changing parts before break-in

[Toby woodman]

I know I'm asking a lot of questions but,1st question. Having understood that with the correct tuning, having a more free flowing exhaust will keep it cooler, I ordered a banana pipe expansion chamber with no header, just the banana piece. I know these are not good for performance, but I want a more free flowing exhaust with out the big fitment problems of an mz65 clone. should I install this on the motor when its new, or should I install it after a few tanks of fuel, and then retune the carb to the new pipe.

secondly, on my other motors which were bought at the same time as each other so they could be from the same manufacturing batch. on anything but the most free flowing exhaust (stock exhaust with the cap taken off) the engine would always overheat, lose power, make grinding noises and then eventually seize. could this be a manufacturing issue, (Im thinking its unlikley because it didn't happen with a free flowing pipe) or is this just what happens with these motors. Bearing in mind that the seized motors happened on cold days after only about 5 or so minutes of running. building my third two stroke, I'm at a loss for how to make the motors last longer than a few hundred miles - if that with the first motor. any ideas on how to make these motors last longer? The engines were always jetted a bit rich for extra oil and fuel and I checked for air leaks with carb cleaner.

sorry for the long post, all help would be appreciated

 

[DAMIEN1307]

but I want a more free flowing exhaust with out the big fitment problems of an mz65 clone. should I install this on the motor when its new, or should I install it after a few tanks of fuel, and then retune the carb to the new pipe.

We always stress to run these little beasties in stock condition until breakin is over with...Then if you want to do modifications, do only one at a time to be sure each mod you make is one you can identify and retreat from if necessary before trying the next one, that way you at least know everything is running correctly before trying out any other mods you may have on your to-do list.

The engines were always jetted a bit rich for extra oil and fuel and I checked for air leaks with carb cleaner.

What were the mix ratio's you were using and how were you mixing it all together???

 

[Toby woodman]

i was using 25:1 with conventional oil and was mixing it half a litre at a time in a small chainsaw mixing bottle. I the motors I had just seemed to soft seize after only a few minutes. The only thing that helped stop the seizing was running a free flowing exhaust.

 

[DAMIEN1307]

i was using 25:1 with conventional oil and was mixing it half a litre at a time in a small chainsaw mixing bottle.

Please don't do it at only half a liter at a time...In the States we mix it a gallon at a time to insure a more uniform mix...In the UK you would want to buy a regular 4 liter petrol container and mix it that way being sure to vigorously shake the mix for uniformity everytime before filling the petrol tank......I do not know the quality of the petrol your using over there such as the octane rating, how much ethanol in the petrol if any, and the other thing is are you using a good quality 2 cycle conventional oil for breakin???...I am stressing the words oil for 2 cycle here, not regular car 4 cycle oil.

I always use quality conventional 2 cycle oil only during breakin and never use synthetics or synthetic blends until after breakin is over.

I don't know much else since I didn't build your motors, but when I build mine, provided there are no bad factory defects in them, I get many thousands of miles out of mine...I have one old Seeutec motor sitting on a shelf that I have 6000 miles on it over a 5 year span of time running it almost daily.

Not knowing the brand of motor or where you got it leaves me at a disadvantage to say much more on that, but for me, I run the best motors that are available to me here in the States, either the Zeda 80 or what I am running right now, the Phantom 85, with ceramic lined cylinders, (also made by Zeda), and both come with 6 month no hassle warranties that cover everything in the kit, they are not the cheap motors like folks buy on Ebay...With shipping and tax, my Phantom cost me $356.00 USD and many times, these motors reflect the old adage of getting what you pay for.

 

[DAMIEN1307]

Just for grins and giggles, what is elevation your elevation above sea level and in what groove have you been placing the C clip to raise or lower your needle valve using the pic below as that will tell me how rich or how lean you actually are at your altitude...You also have to have that carburetor at a correct angle with no more than a 10 degree tilt in either direction as that can also cause you untold problems regarding rich or lean, flooding or starving the motor.

 

[Toby woodman]

standard petrol which is equivalent to 89 united states octane. The oil I used was specific conventional, two stroke motorbike oil. I know mixing it in a larger container will be more accurate so I will try that in the future but I always made sure to be as accurate as possible. the engine came from amazon and was a 1 piece cylinder and head. the carb was almost perfectly level and I am at 750ft elevation. the carb was jetted to a 70 jet but the needle was one spot richer as I was mindful that two strokes get their oil from their fuel.