Q&A Questions for CISON FG-VT9 9cc V-twin V2 Engine

Q&A Questions for CISON FG-VT9 9cc V-twin V2 Engine

Q&A Questions for CISON FG-VT9 9cc V-twin V2 Engine

buy accessories of this v twin engine. click


Before starting,

  1. please check whether the CDI is normally powered on, turn on the switch, and then rotate the flywheel to observe whether there is a high-voltage spark at the top of the spark plug. If there is no high-voltage spark.
  2. Please check whether the power supply is connected.
  3. Whether the voltage is normal.
  4. Whether the hall sensor is damaged, etc.
  5. please open the carburetor throttle to the maximum, then block the air inlet by hand, rotate the flywheel for 3-5 turns or more to let the fuel enter the cylinder in advance, and then start the engine with a hand drill or motor
  6. The fuel used in the factory test may be different from yours, so the carburetor needle may be slightly different. If you can't start, please try
  7. Adjust the main oil needle to 0.8-1.5 turns and try to start it, but it may not be accurate. Ambient temperature, tank height and so on may affect it. Please operate according to your experience.


Oil: The engine is designed to run on gasoline next at 25:1 ratio with 2 stroke engine oil.  Zippo fuel may also be used, mixed at a 25:1 ratio with 2 stroke engine oil.

Fuel used: 95# and above gasoline
Lubricant: 2T engine oil
Mixing ratio: gasoline/oil=25/1
Lubrication method: Mixed oil splash lubrication (allow the oil to fall freely to the connecting rod through a simple oil channel for splash lubrication)
Crankcase lubrication: In order to allow some lubricating oil to enter the crankcase smoothly, please check that the breathing port (vent) is not blocked. But if you want to upgrade the independent lubrication system later, you can block the vent.

Fuel Tanks: Various fuel tanks/containers can be used, that are made for use with gasoline. We also sell fuel tanks that can be purchased separately. For additional fuel tubing, please use Tygon type tube and NOT silicone, as it is not appropriate for gasoline-based fuels. The included fuel line can be easily attached to the carburetor’s inlet nipple gently using a pair of small needle-nose pliers. the size of the fuel line used on Cison V-Twin engine: Inner 2.5-outer 3mm.

Needle: The engine carburetor’s high-speed fuel needle is accessible from the flywheel side of the engine. This needle is factory preset but may need to be adjusted in small increments due to fuel type/humidity/altitude. Turn needle adjustment clockwise to lean mixture and counterclockwise to richen fuel mixture.

Idle speed: Idle speed may be adjusted by turning the small hex screw on the side of the carburetor. This screw determines the throttle barrel position. Turning the screw clockwise increases the idle speed, turning counter-clockwise decreases idle, by closing the throttle barrel opening.

Tool: The FG-VT9 engine is started by using a starter shaft in a cordless drill. The drill needs to be rotating in a counter-clockwise rotation. Please note that it’s normal to see a prominent vibration "signature" for 45-degree Vee angle engine.

Ignition: The Hall-type ignition system sends power to the spark plugs. We recommend using a LiPo battery with JST type plug from 6v to 7.2 volts. Connect spark plug leads to each spark plug. Make sure the spark plug wires will not come in contact with the flywheel once started. (I recommend you use the 6-7.4V li battery or 4pcs 1.5v cell batteries packs.)

Exhaust: Insert a green NBR O-ring into each exhaust port, and attach exhaust tubes to the engine by threading the exhaust pipe nuts clockwise in each cylinder exhaust port.  Snug the exhaust nuts using a 10mm open-end wrench. Do not over-tighten.

Connection: Connect the ignition’s 3 wire connector plug to the engine’s ignition plug. The single solid black wire is the ignition’s ground wire. Connect the wire’s ring terminal to the bolt threaded in the rear of the engine.  An M3 nut or a couple of M3 washers can be used for a spacer when attaching the ground ring terminal to the engine.


Now it’s time to start your engine!

