Problem with my engine
- Thread starter Petter
- Start date
Okay so im back arter a while, i really didnt want to order a new kit, but after hours of trying to start it without success I had to. I arrived yesterday, and I finally swapped cdi, throttle and engine block. It took a while but I got it done l. I biked away and it started on the first attempt. It was amazing. However, I noticed I forgot to install the muffler, and it was super loud. I couldn’t keep it going as it was late and I was making a ton of sound. I tried the kill switch and it stopped right away. As I was installing the muffler I noticed the carburettor was leaking, as the previous one. I have now had three different carbs. Anyway I installed it quick so maybe just a spoon of gas got out of the carb and on to the block. I tried starting it with the muffler on, it was a lot weaker now. It could barely ever pull me up the slightest off hill without stopping. I had to kick to keep going. I was happy either way as my engine finally was running. After a 5 minutes long trip I went back home to let it rest as I have read you shouldn’t push these things too hard to start off with. I let it sit for 10 minutes before I couldn’t help myself but to go for another short ride. Then it happens again. It would not start. I tried 6 times and I just ran with no signs of ignition what so ever. The last two attempts it ignited like 5-6 times but not in a row, so it would not start. Any tips on what the issue could be? There is not a lot of fuel in the tank. I only had about 0,2 litres left of the last bottle. Here is a video of me right after I installed the muffler on the trip.
Here is a small picture of the current setup, and the small amount of gas in the fuel line.
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Happy to hear that you finally were able to have a ride on your bike. The power should not have been so dramatically reduced by the installation of the muffler. I suggest you check the exhaust system for blockages or restrictions.
The leaking carburetor could be caused by a sticky float valve which could be allowing excessive amounts of fuel to enter the carburetor.
I had that problem myself when my installation was new, but the condition righted itself after a while. I controlled it by shutting off the fuel valve and tapping on the carburetor body with a screwdriver handle. The problem may be complicated by a carburetor not sitting in a horizontal plane. I cant tell by the picture if this is the case with your installation or not.
As far as the engine not starting every time, tat could be caused by something like a loose wire or something simple like that.
Good on you for sticking with it until eventually success.
Did you have to buy a whole new engine or just a few parts to finally make it run, just curious to know what the root of the problem was.
Hi, today is the day I finally got it running for good. The problem was that the choke was on so it was starving for air. I adjusted it and it ran nicely. I ordered another version of the kit I had and simply swapped engine block, cdi, clutch and throttle. I also installed the new carb to the new throttle. For now it is running nicely, I want to thank you for the great help all through this. I wouldn’t be able to fix it without your help, thank you so much. If anything ever breaks down I know exactly where to go. Petter.
You are very welcome. It is my new hobby and I love it when I can help a fellow motorized bicyclist. Some day you should get a better bike for your next build, just a thought.
Update, bike has broken down. It didn’t even last the first day. I am devastated. I was riding on this road and suddenly I just hear a loud sound from the wheel, the chain tensioner got caught in the wheel. The chain snapped and the wheel lost some of the metal bars. All this hard work for nothing, I don’t know what to do anymore. I even screwed on a wooden pillar for the tank.
picture before the trip and after:
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Sorry I should have mentioned it before that those type of chain tensioners are a menace. That is what they do; move into the wheel and get caught in the spokes. I found that out very early when I noticed it was becoming loose. I even drilled an extra hole through the bracket into the bike frame and put a small bolt to lock it from rotating. Eventually I gave up on that type of tensioner and mounted one that attaches to the engine and that has been working fine so far.
You are lucky that the chain broke; it could have been much worse and taken out the spokes, but they appear to be ok in your after picture of the wheel. Those bars only mount the parcel carrier and you do not need that any more.
You learned a valuable lesson today and that is to constantly check your bike before every ride for loose and damaged parts.
The chain can be repaired with a chain breaker tool and a new link.
Petter... don't lose hope. Dumb as this sounds, you were lucky! Two of the "MUST REPLACE OR IMPROVE" items are the chain tension roller and the sprocket mount.
