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Discussion Starter · #1 ·
I have a 78' murray montery with an 80 cc engine from ebay that I just finished putting together but it's not producing enough power like it's holding back some how. I have the throttle pin set at the last ending closest to dish for a rich mix any hints or advice to not be so slow would be apreciated.
 

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retromike3
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274 Posts
too rich ?

If your putting to much gas in you might be flooding it.

after you set it back to stock I would check the seal around the carb for leaks and then make sure the head bolts are on tight enough (12 pounds per inch)

Next check the gap in the spark plug (I think it was 024) Also check to see if you have a good spark(take out the spark plug put the wire back on, lay it on the head let out the clutch and give the pedal a spin, if you have spark then your OK there.

Finally what is your mixture? check the specks and see if you have too much oil in your gas.
Mike Frye the bike guy
 

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retromike3
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one more thing

is your carb being choked? usually up choke and down is off.

If your engine is choked you wont get enough power.

Mike the bike guy
 

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Well with these 2 strokes the whole crankcase should be considered as part of the induction system. And often if the bike is dropped and the crankcase hits the road it can cause induction system leaks.
I am not saying that is the problem just it can be a problem with 2 strokes.

As Mike suggests you may be running it too rich

Go for a ride on the bike and turn the gas off while you are running it down the road if the engine picks up and runs better before it runs the carb dry indicates it running rich:thumbsup:
 

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retromike3
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check the spark plug

Next thing to do would be to check the spark plug. If or when you take it off look at the front of the plug. it should be light tan color, if its black and suety its got to much gas. check the board I am sure that there are pictures of good and bad plugs.

Mike Frye the bike guy
 

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Discussion Starter · #6 ·
ok, let's say I'm running a 25 to 1 gas to oil ratio and I have the throttle clip set on the end of the pin for a rich mix would that deminish the performance or lack of power issue. :)
 

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hey Hack should go faster than that surely
the rear cylinder has a tendency to run hot on those and the studs that hold the head and barrel to the crankcase are inclined to stretch on the exhaust side of the rear cylinder and can blow the gasket
Im not a Harley fan but friends get addvice off me and Ive encountered 2 with blown rear head gaskets:thumbsup:
 

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Total noob (& forum admin)
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Craisin, the solution was to shift into 5th. I've downshifted to pass traffic and hit the rev-limiter a few times. It goes like this "WAAHHHHHHHHHHHHHHHHHHHHHH" to [silence].
 

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a stock Vincent set a record 148mph in the early 50s and the guy lay on the seat with his boots hanging over the back of the seat
Lawrence had a Brough Superior

Yeah Hack that Vincent count put you over the handle bars
 

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you'll need to put the needle clip back to the middle, these carbs run rich as it is. the 25-1 is ok for break in but after the first tank of gas i go to 32-1. the over long break in period recommended by the sellers is over kill, they break in prety fast. most of the kits the carb dosen't seat well onto the manifold, the slots on the carb for the clamp to squeeze it to the manifold are sometimes still exposed when the carb is all the way pushed onto the manifold, you may need to use an O ring or silicon to seal it. once you have it running ok it's still going to be rich, you can buy jets on line or solder the jet closed and redrill it smaller. jetting the carb is the trick to getting good power out of these. also after a few miles it will quiet down some and run better. if it seems to stutter and miss at wot it's still running way to rich. hope this helps.
 
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