My first attempt at a freshen up


New member
I am about to make my first attempt to freshen up a clone engine. I have built car engines before so I ain't Skeered !! I need to know what to look for as far a wear spots, clearances and assembly tips.

What should a useable cylinder bore measure at?
What clearance should the crank to rod measure at?
If my cylinder is within tolerance, what size and type of hone should I buy?
If my crank / rod clearance is tight what size and type of hone should I buy?
How do I know what rings to get?

Any suggestions on what to do other than rings, springs, and lapping the valves?

Thanks for any info.
My suggestion would be/is....'cut & try'! I don't think most good (competitive) engine builders are going to 'offer' too many answers to ur (?). Also, if you have too purchase a bunch of tools too re-build 'ur' motor/ would be far less expensive too have it done by a 'pro'....jmo
Im not looking to get top secret info. I am just wanting to freshen my engine on a budget.

So I will rephrase my questions.

How do I know if a cylinder is just to worn to use? What does a worn out cylinder measure?

How do I know if the rod or crank is to worn to use? How much clearance is too much?

I am not looking to be an engine builder, I just want to take this years engine and do what I can to freshen it up to make it a back up for next year. Saving all I can to buy a new motor.
You can either look in the owner Manuel.
Or goggle honda specs gx200
There you will find your min and max specs. And go from there.

Or try
Hit service tab, scroll down to bottom...gx200 service/owners Manuel download file...
put an old ring in the cylinder measure end gap divide by 3.14.
move down cylinder 3-4 places till you get to the bottom same way each time. difference top to bottom should not be over.002 max. .001 is best.
if you see any wear on crank its done.
replace rod. period.
new rings, new valves springs and retainers.
all gaskets
flattop1 what is the reason for dividing by 3.14. If you measure the ring gap at more than one place and subtract one from the other it will tell you taper and cylinder wall waviness but it will not indicate out of round. It is a simple method but not precise enough.

racer47 you said you have done car engine surprisingly the methods and tolerances are very similar. Yes I know there are many that build car engines by sight and feel but that is not how it is properly done. There are domestic cars that have rebuild tolerances closer than these race engines are being built to. If you can build a car engine, have and can use traditional measuring tools you can build an impressive clone engine. My cylinder spec taper and out of round is .0005" to .0000, crank journal taper and out of round .0000.
refines the measurement.
Did not see he had experience. In that case The op should know basic building skills and tolerance.
you are unlikey to find an engine that need a freshen up with the tolerance's you mentioned.
Glad your able to maintain those spec's
not every one has that ability or equipment to do so.
as to visual on crank I stand behind that statement egg or worn , even finish. at only 37.00 junk it
no I can not see .001 out of round, but Feel I can tell good from bad.
Let me clarify ... I "assembled" my own car race engines. I do not have a machine shop. I had machine work done with requested tolerances and put the pieces together. Must have done something right because I never had one to blow and turned them 6500 RPM. But I do not know what these clone motors need for tolerances or do not know if a cylinder is too worn to just hone and re-ring. That's the help I am asking for. Along with the rod to crank measurement.
rod to crank with plasti gauge .0025- .003
piston to wall .0015-.003 anymore an your the judge
unless you got a ton of laps with dirty air , cylinder seems to hold up pretty good
the ring trick will work to check bore
With true BSP engine kits from coming with max stroke crank and a high flow head selling for $155 there isn't any reason to freshen your old engine. Just tansfer your built carb (hopefully dover),exhaust, and top plate over and you are done.