Just went on a beautiful 25 mile ride woohoo!

[Nahom]

K here is the pic of it:

the thing that's supposed to be white was black but I put my finger on it and wiped so now in the pic it looks more grey than black or white. The fact that I could wipe it off surely means it was fuel and not carbon (I believe any carbon deposit would need to be burned off?) and also the slimy shiny wet black on the tip so fuel fouling?

 

[Nahom]

Fit a new spark plug and the engine started stopped for 5 mins - took out plug and this was what happened to the new spark plug

Didn't wipe off anything. The bit that's supposed to be white is grey like carbon. I'm really confused now and I don't want to put the clip up unless I am sure it is a fuel problem- one the hassle, two might be in vain.
Also the front of the petrol engine- the side where the exhaust pipe is attached to is spitting out black stuff . Fuel, carbon? theres black stuff on all the fins on the front side.

 

[Nate888]

Fit a new spark plug and the engine started stopped for 5 mins - took out plug and this was what happened to the new spark plug View attachment 74865
Didn't wipe off anything. The bit that's supposed to be white is grey like carbon. I'm really confused now and I don't want to put the clip up unless I am sure it is a fuel problem- one the hassle, two might be in vain.
Also the front of the petrol engine- the side where the exhaust pipe is attached to is spitting out black stuff . Fuel, carbon? theres black stuff on all the fins on the front side.
View attachment 74866

maybe tighten or re gasket the exhaust pipe where it attaches to the engine, but that part's pretty normal. your exhaust isn't sealing perfectly so some exhaust gas is leaking out. even a perfectly set up two stroke will have in its exhaust stream some unburnt gasoline and half burned oil that condenses as a kinda greasy sludge - and you're still in the early stages of getting the kinks out, so a lot of times the mix is gonna be off and you'll have more unburnt residues. if you need to file the interface between the exhaust pipe and engine try to do more of the filing on the pipe itself while it's off but if you need to file on the engine side to make it flat and get a good fit be sure to at least stuff some oily Rags or something in there between where you're filing and the Piston so that you don't F your crap up with a lot of aluminum and iron filings getting in your cylinder

 

[Nate888]

take apart and study the carb, cuz that's where your problem likely is, and once you get good at disassembling and reassembling your carb - ie. you understand how it works and connect that with what you're seeing when you take it apart - you've mastered like 20% of your engine, which makes life with one of these bikes a lot easier

 

[Nahom]

maybe tighten or re gasket the exhaust pipe where it attaches to the engine, but that part's pretty normal. your exhaust isn't sealing perfectly so some exhaust gas is leaking out. even a perfectly set up two stroke will have in its exhaust stream some unburnt gasoline and half burned oil that condenses as a kinda greasy sludge - and you're still in the early stages of getting the kinks out, so a lot of times the mix is gonna be off and you'll have more unburnt residues. if you need to file the interface between the exhaust pipe and engine try to do more of the filing on the pipe itself while it's off but if you need to file on the engine side to make it flat and get a good fit be sure to at least stuff some oily Rags or something in there between where you're filing and the Piston so that you don't F your crap up with a lot of aluminum and iron filings getting in your cylinder

Cheers for this- And what about that spark plug diagnosis? Is it too much fuel?

 

[Nate888]

Cheers for this- And what about that spark plug diagnosis? Is it too much fuel?

I'm not hundred percent sure from that pic and I don't want to tell you to lean it out and be wrong because you could more easily do damage to the engine potentially by running it with inadequate fuel then killing it with too much fuel.

does it put out much smoke when you do get it to fire? that's a sign of rich on fuel

make sure about the choke too - maybe need it first few sec if it's cold, then it'll kill it usually. if it runs s**tty but putting choke then letting off makes it fast for a sec, that's probably air leak at or after the carb.

I hope less likely but possible: I had my choke escape from the lever assembly and it took me a day and a half to figure out why my bike had gone from about 3HP to admit 0.3HP - the choke was just floating there on full, no regard for choke lever position. so I fished it out and now my lever is decorative but useful still because I can use it to anchor nylons from the dollar store, wrapped around my intake as an economical air filter replacement. I have to do my choking by hand now - by covering the air intake with my palm

 

[gary55]

Nate sounds right. With the fuel left on, and the float needle not sealing raw fuel ran into the engine. That is why it's running crappy. Cleaning out the carb, and resetting the float should cure this. You can get info on float adjustment on Jag's site under tune up tips. I believe. there is also info on you tube for the carb..
The plug looks lean to me being gray. moving the clip up will make this worse. A chocolate or root beer brown is what you want. The lean condition may be helped some by getting the exhaust to seal better. The leak looks excessive for only 25 miles, and could be allowing air into the cylinder causing lean condition.
Step 1. Clean carb and set float level.
Step 2. Get exhaust to seal better.
Step 3. ride and see if plug color has changed. If still gray move clip down 1 notch, and repeat test.
I also noticed that the exhaust studs seem to be sticking out farther than most I've seen. Make sure they are ran all the way in, or you risk pulling the threads out of the cylinder. You can run them in by putting two nuts on the stud, and tightening them together. Snug is good don't over do it. Glad to hear you finally got to ride the damned thing.

