cold air better??

hi all, i was just wondering if the cold air will sometimes make peds run better? my puch was running raped ape today. it seemed like it just wanted to keep going faster today, more so then in the warmer weather. anybody know what i mean? hope i didnt sound confusing......... thanks

Re: cold air better??

I agree with you.

Two reasons

Yes.. they do run better and make more HP... this is the time of the year when dirtbike riders come back from a ride and say.... "man.. my bike was just running SOOO crisp in this cool air!"

Cooler air is more dense... so it is like you have a 60cc engine... because there are more air molecules in a given volume at lower temps.

But another reason.. is that the carburetor sends fuel to go with the air... but now that there is more air... it is now leaner... so it is now running the way it always would if you jetted it correctly for the weather all the time... (in other words they are really a little too rich for max HP in hot weather).

Modern fuel injected vehicles with little computer sensors and controllers all over the place don't do this so much... because the computer takes into account the air temp (and other things) all year long... and is adjusting the air/fuel all the time.

Re: cold air better??

thanks fred!!!!!!!!!

Re: Two reasons

You ever been to the drag races where they Ice down the fuel? It burns really great..... Doug D.

I wish

My ped runs like shit in the cold. Constantly dies -_-. Yet if its warm out, it runs fine.

Then its screwed up... nm


Re: Then its screwed up... nm

my bianchi runs like a demon in the cold. wow! i'm talking passing cars on the i-94 business loop fast.

Re: Then its screwed up... nm

Wow my Moto Guzzi definitely sucks in the cold air - I can only hit 25 if the airbox is on, as if it isn't getting enough air. But when it's off, it runs a round 35. In the summer I can get 40 or so though with the airbox on. Hmmm......

Well,Motoman........ probably need to either clean your air filter or check for clogged exhaust.If that's not it,increase your air flow by opening up your air box(remove inserts or drill a coupla' 3/8 air holes).Then do a plug chop on a good spark plug to make sure you're not running too lean.

Re: I wish

It might be that you have an air leak that isn't showing up in the warm air or isn't too much of a leak when the air is warmer. A leak after the carb will show up a little better when the air is cold. Also check the gasket around your manifold to see if it might leak a little when it is cold. It could be running way way lean.

Can you tell a differance during the mid part of the day when it is a little warmer?


manifold gasket

woa! i just discovered that i don't have a manifold gasket at all. my carb actually popped off my bike as i was riding. any suggestions on materia to use? i was thinking of just riding out to a hardware store and getting some thin sheet metal for a shim.

Re: manifold gasket

As a `stop-gap' measure you could wind teflon tape around the intake pipe,and press the carb over that and tighten it.But you really need to get the proper gasket for it.

Re: manifold gasket

yeah .. i have no idea where i lost that. somewhere along the line when i changed to a bigger carb. doh!

Re: manifold gasket

Make sure you stop that excess air Miguel,`cause it can burn your piston or cylinder if it's aluminum.Just do the teflon thing and tighten it,and then drip some carb cleaner (I like to drip it on the connection so it doesn't get sucked in the airbox)on the connection and see if you have a noticeable change in rpm.If you do,you still have an air leak,so back to the teflon tape you go.Still,get the right gasket soon.

Re: manifold gasket

Ron Brown /


Metal is not a good gasket material except for cylinder heads sometimes.

If this is the carb to manifold gasket and it is a slip on cylindrical fitting, try to find an o-ring of the correct diameter to match the outer diameter of the inner part and the inner diameter of the outer part, this should squish as you install the carb.

If you are repacing a flat gasket beween two flat surfaces, buy intake manifold gasket material at an auto parts store. If you are carefull making it, this will be as good as the original.


Re: manifold gasket

it's the plastic gasket that goes between the manifold and the carb. i'll look for an o-ring. thanks.

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