Laser Thermometer Fine Tuning…..

xsjohn · Last edited by xsjohn on June 24, 2008, 5:25 pm; edited 146 times in total

Here’s a way you might take tuning to a higher level…Once you have set the carburetors to your satisfaction and have checked the floats and all the jetting and you are pretty much satisfied with the overall performance there is one more way to possibly improve performance and smoothness.

Using a Laser Thermometer find two or three places on each side of the cylinder head that you can take temperature reading from. The tip of the plug or next to it and up front of each cylinder on the aluminum there is a nice flat spot and this flat spot right above where the exhaust pipe exits the head... Run the machine until it is at full operating temperature say at least 10 miles and stop and check those spots and record the temps. If both sides are within 5 degrees you could consider this good…..But not great....230-235 degree head temp is optimum......85-90 degrees ambient...

Test point 5 on the cylinders is also very important place.....Cylinder temps can be way higher than the head temps......Piston damage can occur if long runs are made with the cylinder temps above 250 degrees......If temps go over 250 on the cylinders the carbs are to lean....and a top end cooler is smart.......THe plugs I am beginning to find are the most important temperatures........around 220-240 are good readings on a warm day......

BEEN SETTING MY FLOATS A TAD LEANER AS SHOWN BELOW ......NOW USING 23MM FOR ON THE BIKE SETTING......GAS PRICES AND ALL.....STILL GOOD PERFORMANCE BUT THE BIKE SEEMS TO SETTLE DOWN AT CRUISE A LITTLE BETTER.......WOULDN'T DO THIS WITH STOCK JETTING THOUGH........

PM me for custom needles............tested.........

John

650rider · WebMaster Joined: Feb 09, 2005 Posts: 431

We are going to have to start posting your writes ups to a "how to" section so site users can have direct search of your great works. Contact me if you would like to get set up with your own section to post to.

In other words do you want to be a "formal" site reporter? PM me if you do and We will hook up and find out what works best for you.

wally

Laser Thermmeter

Hows that all work
Could you paste a pic of one for me

Wally

xsjohn · Last edited by xsjohn on September 16, 2007, 6:51 am; edited 2 times in total

Just measure the heat and adjust carbs accordingly......Lean is hot rich is cooler

John

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

I know its some where, but can some one put it in simple terms how to adjust float, which way rich wich lean, I dont want to take the carbs off the bike if not nessessary (80 ) special

rwreed

Joseph,
If your bike is running semi-good (to your liking) wait until fall and pull the carbs for a good cleaning and major re-do (jets, floats, whatnot). Enjoy riding this summer.

How long is it since your carbs were off the bike, dis-assembled and cleaned really good. every 3-5 years is a good practice (for me anyway).

I still use the factory jets, filtering and exhaust. Like John says, each bike will differ depending on how you have it set up. What John is suggesting, I think, is doing this adjustment after you are relatively sure the carbs are set up right. Thus "Fine Tuning".

btw: Floats don't adjust rich and lean. They control the amount of fuel in the bowl. Too low, not enough fuel. Too high, flooding and fuel leakage

The bowls can be removed with the carbs on the bike to set float levels, but best done when off the bike so you can invert the carbs and let the floats rest naturally on the needle valves.

Suggestion: get a shop manual for the bike.

Just my 2c,
Slim

Joseph · Full Member Joined: May 22, 2007 Posts: 767 Location: NY

Thanks i didnt realise that did't ajust lean rich, The carbs are running verry good last year when the bike was baught by my uncle he had the carbs rebult. I wanted to richen them a little the right feels just slightly hoter barely noticible so after reading posts from john I wanted to richen it a little.

xsjohn

rwreed.....Floats can make for a lean or rich situation if not set properly...
To high and the carbs will flood making it rich....To low and the carbs have difficulty pulling the fuel up so it runs lean........And harder to start...

John

rwreed

I suppose so if you want to get technical. But that is not their intended/designed purpose. For that matter a missing air filter will make the mixture leaner right? A clogged air filter will make it rich.

Happy Fathers day!!

Slim

xsjohn · Last edited by xsjohn on July 16, 2007, 8:39 am; edited 13 times in total

First try to set balance using vacuum guages or your best method....

Cheapy Fix.....
Here is something to keep in mind.......When the carb balance is set with vacuum gauges the engine is not under a load....when you are riding there can be one cylinder that under load will run hotter....To cure this common problem....

To set cylinders turn idol up so it runs at about 2000 rpm...Warmed up
Then quickly turn on bike a remove one plug wire and see what rpm..
The do it with the other cylinder and turn the balance until both cylinders by themselves pull at the same rpm....Check back and forth until both do the same thing....This will balance the cylinders under a load and be better than vacuum balancing........