 

[gary55]

I'll just add one more thing. You are now looking for a reliable means of transport for work. There is little you can do in mods. to increase reliability over stock. Performance mods. come at a price. I suggest waiting till you have your second build complete before going in the direction of performance mods. It will cut your stress levels in half.

 

[Nahom]

Nate sounds right. With the fuel left on, and the float needle not sealing raw fuel ran into the engine. That is why it's running crappy. Cleaning out the carb, and resetting the float should cure this. You can get info on float adjustment on Jag's site under tune up tips. I believe. there is also info on you tube for the carb..
The plug looks lean to me being gray. moving the clip up will make this worse. A chocolate or root beer brown is what you want. The lean condition may be helped some by getting the exhaust to seal better. The leak looks excessive for only 25 miles, and could be allowing air into the cylinder causing lean condition.
Step 1. Clean carb and set float level.
Step 2. Get exhaust to seal better.
Step 3. ride and see if plug color has changed. If still gray move clip down 1 notch, and repeat test.
I also noticed that the exhaust studs seem to be sticking out farther than most I've seen. Make sure they are ran all the way in, or you risk pulling the threads out of the cylinder. You can run them in by putting two nuts on the stud, and tightening them together. Snug is good don't over do it. Glad to hear you finally got to ride the damned thing.

It already is going wrong- I think the big sprocket is not screwed on properly at the back (the one opposite the casette) or I'm not putting the tensioner on properly. Everytime I use the bike on the roads heads are turning are this weird contraption and I feel so good- then the 415 chain comes off and sometimes the wrist pin comes loose and it just dangles uselessly- I'm left revving but not moving like a fool with clink clink clink behind me. When I spin the back wheel the sprocket turns but it kind of wobbles - when I put my finger to it and some points in the rotation its touching at other point it gets varyingly further away.
I never fitted that big sprocket which came with the kit- it was already there with the bike when I bought it- I did learn about and change absolutely everything else though- there isn't time to master all of the things I need for motorized bikes and become even a semi pro at troubleshooting and fixing them fast for a 5-6 hour grind daily- already so many problems.
Went to a bicycle shop today and they said the rear wheel was also misaligned by the same method of putting finger close to it. The bicycle transmission is all gone the pedals, the crank arm.
The tyres were totally bald- indeed everytime I start up that moment when I let go of clutch and the back wheel seizes hard before the vrooom of engine, there's always a dangerous skid. He suggested proper fat schwalbe marathon plus tyres.
The guy was alarmed at the thought of motorizing the bike with so many problems already and even more so when he realised there was not even a back brake- It's an 80cc engine and the bike not designed for that kind of power and acceleration even though same speeds can be reached by a good cyclist.
There front brake pads were worn out and given that's the only thing which is stopping the thing not a good idea. All in all the conclusion was it was a bit of death wish to continue using this on the road.

I seemed to have forgot that this was a motor BICYCLE. I took ages to reply today because I started working for Deliveroo today on my normal push bike. I will take the time to learn everything about push bikes and maintaining those (I will be forced to now I have to cycle 40-50 miles a day). I will use my already reliable road bike had that serviced cos I needed it fixed fast for work. I will slowly buy parts for the motorized bike and learn using youtube (also buy a bicycle tool box) and swap parts on motorized bike whilst learning to maintain push bike (can't experiment on the pushbike cos I need that for work).
I will also in the meantime learn about the carb because it seems to really be at the heart of the way the motor fuctions.
My gear puller (the one with the legs) and harmonic balance will arrive tomorrow- I will see how they fare with my pains to take out the clutch shaft and camshaft of the old engine. If not will use WD40 and try to get off using the idea of someone from this site.

 

[Nahom]

I'll just add one more thing. You are now looking for a reliable means of transport for work. There is little you can do in mods. to increase reliability over stock. Performance mods. come at a price. I suggest waiting till you have your second build complete before going in the direction of performance mods. It will cut your stress levels in half.

Very confused about your spark plug diagnosis- it was black (the bit that was supposed to be white) and so was the tip and there was fuel around the base- I was so sure it was too MUCH fuel- I was worried it might be something else like carbon fouling but lean certainly wasn't one of them- what made you say that?
2) ) If I take it to a motorbike mechanic and the fuel is already cleaned off- can they still be able to tell what kind of fouling it is? I totally trust your judgement but it could be the pic that might be bad and me wiping affecting and of course it's hard to say without seeing in person
3) Also if I run it for 5 mins and check and it looks fouled and not right colour- that's it? I have to throw it away because it's fouled?