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[Technical] Possible Solutions to your Phantom's Problem


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see below for the fuel/air mixture screw (screw A). turn anti-clockwise to lean, or turn clockwise to richen the pilot circuit a/f mixture.

warning: take note adjustments of a few degrees can change alot.

 

***before adjusting the screw, i recommend you change the air filter, or blow the air filter with compressed air first before adjusting the a/f screw.

most of the time its because filter dirty then will affect the a/f mixture and cause backfiring.

if you adjust your a/f mixture for the pilot circuit with a dirty air filter, it will screw up your tuning later when you change filter and then you'll have to readjust again thereafter.

 

[ATTACH=CONFIG]308940[/ATTACH]

 

 

Just to confirm with u, clockwise is to richen? This screw actually controls the air or the fuel?

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Clock wise tighten to richen. It controls the air intake to be exact for the pilot circuit for small throttle opening.

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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Well my air filter is as clean as the day I bought it. I read an old post by VariK that said to adjust the screw until your idling engine sound seems the fastest. I made it leaner by half a turn. Hope it solves the backfiring because I jump every time it happens haha.

 

Sent from my Nexus 5 using Tapatalk

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Lol did u say backfire everytime you jump? Watch out for engine heat due to too lean! Most of us actually richen slightly after the fastest idle.. Too lean too hot I had my spark plug insulator melted over my piston before....

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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Lolololol I don't understand how jumping can cause a huge bang leh! Must see to experience!

 

.... on second thought if you literally mean *jumping* on the bike i keep thinking something along the fuel circuit is cracked or loose.. vacuum leak..

Edited by sawfly

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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Just an update: Changed my air suction at planet today for $65. Totally no backfire now. Peaceful ride home!

 

good to hear! i had my replaced sometime back when tuning wouldnt work.

actually someone told me the air suction v/v spoil quite easily one - the valve kicks in when throttle suddenly closed.. replace for a while then will spoil again but im not too sure as i changed my throttle habit after the replacement.. 65sgd quite abit for a lump of metal!

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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how does the air suction pump work? I heard that instead of venting it into the exhaust, it can be vented into the atmosphere? My first one spoil and i replaced it and now it is popping a little.

 

is it necessary?

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how does the air suction pump work? I heard that instead of venting it into the exhaust, it can be vented into the atmosphere? My first one spoil and i replaced it and now it is popping a little.

 

is it necessary?

 

from what i understand, they actually call it the air cut off valve in the com service manual.. when throttle is suddenly closed, the a/f mixture suddenly becomes lean so the the v/v replaced supposedly cuts of the air intake in the pilot circuit to richen the mixture.. otherwise the supposedly original lean mixture will ignite in the exhaust instead of in the cylinder.

 

that's my understanding so far though for ta200 but until now i not so clear because when i disassembled the 65sgd valve that i replaced, it seems to be have other components other than the air cut off v/v - saw a reed valve in addition to the diaphagram v/v for the air cut off. i thought it might be a package of valves for the entire fuel system.

so when u say venting into atmosphere instead of into the exhaust, i not too sure what u read is related to secondary emissions system.. someone jollywell correct me if i salah..

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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speaking of necessary or not, i get inputs from some mechanics to just bypass and dont care lol. i think the popping cant avoid for me and its like once in a blue moon on a really cold night.. maybe lean but i dont know.. maybe u richen the pilot circuit and try your luck maybe it will go away? - this is for a back fire on closing throttlesituation. backfire on acceleration would be a different treatment which i cant advise..

Edited by sawfly

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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the mechanic was saying it is unnecessary to change, just pop only. Anyway when it is gargling and popping, other cruiser riders would sneak a peek to see what is that behind them. Even after I change after a while it also pops but not so often but the loud bang type.

