First time starting Phantom 85

OrionSphere

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Feb 19, 2024
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Shawnee, OK
I slapped my new phantom 85 onto my old bike

First time starting was just now at 32 degrees outside, lots of engine sputtering on the startup, sounded real nice and I probably got up to 20mph, I didn't push it and held the throttle for no more than 5 seconds at a time as per break in instructions.

It ran best on half choke, but it absolutely refused to idle. I haven't tweaked the idle much but from previous engine experience and by looking at removed air filter during installation, it's already open plenty.

Will the bike run better as-is in warmer weather and broken in or is there some tweaking i need to do? Is there anything I should know going forward? I'm planning on moving my phantom to my brand new hyper with 3 spoke mag wheels (DAMIEN's design copied) as soon as some other parts come in)
 
I slapped my new phantom 85 onto my old bike

First time starting was just now at 32 degrees outside, lots of engine sputtering on the startup, sounded real nice and I probably got up to 20mph, I didn't push it and held the throttle for no more than 5 seconds at a time as per break in instructions.

It ran best on half choke, but it absolutely refused to idle. I haven't tweaked the idle much but from previous engine experience and by looking at removed air filter during installation, it's already open plenty.

Will the bike run better as-is in warmer weather and broken in or is there some tweaking i need to do? Is there anything I should know going forward? I'm planning on moving my phantom to my brand new hyper with 3 spoke mag wheels (DAMIEN's design copied) as soon as some other parts come in)
It's the clutch 100% garuntee. The Pads are absolute garbage. Take off the clutch case cover. Remove the flower nut screw. Pull your clutch lever in. Use your fingers to screw in the center flowernut on your clutch plate.

With clutch lever dissengaged trying pushing rolling your bike back and forth. Pay attention to see if your clutch plate is rolling gears back and forth and the plate is not free spinning. Hold down your clutch lever again, see if the clutch plate spins freely. Now that it does or doesn't either adjust the flowernut more or less. Vice Versa. Once you see it work on both ends. Try starting now. You should be gold.

Correct the pads are crap. The plate normally has to heat a bit. You will want to replace pads, ASAP. I recommend a utility knife to trim the edges on the pads slightly to fit them in the clutch basket properly with your clutch plate off. Here's a standard goto on decent preforming pads:


Comes with three sets. Should last a long time.
 
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I slapped my new phantom 85 onto my old bike

First time starting was just now at 32 degrees outside, lots of engine sputtering on the startup, sounded real nice and I probably got up to 20mph, I didn't push it and held the throttle for no more than 5 seconds at a time as per break in instructions.

It ran best on half choke, but it absolutely refused to idle. I haven't tweaked the idle much but from previous engine experience and by looking at removed air filter during installation, it's already open plenty.

Will the bike run better as-is in warmer weather and broken in or is there some tweaking i need to do? Is there anything I should know going forward? I'm planning on moving my phantom to my brand new hyper with 3 spoke mag wheels (DAMIEN's design copied) as soon as some other parts come in)
If you need some help with it we will be happy to help.
 
It's the clutch 100% garuntee. The Pads are absolute garbage. Take off the clutch case cover. Remove the flower nut screw. Pull your clutch lever in. Use your fingers to screw in the center flowernut on your clutch plate.

With clutch lever dissengaged trying pushing rolling your bike back and forth. Pay attention to see if your clutch plate is rolling gears back and forth and the plate is not free spinning. Hold down your clutch lever again, see if the clutch plate spins freely. Now that it does or doesn't either adjust the flowernut more or less. Vice Versa. Once you see it work on both ends. Try starting now. You should be gold.

Correct the pads are crap. The plate normally has to heat a bit. You will want to replace pads, ASAP. I recommend a utility knife to trim the edges on the pads slightly to fit them in the clutch basket properly with your clutch plate off. Here's a standard goto on decent preforming pads:


Comes with three sets. Should last a long time.
Do NOT be jumping to the conclusion that it must be a clutch problem just because his P-85 does not hold an idle on its very first start out of the box...This can be very misleading to a new builder of a P-85 and you should know better than that.

