Advice needed for challenging daily commuting.

SkyArc

New Member
Joined
Dec 21, 2019
Messages
11
Hi all,
Firstly thanks to the tons of posts I've spent the past 3 weeks reading up on China made 2 stroke motorized bikes.
That and watching hours of YouTube on the subject made me purchase one to use as a daily commuter. šŸ˜
I normally have to travel 2 hours using public transportation on a one way trip to work, before I was using my car it was 1 to 1 & 1/2 hours due to traffic. It's only a 26km (17mile) trip one way. The car was at the point where it would only make sense to repair if it had some serious sentimental value to it, so I sold it for dirt cheap and used that to buy a 2 stroke motorized bicycle pre-built.
Thanks to the above mentioned research I asked them to put on a performance head (basically a cnc head with large fins not sure if it indeed does increase compression) and a 52 tooth sprocket.
I did ask for a large frame bike but I have no space left on the mtb aliminium frame.

Basically its just like so many of the pictures here, China built 2 stoke with HT basic carb, the intake is that round black plastic one with 3 pipe type holes pointing down.

I use Castrol 2T fully synthetic oil in a red bottle. The most expensive I could find at the general hardware store.

I'm m in the break in period, 1 and bit tanks in. The first tank was at 16:1 ratio and the bike was ridden conservatively not exceeding 32kph (20mph) with varying the throttle and hitting a few hills where possible (while having to wot it to maintain speed and fear of not making it uphill) but not riding for longer that 15min at a time as per the manual.

Anyway one tank and one oil fouled plug (the standard LS.. Something thing) this was a huge blow as I happened to be at the bottom of a 2km hill that I needed to get back up to get to work...(big respect to cyclists after that)

I called the guys I bought it from they said it sound like the plug so I cleaned up the plug and added a 1lt fuel to the 1/2 tank that was at 16:1, it literally ran for 3 minutes before dying on me again. So after having done a ton of reading here I decided and the advice from the dealer to use NKG BP7HS plug, I couldn't find it anywhere near me but could get the BP6HS or the BP8HS being on the near the sea in a hot tropical area I decided to go for the BP8HS and she ran nicely.

Again taking what I've read here into account I open her up a bit today still varying the throttle but did WOT her here and there on the straights hoping that this would help the burn and set rings better. It was a 20 min run and she was quite smooth.

I noticed the black oil coming from the end of the exhaust was much thinner than before and seemed as if fuel was also passing out the exhaust as clean little cear clean rivers were noticeable within the black oil, (there is a slight leak from the top weld of the exhaust where the big part is weled on the pipe that leads to the cylinder housing. This I where I noticed what appears to be fuel passing out as well)

II did feel bad about the oil mixture being so low so I did a 25:1 mix on 1 lt of fuel and added this to the half tank. But found she was vibrating alot more and had a bit less responce on the throttle, less power up hill, less power on low revs and less top end.

Changing the plug is a nightmare, I have to lossen the chin tensioner and the engine mountings so I can tilt the motor sideways enough to get the spark out from under the frame. (motor is slanted in the frame as this is the only way it fits)

I'm really trying to avoid burning plugs as this won't be fun to change.
I've already had to replace the cheap screw on the chain tensioner and the Ubracket, the frame is rather fat and the original snapped right off when opening it as it was bent in a ohms simbol shape that weakened it. I've since added a extension bracket to the plate allowing for Ubracket not to bend.

One thing I'd like to know is how often could I expect to change the spark plug? I know this depends on a bunch of variables so let me state the here then hopefully you guys can give me advice on what oil ratio to use and cheap or cost free improvements to make.

I stay 147m (482ft) above sea level, taking laws into account I'll be driving back roads to work 31km (19mile) on a VERY mountain /hills terrain (some graidents of 35Ā°) my clime to work is 640m above sea level (2099ft) that's a 500m climb above sea level (hense the 52tooth sprocket)

I've currently only done 56km (34miles) on the bike according to the bike computer thing I got with the bike.

