Question to those with 38 lows

[Patrick]

Has the cold weather starting and running improved with the 38s ?? I've tended to stick with 35s but the cold weather starting and warm-up has always left a bit to be desired..

[mmurffy03]

installed 38s this past summer and after the swap i hardly used my choke at all and so far this fall just a bit of choke fires it up instantly and seems to warm up to running temp smoother and faster than the 35s

[JC]

38s certainly made mine easier to start in cold weather.

[Ricky-D]

Running more richly, changing from #35 to #38 idle jets, will have both, good results and bad results!

You decide what you want to have!

Honda thought #35 jets.....

***

[Patrick]

Thanks.

[signart]

I have a '97 w/38's and a '98 w/35's, guess which one starts & runs better? Seriously what IS the downside?

[SANDMAN5]

I switched mine before last winter. Don't think I've
used my choke since. YMMV.

[Hook#3287]

Honda thought #35 jets.....

Before 10%??

Seriously what IS the downside?

Good question.

[whitestroke]

"Can't we all just get along"

and run 36.5   

[valky1500]

After changing to 38's the first thing I needed to do was turn the idle down some.
I could smell gas when starting or sitting at idle and thought it was normal.

Then one day I was checking the plugs to see how things were looking in there and I noticed the back 2 cylinder plugs (#3 and #6) were carboned up some while the rest looked good.

At that point what I did was to take out the shims of said needles so as to let them sit lower and run leaner while the others stayed raised.

And they have both run perfect ever since on that setup. 

[shooter64]

When I got mine it already had 38's in it. Installed with the cobra exhaust. So I don't know anything about how 35's run. If the weather is 60 or higher no choke is needed at all. I think that is the first 4 cycle engine I have ever had that could start and run smoothly without any choke from a first start up.

[98valk]

a pilot jet (PJ) should be in the adjustment range of 1.5 to 3 turns out. if the engine needs 3.5 to 4.5 turns out then the next larger PJ can be used which then should allow the 1.5 to 3 adjustment range again. This is the formula that FactoryPro uses and is on their website.
going to a larger PJ than needed will result in reduced MPG.
ethanol in the fuel does cause leaness which requires opening up the mixture screw more or past the range a larger PJ.

[Patrick]

I just don't like having to start this thing 2 or 3 times before it decides to stay running and having to wait several minutes before taking off when the weather is below freezing.. These monsters run rich with the 35s,, but,, maybe I need to get over my stubbornness and change.. After 15 years I'm thinking of changing,, I must be getting soft in my old age..

[98valk]

I just don't like having to start this thing 2 or 3 times before it decides to stay running and having to wait several minutes before taking off when the weather is below freezing.. These monsters run rich with the 35s,, but,, maybe I need to get over my stubbornness and change.. After 15 years I'm thinking of changing,, I must be getting soft in my old age..

open up the mixture screws 1/2 turn, this will affect how long the choke needs to be used.

[Patrick]

I just don't like having to start this thing 2 or 3 times before it decides to stay running and having to wait several minutes before taking off when the weather is below freezing.. These monsters run rich with the 35s,, but,, maybe I need to get over my stubbornness and change.. After 15 years I'm thinking of changing,, I must be getting soft in my old age..

open up the mixture screws 1/2 turn, this will affect how long the choke needs to be used.
end quote

I could try that.. They are set at 2.25,, but,, I've cut the pilots so they are easily adjusted.. For some odd reason,, the temps have been in the 20s and I'm still taking it for coffee in the mornings..

[Ricky-D]

I have found that you dare not try blipping the throttle when you first get it started.

That's when it's cold and the choke is full "on".

Myself, I've a throttle lock that I use to hold a little faster idle as soon as it starts, doing this mainly on the coldest mornings when it will not idle up quickly with just the choke.

Ever since the bike was new it has been like this!

It always makes me think there is a carburetor or two has dropped out from the cold.

Also, and even though not related I want to mention that occasionally on really freezing mornings I've had ice form in the float bowls that will clog up the jets temporarily. Took me a long time to figure this one out.  After warming the motor up the problem disappears.

Now I drain a little out of each float bowl a couple of times each year. Actually this is a good thing to do regardless of the reason. Drain a little from each carburetor to rid it of anything that settled out to the bottom of the bowl.