John Underwood

xsjohn · Last edited by xsjohn on August 3, 2007, 1:06 pm; edited 1 time in total

Just wondering if you guys have taken the time to read some temps to see if you are going to burn up like I did last summer..........By tuning mine correctly and richer I went from 60 to the gallon to 52 to the gallon and much cooler....

With all the choppin and bobbin you might be overlooking something far more important.......

Testing should be done in hot weather.......above 80 degrees........

....Burn baby burn....

John

KYLEPRESTON

JOHN,
I MUST SAY ONCE I GET MY ENGINE OUT I WILL BE MAKING SURE I AM RUNNING LIKE A TOP I AM ORDERING MY LASER THIS WEEKEND.

I WILL BE SIPPING ICE COFFEE RIDING MY CAFE.

KYLE

xsjohn

The harbor freight one Cen-Tech I got is a good one if you change the cheap chineese batteries......Make sure it will go to 400 some of them only read to like 225....Kinda useless......

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok - here is a new trick for me to try -

A guy has a laser thermometer here at work - I am taking it home over the weekend to try your trick.

Just out of curiosity - where did you get your 230 degree figure?

xsjohn

Experience......And above 230 is when the engine starts loosing power and starts making wierd noises like a car does when it's overheating........Right at 225-230 is where it seems to perform the best and get the best gas mileage and sound the best....And a reasonable goal without having to run it so rich it craps plugs all the time......230 also gives you a bit of a buffer for stop and go....Also the cylinders tend to run 15 degrees hotter than the head after it fully warms up.....Above 250 on the cylinders I would worry.........

Water cooled bikes run at 190 degrees so the cooler days when the bike runs at 210 is ok..........250 degrees head temp is not good any time........

Kinda have to not make it so rich that it won't run in the winter without fouling plugs constantly......I't all a compromise with an air cooled engine....

We are talking about ambient 85-90 degrees ..... not 68 degrees..........

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok - after a 1/2 hour riding - 77 degree day - measuring at idle WITH BIKE RUNNING - I got about 280 on each cylindar.

But it ain't running lean -

Are you sure of those temps?

xsjohn · Last edited by xsjohn on September 20, 2007, 9:20 pm; edited 2 times in total

280 wouldbe lean on mine that's for sure........I have a top end oil cooler that I have been preaching about...Few are listening.......way way way to hot..........And you are only 77 degrees ambient....that figure could touch 300 at 90 degrees ambient.............Wow...........Think of the extra power you would have.....With my 18/29 gearing it barely picked up on the expressway at 70 now it just roars on up like nothings holding it back.......

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

I am going to re-check my temps again when I get home tonight -
You know this is the bike that carbons up (like it's too rich) anyway -
I can't believe it's running lean -

There is just no stumble - pop - or knock at any speed.

But I will check the temps again!

Boy - you sure find ways to keep me busy!

xsjohn · Last edited by xsjohn on January 2, 2008, 8:50 am; edited 1 time in total

jimdi:.....Working on a kit to make these BS34's fun......

Allen screws and a allen socket (use pliers onthe socket) and both bowls are off in 5 minutes.........Louvers may even pull off a few degrees too.....

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok - went home and re-adjusted my mix (2.75 turns out now) -
Re-adjusted a float back up to 23mm
Re-attached my oil breather set-up back to the carb boxes (stock)

took new temp readings 80+ ambient temperature:
(+- 2 degrees)

Head (spot2) 240 each side (if I take the temp on the plug it's about 230)
Cylinder (spot 5) 230 each side

Both temps taken the minute I turn the key off - and after a 10 mile ride

I also remembered I have some carb cleaner mixed in the gas to clean up my carboned up mess from the old carbs - that is probably heating things up a bit too.

Oh yes - and both plugs look like yours

xsjohn

What was the ambient...I question your cylinder temps..theyare usually higher than the head temp....Much better though....Stay with it.....Top end cooler will bring the head temps down to 230....

John

paulson_shawn

if i try fine tuning with a lazer thermometer and find temps out of norm, how will i know if its my mains, needles, or pilots out of whack?

xsjohn · Last edited by xsjohn on January 29, 2008, 5:53 pm; edited 4 times in total

Since lots of people don't understand this subject and how it effects their ride I typed in “lower intake temperatures more power” in google……found some interesting discussions on the topic………imbalanced temperatures definitely causes a power imbalance…….or vibration in laymen’s terms……..

xsjohn

paulson_shawn

i already uped my mains by trying different sizes and picking the one with the best top speed, then raised my needles one notch because it didn't seem to pull hard at midrange because of pod filters and different mufflers. i did the pilots by running one cylinder at a time but i was only at 1500 on the idle screw and i think i might be a little lean at 25 - 30 mph because it runs the hottest there. i'll try setting them again at 3500 rpm like u suggested.

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