I know I'm late to The Game on your starting problem, but one of the perplexing issues with my engine was a leaky head casting. I had spark, fuel/air/oil and LOTS of pedaling, and it would sputter/half-run, barely with enough power to move the bike along at jogging speed. Once I ordered a new stock head, BAM! Worked like a champ.
HANG IN THERE!
I know I'm late to The Game on your starting problem, but one of the perplexing issues with my engine was a leaky head casting. I had spark, fuel/air/oil and LOTS of pedaling, and it would sputter/half-run, barely with enough power to move the bike along at jogging speed. Once I ordered a new stock head, BAM! Worked like a champ.
HANG IN THERE!
Thank you guys for your tips, i refuse to give up. I am getting the spokes fixed, I have ordered a different chain tensioner and I have ordered a new chain. I appreciate your advice and motivation to keep the project going. Here is the type of tensioner I bought, this doesn’t allow the tensioner or chain to come in contact with the wheel. Do you recommend getting any other upgrades? I am sick if the stuff breaking.
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I personally have no experience with that type of tensioner but I have seen them around. I noticed from pictures of your bike that the chain seems to be too long to my liking. I like to make it as short as possible and limiting the possibility of it jumping off the sprocket.
This is the type of tensioner that I have on my bike.
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I’m getting a new wheel, just thought I’d les you guys know. I have another question, I have a different carburettor and a different spark plug thank the stock ones, do you recommend swapping or having it the way it currently is? Here are the carb and spark plug:
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The plug is a definite, if it runs good with the stock carb it will be best to get some miles on it first.
Just got the new sprocket on to the wheel, don’t think I can get it much better than this. Now I just gotta wait for the chain tensioner. Does it look okay?
Today I got the bike going again. I mounted the new chain tensioner and it worked well, the chain is now very good, it runs in almost a perfect line and is fairly paralleled in each direction. The slack is about 2 cm. at first I rode it for 10 minutes, it started running like crap, it only fired every second/third rotation. I looked down at the exhaust and it was completely black. There was a lot of oil all over the place. I took it back to the garage, took off the muffler and it was full of oil. I cleaned everything and remounted it. The fuel mixture consisted of way too much oil, maybe 10%. My friend suggested to use a lot of two stroke oil as the engine was brand new so it the piston could penetrate the head or the friction could cause the cylinder to become uneven if not lubricated enough, he also said it was a Chinese engine so they often need more lubrication. I drained the carb and filled up the tank with more petrol/gas to see if the case was too much oil as it was literally spitting out black gas/liquid all over the exhaust and pedals. I made sure to even out the mixture with petrol/gas, and it ran a lot better instantly.
The gasket unfortunately ripped when I was remounting the exhaust so it’s currently pretty loud. Therefore I can’t really ride it around as it’s pretty disturbing and also illegal where I live. There is however a dirt bike track like 200 meters from where I live but I don’t think this bike has the power or suspension for that. It is fun to build and adjust though, and I can always run it around the neighbourhood every once in a while.
the speedometer worked fine, but at 33km/h it started vibrating a lot and seemed to hit some kind of rev limiter. This is fine to me, I’m just happy it’s running fine. Thanks for your support and tips.
The gasket unfortunately ripped when I was remounting the exhaust so it’s currently pretty loud. Therefore I can’t really ride it around as it’s pretty disturbing and also illegal where I live. There is however a dirt bike track like 200 meters from where I live but I don’t think this bike has the power or suspension for that. It is fun to build and adjust though, and I can always run it around the neighbourhood every once in a while.
the speedometer worked fine, but at 33km/h it started vibrating a lot and seemed to hit some kind of rev limiter. This is fine to me, I’m just happy it’s running fine. Thanks for your support and tips.
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For running in 20-to one is a good petrol to oil mixture. and after a few hours of running it can be safely increased. I am currently running the same engine at 40-50 to 1 because I don't want the engine to smoke.
I think 30 km per hour is plenty fast for a bicycle so you should be happy with that. Remember to check for things coming loose and torqueing down the head bolts, but be carful because they can be easily broken with over torqueing.
Good luck and enjoy the rides.
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Thanks for the tip, I am happy with 30 km/h but I have seen other bikes go faster so I was just wondering if there was something wrong.