  1. When the engine is ready to be started, please add 10ml of 2-stroke oil to the hole designated for the starter motor/generator location. This will lubricate the bottom-end of the engine, camshaft & camshaft drive for its initial start.
  2. Rotate the flywheel 3 complete revolutions by hand to prime the engine. Return throttle lever to the idle position.
  3. Connect the 6v - 7.2v battery to the ignition module. I recommend 2s battery.

 5. Using a cordless drill set to turn counter-clockwise and included starting shaft, insert the starting shaft into the center bearing on the flywheel and start the engine. Once the engine starts, engine RPM can be adjusted by moving the throttle lever arm.

 6. We recommend keeping engine RPM low during the first few runs to allow the engine to be lubricated properly and - short “breaking-in” period.

7. The FG-VT9 dissipates heat efficiently when a small desktop-type fan is used while running.  Engine & exhaust parts do get hot, so avoid touching cylinders and exhaust while running. 

8. The brass nipple located at the front of the engine is used as a crankcase vent. Do not block this nipple; oil vapor will exit through this fitting, which is normal.


Common problem

  1. Carburetor does not feed oil

A: Probably the needle valve is completely closed or blocked

  1. Carburetor injection

A: Incorrect valve timing, valve leakage, too small valve clearance (correct 0.1mm)

  1. Compression but not start-up

A: The CDI igniter is damaged, the sensor is damaged, and the power supply is dead.

  1. Idle speed too high

A: Incorrect commissioning of carburetor, unbalanced operation of left and right cylinders, insufficient cylinder pressure and incorrect valve timing

  1. Suddenly start without compression

A: It is likely that the valve structure is misaligned or that the valve has foreign material.

  1. Crankshaft abnormal sound

A: Because the crankshaft is a split structure, it is very likely that the crankshaft will be loose.

  1. Engine Overheating

A: Make sure there is heat dissipation, whether thinner gaskets have been replaced to improve the compression ratio, whether lubricants have been added to the fuel

  1. How to Achieve Ultra-Low Idle Speed

A: Replace the oversized flywheel and reduce the compression ratio

    9. If the engine cylinders become flooded from an excessively rich fuel and air mixture, remove the spark plugs (and the spark plug sealing washers) with a 9mm metric socket, invert the engine, and rotate counter-clockwise to clear excess fuel from the cylinders. Wear eye protection to avoid fuel possibly getting into your eyes. If flooded with excessive fuel, the engine will not rotate.

Important:  Do NOT attempt to start or rotate the flywheel if flooding occurs. Engine damage can occur.

 Other Problems People May Ask

1. will you do a water cooled version?

not yet. we have only the air-cooled version now. This v2 is a desktop machine, instead of a high-performance one. So it doesn't make big sense to do a water cooling version. If you want, you need to redesign the water channel and can DIY and change the external water pump.

2. Adjustable rockers or not?

yes. this v2 has an adjustable rockers and pushrods.

3. Does it leak?

The valve gap should not be too large, otherwise it will definitely leak, no matter what engine it is. As long as it is within a reasonable range, adjusting the atmospheric valve clearance is equivalent to understandably increase the speed.

4. What is the displacement?


5. Any turbo or supercharged engines?

not yet. it's hard to make. we might do it in the future.

6. How is it carbureted and type of ignition timing ???

7. What about the oil pump?

Oil pump is not released yet. it's a little bit complicated to do it.

8. Will this power my automobile? I need a new motor, and I'm not picky about size.
9. Why no valve covers

10. i run 1/5 scale two strokes. They are all heavily modified 34cc. No way would this engine make enough power,lol.

This is an engine model. if we make it 34cc, the size must be bigger.

11. Does V2 have an output shaft? I mean, I will be able to hook it up to something right? 

12. I got the Cison FG-VT9 last week, the engine is very nice but unfortunately it doesn't run. I know a lot about engines and have already built some myself. When I start the engine, it runs approx. 2-3 seconds and then goes out again. I tried every possible carburettor setting and also used different fuels. I suspect a faulty ignition or tax times. Furthermore, the front cylinder has very little compression. I have already bought the M12 engine and the M16 engine from them and am very satisfied with it. How can we proceed? 