Also your clutch adjusting instructions as you have written them are chaotic with zero sense of order about them.

Below is the proper clutch instruction technique, just for the sake of argument, that is in a logical and concise order.


In the meanwhile, just to eliminate the clutch adjustment as part of the problem, once it is started and rode for a few minutes, all he needs to do is keep goose-ing the gas to keep it running whilst holding the clutch lever all the way in, and just simply lift the rear wheel off the ground while it is running...If the wheel is moving, then the flower nut probably needs to be backed off one or two notches.

If it does not turn with clutch lever held in while running, then we are looking for another cause of idle problem.
 
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Do NOT be jumping to the conclusion that it must be a clutch problem just because his P-85 does not hold an idle on its very first start out of the box...This can be very misleading to a new builder of a P-85 and you should know better than that.

Also your clutch adjusting instructions as you have written them are chaotic with zero sense of order about them.

Below is the proper clutch instruction technique, just for the sake of argument, that is in a logical and concise order.


In the meanwhile, just to eliminate the clutch adjustment as part of the problem, once it is started and rode for a few minutes, all he needs to do is keep goose-ing the gas to keep it running whilst holding the clutch lever all the way in, and just simply lift the rear wheel off the ground while it is running...If the wheel is moving, then the flower nut probably needs to be backed off one or two notches.

If it does not turn with clutch lever held in while running, then we are looking for another cause of idle problem.
First check your carb, make sure the inside of it has an O-ring gasket. If so slide it back on as far back as it can go and tightly tighten it back down. This will validate the carb isn't leaking. Let's cover all the basics of what i found wrong with this motor kit to get running properly.


Also try blooping the lever. When you're starting it. Ride it a good 50-100ft. hold down the throttle to full. Once it starts let go and bring to 1/4 or 1/2 throttle, run this bike like this for quite a few tanks! Release the clutch lever Then quickly rengage it and letting go again quickly. Kind of like a trigger gun effect. If it starts going bring your throttle down to 1/2. Don't keep running at full. You want to avoid full throttle until maybe three tanks. It's ok to briefly "bloop a full throttle on hard starting" I'm only speaking from personal experience of having the same issues when I installed a Phantom 85 v3 and got it to run. Regardless if you're new to this the bicycle-engines.com instructions are rather daunting but very specific for a purpose. First initial run of this motor. I had to readjust my clutch plate as the clutch was slipping because the clay looking pads wern't grabbing 100% and the plate would slip. I'm actually about to install a RDM clutch plate to my Phantom 85 v3 to avoid the slipping issues it has with the plate and heat on the pads. One important note on these Boefang carbs. Is you need to run them 10% open on choke sometimes and warm up the engine, Then bring down the lever 30-50% once it's warmed up for 5 minutes. REMEMBER the level on your choke facing fully up is the choke fully on. The lever facing down is the choke fully off. Also I would want to importantly NOTE that some Boefang carb levers need the nut to be tightened inside as sometimes the lever feels like it's being brought down but it isn't. I confirmed this with two different identical carbs of the same kit.

These bikes won't run with the choke fully down until their well broken in. I couldn't get mine to run with the choke open from 80% or below for the first few tanks of 2.5 litres. It would always start at 90-80% of the choke ON. Secondly bicycle-engines sent me a kit with a defective carb. They sent me another one that had casting issues also. So i had to make sure it had zero leaks and tightened properly. Besides that...

Also don't use a fuel line filter. Your tank that came with the kit already has one plus they recommend not to use one. On my testing and experiment the bike wouldn't run properly with two fuel line filters. It may be a problems with PSI and compression.

Choke almost full on means you're COLD STARTING your engine. The engine hasn't warmed up fully. Once it's running for 2 to 5 minutes its fully warmed up. You can gradually bring down your lever without bogging out your motor on throttle.

