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2000 Honda CR80 Leaking oil out of silencer.

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Ok before i changed the jetting to pro circuits jetting specs. it was leaking a lot of oil out of the silencer. But now it doesnt leak much when i changed the jets to a 122 man jet(125 Stock Main) and a 55 pilot jet(62 pilot jet STOCK) and after i ride i notice i see gas leaking out of the carburator so i turned the gas lever half way not full on, and it worked but im afraid if i go down to a 52 pilot jet it will leak gas out of the carburator, even if the gas lever is half turned. So i was wondering if going from 32:1 mix ratio to 40:1 mix ratio would solve the problem. would there be a power difference if i stop using 32:1 mix ratio, and start using a 40:1 mix ratio?

 

 

 

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Your 'fixes' are going to create other problems,

running with the petcock half closed may starve the fuel to the carb to the point of running lean and seizing your engine when at high rpms.

 

-if fuel is leaking from the vents & overflow, that means the float is set too high, doesn't float anymore or,

there is an obstruction between the fuel inlet needle and seat (or they are worn out)

 

-stick with 32:1, going to 40:1 may require even more fine tuning of the jetting as:

less oil = more fuel = richer = cooler combustion temps = more un-burnt oil = more chance of fouling.

 

-that's an old engine, before you fine tune the jetting you must confirm everything is mechanically sound in the normal wear items:

good crank seals (no air or oil injestion), good fresh reeds that are less than 2 years old ('looks okay' isn't good enough),

fresh piston and ring in a still serviceable cylinder, silencer packing, fresh gasoline, cleaned and moderately oiled air filter, float level adjusted etc.

 

You can start with leaner pilot and needle settings and gradually richen those circuits for best performance

but keep the main jet stock for those wide open throttle moments. Recommended jetting specs are for all-out MX racing,

if you trail ride this bike or MX moderately, the Pro Circuit settings will most likely be too rich for you.

Edited by mlatour

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ok so basically i just need to get a new float becuase my silencer packing is brand new, and i got a new air filter its pre oiled, my reads are carbon dual stage pro series boyesen reeds, only been used for 1 month. And we bored the by 49.00mm with the oversize 2.00. Webored it 1 year ago. And I forgot to mention. im usually on the throttle a lot. Like 85 percent on the throttle and the rest not as much.

Edited by 2000HondaCR80

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Of course a new float, inlet needle and seat aren't a luxury in a 17 year old engine,

but making sure the parts you have now are clean and adjusted to specs is important.

 

2 things from your last post:

 

-originally that cylinder was Nikasil plated, when you 'bored' it did you install a sleeve or, have the cylinder re-sized & replated ?

 

-when increasing displacement, it's common to require leaner carburetor settings that stock, 

as the increased vacuum signal draws in more fuel mixture.  (quite common when increasing a YZ125 to 144cc)

 

-

Edited by mlatour

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Yes but it only affects the 0 to 1/4 throttle settings. You could be rich in other settings as well. Maybe drop the needle a clip as well.

 

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27 minutes ago, CRJohnny said:

Could be a number of things. Top end needs a rebuild
Reeds are worn
Jetting is too rich for the temperature
Right hand crank seal needs replacing

I have a brand new top end and con rod, my reeds are also new, my jetting is stock 125 and 50 and all engine seals are new, and could the air mixture screw also effect the temp of my bike

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You can also add :

- improperly set carburetor float/fuel level 

- riding too slow/easy, combustion temps too cool (it is an MX race bike after all, not a trail bike)

- using a high flash point 'racing' premix in a lower speed recreational usage

to things that may make the engine prone to spooging / foul.

 

As someone mentioned earlier, the air screw only fine tunes the pilot jet circuit,

compensating for ambiant temps and humidity changes,

simply explained, say going a 1/2 turn either way can be equivalent to changing the flow 

using the same #50 pilot jet to act like it was a #49 or #51.

 

Anything above idle speed is metered by the needle (say 1/4 to 3/4 throttle) and the main jet (3/4 to full throttle).

Edited by mlatour

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My jetting specs are stock at 125 main and 50 pilot and i turned the air screw out a few because, i heard if i turn it out the bike will run more lean than rich. it still runs but its leaks black oil out of the silencer and the pipe. Should i maybe go down to a 48 pilot or 45 pilot jet? or what could i do to stop this leakage. I am on the throttle a lot as i should be, the only time im not on full throttle, is when im entering a corner, but thats it.

Edited by 2000HondaCR80

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You've posted this question before and had suggestions, did you try checking anything?

Spooge isn't always a jetting issue, the engine has to be mechanically sound before fine tuning.

Edited by mlatour

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By sound I mean in good mechanical condition.

2-strokes are very simple with very few moving parts but some of them if worn can cause the engine to 'act' rich.

You can only start fine tuning the jetting once you've confirmed everything else in in spec.

 

-worn or damaged clutch side crank seal (gearbox oil injested into the crankcase)

-worn or damaged reeds (they are a wear item just like a piston, despite no visible damage they loose their tension with usage)

-too high fuel level in carburetor caused by a bad float, worn or dirty fuel inlet needle and seat.

-low compression, worn top end (installing a new piston in an out-of-spec cylinder doesn't help much)

 

Your other post (now merged into this one) suggests your top end, reeds and seals were replaced recently,

a crankcase leakdown test would rule out a least the RH crank seal.

 

- riding too slow/easy, combustion temps too cool (it is an MX race bike after all, not a trail bike)

- using a high flash point 'racing' premix in a lower speed recreational usage

are common to fouling and spooging problems.

Edited by mlatour

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Going too lean on the pilot jet is a recipe for disaster if you are the type to hold it wide open and max it out and then chop the throttle. The motor is still spinning fast but all on the pilot when you chop the throttle. I'd work my way down to a 42 before just tossing it in. You might need to change your needle....

 

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4 hours ago, seanmx57 said:

Going too lean on the pilot jet is a recipe for disaster if you are the type to hold it wide open and max it out and then chop the throttle. The motor is still spinning fast but all on the pilot when you chop the throttle. I'd work my way down to a 42 before just tossing it in. You might need to change your needle....

 

Ok i reset my air screw back to all the way in position and turned it out 2 1/4 turn out. Is that amount of turn out ok? or should i turn it in a bit more

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