A:There is a problem with the timing of your v2. Follow the below method and then check if there is a spark in the high-voltage cable cap when starting the ignition. Due to feedback from some users, we found that the timing gear jacks of several V2 engines did not reach the maximum tight fit. This may cause timing misalignment when the engine runs for a period of time. After you receive the engine, if you encounter timing problems, please remove the cover and tighten the top wire of the timing gear. When disassembling, be careful not to get the gear out with the cover, otherwise, it will cause the timing to be messed up. After unscrewing all the screws, shake the cover easy to keep the gears in the crankcase, and then find the screw as shown in the picture and tighten it. If you find that it is the tightest after checking, you can ignore it.

We will use keyway to fix all subsequent engines to completely avoid the possibility of timing errors.
In addition, we will send you a video of the timing adjustment method:


How to Adjust the Timing?

a. First, confirm the direction of the magnet angle as shown in the photo below. Then connect the igniter to the high voltage cap and the ground wire and then connect the Hall sensor wire. Adjust the gear to find the proper lead angle. Generally, 0-6° quality inspection can make the idle speed lower.

b. Then rotate the flywheel to the position shown in photo 2 below.  Please align the flywheel hole with the middle screw or 0-10°. Normally, 0° would make the engine more aggressive. Please note that the minimum angle of the trigger magnet should be upward at this time.



c.Then insert the camshaft so that the camshaft groove points are perpendicular to the engine gearbox.

13. I bought my mini V twin panhead motor for a display in my bike shop ,I made a motor mount and a stand to keep it on ,the first time it started right up and ran great the second time it ran for a minute and then just died in further checking it out there was no spark it is getting power but looks like the cdi box stopped working I only have it a month . will you send me a CDI box?Please let me know Thanks for your help this is the coolest little motor.

A: if you find there is no spark in the CDI igniter, I think there is something wrong with the ignition or the hall sensor. Because if there is no induction with the Hall sensor, there is no spark too.
So we need to know whether it is the problem of the igniter or the Hall sensor first. Please check by the following operation.
First,Use tweezers or clips for the wire of the CDI igniter and touch the black and white wire of the Hall sensor. Second, remove the wiring heads of the igniter and the Hall sensor, and then take the wire of the Hall sensor to short-contact the black and white wires to see if there are any sparks.
If there is a response, it is a problem with the Hall sensor. Replace the Hall sensor. contact me and i will resend it to you.
If there is no response, it is a problem with the igniter. Replace the igniter.  contact me and i will resend it to you.
now pls go and check and then get back to me.

So How to Replace and Install the new Hall sensor?

pls note that on the left is the new hall sensor. on the right is the old hall sensor.

you can buy it here. click

a. Install the Hall sensor into the place as shown in the photo below, and tighten the screws to fix the Hall sensor.

b. A gasket should be placed for the installation of the new Hall sensor. The gasket is to isolate the direct contact between the cylinder body and the circuit board. Because the circuit board is too close to the cylinder, it is easy for the Hall to generate a circuit with the high voltage and break down.

c. as you can see, the trigger magnet is installed in flywheel for all the new v twin engine. The magnet is installed in the hole and slot, with the colored side facing out. remember do not install it backwards.


14. Hi ! i have plane to buy a "Panhead engine" . I have seen two different carburators on it. Why is that? And i heard that it was some problems with the Hall-sensor. Is that right?

