How to figure out engine trouble?

[Carl Walichnowski]

So my stock Skyhawk was getting the typical top speed of around 28-30 mph and that's with me being 255 lbs. So in an effort to increase top speed and over all performance I purchased a head and expansion chamber but now I'm getting around 20-25 mph. So later today I will be doing a compression test to see if there is any leaks but in addition to that what could I possible do to troubleshoot the issue?? I have a new NGK spark plug in and I did torque down the head properly..... trying to learn what to do next in case it's a bigger issue then an air leak. Thx

 

[crassius]

first thing to do is put old parts back to see if problem goes away - after that, change one part at a time to see what happens

 

[Carl Walichnowski]

first thing to do is put old parts back to see if problem goes away - after that, change one part at a time to see what happens

Good advice. A pain to do but good advice.

 

[Carl Walichnowski]

Good advice. A pain to do but good advice.

I'm going to change my jet from the stock #70 (?) to a #67 and also clean out my filter, I heard gas works well to clean the filters with, will that do the trick?

 

[Street Ryderz]

I'm going to change my jet from the stock #70 (?) to a #67 and also clean out my filter, I heard gas works well to clean the filters with, will that do the trick?

Yes gas works well! The jetting will be up to you to see what works best for your set up!

 

[Carl Walichnowski]

Ok since I had no choice but to reuse my old head gasket I'm thimking that may be causing a leak, I'll order new ones but until they arrive could I make my own from the gasket material in these pics?? And if so which one would you use?

 

[crassius]

if not damaged, I'd just flip it over so the head can get a fresh bite on other side

 

[Carl Walichnowski]

if not damaged, I'd just flip it over so the head can get a fresh bite on other side

And that's better then making my own? And what about gasket maker or sealer? Do you guys use that?

 

[Street Ryderz]

Ok since I had no choice but to reuse my old head gasket I'm thimking that may be causing a leak, I'll order new ones but until they arrive could I make my own from the gasket material in these pics?? And if so which one would you use?

I'm not sure about etheir one as the thickness is not given!Teflon tape works well rolled into a 2mm dia and laid around the cylinder top 2-3 mm out from bore dia!A peice of tin would work as will many things just make sure that it's not to thick about 1/2 a mm is good!

 

[Carl Walichnowski]

Here's a young grasshopper question. When a 2-stroke motor 4-strokes what does it sound like? Does it sound like a healthy 4-stroke motor? I was asked if my motor is 2-stroking & since I have no clue as to what that sounds like. I searched on YouTube and couldn't find anything, probably cause it's a dumb ass question.