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87 aero won't rev up.
Posted: Wed Feb 06, 2013 6:08 pm
by jax chaeles
So here is my dilemma,
I have an aero 50 with a custom 'arrow' exhaust, from day one it has been gutless. One day last year I was riding at full speed(35+) and about 5 mins in it started to cut out and slow down I had to hitch a ride home... Since then it has toped out at 12-15mph
How do i get it past this?
I cleaned carb, checked clutches without a load on and they operate just fine. I have tried swapping exhausts to the stock one with no change in power.
How can I make the thing a torque monster off the line? My brother has the same machine and it will pop a mean wheelie. Which is really what I'm going for. I don't care about top speed.
Maybe my bystarter is junk?
What else could it be?
Thanks for the help!
Jackson
Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 8:14 pm
by swflcarl
How does the belt look?
If it gets up to speed on the stand... without load -you may have lost compression? Get a tester and report.... needs to be greater than 120 psi.
If your Aero starts with ease... probably not the bystarter. Others can weigh in if they think if it is stuck open would your symptoms relate to an over rich condition. I dont think so.
Really think it may be compression.
Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 8:23 pm
by jax chaeles
I tried that last night and my compression tester came apart..
I successfully tested it a few months ago with another tester and got in the neighborhood of 90 psi.(if i remember correctly)
what's my best bet for a boost in compression? BBK or OEM parts?
Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 9:44 pm
by swflcarl
My aero is 124 psi.... and I havent had to rebuild any of my scoot jugs and pistons yet. You need a good read... under 110 psi have been told wont start.
Get a good tester... got mine from Advance for under 30. Opted for it over HF tester.
Remember to have good charge and crank with WOT till the pressure stops rising.
87 Aero you have options.... its your call and others can help you better than me. Treatland is a popular place for kits and pricing looks good.
Get a reading... and confirm.
You might be above to do a simple hone and new rings .... cheap.
Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 10:20 pm
by patthesoundguy
Does the engine go slower or does the engine speed stay constant while the speed of the scooter slows. That will tell you if belt or clutch are toast. I feel you have a worn cylinder that needs deglazing and possibly new rings as well. Get the compression tester on the go that will tell the tale. If it were me I'd be pulling the cylinder to inspect. I willing to bet when you pull it apart the cylinder will be super shiny like a mirror. When cylinders get like that there is no place for the oil to live so when the motor gets up to operating temps there is not a lot of lubrication and the compression drops as well.
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Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 10:46 pm
by jax chaeles
Engine sounds change relative to speed with no abnormal fluctuation...
Sounds like I need rings!
Supposing my compression is low.
Re: 87 aero won't rev up.
Posted: Wed Feb 06, 2013 10:56 pm
by patthesoundguy
Get yourself a brake cylinder hone and some rings and the gaskets and off you go. The deglazing the cylinder is the important part.
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Re: 87 aero won't rev up.
Posted: Sun Feb 10, 2013 2:48 pm
by jax chaeles
So I have concluded that I need to replace rings and hone the cyl. Am I best off
A: oversized piston & rings (either .25 or .50) ~ $100 + machining
B: replacing the rings (std bore) ~$40
C: getting a BBK ~$150 +??
Re: 87 aero won't rev up.
Posted: Sun Feb 10, 2013 10:55 pm
by patthesoundguy
I'd look at how much tuning you want to do. If you just want to restore the lost power and not have to mess with then I'd go rings and possibly a piston. Go out and spend the 8 or 10$ on the brake cylinder hone, hone it to the nice cross hatch see how the bore cleans up. Then clean up the piston or replace it, clean the groove and cross hatch the piston (if reusing old one) a little and give it new rings, bearing, pin and circlips. Assemble with new gaskets and break it in.
I'd replace the piston now that I look more closely at it. Looks like it was soft seized pretty good. Which was what probably caused your being stranded by sounds of it. I would make sure you check the intake system very carefully for air leaks and such. And make sure the screen is not blocked in the tank and fuel flows freely. Also make sure its getting oil properly. Sometimes adding too much oil to the fuel tank when using the oil pump can cause it to run lean if you don't up jet.
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