My SIKK 2 stroke performance cruiser

Lowryder62

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Jul 4, 2019
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New to the science of it all concerning getting my used basket case cruiser going right. I bought this bike about a month ago on marketplace and the seller had it stored for some time, so I knew from being a motorcycle owner there are certain measures that must be taken (that he did not do), when mothballing a motor, especially these little guys,. The best I can gather is its about 5 or 6 years old but I looked the bike over and with the cruiser frame and upgrade performance parts (pirate cycles out of Mass. is the parts company), with lots of miles still on the tires and sprokets, good compression etc., I felt it was worth 180 bucks. In a nutshell, I have cleaned the tank, new fuel line, filter, a new Dolphin performance carburetor, spark plug. High test with a fuel ratio of 25:1 semi synthetic, since I felt the motor was broke in. Took the head off and all checked out clean, retorqued the head bolts at 12 ft lbs. It fires up easy without the choke but I cannot get it over 25 mph and slow throttle response, spark plug is black with powdery black carbon and slow acceleration. Thinking on ordering and replacing the magneto, spark plug and coil even though they look clean. Any help would be appreciated so I can start enjoying this rebuild.
Thanks (slowryder) Dan
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GreasyChris

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Jan 3, 2019
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Hello looks like it's running rich, you'll probably need to rejet your carb. Also I'd change that plug to an ngk b6hs. After that you should notice an improvement. Has the cylinder had any port work done?
 

Lowryder62

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Jul 4, 2019
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Hello looks like it's running rich, you'll probably need to rejet your carb. Also I'd change that plug to an ngk b6hs. After that you should notice an improvement. Has the cylinder had any port work done?
Thank you , not sure on the cylinder head porting, if it has been done this would require a bigger jet and backing out the fuel air screw atad at a time after warm up and riding a bit ? I just ordered a new High Performance CDI Ignition Coil + Magneto Coil + Spark Plug for 49cc-80cc 2-Stroke Engine Motorized Bicycle Bike
but I should order the jets and spark plug first right?
thnx.
 

GreasyChris

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The new cdi won't hurt anything and will tell you if the old one want working properly and if there no difference, well then you have a spare one. You'll definitely need to get some Jets for whatever carburator you're using. I have found these small engines very sensitive to the fuel mixture. We are having a bit of a heat wave the past few days and my bike runs noticably worse once it warms up when it's this hot out. At night when it's cooler out it runs great. Do you know what carb you're using? Jetting is dependant on your altitude and weather conditions so there is a specific setting. It's just dialing it in for your specific area.
 

Lowryder62

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Jul 4, 2019
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The new cdi won't hurt anything and will tell you if the old one want working properly and if there no difference, well then you have a spare one. You'll definitely need to get some Jets for whatever carburator you're using. I have found these small engines very sensitive to the fuel mixture. We are having a bit of a heat wave the past few days and my bike runs noticably worse once it warms up when it's this hot out. At night when it's cooler out it runs great. Do you know what carb you're using? Jetting is dependant on your altitude and weather conditions so there is a specific setting. It's just dialing it in for your specific area.
Decided to cancel the order for the cdi ignition pack and start off with the jets and the plug. I'm in central Florida, yes very warm here and not much above sea level hence no choke needed. Its a Dolphin high performance carb. suppose to be ready. What size jets should I start with? I seen a multi pack for about ten bucks.
dolphin1986 High Performance... https://www.amazon.com/dp/B071GY8G1S?ref=ppx_pop_mob_ap_share
Thanks again
 

GreasyChris

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Jan 3, 2019
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And yes I would recommend the ngk spark plugs. They are under$5 at any auto parts store. The noname Chinese plugs are hit and miss with reliability
Decided to cancel the order for the cdi ignition pack and start off with the jets and the plug. I'm in central Florida, yes very warm here and not much above sea level hence no choke needed. Its a Dolphin high performance carb. suppose to be ready. What size jets should I start with? I seen a multi pack for about ten bucks.
dolphin1986 High Performance... https://www.amazon.com/dp/B071GY8G1S?ref=ppx_pop_mob_ap_share
Thanks again
Do you know what size is in it now?
 

Lowryder62

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Jul 4, 2019
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And yes I would recommend the ngk spark plugs. They are under$5 at any auto parts store. The noname Chinese plugs are hit and miss with reliability
Do you know what size is in it now?
I will pull it apart this evening and check it after work. Thanks again.
 

gary55

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I will pull it apart this evening and check it after work. Thanks again.
Here's my 2 cents. Maybe 3.
That carb is a poor choice. It is most commonly known as a CNS carb and is notoriously known for running like crap. StreerRyderz use to use them successfully with high modifications, but even he has gone to something different. It is not high performance just high price with a lot of hype to make a sell.
You are right in thinking it's over 3 years old as around 3 years ago they started putting a gusset where the top and down tubes connect to the head tube.

One suggestion I would make to prolong the life of your frame is to split some tubing and place it between the down tube and front motor mount. Even better to use a muffler clamp at the mount along with the split tubing. These frames will break with the mount the way you have it. The reason I know this is I have build around 100 of these Sikk bikes and found early that this simple solution at the front mount made them last a long time (over 3 years) with no frame damage. without it it's almost guaranteed to break.
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