Hello, trying to get there, Newcastle NSW

[murphyzpug]

Hey recently got my 66cc kit about 8 weeks ago off ebay for $118, so i think i've done rather well. so far i've got 1800kms on my bike and loving it. i will say that you do get what you pay for though. i've had a few problems, but nothing too major just yet. first problem was the fuel filter that was connected to the fuel tap clogged up with rust from the fuel tank (rust in the tank from new). secondly i fitted a o-ring to the carby intake, then somehow the bolt clamping the carby to the intake stripped itself, so i was stuck with a carby which was slidding everywhere and couldn't go anywhere. i've picked up a couple of bikes of the side of the road with the council cleanups and stripped certain parts off them, wheels, tyres etc. so got pretty much everything i need. i did get one puncture so i now carry a spare tube. also built a heavy duty rear carrier and fitted front suspension, front disc brake and gel handgrips. although today i still had numb fingers after about 25kms. i have a 50 tooth rear sprocket atm, which tops out at 62kmph (37mph) but i have some very steep hills around my area, so i was actually considering trying to get a 60 tooth if possible. i have a problem with what i presume is 4-stroking. it only seems to happen when the motor is under next to no load. if i cruise along at 24kmph, it seems to constantly "sudden" surge but if i open it up to about 33kmph it is soooo smooth. which is another reason why i'd like a higher reving rear sprocket. by the way legally i can only do 25kmph which i tend to stick too. anyhow happy riding everyone ...

 

[Dave31]

Welcome to the forum murphyzpug, glad you joined us.

 

[thegnu]

4 stroking ,so the engine surges ? I have never heard of such a thing could the clutch be slipping? an contributing or causing that ?
Gary

 

[ratrod]

welcome bruther from another muther

that reving sounds like you have air leak in your carb set up maybe.

any pics of your machine.....

 

[murphyzpug]

Ok i've had the surging since new, which is why i fitted a o-ring at the end of the intake, i also put another small o-ring even on the accelerator cable, and i can't seem to find any air leaks, the clutch is perfect and grips very well. i've even swapped over the ignition lead to something a little higher quality plus went to a NGK B5HS and leaned out the motor by putting the circlip on the highest setting (only have 4 notches, was already 3 up). but otherwise than this little problem i'm throughly enjoying myself. i am trained as a marine engineer so i am familular with small two strokes (outboards) although i mainly work on larger diesels, but these little chinese things have me shaking my head......lol....they are so simple and roughly made but awesome fun and the bike has already paid for itself in fuel savings. i will post some pictures up soon.

 

[murphyzpug]

Finally got around to taking a few pics of my build..... The rear rack is new and can easily carry another 100kg onboard.....found that out the other day when leaving the pub with my brother.....have fun people

 

[SAVED1]

Welcome to the MB forum. the ride looks nice.

 

[murphyzpug]

Just to update everyone. i worked out that one of the baffles in my muffler was loose and was blocking the exhaust at some stages. anyhow fixed up my exhaust, jumped on my bike then bang, it would kinda run but no idle. by this stage i had the major ****s and quickly ripped the head off. i found my head was majorly pitted and so was the top of the piston. long story short i've pulled her all apart, has picked up a port and ground the f**k out of the motor. my pics arn't that detailed, but will give you a little idea, especially when you look at the intake port (no longer rectangle). Just need to get a full replacement motor now. although i did get 2200kms (1400miles) so the money i saved on fuel will be going on a new motor. not happy i expected more......although i did have alot of fun whilst it was running.....

 

[MEASURE TWICE]

Yikes, I guess the plugged muffler might be what if from the engines dismanteling itself.

I had taken old Briggs lawn mower engines and they needed carbon removed and the valve and seat angles recut, but no missing metal other than cylinder wear. That wear didn't even need new rings.

The scrape on the side of the piston I'd say it would be lossing a lot of pressure.

Having fun riding though is what it is all about, get it running again soon

Measure Twice

 

[murphyzpug]

yeah i'm guessing that the blocked muffler was stopping my motor from breathing properly, which caused a hot spot, and it caught one of the intake ports. it made a interesting sound too.......lol. the bottom end seems solid enough, but i think i'll just keep it for spares and good experience too pull apart. anyhow hope to be going soon.....

 

[murphyzpug]

and although there are 3 major grooves down the side of the piston and the top ring is in about 5 pieces, kinda melted into the groove, it still has surprisingly good compression, and it still ran, just down on power and would not idle at all.......still can't get over this little **** of a thing.......lol....

 

[CTripps]

The second time I lost (and found) the end cap off my muffler, the baffles came out with it. Crappy tack welds when made. I still have them on a shelf somewhere. The bike's a little louder without them, but runs fine for me.

 

[MEASURE TWICE]

Murphyspug, thanks for the explanation of what probably happened in detail.

Yes I too had a muffler that I was using after it being stored for quite a while.
The last time it was run with that muffler it probably had a bit of carbon build up left in it.

I had started the engine and was running it. I saw the muffler glow red and didn’t really think too much to be worried, because eventually within a few minutes it was back to normal and had not happened since.

I have a new muffler anyway, for the State requires the OHV to have spark arrestor type mufflers and my bike no longer has pedals it is for off roading when it is completed.
Later I took a video of it while messing with the throttle and while it was dropping from high rpm to idle the video captures a blue pointed flame out the muffler with a backfire!

I guess the spark arrestor muffler stops the flame from getting out the back for good reason. I have not tried it yet as I am just finishing other parts of the build and hope to have it running and with an OHV Sticker before New Years.

Measure Twice

 

[murphyzpug]

i've ordered a new motor from a local dealer, so hopefully i'll be back up and running soon. i'm still annoyed as i was expecting at least 3000miles out of my old motor and only got 1400. i'm also in the process of making my own muffler and airbox so i can try and quieten the motor down to a whisper.....lol(if even possible). anyhow have fun people. btw does anyone else have problems with keeping their brakes working? i have put a disc on my front end and still have the stock v-brakes, but my bike weighs 36kgs(80 pounds) and i weigh 90kgs (200pounds), and the other day while going down a huge hill riding the brakes the whole way, they started squealing and not working very well, i realise some fade will happen, but where i live it is very hilly so don't have much of a choice, plus legally i'm meant to stay under 25kmph. Cheers....