What advise can you guys give me?
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
4,231
Hi all,
Firstly thanks to the tons of posts I've spent the past 3 weeks reading up on China made 2 stroke motorized bikes.
That and watching hours of YouTube on the subject made me purchase one to use as a daily commuter. šŸ˜
I normally have to travel 2 hours using public transportation on a one way trip to work, before I was using my car it was 1 to 1 & 1/2 hours due to traffic. It's only a 26km (17mile) trip one way. The car was at the point where it would only make sense to repair if it had some serious sentimental value to it, so I sold it for dirt cheap and used that to buy a 2 stroke motorized bicycle pre-built.
Thanks to the above mentioned research I asked them to put on a performance head (basically a cnc head with large fins not sure if it indeed does increase compression) and a 52 tooth sprocket.
I did ask for a large frame bike but I have no space left on the mtb aliminium frame.

Basically its just like so many of the pictures here, China built 2 stoke with HT basic carb, the intake is that round black plastic one with 3 pipe type holes pointing down.

I use Castrol 2T fully synthetic oil in a red bottle. The most expensive I could find at the general hardware store.

I'm m in the break in period, 1 and bit tanks in. The first tank was at 16:1 ratio and the bike was ridden conservatively not exceeding 32kph (20mph) with varying the throttle and hitting a few hills where possible (while having to wot it to maintain speed and fear of not making it uphill) but not riding for longer that 15min at a time as per the manual.

Anyway one tank and one oil fouled plug (the standard LS.. Something thing) this was a huge blow as I happened to be at the bottom of a 2km hill that I needed to get back up to get to work...(big respect to cyclists after that)

I called the guys I bought it from they said it sound like the plug so I cleaned up the plug and added a 1lt fuel to the 1/2 tank that was at 16:1, it literally ran for 3 minutes before dying on me again. So after having done a ton of reading here I decided and the advice from the dealer to use NKG BP7HS plug, I couldn't find it anywhere near me but could get the BP6HS or the BP8HS being on the near the sea in a hot tropical area I decided to go for the BP8HS and she ran nicely.

Again taking what I've read here into account I open her up a bit today still varying the throttle but did WOT her here and there on the straights hoping that this would help the burn and set rings better. It was a 20 min run and she was quite smooth.

I noticed the black oil coming from the end of the exhaust was much thinner than before and seemed as if fuel was also passing out the exhaust as clean little cear clean rivers were noticeable within the black oil, (there is a slight leak from the top weld of the exhaust where the big part is weled on the pipe that leads to the cylinder housing. This I where I noticed what appears to be fuel passing out as well)

II did feel bad about the oil mixture being so low so I did a 25:1 mix on 1 lt of fuel and added this to the half tank. But found she was vibrating alot more and had a bit less responce on the throttle, less power up hill, less power on low revs and less top end.

Changing the plug is a nightmare, I have to lossen the chin tensioner and the engine mountings so I can tilt the motor sideways enough to get the spark out from under the frame. (motor is slanted in the frame as this is the only way it fits)

I'm really trying to avoid burning plugs as this won't be fun to change.
I've already had to replace the cheap screw on the chain tensioner and the Ubracket, the frame is rather fat and the original snapped right off when opening it as it was bent in a ohms simbol shape that weakened it. I've since added a extension bracket to the plate allowing for Ubracket not to bend.

One thing I'd like to know is how often could I expect to change the spark plug? I know this depends on a bunch of variables so let me state the here then hopefully you guys can give me advice on what oil ratio to use and cheap or cost free improvements to make.

I stay 147m (482ft) above sea level, taking laws into account I'll be driving back roads to work 31km (19mile) on a VERY mountain /hills terrain (some graidents of 35Ā°) my clime to work is 640m above sea level (2099ft) that's a 500m climb above sea level (hense the 52tooth sprocket)

I've currently only done 56km (34miles) on the bike according to the bike computer thing I got with the bike.

What advise can you guys give me?
It's normal to foul plugs during break in with that much oil in the mix,after break in and rejetting the carb the plug can last for years though I change mine out every other year just because I like max performance.Most will run the mix at 32:1 some a bit higher but 32:1 is safe all around,concentrate on getting it broke in and setup right running it's best before worrying about changing things then do one thing at a time so you have a solid base line for comparison and it's easy to revert back if issues arise.The most important thing is the initial setup being solid and reliable then the jetting for good throttle response and no four stroking at wot,after that asses your needs and go from there.
 

SkyArc

New Member
Joined
Dec 21, 2019
Messages
11
Thx, so I'm assuming the fuel I noticed in the exhaust residue could be from the 4 stroking happening while I was WOT...

Would adjusting the needle clip help make run better even with stock jet?
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
4,231
Thx, so I'm assuming the fuel I noticed in the exhaust residue could be from the 4 stroking happening while I was WOT...