A: hello, we have already fixed the problem with the hall sensor. The solder joints are weak and the 45° engine shakes a lot, so it is easy to desolder during operation. so we change the design. The engines are embedded in a new way of fixing, so they won’t fall off easily. If your new version of the Hall sensor is damaged, you may not need to disassemble a lot of parts when replacing it, you only need to turn a screw, but in the experiment, we added a screw hole in version 2.0 to fix the Hall sensor. If you don't want to make holes for your machine, we can design a new bracket for you to ensure non-destructive installation, but it may take a while.

and in the left photo is what we produce and send originally. in the right photo is the picture from one of our customers who modify it himself for a better idle speed by changing the carburetor and adjusting the needle.

 15. What should i do if one of the cylinders does not fire and does not work?

 Because the engine is not run-in, the cylinder pressure on both sides is unbalanced, resulting in different oil intake at idle speed, because it is a single carburetor, the carburetor offset problem, and the short intake pipe. So causing this problem.
Based on the direction facing away from the flywheel, the left cylinder is the left cylinder and the right cylinder is the right cylinder. You can adjust the carburetor first to see if the engine cylinders can fire normally at medium and high speeds.

16. Why does it always happen that the cylinder on the right does not fire, but not the left?

When the carburetor is removed, you will find that when the throttle is the smallest, the carburetor air intake is offset, just to the right, resulting in more oil intake on the right. Of course, if the carburetor is installed sideways, there will be no such problem, but this is impossible, because the engine has no space, so it can only be designed this way.
how to solve this problem?
1) Try exchanging the ignition high-voltage wires first. If the 2 spark plugs have replaced the cap heads, it is the same as before, then it can be ruled out that it is a circuit problem.
2) If it is not a circuit problem, then you need to open the idle damper a little larger, about 1-2mm, and then find the balance point of the two cylinders, so that he can run, run in for 30-60 minutes, it should be improved.
3) Another method that is generally not recommended but very effective is to make a small hole in the intake pipe of the oil-rich cylinder with a 0.5mm drill bit, so that the cylinder can reduce part of the negative pressure. If the engine is loaded, the probability of missing cylinder misfire can also be reduced.

17. If the throttle is opened two millimeters still only the right cylinder does not operate. So do I keep running in or stop running in?

Please continue to open the big damper first. If there is no change, try to open the oil needle larger or smaller at low speed, and test which side is getting more oil. Slowly straighten the two and they can barely start. After running in for a period of time, it is basically stable.
In addition, please check the valve lifter, if the lifter does not reach the valve, the valve will not open and the ignition will not work. This is because the structure of the V2 causes the vibration to be relatively large, and it may sometimes vibrate and fall off the top rod screw. Just pay attention to this small detail.

18. Is it necessary to add lubricating oil on the side cover where the gears are located, which one is appropriate?

The gears and cam lobes of the v2 are pre-greased at the factory. Grease is recommended as it will remain on the camshaft all the time. The liquid lubricating oil will disappear faster, and the aging time is not long.

19.When it is found that the rotating flywheel will push the crankshaft bushing and the shaft to rotate together, how to adjust it at this time?

 If the bushing rotates, the simple solution is to clean the periphery of the bushing with gasoline or other solvents, then apply some anaerobic glue, and then rotate it to let it enter a little slowly.

 20. How to Connect the base of the V2 Engine Model?

 Green swith: base power swich

Toggle switch: ignition switch

learn more about :How to Install V.twin Engine Wiring to Base & Air Filter  | Stirlingkit


•Do not pull out the high voltage wire while in operation, so as not to cause harm to you by the high voltage wire

*        After the engine has been running for some time, please pay attention to whether the temperature of the engine is too high to dissipate heat in time, and do not touch the radiator fins to avoid scalding.

•If the engine does not start and the exhaust pipe sprays a lot of fuel when you try to start it, probably too much in the cylinder, remove the fire.

"        After the plug, quickly rotate the flywheel to flush out the fuel or clean it with a paper towel
Installation Hole Spacing
Center hole distance between front and rear of mounting bracket is 17mm

Retrofitting oil pump

During the design, the oil pump modification space is reserved for engineers to install the lubrication system.
Reserved transmission gear model: 0.5 die 45 degree left-hand helical gear 10t Reserved oil pump gear model: 0.5 die spur gear 12t
It does not necessarily meet your needs. You can make the oil pump according to your own design.