***

[98valk]

Also, and even though not related I want to mention that occasionally on really freezing mornings I've had ice form in the float bowls that will clog up the jets temporarily.

what is water doing in your carb bowls? u trying to run the girl on water like henry ford did? 

more likely its the thin film of ice that will form on the throttle blades when cold before the carbs warm up.
removing the aircleaner heat riser from carb'd performance cars from the 70s and 80s did the same thing during cold starts.
my bike does the same during 20-30F cold starts, I know there is no water in the bowls.

[Patrick]

It would be very easy for frost to develop on the outside of the float chambers,, but,, I would doubt there is any in the chambers causing problems.. The way this system is designed though I can easily see ice forming in the throats even though I don't think there should be much venturi effect due to design.. A carb heat system of some sort may help..

[Ricky-D]

what is water doing in your carb bowls?

I know that gas stations have to keep always measuring for water in their underground fuel tanks and that small particles of water can be pumped along with the gas when I fill my tank.

Over a period of time the bits of water will settle out in the gas in my tank and will progress to the float bowls.

Not a lot of water mind you, but more like a drop or two of water accumulation.

It doesn't take much water to reach the main jet since it sits in the bottom recess of the float bowl. That's some of the reason for the main jet to be so far down in the float bowl. It will tend to scavenge the contents helping to keep it clear and clean. Of course there are other reasons too.

But regardless, it takes only a drop of water freezing right there in the bottom of the carburetor to be able to clog the main jet.

I use non-ethanol gasoline exclusively. I don't subscribe to the theory that ethanol enriched gasoline will tend to absorb free water molecules, so water in the gasoline will not occur. That's bull.

I have always professed to drain the carburetors (just a little bit) a couple of times a year as a very useful preventive maintenance procedure.

***

[Farther]

I don't subscribe to the theory that ethanol enriched gasoline will tend to absorb free water molecules...

It's not a theory, it's fact.  Underground storage tanks (USTs) have a measuring device called automatic tank guaging (ATG) that measure the fuel volume and water volume in USTs.  Since the introduction of E10 the water content of USTs has dropped to zero in my area of the country.  The only time you will get free water with E10 fuels (phase separation) is during long storage usually in marine environments.  The solution is ride your bike more and purchase your fuel from high through put stations using preferably top tier fuel eg. Texico, Shell, Chevron, Costco etc. 

[Jess from VA]

38 lows:



Sorry, wrong thread.   

[JC]

38 lows:



Sorry, wrong thread.   

Now dats funny!!!!!     

[John U.]

I have a '97 w/38's and a '98 w/35's, guess which one starts & runs better? Seriously what IS the downside?

The only downside I'm aware of is potentially reduced gas mileage.
I've been running 38s in two Valks for about 5 years. If you adjust the pilot screws to 1.75 turns out
the gas mileage will be very close to what it was before. I found 1.5 turns out to be too lean, though my mileage improved over what it had been with 35s. The slow jets don't only pass fuel at idle, so they can definitely have an effect on fuel mileage.
At either setting I still needed and need the choke in cold weather.

[whitestroke]

38 lows:



Sorry, wrong thread.   

Now dats funny!!!!!     

Definitely water in those bowls.      

[valky1500]

I have a '97 w/38's and a '98 w/35's, guess which one starts & runs better? Seriously what IS the downside?

The only downside I'm aware of is potentially reduced gas mileage.
I've been running 38s in two Valks for about 5 years. If you adjust the pilot screws to 1.75 turns out
the gas mileage will be very close to what it was before. I found 1.5 turns out to be too lean, though my mileage improved over what it had been with 35s. The slow jets don't only pass fuel at idle, so they can definitely have an effect on fuel mileage.
At either setting I still needed and need the choke in cold weather.

Let's put this into a better perspective here while on this topic.

It's true that 35's and 38's are slow jets with the 35's being leaner. It's a myth saying they will affect the gas mileage while the engine is running.

Their purpose is to provide the engine with a proper fuel-air ratio for idle and starting only. From that point they incorporate with the other systems within the carburetor.

The pilot jets adjust the mixture (fuel-air) of the slow jets for proper running at idle and the starting enrichener (choke) enrichens this pre-set mixture for cold starting only. After that point is crossed it's the needle and fast jets that take place and this is where gas mileage and power are effected.

