Rear friction engine: faults

[bilboby]

Also, it is more expensive, but synthetic oil will cut down on the smoke.

Took note of your advice & spent a few more euros extra for purchasing the Castrol Top 2T semi synthétique oil.

Attached is a photo showing three types of oil i have

The Carrefour brand is 2T normal non synthetic oil

Castrol 2T semi synthetic

Total 2T synthetique but is over 5yrs old & was kept outdoors in all weathers thus probably not good for MB use.


Cheers & 73's

 

[GearNut]

Also i've noticed after watching some youtube videos concerning rear friction drive engines that when the user pulls the starter cord the MB user's engine + drive roller turns even when placed on the back wheel. However the back wheel only turns when they start pulling the accelerateur handle but on my setup the back wheel turns when placing the drive housing onto the wheel regardless if i pull or not the gas handle. So something's still not correctly setup but what?

Cheers

Good find on your missing exhaust gasket!

As for the drive roller issue, Is something stuck or hung up in the centrifugal clutch?
If I am understanding you correctly, the drive roller on your set up is always driven by the engine at any engine speed, even at idle, as if you have no clutch.
There should be a automatic centrifugal clutch that disconnects the drive roller from the engine at low engine speeds, and connects the two at higher engine speeds. Some of these clutches have a slight drag to them and can cause the roller to turn when the engine is at idle and the roller is not in contact with the tire. In extreme conditions, such as when the springs in the clutch are weak or the clutch bell is misaligned, the engine is at idle, the drive roller is in contact with the tire, and the tire is lifted off of the ground, the tire will rotate.

 

[bilboby]

Good find on your missing exhaust gasket!

Thank's but if i'm being honest it was only by chance i found it missing after taking of the exhaust box for cleaning and wondered why the active 50cc engine had this gasket fitted but not the BGF.

As for the drive roller issue, Is something stuck or hung up in the centrifugal clutch?

Hmm now you've lost me as i'm not very machanical minded i wouldn't know where starting to look?

If I am understanding you correctly, the drive roller on your set up is always driven by the engine at any engine speed, even at idle, as if you have no clutch.

Exactly correct in your understanding.

There should be a automatic centrifugal clutch that disconnects the drive roller from the engine at low engine speeds, and connects the two at higher engine speeds. Some of these clutches have a slight drag to them and can cause the roller to turn when the engine is at idle and the roller is not in contact with the tire.

Again you've lost me but as you've explained the workings of such clutches i'll spend sometime googling for references you've given. I should point out that the Active motor is exactly the same method as you're describing but not for the BGF?

A neighbour friend impressed with what i'm trying to achieve MB wise this afternoon asked why not simply replace the new BGF motor for the working Active type thus i explained that because the BGF is new i need to run it in & hopefully during this period resolve/get rid of any future problems, if you follow my meaning?

Cheers & 73's


NB: Took the MB for a ride earlier & though still had some niggly problems they weren't anything that could not be repaired on site. Now waiting to see if the oil/fuel leak is resolved, touching wood so far all is okay but will only know more tomorrow morning after the bike has been standing idle. Keeping my fingers crossed.

 

[GearNut]

http://en.wikipedia.org/wiki/Centrifugal_clutch
The skinny on the clutch.

 

[bilboby]

http://en.wikipedia.org/wiki/Centrifugal_clutch
The skinny on the clutch.

Thank's for the URL link as having read it i understand now more about what your saying so now i'll be removing the engine for taking a good look at the clutch area. I'll post a photo of the BGF clutch on this thread along with that of the Active model showing any differences.

Once again cheers


NB: Just wondering if i can pick further your MB knowledge by asking if i'm correct in thinking that the photo i've posted show's 'C' as being the fuel/air adjustment screw? Thanks

 

[GearNut]

A= Idle speed adjusting screw.
B= High speed fuel mixture adjusting screw.
C= Low speed/ idle fuel mixture adjusting screw.

 

[bilboby]

A= Idle speed adjusting screw.
B= High speed fuel mixture adjusting screw.
C= Low speed/ idle fuel mixture adjusting screw.

Cheers a million for that as i can now once the clutch problem is resolved progress onto adjusting the fuel/air mix something i was unsure about doing before due to my lack of machanical experience.

Enjoy yer Sunday & 73's

 

[bilboby]

Hi,

Well having inspected the BGF clutch assembly it would seem i've found the reason for the drive roller turning without gear engaged? A spring inside the clutch are has snapped leaving only one end attached to a clutch plate thus i'm now assuming a major fault?

Also enclosed is the Active 50cc Clutch assembly which seems to be made of higher quality materials.

Cheers on your thought's for what i should do next including replacing the spring though such a spring might be hard to find here in France. Should i ditch the BGF motor as a bad job & install the Active, pity really as the BGF was going to be the main MB motor. Still my fault as now i realise that buying cheap chinese engines in the long run can be short lived and very expensive.


73's

 

[GearNut]

While it may not be an exact match for the BGF spring, I bet you could find a suitable replacement spring at a local lawn mower repair shop.
Drain all the gas out of the tank and bring the engine with you so as to make it easier to match up a proper length spring.
If one shop gets all snotty over helping you out, try a different shop.

 

[bilboby]

While it may not be an exact match for the BGF spring, I bet you could find a suitable replacement spring at a local lawn mower repair shop.
Drain all the gas out of the tank and bring the engine with you so as to make it easier to match up a proper length spring.
If one shop gets all snotty over helping you out, try a different shop.

Followed up your advice and visited seven shops who all told me the same reply "We don't stock the part" hence i'm now scouring the Internet in the hope of finding an identical spring. I'll let you know how i get on though i'm also going to try using a spring from another 50cc clutch assembly but chances are it won't fit?

Cheers & 73's for your help