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the mechanic was saying it is unnecessary to change, just pop only. Anyway when it is gargling and popping, other cruiser riders would sneak a peek to see what is that behind them. Even after I change after a while it also pops but not so often but the loud bang type.

that's what ppl told me. I did get opinion that very regular backfire no good since u won't know if the exhaust can tahan and is designed for fuel ignition..

http://img.tapatalk.com/d/14/08/05/apytydyd.jpg

 

Here's a pic of the box of the air suction part I took for fun.

 

Sent from my Nexus 5 using Tapatalk

Attached below is the air suction assy that is replaced for 65sgd.. Metal box thingy with hoses attached http://img.tapatalk.com/d/14/08/05/epa8e6a3.jpg

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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  • 3 weeks later...

When I got my phantom, it would start and then stall after a few seconds, unless the choke was pulled. It would only idle properly after it was warm, but to do that I had to run the choke. It also had an exhaust that sounded like it was spluttering and burbling, on the verge of a backfire. After doing a lot of reading, it seemed like I had a problem with my idle fueling, and no amount of tweaking seemed to fix it. Here's how I eventually sorted out the problem.

 

What you will need:

Small flat head screw driver

Medium phillips head screw driver

Spark plug NGK DPR8EA-9 or Denso X24EPR U9 ($3.00 from stockists)

Viton O-ring, 3mm ID, 5mm OD (I paid $0.20 each, got a few spare, if anyone wants, just pm me)

About 15-20 mins total.

 

Remove the fuel mixture screw from the carb:

http://i61.tinypic.com/33w9wmq.jpg

 

Be careful when you do, there is a small rubber o-ring, a small washer, spring, and the screw. Don't lose any of the bits!

First thing I noticed was that the old o-ring was flattened and not flexible anymore. I suspected that this was part of the problem as it was not sealing properly and allowing air to enter the system.

I went to Hypax in Kaki Bukit and picked up some o-rings:

http://i60.tinypic.com/2qa0myc.jpg

Of course you can go to any o-ring supplier that has the correct size.

 

The rest of the assembly was in fairly good condition, so I just gave it a quick spray with carb cleaner to get rid of any residue, and reassembled the mixture screw (Screw>spring>washer>o-ring)

 

Screw back the whole assembly back into the carburetor, gently, until the screw JUST stops turning. Don't over-tighten the screw!

Then turn the screw counter-clockwise 2 complete turns. This is the base setting, we will do a bit of adjustment later.

 

Next, check the spark plug. In my case, the bike came with the wrong type of plug fitted. You can see from the picture that the new plug has a tip that extends a bit more than the old one:

http://i58.tinypic.com/2vudbp1.jpg

 

Better view:

http://i58.tinypic.com/10fn892.jpg

 

With the new plug fitted and connected, it was time to do a bit of tuning.

 

First, the idle speed screw:

http://i57.tinypic.com/zkrbis.jpg

1) Turn this out until it is no longer touching the throttle swivel plate.

2) Turn it in until it just touches the plate.

3) Make a little mark on the knob, and turn it 1 1/2 turns.

 

I started the bike and it immediately started and idled smoothly.

 

4) Let the bike warm up for about 3-5 mins, to get to operating temperature.

5) Use a small flathead screwdriver to adjust the fuel mixture screw CW is richer , CCW is leaner. What you want to do is make small turns, about 90 deg at most, and listen for the change in the idle speed. Reference all turns from the base setting of 2 full turns as what was done earlier. If you turn the screw CCW, it will lean the fuel mixture, and the idle may increase, and further turning it will cause the idle to drop, too rich, you will end up with a fuel smell from the exhaust, as well as fouled plugs. Turning it CW will richen the mixture, and you might experience the idle speed increasing, then if you turn some more, it will drop again. Too lean, and the bike won't have enough fuel to keep the engine going, and also risk damaging the engine from pinging. The idea is to slowly adjust the fuel screw +/- from the initial reference point of 2 turns out, until you get the fastest stable idle. Rev the engine with a few quick blips. There should be no lag or hesitation to rev, and also it shouldn't take too long for the rpms to come back down.