Gas distribution time

1.Rotate the crankshaft to the highest position of the right cylinder in the picture, or back 10 °
2.The camshaft is in the state that the inlet valve is about to open and the exhaust valve is about to close or has been closed

 What Can You Do with Your CISON FG-VT9 V2 Engine?

1.play and run it in your palm

(shared by Jon Cook)

2. Make a Base

(modified by Marijn Lenting)

(modified by Jon Cook)

(modified by Darren Fawcett)

(modified by M.U.)

(modified by Frank Schiavo)

(modified by a customer who doesn't want to leave his name)

(provided by the factory. buy it here. click.)

(provided by the factory. buy it here. click.)

2. Make a Motorcyle Frame and Install it

(modified by Cole Phillips)


(modified by Dennis Dempsey)

(modified by Brian Spitz)

(modified by William)

(modified by Seb)

(modified by George W)

 3. Install it into the boat

(modified by Robin Brubaker)

 3. Install it into the rc car


 (modified by Tony Mulraney )

 (modified by q90 )

 4. Make 220V Generator with V-Twin Gasoline Engine


 How to install the kick start

Only these parts are needed, the clutches are below the picture. 

First, replace the original flywheel, fix the gear and the new flywheel to the engine, and then tighten the screws.

Note: This new flywheel has no magnets and is only suitable for the old version hall sensor for the time being.
We will design and release a flywheel suitable for the upgraded hall sensor as the upgraded part as an optional choice. 




  • Orest Mysko: July 02, 2024

    Where do I install the engine oil for the crank case?

  • Hans de Bruin: March 29, 2023

    I’m confused about the exhaust seals. You push them into the ports and then tighten the exhaust pipes on top ? That doesn’t feel right ? Is this really how it should go ?

  • Pascal Meurtin: January 02, 2023

    Hello, I have a problem with the CISON V twin (Pan Head) engine I recently received:

    The fuel hose supplied was probably made of silicone, and dissolved with the fuel and clogged the carburettor!
    I have dismantled the whole carburettor to clean it, but I would like to know the settings of the needles and tappets,
    because everything is out of order!

    Moreover, on cylinder N°1, the rocker arm adjustment screws are loose, and the exhaust valve doesn’t open anymore
    (the engine worked only 5 minutes!): how to block these adjustments, because there is no lock nut.
    Should I use loctite?

  • EDI: December 22, 2022

    Gibt es einen Elektro Starter mit Freilauf für das model?

  • jairus thomas: March 13, 2022

    Hello, my engine doesn’t seem to have the hole that goes into where the breather gear would be on a Full size Panhead but I want to add a independent circulating oil system. What would be the best way to do that? Would the Vent be used as the oil return in that situation or would I have to add new hole? Thanks.

  • Joe deHerrera: February 26, 2022

    I have the Cison v2 engine which will not start. After reading the page I am not getting spark. I replaced the CDI system , checked voltage power , I.believe it’s the hall monitor sensor. Can I purchase at least 1. My address is Joseph DeHerrera, 3039 Renee ct,, Simi Valley , ca 93065 thank you my phone 805-813-6019

  • Edimilson: February 08, 2022

    I have purchased the CISON FG-VT9 engine.
    I found that cylinder number 2 is not firing. I checked the timing and found that it was not correct. I have set the timing gears according to your video instruction. It got better but still not firing properly (it fires sporadically). I observed that in slow-speed it works more consistently but still failing.
    Now to get the situation worse, the hall sensor is burned.
    How do I get a new hall sensor assembly (PCB board)?
    I leave in Brasil. Can I buy a new one from you?

    Looking forward to hearing from you soon.


  • Roger Andrist: December 30, 2021

    Can this Cison fg vt9 use a 7.4 volt lipo battery instead of a 7.2 lipo? Thanks.

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