Does anybody still mess with carburetor tuning/jetting?

[mikkelstuff]

I quit rebuilding Holley 4-barrels years ago. They were cheaper to buy new than buying a tank of carb cleaner.

With the recent rebuild of my '75 Ranchero 460 and a move from Alabama to Colorado (with all the altitude variations), I upgraded to a Holley Sniper fuel injection system.

 

[sgtsandman]

I had to replace the primer bulb on mine. Hard to tell but it was cracked. Picked up a 3 pack on fleabay for a few bucks.

On my little stihl chainsaw the carb was bad...replaced the whole thing...I think it was $40 bucks for a brand new oem carb. The mower shop fixed that one.

I changed the bulb out of gut instinct and the fact that the local Stihl dealer tried to give me the wrong fuel line. It seems to have fixed the problem. I re-tuned the carburetor and will see tomorrow if it's truly fixed. I'll be two hours north. So, I'll be bringing some basic tools just in case.

 

[Eddo Rogue]

I changed the bulb out of gut instinct and the fact that the local Stihl dealer tried to give me the wrong fuel line. It seems to have fixed the problem. I re-tuned the carburetor and will see tomorrow if it's truly fixed. I'll be two hours north. So, I'll be bringing some basic tools just in case.

The bulb isn't always visibly cracked, but usually the culprit. Seems like the weak point of air getting in...

It took me two tries to get the right size bulb lol.

My fuel line is still good, but did get knocked out of place to where it it wasn't picking up below 1/2 tank...I fiddled it back into the bottom corner.

 

[bilbo]

are they 4 cycle engine in the snow machines? I ask because I know they have 2 cycles as well, just like bikes.

My MX machine is a 2 stroke smoker and is usually the best about firing up after sitting a while...Probably has big jets...

Ive had amazing luck w/ the lil inverter HF genie...Although I use it often, so it probably just has't sat long enough to gunk up yet.

They’re 2-strokes. Many of the newer ones are 4-strokes but mine are all fairly old.

I have a Polaris Ultra, which has a 680cc triple. It’s always been the one that’s most likely to misbehave. I swear it’s cursed; maybe the odds are just better with three carbs. Every year it screws with me somehow when I go to start it up for the season and I convince myself to sell it. Then I get it to run and hear that glorious noise only a 2-stroke triple makes and all is forgiven.

 

[rusty ol ranger]

Update:

I think one of my bike carbs is cursed. The seller threw it in a the original carb of the bike, which he modified to a bigger carb. Ended up needing it for another bike (same model) and for the life of me I cant get this thing to run.

I have thrown everything at this carb. Oem rebuild kit, messed with jettings, needles etc put it all back stock...Figured its the float and ordered a new one, making every part in the carb new. Bike still runs like crap. I'm starting to think something internal is busted idk....never had a problem like this before.

All the other carbs I cleaned half assed and they all work perfect lol.

Mikuni BSR36. I hate this carb.

You sure its the carb?

There are other things that make the piston pound ya know

 

[Eddo Rogue]

You sure its the carb?

There are other things that make the piston pound ya know

It was the carb. I swapped in the same model carb off my other bike and it works perfect.

Both carbs are same jetting etc...the bunk one is actually cleaner and rebuilt with new oem parts...its very baffling.

 

[rusty ol ranger]

It was the carb. I swapped in the same model carb off my other bike and it works perfect.

Both carbs are same jetting etc...the bunk one is actually cleaner and rebuilt with new oem parts...its very baffling.

Sometimes they just get plain worn out. Hows the fitting of the throttle shaft?

 

[19Walt93]

It was the carb. I swapped in the same model carb off my other bike and it works perfect.

Both carbs are same jetting etc...the bunk one is actually cleaner and rebuilt with new oem parts...its very baffling.

I don't know much about 2 stroke carbs but I assume they operate on the same principle as 4 strokes do. The first thing I'd do is poke at the air bleeds with a fine tag wire and blast them with carb cleaner before buying another one.

 

[Eddo Rogue]

Sometimes they just get plain worn out. Hows the fitting of the throttle shaft?

I don't know much about 2 stroke carbs but I assume they operate on the same principle as 4 strokes do. The first thing I'd do is poke at the air bleeds with a fine tag wire and blast them with carb cleaner before buying another one.

These are four stroke carbs. Two stroke carbs are easy lol.

I have extremely tiny jewelers drill bits to poke jets with.

I think I found the culprit...There is a stupid plastic baffle that sits over the main jet and hovers above the pilot jet....it looks pretty beat and fit very loose, so I have a feeling its floating around in there causing problems.

I wont buy another one, I already have 4 carbs for two bikes lol. Pretty much got em all working except this one. The identical twin of this one is installed and works fine, same setup. Its weird.

Im just trying to finish this one as well so I can have at it as a spare, or at least in sellable condition if I decide to part with it.

 

[Eddo Rogue]

Sometimes they just get plain worn out. Hows the fitting of the throttle shaft?

True...But thats more common on the Keihin carbs, this one is CV style Mikuni. The throttle is not mechanically connected, its got a rubber boot on top and vacuum operates it. If by throttle shaft you mean needle/slide assembly yes...slide is good and needle is whistle clean.

I may have found the problem....stupid plastic thingy in the float bowl...

 

[rusty ol ranger]

True...But thats more common on the Keihin carbs, this one is CV style Mikuni. The throttle is not mechanically connected, its got a rubber boot on top and vacuum operates it. If by throttle shaft you mean needle/slide assembly yes...slide is good and needle is whistle clean.

I may have found the problem....stupid plastic thingy in the float bowl...

My polaris has that style carb. Luckly ive never really had to mess with it besides idle speed adjustment