 

When you have this point, make a note of it, this is the tuning point for your particular carburetor. different bikes will vary slightly, and even changing the air filter will require re-tuning to get the best performance.

 

6) Turn the knob of the idle speed screw to lower the idle speed of the bike. Honda specifies 1400rpm +/-100 at operating temperature. You can set this with an induction tachometer which you can buy cheaply for on the internet. Such as THIS

 

My bike runs smoothly now, no sputtering, starts first time nicely, and I am happy. Total damage $3.20.

 

Hope this helps!! Mods, if you find this useful, please feel free to sticky.

Edited by ricebandit
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When I got my phantom, it would start and then stall after a few seconds, unless the choke was pulled. It would only idle properly after it was warm, but to do that I had to run the choke. It also had an exhaust that sounded like it was spluttering and burbling, on the verge of a backfire. After doing a lot of reading, it seemed like I had a problem with my idle fueling, and no amount of tweaking seemed to fix it. Here's how I eventually sorted out the problem....

 

5) Use a small flathead screwdriver to adjust the fuel mixture screw CW is lean, CCW is rich. What you want to do is make small turns, about 90 deg at most, and listen for the change in the idle speed. Reference all turns from the base setting of 2 full turns as what was done earlier. If you turn the screw CCW, it will enrichen the fuel mixture, and the idle may increase, and further turning it will cause the idle to drop, too rich, you will end up with a fuel smell from the exhaust, as well as fouled plugs. Turning it CW will lean the mixture, and you might experience the idle speed increasing, then if you turn some more, it will drop again. Too lean, and the bike won't have enough fuel to keep the engine going, and also risk damaging the engine from pinging. The idea is to slowly adjust the fuel screw +/- from the initial reference point of 2 turns out, until you get the fastest stable idle. Rev the engine with a few quick blips. There should be no lag or hesitation to rev, and also it shouldn't take too long for the rpms to come back down.

 

 

dont mind me asking, i thought turning the fuel mixture scruew (marked VE) CW is richen, CCW is to lean the a/f mixture??

for my carb it works the reverse of what you have described.. (CW to richen and fuel smell comes from exhaust); my carb looks almost like yours..

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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I used the advice from http:// http://www.motorcycleforums.net/forum/mechanics-corner/42759-fuel-mixture-screw-how-does-work.html from what I gather, ours is a fuel mixture screw, not an air screw. But if I'm wrong please tell me!!

 

i think we need someone else to verify this.. i always thought its an air screw because of the direction it richens on my carb.. and through the history of the forum IIRC its always CW to richen unless i remb wrongly.. when i performed idle drop procedure according to shop manual it also performs like an air screw..

 

silent hunter or naim will know about this.. (search on pk for carb adjust, i too lazy and need to go work so i found only this =X

http://www.singaporebikes.com/forums/showthread.php/242978-Technical-Queries-for-TA200?p=7837052&viewfull=1#post7837052)

 

btw the tachometer u recommended.. must by the correct one.. i bought a 2 stroke one by mistake before.. all RPM must multiple by 2! now i use a different brand..

Edited by sawfly

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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Ok, confirmed with an exhaust gas tester, cw is richer, ccw is leaner. Thanks bro, and my post corrected accordingly!!

 

no prob! glad we have an actual confirmation!

(btw.. your point 5 in your previouse post haven corrected yet.. lol)

operate a vehicle in a way that you benefit other road users pls - and meanwhile, stop whining! be responsible and be safe.

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  • 2 weeks later...

Hey guys,

 

Oil is leaking and the engine stinks when running. I can see oil on both the crank case and the cylinder block. Reputable mechanic in ubi told me that I need to replace on of the crank case gaskets, but he's got limited time. I'm thinking of buying from Chong Aik and getting my regular jb mech to fix it. Problem is, I don't know if it is the left or right gasket. Any experienced souls can help me out?

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