1991 PHAZER MOD: 38mm flatslide tuning

phazerduece

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Mar 14, 2017
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Lake Zurich, Illinois
Hello..New to totallyamaha here. I was hoping someone could help me out with tuning my 91 Phazer w/ 1996 vmax flatside carbs.
I have purchased an AAEN race pipe: PIY11068, Boyesen 2 Stage Reeds (#534 i believe), and a gutted airbox. I plan i riding around the midwest area so the altitude will be around 0-1000ft. I was reading on here that the jets will not need to be changed out with this pipe, but cant seem to get her to run right.
Also which spring will work best for the primary clutch?
 

run us threw what mains and pilots are in the carbs right now plus the clutching needs to be changed up to see the performance gain .... and the air box must be completely gutted
 
Yamaha Nutz, I've got pretty much the same set of questions on a back country mod phazer project I'm just finishing. Here's what I'm working with:
1991 ST
-38mm flat slides from 1996 Vmax 600 (have 145 mains and 47.5 pilots in currently)
-engine is a crank up fresh rebuild / 10 over pistons to clean things up stock porting and heads
-oil pump delete / mixing gas / fresh 91 octane with 40:1 mix but added more oil for break in so probably closer to 32:1
-have done 3 heat cycles before taking for a ride on the road that was ice/snow with 1 inch of fluff
-Temperature was -6C/21.2F during my testing today in central Ontario
-altitude is ~ 750
-no tach yet / will need to get an electronic one
Machine starts and idles well. The rpm's sound/feel good off engagement but started to sputter on the second or third blip of the throttle and would not rev out/clear out. I went about half a mile down the road and cut the engine while on the throttle for a plug check. The PTO side was showing ever so little tan below the electrode on the ceramic but the round tip was black and the tip of the arch was starting to ebb from black to some brown. The mag side was black and wet. Tried again blip the throttle, hold it open a few seconds etc. but did not clear up. I changed out the fouled plug and repeated. Was a bit of improvement but both plugs were essentially black and wet by the threads. Seems too rich?

Let's start with jetting this carb/pipe/airbox set up and then I'll start asking for clutching help! (lots of suspension/track/driver/gear mods to over come on the clutching tune)255.jpgalmost finished.JPGIMG_0509.jpg
 
Same setup here. Same problems. With the setup listed below, I am super fat in the midrange, takes a good 4-5 seconds of WOT to even begin to clean up. I am guess that I have some needle/clip/nozzle work to do, but it is really hard to find any info on needle tuning for these carbs. I have read that some people have the 8CFY6-55 needle. Google is really failing me when trying to figure out the difference between these two needles. Heck, I cant even find where to buy the 8CFY6-55 needle to try out :o|

94 Phazer
  • AAEN pipe
  • TM38 carbs
  • 148.8M
  • 50P
  • Needle 3 clips down from top w/one spacer under clip
  • Gutted airbox
  • 687 Q6 Needle Jet
  • 8FLZ2 Needle
  • Air Screw 1T


I ran this ski all last season with the stock carbs and the AAEN pipe and a stock airbox and it ran pretty dang good. Trying to clean up that midrange lean bog with the flatslides
  • 148.8M
  • 110P
  • Aaen recommend clutch spring (cant remember off the top of my head, yellow/white?)
 
Turns out I had a choke (enricher) that was a tiny bit hung up by the cable. After I fixed that, the thing ran great. Might want to check your chokes.
 
Thanks - windshield is gone now, running a K/N pre-filter cold air intake up through the vent shroud to get good cold air. I dropped the needle so I'm in the top clip and turned in the air screw on the bottom of the car so it's at 1 turn. I also changed the secondary from C2 to A2. It was going in to over drive/too tall a gear which I was mistaking for fuel related in the main circut. Once I did A2 change it was very responsive. I was worried about being lean in the middle so did a solid mile at half throttle and then did a plug check (cut engine while on the throttle) and was a beauty light tan. Was -14C (6.8F) which is on the cold end for most days riding. Should be safe to -20C.

Unfortunately I was not smart enough to note what the needle part number was when I changed the position...rookie mistake! The flat slides are a PIA to make changes compared to the old round slides!!!

I also had to adjust my expectations! I run a 17 RMK Pro in the big hills and built this Phazer for around my cabin that is about 750' elevation. It's not electronic direct fuel injected with 160 hp. Once I rode my buddies similar modded Phazer (he has stock carbs jetted for his pipe) and they felt very close I'm happy.
 
Thanks - windshield is gone now, running a K/N pre-filter cold air intake up through the vent shroud to get good cold air. I dropped the needle so I'm in the top clip and turned in the air screw on the bottom of the car so it's at 1 turn. I also changed the secondary from C2 to A2. It was going in to over drive/too tall a gear which I was mistaking for fuel related in the main circut. Once I did A2 change it was very responsive. I was worried about being lean in the middle so did a solid mile at half throttle and then did a plug check (cut engine while on the throttle) and was a beauty light tan. Was -14C (6.8F) which is on the cold end for most days riding. Should be safe to -20C.

Unfortunately I was not smart enough to note what the needle part number was when I changed the position...rookie mistake! The flat slides are a PIA to make changes compared to the old round slides!!!

I also had to adjust my expectations! I run a 17 RMK Pro in the big hills and built this Phazer for around my cabin that is about 750' elevation. It's not electronic direct fuel injected with 160 hp. Once I rode my buddies similar modded Phazer (he has stock carbs jetted for his pipe) and they felt very close I'm happy.

I know this is an old thread but can you tell me more about your build? What Polaris seat did you use and what windshield? Also what skid and led light? I'm just starting my build on my '93 and need some direction.
 


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