Would adjusting the needle clip help make run better even with stock jet?
The needle adjust's between 1/4 and 3/4 throttle so you can improve throttle response in that range but wont help with the wot four stroking or overly rich idle.
 

SkyArc

New Member
Joined
Dec 21, 2019
Messages
11
Thx again, as for the idle I did adjust it in full (clockwise) then back 3 & 1/2 turns, it idled fine and smooth without any rattling on the diluted file, but once I added the 25:1 mix it couldn't hold the idle for long so I turned it in one full turn. It's a bit rough ldle at the moment but holds... I'm not sure if she just doesn't like a heavy oil mixture... Thr Castrol synthetic does say upto 50:1 but I'm trying to stay within the guidelines I read here in threads for low speed, heavy load, uphill climes, of 20 - 25:1

Tomorrow I'm going to use the remaining fuel in the tank to do a couple of 30min break in runs and try not to WOT as much.

Guess I'll also take another strip off to look at the plug. The engine is fine on the outside so far with no leaks and all the gaskets look good.

Do you think I can attempt the daily commute or should I run her in on another tank or 2 to make sure she's reliable first?
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
4,231
if you've done more than 6 heat cycles your break in is done,and tbh hard pulls up to wot are best suited to seating the rings with the most pressure and in it's ideal operating conditions not over oiled but anyway,again tbh the reliability is determined greatly on your ability to deal with the issues that will arise straight up!That said your off to a good start! These bikes can be a pita when you rely on it for transportation and you'll most likely encounter various things that happen over time along with the initial things that it sounds like you have a handle on,keep reading,ask question's when stumped you'll be good!
 

mark20

Well-Known Member
Joined
Sep 26, 2018
Messages
2,164
Thx again, as for the idle I did adjust it in full (clockwise) then back 3 & 1/2 turns, it idled fine and smooth without any rattling on the diluted file, but once I added the 25:1 mix it couldn't hold the idle for long so I turned it in one full turn. It's a bit rough ldle at the moment but holds... I'm not sure if she just doesn't like a heavy oil mixture... Thr Castrol synthetic does say upto 50:1 but I'm trying to stay within the guidelines I read here in threads for low speed, heavy load, uphill climes, of 20 - 25:1

Tomorrow I'm going to use the remaining fuel in the tank to do a couple of 30min break in runs and try not to WOT as much.

Guess I'll also take another strip off to look at the plug. The engine is fine on the outside so far with no leaks and all the gaskets look good.

Do you think I can attempt the daily commute or should I run her in on another tank or 2 to make sure she's reliable first?
personally, id run a endurance test first, see how far you and the bike can make it (be sure to have a buddy with a car encase things go south)
if it can do say 80 miles of hard riding, then its reliable enough to handle what your doing.
be sure to have a extra gas in the car because chances are that itll run out of gas before you manage to break something.
 

SkyArc

New Member
Joined
Dec 21, 2019
Messages
11
Thanks Street Ryderz & mark20.

I'll be riding it today as mush as possible for 20 - 30min runs at a time and try get through a tank or 2 of fuel. After that I'll try a 1h+ drive and see what happens. I'm sure I can experiment with fuel ratios more after that and look and getting the right type of jet for my needs.

Will be back to update, thanks again
 

Frogslayer

Well-Known Member
Joined
Jan 20, 2019
Messages
2,576
What happened when you switched your fuel mix to less oil is now there is actually more gas going through the jet causing your fuel to air ratio to be high. Once you jet down a few sizes it will smooth back out, be able to idle lower again, have considerably more and smoother power, and use maybe 1/2 the gas. Everything else attached to bicycle will last longer as well just by decreasing the vibration. Once you rejet it's like going from a 3 cylinder geo metro to a 4 cylinder Honda civic lol.
 

SkyArc

New Member
Joined
Dec 21, 2019
Messages
11
Thanks frogs layer,

I did a 30k run today, only stopped to tighten the chain. Everything ran fine, a bit of slower power and vibrations from a 25:1 oil ratio but over all nice, I let it cool down a few hours while getting some work done and decided to run through the last remaining fuel in the tank just around just going around the office park. Well only made it around once peddling while it idled warm, then she started doing the same thing as when I fouled the first plug.

I'll take it out tomorrow and check it and update my findings.
 
Top