Mechanical noise and oil leak query

[Robsalvv]

Hi folks.

I'm new to motorized biking and also new to two strokes. So apologies for the noob questions that might follow... I have spent the last 20 -30mins searching for answers to these questions but no real specific answers...

I've installed an 80cc 2T Grubee skyhawk to an old mountain bike and got it working. Yay! This is such a noob question and I feel silly for asking it but do all two strokes make that mechanical clanging noise??? I've had a listen to some youtube clips and it seems it's normal... I'm just used to 4T tuned engines where it's the exhaust pipe which is usually the loudest thing! If this is just a running in issue, I'll persevere.


The other question is, I've only taken the bike for a few small runs, but I note that an oily fluid is leaking from behind the clutch cover. Does this mean the drive gear shaft seal into the engine is compromised?? There are no obvious gaskets or bolts to do up in this area.

It's making a bit of a mess of the left crank and the left horizontal bike frame beside the chain.

Any advice would be appreciated.



I'll post up some pics as soon as I can organise them.

Thanks in advance

Rob

 

[Brains]

Hey Rob, no noob questions mate, firstly what they call 80cc aint really 80cc, its just the way some sellers market their product, they range from anything from god knows what to 69.3. I call a spade for a spade so its either 50cc or 70cc when I build my motors.

And yeah most of the noise your hearing is coming from the clutch housing area, sick bike parts sell a clutch cover which helps & they are sponsors of this forum as well, I have made a billet cover which is meatier in the wall and works a treat as well as looks flash.

I would like to be clear if the oily substance you are seeing is from the clutch lever side? let me know if it is, then I will explain my two bobs worth Rob

Cheers mate

Brains

 

[Robsalvv]

Thanks for the reply Brains. Interesting about the marketing side of these things isn't it. Call a spade a spade me thinks as well.

So all that mechanical noise is clutch noise? Holy crap. lol. Are these things little ducati's or somethin?! lol.

I searched a few noise threads before I posted up my OP and stumbled across some proposed clutch noise solutions, so I'll have a closer look at them. It's such a repetitive clang, I was sure it had to do with the piston slapping or something equally ominous.

And yes, the oily fluid dribbles out from the clutch lever side from beneath the drive gear/chain drive cover. I've taken it off and done a good clean. When I get a chance I'll go for a spin, come back remove the cover again and see whether I can find an oil trail.

Cheers and thanks again.

Rob

 

[brisbane_boy]

hey rob. u should always have the sprocket on the engine lubed up and also the clutch arm should have grease inside it.
When u say the nosie is a repedative clang that isnt clutch noise. to check if its the piston take ur spark plug out and see if the gap has been shortened!!.
other wise it might be the chain or sumthing on the bike just being hit.

wen u get some pics we will be able to know more.
Good luck and keep ridein.

 

[Robsalvv]

A pic or two:

Oil drips from the clutch cover near the bottom screw.


Some trouble shooting will follow

 

[Norman]

under the clutch arm cover is where there is going to be a little grease come flying out if its all lubed up good and if you oiled up the chain it will get really nasty until the excess oil if slung off.
When you park the bike your carb will seep oil out of the air filter and that can find its way to the bottom of the bike. The oil seeping out of the filter is just the nature of the beast sort of like a Harley marking its spot. The intake pulses will allow a little bit of the fuel mix to get on the filter and over a short time the gasoline will evaporate off leaving the oil to coalesce in the foam air filter and then it just jumps ship from the filter housing and TADA its on the bike.
When I clean the air filter(wash it in warm soapy water) I do not oil it cause after just a short ride its oiled by the bike gremlins.
If you are getting oil out of the mag cover then that is a main crank seal leaking and that is not good.
Your carb will also leak out of the fuel hose connections the fuel inlet brass nipple with the little red gasket will drive you nuts getting it to stop leaking and it very fragile and will break off easily so be gentle with it. And your float can be set a little high causing a seep along with the gasket that goes between the float chamber and the carb's base. so you see it going to get nasty one way or the other. Brake clean will fix it up pretty quick by cleaning off the poo as they say on dirty jobs. I see you have the carb with the float bowl drain there is one more place for fuel to seep from. Ain't it fun?!
Norman

 

[Robsalvv]

Thanks for the detailed reply Norman!

I haven't done the first tank of fuel yet but I note that the leakage rate has really dropped off, so it could have been a combination of clutch arm grease and chain oil as you suggested... just seemed too fluid though. Anyway, there's still a little oily fluid leaking, but it's hardly excessive, so could be from one of the fuel leakages you spoke of. I'll keep an eye out.

I'm convinced now that the noise is clutch/drive related. I had the clutch cover off and noticed when rocking the bike and forward a little, that the metallic noise was quiter (obviously, since no engine power) but clearer. Greasing up the drive gear and clutch wheel made no difference to the noise. (I couldn't believe those gears came unlubed!!! What the?!?!) I've seen a few more "you tube" vids that have exactly the same noise in them, so it's apparently normal... I might end up employing one of the clutch cover ideas I've seen in here.

I also checked the spark plug and it's fine - so it's not a piston smashing into the plug kinda noise.


By the way, I've lubed the chain with transmission fluid - anyone violently reacting to that idea?


Cheers all and thanks for the responses.

Rob

 

[Norman]

you might find that your rear brakes will take a hit from the tranny oil when it gets on the rim I run my chains pretty dry I use a special chain oil( spray on type that dries quickly) if any at all and try to keep the rear wheel/ rim cleaned off.
Have fun and be carefull
you have a nice looking bike!
Norman