Fouled Plugs, Chain Breaking

[bigkev81]

Hey guys,

A while ago I bought myself a motorized bicycle with an r80 engine kit installed.
Was purchased fully assembled and brand new from the shop.

Anyways, while running the motor in, I found that it constantly fouled up spark plugs which I changed 3 times in its short life. Also, the chain broke just as often.

On my last ride, the chain snapped, the bike bucked and I had a nasty crash in the middle of the street. Luckily it was a quiet cul de sac with no traffic at the time.

That was 3 years ago, and the bikes been sitting in my garage ever since. I've always meant to fix the bike up again, but have lost contact with the guy who used to re-do my chains for me.

I am wanting to have a go at fixing it myself. Can anyone out there shed some light on what may be going on with my bike? I haven't ridden it much, maybe gone through less than half the petrol tank.

Why do the spark plugs get fouled so often and why does the chain keep breaking?

Cheers
Kev

 

[crassius]

fouled plug is probably bad mixture in mixing oil & gas, or in carb being too rich - no biggie to sort out

chain breaking means something wrong with sprocket alignment or incorrectly tensioned

all info you need is here on the board

 

[bakaneko]

Yeah, and you need to clean and oil your chain periodically. It will extend the life of your chain and keep it from reaching that critical stretching and breaking point. I like to do it ever 200 miles. WD40 and toothbrush to clean and just regular oil to lube or if you can get actual motorcycle chain lube...

 

[bigkev81]

Thanks guys.

Now the fuel tank is almost full and has been sitting for a couple years. Should I drain the tank and start again? Or should it still be okay.

Also, I can't remember what ratio to mix the petrol and 2strokeoil. Any advice?

 

[bakaneko]

definitely drain the tank and safely discard the petrol. the ratio is 32:1.

 

[Steve Best]

Try good synthetic oil at 32:1 to keep from fouling.
Chain alignment is critical for chain life, as is a small amount of slack.
That said, cheap chain is garbage.
I am having good luck with Giant brand BMX (410 or 1/2"x1/8") bicycle chain. Light, cheap, strong.
Make sure all your (esp drive) sprockets are under 0.125" wide to use it.

Cleaning? I pull my chain off, slosh it in a coffee tin of lamp oil (kerosene) and hang it to dry.
Next day I lube it up with my favourite lube of the day. Have not found a perfect one yet.
Chainsaw chain oil, soaked the chain in it overnight in a coffee can. Very cheap, effective.
Beeswax, often from a toilet seal, heated up in a pot, often with additives like alox bullet lube or moly or graphite.
Soap, either heated and melted into the links, or a liquid soap like dish detergent soaked overnight.
Dry lubes like moly, teflon and graphite applied with a solvent and allowed to dry.
And of course, all the commercial preparations, sprayed or soaked, heated or cold.

All worked about the same.
Maybe the soap and dry lubes needed more frequent applications but worked better in sand.
None would make a cheap chain last longer and a good chain worked with them all.
When MX'ing with a non-"O"ring chain in sand and grit, it was practice to remove, clean and lube the chain every night.

This was all from 30 to 40 years ago. Since "O"ring chains came out I "ride and forget".
Might clean and lube it before a big run, but "O"ring chains are hard to remove.
This might be fertile area for study...

Steve

 

[WINDY CITY BOB]

It's possible that your sprocket teeth may need to be brought down a bit, if they are too big and pointy? They may Mr catching the edge of your chain.
I had a similar accident buy the chain just broken. Twisted, & wrapped aroundy rear sprocket. Hzf to pedal home . My problem was that the front engine mount was off by s FRACTION! Wich caused a clicking sound (IT WAS SLIGHTLY OF CENTER) so. I got a billet mount smd all was better.
Accept my soiled frui-o-da-looms that scared the s**t out of ME.
P.S. I USE a 415 chain.

 

[bigkev81]

Thank you for all the helpful info everyone.

I have ordered spare parts which should be delivered tomorrow. A 415 chain, and an air filter. My mate pulled the bottom cap off the filter 3 years ago and its been sitting like that so long, it will no longer close.

Both tyres were flat but luckily they reinflated with a bike pump.

As for the chain breaking, everytime it happens the chain seems to get stuck in the engine. If you look at the sample photo, the chain tends to get bunched up going around the top leftcorner.

And everytime the chain has broken, it has gotten stuck in the same manner.
I am thinking that maybe my chain has too much slack in it?

 

[WINDY CITY BOB]

That's kinda what happened to me with my chain except mine was rubbing it on the seat post motor mount so I took a grinder and took a little off this the motor mounts just the hair. However that didn't solve the problem it was my dad like I said off kilter just a little bit so I got a big mouth and straightened it out. Like I said the front engine mount was off by just a fraction which made the engine off to the one side just a little tiny bit and that's enough to make it cockeyed, and grab the teeth on the rear sprocket and get caught up. And snap good luck to you mate
WINDY CITY BOB

 

[WINDY CITY BOB]

P.S. I Also switch to an idle arm tensioner chain tensioner. It's a crescent-shaped piece of metal that goes Across the frame on the rear at the wheel to both bars