Bicycle Engine instructions are specific for a purpose. The Phantom 85 v3 is entirely a different beast from a China Girl. I just wish they had better instructions on the manufactures neglect to intrigrate better clutch basket pads and troubleshooting. But this can be an issue with any motor. I HIGHLY recommend following their instructions as it would otherwise void their warranty. That being said all the info on the forum is usefull and helpful. But don't run this engine at full throttle "BRIEFLY" until you've ran about 3-4 tanks of Vavoline conventional 20:1 through it. I still only full throttle mine very seldomly because long intrevals of full throttle on these 2 strokes is risky task for the first 310 miles breaking them in. RUN IT at 1/4 1/2 throttle for the first 310 miles to play it safe. I have only tested full throttle after 4 tanks of 2.5.L very briefly. You bike shouldn't have an issue accelerating past 40 on 1/2, just takes longer. Normal commutes around city roads limits me between 20mph typically and 35 on straight shoots until i get to a light. Season the motor. Once you gett it running after desyphering this crappy carb and clutch. Run it for 10 minute sessions and cool it down fully for 30 minutes and keep repeating the process. Be patient. After each ride YOU will notice a difference in the engine preformance and notice the piston rings are finally starting to set into the motors cylinder. Valvoline Conventional will help set you pistons rings right for the first 310 miles. Some people switch to semi sythetic after the first 2-3 tanks. That's entirely up to you. I'm still running conventional just to play it safe. They recommend semi synthetic straight out of the box and conventional as a only option. Their recommendation of Valvoline Semi sythetic is misleading. There is no such thing they describe. But there's this: https://www.walmart.com/ip/Valvoline-2-Cycle-Marine-TCW-3-Synthetic-Blend-Motor-Oil-1-GA/766026279 It's misleading because it's called Marine oil specifically for boats.

I'm not here to lead you in the wrong direction and throw any guides at you. I'm just speaking from my own personal experience of buying this motor a month and half ago, to having bicyle engines send me a new carb and having to physically service and run this engine. I really hope this covers all basis and gets you running. Wear a helmet :). Positive input from all users. What damien mentioned in his response is a constant battle with mine, I always need to adjust my plate to get it running for 30 minute sessions. So now I'm going to replace the clutch plate with a RDM clutch plate and hopefully that eliminates the issue. I already replaced the pads also, same issue.
 
It’s brand new. I’d run it a bit.

If it was mine…

If you can pull the clutch lever in and roll the bike freely with no obvious engine drag then leave any clutch adjustment alone.

If a drag problem is present follow Damien’s instructions to adjust.
These instructions are easy and very explicit.

It is not unusual for a brand new engine to have a stubborn idle.

After a few runs you can turn the only adjustment screw on the side of the carb 1/4 turn clockwise at a time till you get it to idle.

Follow the vendor instructions precisely.



Then go from there.

New engines need a bit of running to behave correctly.

Good Luck!
 
It’s brand new. I’d run it a bit.

If it was mine…

If you can pull the clutch lever in and roll the bike freely with no obvious engine drag then leave any clutch adjustment alone.
If a drag problem is present follow Damien’s instructions to adjust.
These instructions are easy and very explicit.

It is not unusual for a brand new engine to have a stubborn idle.

After a few runs you can turn the only adjustment screw on the side of the carb 1/4 turn clockwise at a time till you get it to idle.

Follow the vendor instructions precisely.



Then go from there.

New engines need a bit of running to behave correctly.

Good Luck!
This is all true but the OP said the slide is already high,

It ran best on half choke, but it absolutely refused to idle. I haven't tweaked the idle much but from previous engine experience and by looking at removed air filter during installation, it's already open plenty.

I'd look into the float and cable adjustments
 
This is all true but the OP said the slide is already high,

It ran best on half choke, but it absolutely refused to idle. I haven't tweaked the idle much but from previous engine experience and by looking at removed air filter during installation, it's already open plenty.

I'd look into the float and cable adjustments
I did notice after about 150 miles of running and cooling down for 30 minutes after giving a test drive full throttle briefly a few times it allowed me to almost fully de-choke the carb. But you can't expect the best preformance from such a simplistic 16mm carb.
 
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