It's the needle jets that are constantly making the adjustments to this fuel-air ratio within each separate carburetor, according to its' vacuum, and this is where the magic takes place. What is so important about changing these jets depends on what limits you are looking for in power from idle to WOT. 

[Blackduck]

Sorry, slows do have an effect on areas of carb operation other than just idle.
There is a good article on tuning Mikuni's that covers this. ( you will find much the same info on Holley's etc)
All carbs with multiple fuel/air systems have a blending of operations to ensure a smooth transistion during use.
Cheers Steve

[98valk]

Sorry, slows do have an effect on areas of carb operation other than just idle.
There is a good article on tuning Mikuni's that covers this. ( you will find much the same info on Holley's etc)
All carbs with multiple fuel/air systems have a blending of operations to ensure a smooth transistion during use.
Cheers Steve

factorypro.com  covers everything in detail also

[Ricky-D]

I don't subscribe to the theory that ethanol enriched gasoline will tend to absorb free water molecules...

It's not a theory, it's fact.  Underground storage tanks (USTs) have a measuring device called automatic tank guaging (ATG) that measure the fuel volume and water volume in USTs.  Since the introduction of E10 the water content of USTs has dropped to zero in my area of the country.  The only time you will get free water with E10 fuels (phase separation) is during long storage usually in marine environments.  The solution is ride your bike more and purchase your fuel from high through put stations using preferably top tier fuel eg. Texico, Shell, Chevron, Costco etc. 

Naturally, I cannot comment on what you say is happening in your "area of the country" but this article
surely debunks the myth you are trying to perpetuate regarding free water molecules in E10 being nonexistent.

http://www.petrolplaza.com/technology/articles/MiZlbiYxMTg2NCYmMSYxJiY%3D

***

[98valk]

Naturally, I cannot comment on what you say is happening in your "area of the country" but this article
surely debunks the myth you are trying to perpetuate regarding free water molecules in E10 being nonexistent.

http://www.petrolplaza.com/technology/articles/MiZlbiYxMTg2NCYmMSYxJiY%3D
[/quote]

thanks.
This is a good reason and the only reason to use acetone. it causes the ethanol, water and gasoline to stay in phase together.

[valky1500]

Naturally, I cannot comment on what you say is happening in your "area of the country" but this article
surely debunks the myth you are trying to perpetuate regarding free water molecules in E10 being nonexistent.

http://www.petrolplaza.com/technology/articles/MiZlbiYxMTg2NCYmMSYxJiY%3D

thanks.
This is a good reason and the only reason to use acetone. it causes the ethanol, water and gasoline to stay in phase together.


[/quote]

Well you can say it that way if you want...

but Diesel fuel has the very same problem...

and that's why they use dry gas so often in their engines. 

[valky1500]

Sorry, slows do have an effect on areas of carb operation other than just idle.
There is a good article on tuning Mikuni's that covers this. ( you will find much the same info on Holley's etc)
All carbs with multiple fuel/air systems have a blending of operations to ensure a smooth transistion during use.
Cheers Steve

Yes and that's just what I stated ever so lightly above...

and FYI, the Valkyrie carbs are not Mikini or Holly's.   

[Ricky-D]

There was a thread a few years ago regarding adding acetone to the gasoline and the consensus was that adding acetone was not a good idea.

If I find it or find other info regarding this particular treatment I'll go ahead and post it.

Here it is:It was easier to find than I thought it would be.

http://www.valkyrieforum.com/bbs/index.php/topic,5952.msg44451.html#msg44451

***

[valky1500]

There was a thread a few years ago regarding adding acetone to the gasoline and the consensus was that adding acetone was not a good idea.

If I find it or find other info regarding this particular treatment I'll go ahead and post it.

Here it is:It was easier to find than I thought it would be.

http://www.valkyrieforum.com/bbs/index.php/topic,5952.msg44451.html#msg44451

***

Dry gas is an alcohol product to prevent any water in the fuel from freezing and to restore combustive power to gasoline spoiled by water...

and acetone is a solvent that is used for the prep of cleaning metal surfaces...

and the the biggest difference just might be the cost associated.