Hotstart question

Who uses the thing? Should i use it? It starts fine with out using it. What do you think?

What does it do exactly?

Thanks

SD

Only use mine in a hot stall/crash. haven't had too many since I spent time with jetting but it does help a restart on a hot stall.

Bill

What does it do exactly?
It works almost exactly opposite the choke. Where the choke richens the mixture for cold starts by opening a fuel port to the carb, the hot start opens an air passage to the carb to lean it out.

I have found the need for the hot start changes with temperature and jetting. If I'm right on, or a little rich with the jetting, or if it's hot and getting hotter (meaning I should have leaner jetting) I'll need it for hot starts. If it's a little cooler and/or I'm jetted a little on the lean side I won't need it.

Perfect example: I have a jetting combo that I use between 75 and 95 degrees. I'll need the hot start at the higher temps and won't at lower temps.

Who uses the thing? Should i use it? It starts fine with out using it. What do you think?

What does it do exactly?

Thanks

SD

As I understand it, it opens/cracks open one of the intake valves allowing cooler air into the combustion chamber.

As I understand it, it opens/cracks open one of the intake valves allowing cooler air into the combustion chamber.
What? :applause: Who told you that?

How would a small plunger, entirely located within the carburetor, open an intake valve?

The only thing it does is, as mentioned earlier, is open a small air passage that allows additional air into the intake, and is almost exactly like opening the throttle 1-2mm. It reduces the amount of fuel output by the idle circuit, and adds air, making the idle leaner. There's no more to it than that.

Who uses the thing? Should i use it? It starts fine with out using it. What do you think?

What does it do exactly?

Thanks

SD

Wait until a hot day when, after riding a while, you dump the bike and go to restart it. After kicking six or seven times to no avail, try pulling the hotstart lever and kicking. Voila! It will start. Then you will see why it exists. Me, I switched to a GYTR push style, because it's ergonomically better and not prone to breakage. Pulling a lever while kicking is goofy.

It works almost exactly opposite the choke. Where the choke richens the mixture for cold starts by opening a fuel port to the carb, the hot start opens an air passage to the carb to lean it out.

I have found the need for the hot start changes with temperature and jetting. If I'm right on, or a little rich with the jetting, or if it's hot and getting hotter (meaning I should have leaner jetting) I'll need it for hot starts. If it's a little cooler and/or I'm jetted a little on the lean side I won't need it.

Perfect example: I have a jetting combo that I use between 75 and 95 degrees. I'll need the hot start at the higher temps and won't at lower temps.

this is how it really works...make sure when u do use it that it properly seats in after u release the lever...or else u'll be running a hot lean bike.....make sure to grease it...:applause:

If my bike doesnt start after two or three kicks when its warmed up, I use the hotstart and it usually fires right up. I went to the Dr. D hotstart lever because it mounts on the throttle side and you use your thumb to use it (push instead of pull). That way your not accidentally twisting the throttle while youre kicking. :applause: Plus it replaces the cheap plastic threaded stocker which loves to crossthread during install.

What? :lol: Who told you that?

How would a small plunger, entirely located within the carburetor, open an intake valve?

The only thing it does is, as mentioned earlier, is open a small air passage that allows additional air into the intake, and is almost exactly like opening the throttle 1-2mm. It reduces the amount of fuel output by the idle circuit, and adds air, making the idle leaner. There's no more to it than that.

Didn't the older models do it that way manually with the lever by the cylinder at the front right side? Your right about the plunger assembly though :applause: Guess I got it backwards?

Didn't the older models do it that way manually with the lever by the cylinder at the front right side? Your right about the plunger assembly though :applause: Guess I got it backwards?
You are confusing the function of the manual compression release, which lifted an exhaust valve to relieve compression, with the hot start, probably based only on the fact that the OEM lever is in the same place on the handlebars. The '02 and earlier models had exactly the same hot start, in principal, at least, located directly on the carb, next to the choke.

I have an '06 YZ450F with a decompression lever but no hot start. I am still kind of new and was wondering if a hot start would be a wise purchase. Please advise.

I have an '06 YZ450F with a decompression lever but no hot start. I am still kind of new and was wondering if a hot start would be a wise purchase. Please advise.
No, you do not. You have an '06 YZ4540F with automatic decompression, and a hot start lever located on top of the clutch lever perch.

You will find that the hot start will usually aid in a quick restart, as when you stall a hot engine, and especially if it gets partly flooded, as in a crash. If the engine has even 3-5 minutes to cool off, the need for the hot start is reduced considerably, and as was pointed out, changes in altitude and temp will affect it, since they affect jetting.

it leans out the fuel so it will in therory start easier once the bike starts u can take it off imediatly.

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