Okay I blew my top end and was going to wait and bore it out but a buddy had a high compression namura piston left over from a double order he placed. So I used it is there something I'm missing with this high compression piston? Won't start kind of sputters when I kick it and backfires about every 9-10 kicks. it's still on a stock bore stock carb with stock jets please help and thank you in advance
New top end need help
- Thread starter Newtoblastys
- Start date
Two strokes are not like 4pokes, they do not use high compression pistons. Compression value is determined by combustion chamber volume. Calling it Hi-comp is marketing ploy. 8-|
With that said on to your problem.
Is your cylinder to piston clearance in spec? Out of round/taper? Did you set ring gap? Rings right side up? Piston facing correct way? Carb clean with correct settings? Good blue spark? New plug? Leaktested engine? Flywheel tight? Keyway good? No rust on stator poles or inside flywheel? All electrical connections clean and tight? Clean bare ground at coil mount? Ohmed stator and pick-up coil?
With that said on to your problem.
Is your cylinder to piston clearance in spec? Out of round/taper? Did you set ring gap? Rings right side up? Piston facing correct way? Carb clean with correct settings? Good blue spark? New plug? Leaktested engine? Flywheel tight? Keyway good? No rust on stator poles or inside flywheel? All electrical connections clean and tight? Clean bare ground at coil mount? Ohmed stator and pick-up coil?
I just got it all put in yesterday rings are gapped and piston is facing the right way. Cleaned the carb out. Was going to check the spark today but I've been rained out seeing I don't have a indoor workplace. New plug tomorrow for a start I wonder if its the jetting but idk how to check it without it running
It would help to know what happened when it blew and why you think it did.
Did you leak test it yet?
When it went out nothing catostophic just the rings wore out to the point of to much blow by to run
Is the plug fouled?
Is the float level correct?
Have you flooded it?
What were the results of the leak test?
What did the piston to cylinder clearance measure? It should no more than 0.040mm.
Was the bore round and within specs? No more than 66.02mm, and taper no more than 0.08mm.
Was the bore honed or did you just drop a piston in there?
What is the compression reading.
" was going to wait and bore it out but " did you just put a new piston and rings in the old cylinder?
Plug is good floats are right bore is good I honed it its still round and and in good shape I was going to bore out for performance reasons only
What pressure did the leak test hold and for how long.
Can you quote some figures of your measurements, I assume you used a bore gauge to measure the cylinder.
I had friend with me when we measured the bore in his shop used bore gauge and calipers but I don't have the paper we wrote the numbers and did the math on but the bore is good. Believe me we measured twice and did the math 4 times. The bore was my main concern but it's all good just dosent run
I apologise for keeping on harping, but what were the results of the compression and leak test, it would really help to know so as to diagnose.
This seems like a flooding issue, have you tried a new correctly gapped plug yet?
This seems like a flooding issue, have you tried a new correctly gapped plug yet?
try another plug, they can foul instantly, and "fouled" cannot be visually seen, it is when oil gets up inside between the porcelien and electrode.
check the reeds for cracks, chips, broken petals
over boring adds no performance besides what restored compression adds
I don't have the equipment to leaks own or compression test. I canto afford to get them at this time Obama's part time plan of no more than 29 hours a week is killing me lol.
Hmmmm, might need to keep working on those diagnosis skills.
Listen to these guys, they know their stuff. Borrow the tools or make them.
It is all about priorities.
Like forget about blaming some guy in the paper, and look in the mirror.
There are guys from poor families, your same age, getting rich, right now. How?
Get educated, get busy, accomplish something.
It will work for fixing your Blaster too.
Steve
Dude I want help not rudeness ok? I'm poor yeah I make due with what I have I can't help it the papers gone. I can't help it I can't afford the tools tuition is expensive. 18 years old and 2 grand in debt thanks to education. Look man no need to be a prick I'm trying
im 17 with no job, I don't have a cent to my name, I give the guy at the gas station like 200 pennies just to get a half of gallon gas to get to school, I don't have money either but im sure there is some way you could get the money to build your own tester
I have to put atlesst 600 down on my tuition before August 1 so that's were all my pennies are going only reason I got to fix the fourwheeler is beacuse I was givin a piston
it will be like 25ish to build a leaktester, and try to borrow a comp tester from autozone, what state u in?
