1985 Honda ATC 110 Throttle Bog

[NorvNuthatch]

I have two trikes, both 1985 Honda ATC 110s. Both of them bog hard and stall out when I pin the throttle. I'm at a complete loss for how to fix this issue.

They start on first pull and idle fine. Carbs are both set at about 3.5 turns out, and the adjustment screws can be turned out completely with no changes to idle. Seems to be running rich (black plugs), but acts like it's starved for fuel. Will throttle up perfectly when the choke is on.

Here's everything I've tried:
-Carb - cleaned and rebuilt, checked float height, played around with jetting
-Air filter - installed new, checked, cleaned, tried running with it off (to no avail)
-Timing - retarded and advanced timing (for what it's worth, one is so far out of timing, I can't get F mark to line up with any adjustment
-Spark Plugs - replaced more than twice

I'm no small engine pro, but I am pretty handy. Any thoughts? I appreciate any suggestions.

[TrikeKid]

Can you throttle them up slowly? Do they only bog with fast throttle movement or all the time?

The farther you back the air screw out the leaner you're making it, run it back in to 1-1 1/2 out and retry.

[NorvNuthatch]

Yes they will throttle up slowly okay. After the RPMs are up, I can be more aggressive on the throttle, but from idle, fast movement on throttle will bog them out to a stall.

I believe the mixture screw is a fuel screw, as it's after the carb toward the engine.

[shortline10]

Are you running the factory air boxes or just pod filters ?
110s are very sensitive and need a complete factory air box to run correctly .

[NorvNuthatch]

Factory airboxes with Uni air filters.

[Footy]

I have a 1983 110 that was a barn find.
After I went through it and got it running it ran poorly and would not accept throttle input very well.
The solution that I found was to lower the slide needle. It runs much better now.

[shortline10]

Yeah Footy I was going to suggest the same thing , if your needing the choke on to accelerate then its wanting more fuel .
Try lowering the slide needle clip which will raise the needle and that will give it more fuel .

[NorvNuthatch]

That's what I suspected also, so I tried that. No luck. Still having black plugs, still not running well.

I have a suspicion that it may be a timing issue. Does that sound like a possibility?

[shortline10]

You mention they will throttle up fine with the choke on so it sounds carburetor related to me .
What brand carburetor kits ?
A lot of cheap kits will come with the wrong size jets and parts .
Best kit to use is shindy .

[NorvNuthatch]

Carbs are OEM with Shindy rebuild kits in both.

I was also thinking carb issue, but the fact that I have black plugs and can't make it run too rich with the adjustment screw makes it a real head scratcher...