaced both clutches with known good ones and no differance. Also replaced the stator plate and still no differance.

Someone suggested possibly the crank has gone out of phaze just enough to change the timing??? It makes sense if the stator end of the crank has shifted it would cause the timing to be out of adjustment, but if the middle of the shaft has shifted and the two pistons are not 180 appart...? I don't have a dial gauge to check this but I did a rough measure with a vernier gauge and it seems about right.

I'm really grasping at straws now... Please help!

stu · 12-28-2007, 11:31 AM

diverdown 5, this is a little off track...BUT, Maybe you can help me. Mine is a Phazer, I'm guessing 1984-1989. Does the gas and oil mix automatically OR do I have to mix it? ALSO, IF it does mix automatically, how much oil do I put in the oil tank? I've asked this question over and over and it seems everyone helps me but not quite the question/s I've been asking.
It shows on a sticker PZ480, then it shows (250cc 8.5oz.). I picked it up very cheap for the kids to ride in the yard and the previous owner also had kids, who did who knows what to it. He was not very informative on the sled. I've never owned one before also. All I know is that the oil tank had fuel in it and I emptied it out to start fresh. Any help would really be appriciated. Thnx.!

diverdown_5 · 12-30-2007, 11:35 AM

Hi Stu.

I'm not sure you want to just guess at what was done previously on that machine if there was gas in the oil tank.

Normally you fill the oil tank with 2 stroke oil and just put raw gas in the fuel tank. It's supposed to be automatic oil injection, but by the sounds of what you've described... I'd have it checked out by a mechanic before trying to run it our you may destroy the engine.

Good luck!

diverdown_5 · 12-30-2007, 11:40 AM

Ok, we swapped the carbs and it seems to be much better but not 100%. Obviously something in the carbs though. Thanks for all the great suggestions.

Happy trails!

COOKSTER · 12-30-2007, 11:56 AM

Quote:

Originally Posted by stu

diverdown 5, this is a little off track...BUT, Maybe you can help me. Mine is a Phazer, I'm guessing 1984-1989. Does the gas and oil mix automatically OR do I have to mix it? ALSO, IF it does mix automatically, how much oil do I put in the oil tank? I've asked this question over and over and it seems everyone helps me but not quite the question/s I've been asking.
It shows on a sticker PZ480, then it shows (250cc 8.5oz.). I picked it up very cheap for the kids to ride in the yard and the previous owner also had kids, who did who knows what to it. He was not very informative on the sled. I've never owned one before also. All I know is that the oil tank had fuel in it and I emptied it out to start fresh. Any help would really be appriciated. Thnx.!

I could be wrong, but I think the sticker you are talking about that indicates 250 ml / 8.5 oz is refering to the chain case oil capacity. There is a large plastic tank under the hood for your injector oil, you fill it to the top. Its possible that the oil injection system has been removed or disabled by a previous owner as some people dont trust oil injection systems especially on older sleds.

ramblnman · 01-01-2008, 12:21 AM

what is your air/fuel mixture screw set at? that is the screws on top of both carbs. turn them both in (gently)to seated position, then out 3/4 turns and see how it runs

diverdown_5 · 01-02-2008, 11:59 AM

I've tried playing with those and it didn't make a whole lot of differance. They're now back to the original 3/4 turn out.

diverdown_5 · 01-03-2008, 08:18 AM

I'll be soaking the carbs tonight in carb cleaner after complete disassembly. Maybe when it's reassembled the ignition will short to ground causing an uncontrolable thermal incident!

Yamagirl · 01-08-2008, 10:14 PM

when you say it won't go above 5500rpm do you mean that you can drive it around at 5500rpm or does it get to 5500rpm and bog down untill you let off on the thottle then it acts like it catches it's breath and revs back up to 5500rpm???

diverdown_5 · 01-10-2008, 09:43 AM

It seems to have loads of power at take off and revs to about 6000-6500(since the carbs have been swaped), then seems to lose some power as the speed gets to about 70kph and the RPM's fall off to about 5500 and won't go any higher. It's like it's lost all of the top end. It will ride all day at 5500RPM, wide open throttle. I still have not soaked the carbs to see if there's an internal port blocked.