Still running hot, any advice?

[Patch]

I'll write this up for you this afternoon

[Patch]

On 11/16/2020 at 2:34 PM, circa1968 said:

 

Wow I wrote this up went to highlight and the whole thing vanished.

Lets play pin the tail with the use of a bit of logic;)

top plug is #3

next 2 are #'s 1&2

last is #4

[Patch]

On 12/16/2020 at 11:14 AM, circa1968 said:

Thanks @Patch but it looks like the congrats may be premature....  Apparently I need to fine tune my bench sync skills a bit more, haha!  Cylinders 1 & 2 were pretty much spot on, 3 & 4, ehh and then the two banks were pretty far off from each other.  But, that's now sorted out w/ the vacuum gauges.

Not really: if you are sure when you do the bench sync then find a difference using the vacuum side to match you are doing it correctly. The issue really is we don't have compression numbers to apply our experience to.

If you balance to an unbalanced pump then we may find ourselves searching for answers in the incorrect cupboard.

In this case we have a low millage bike that is at least 13 years old, that tells us the it's set around for a while which means its also faced gravity both from lean off the stand and the V shape engine. My guess from here is that around 210* the rings may have settled in on the "landings" or not?

Bike is running great, idle is stable and the throttle response is snappy.  That's the good news!  The bad news, even in 50 degree weather, still lots of heat coming off when riding and still reading high temps on the exhaust pipes.

this is subjective: the true way to tune with heat reading is to measure of the plugs. The front and rear pipes are different, yes we can and to take quick checks as Puc and I mentioned early in the thread at the colours but understanding the carb setups play a role.

So, w/ a tach and vacuum gauges (and my mostly useless ears), I set out to fine tune the idle mixture screws.  Now this is where I get lost.

I get it: some of the club use a gadget called Colortune, I think that this might bring you some peace of mind.

Only on cylinder #2 (actually maybe #3 too, I need to double-check), does the engine bog down when I turn the idle screw all the way in until it stops.  I don't understand this.  Am I not cutting off fuel flow to to the cylinder when I turn it all the way in?  I will recheck #3, but for sure, there is no change when turning in #1 & #4 (rear) mixture screws.

Right: the easy and first things I would inspect are the pilot set/mixing screws, they need to be true and the points must seat to stop the fuel flow into the bore.

Next I would check float setting with the bike straight up as shown in the manual. If the floats are not seating the inlet then this could be a problem.

Next would be the needles not seating correctly while running on the idle circuits. Those that are not responding to the set screws are the suspect ones. Check for proper alignment and any damage at all will cause the power circuit to leak into the bore. The needle jets have a few tricks to improve atomization and can make checking for leaks a challenge. Take a Qtip rap it in a tissue so you can't loose grip and place it below the needle say 40 seconds while at idle, it should be dry when you check it.

Another trick is to maintain a lowish idle when setting the pilots 900 or 850 the reason being that there is no load on the engine and a strong combustion cycle can easily handle a engine idling thru.

At around 1.5-2 turns out, I can see where the RPMS start to increase a bit and then level off, so that part of the process seems ok and I've seem to have gotten each of them at least near the sweet spot.

Then back turn or tighten 1/4 turn.

But what does the above symptom mean, where it does not bog down the engine on three of the four cylinders?

Now I did some looking up not on an 07 rather 06 year. What I found is as follows:

#'s 1 & 2 are mains 122.5

#3 is a main of 117.5

and #4 is 120.0

Even in that small difference between we see that on the plugs.

Of note or say tell, is the main air jets, they remain a constant. That tells us they were looking to produce some set values. I can assure you that one you need to maintain order when rebuilding these carbs and 2, if they were my carbs they would all be matching

Why do this? Well it is target related, that's the short answer.

Because you're a curious fellow lets dive into it: We'll pick a HP goal say 115. Another target can be economy like fuel range. And another lets say EPA targets.

All off of one crank and 1326 cc.

Those 3 targets are the answer as to why they did, and why they could.

Hope this helps

 

 

Edited December 18, 2020 by Patch
Check the quoted box

[Patch]

Not the best focus, lol

[circa1968]

Thanks @Patch!!  I decided the best next step was to do a carb swap for a rebuilt set from eusa1.  My curious mind is still restless however and I'm hoping to find a set of used carbs on ebay for a reasonable sum for me to tear apart and learn more, but that's for later. For now though, I've waited 18 long years to get back onto a Venture and ride and that's my #1 priority.  I gave it a shot, learned a whole lot more about carbs, motors, etc than I knew two months ago and satisfied with my newbie effort, even if I didn't get the desired end result. 

I'm also praying there's nothing else wrong that requires an even deeper dive.  Starting to worry if I made a bad buy on this bike due to it sitting and maybe not having had proper maintenance.  Will keep my thoughts positive though. 

Can't say it enough how I appreciate this site and the fine people willing to help me!

[Patch]

Well I don't think you made a bad decision! 

Regardless of carbs you install a compression test will ease your worries.

We have a thread that I have used many times as have others, it just works to restore, if need be, compression on an engine such as yours!

" A CASE FOR FOGGING" look it up here on the site

That said its been nice walking thru with you, if you do find another old set, change the jetting

[circa1968]

On 12/18/2020 at 6:23 PM, Patch said:

Regardless of carbs you install a compression test will ease your worries.

Well, with it being Christmas and lockdowns and all, what better time to do a compression test!

#1 210 psi

#2 205 psi

#3 210 psi

#4 215 psi

Worries eased!  Thank you!

[circa1968]

Well, as a final wrap to my heat saga, the rebuilt carbs from Mike, the Diamond Cut Guy, has solved the issue.  While I learned a lot through this process, I can't begin to explain what the underlying root cause was (frustrating to me personally as I used to do root cause failure analysis on electronic stuff) and how/why the rebuilt carbs solved the issue.

But in the end, none of that matters.  My beautiful moto is finally running the way she should!!!!!!

Hats off and a big Thank You to everyone who helped and encouraged me along the way.  I was frustrated at times, but also found it fun and challenging. 

And now....its time for miles of smiles.

[Patch]

Once you proved the compression benchmark you also proved the issue. The overheating was according to your reporting of uneven combustion temperatures, this translates to lean V. rich!

Lean was the issue. Today's way of expressing such a condition is "lambda"  with an active fuel management system you can read the results just as easy as balancing your cheque book.

I might suggest you quench this thrust by looking up the lamdba description on the web, its really simplified!

You did well and really did learn a bunch  

[circa1968]

Thanks @Patch for boiling that down to such a simple explanation for me.  I tend to over-complicate things...😆

The lambda stuff sounds really cool.  Wish we had such a closed-loop system on the Venture w/ fuel injection, O2 sensors and computer control.  Wow, wouldn't that make an awesome bike awsomer!

Now that I've got a set of rebuilt and clean carbs, I'm off to put a crankcase breather filter and oil catch can on the bike.  I was working that out while waiting for the rebuilt carb shipment.  No more oily mess @ the intake.

[Patch]

You can also apply your heat sync experience to the compounding of the issue. Would you choose a passive or active cooling sync? We know greater mass for example will maintain a more even BTU exchange V. a lesser mass, then material densities, castings V. stamp will play an even greater role in conduction transfers... An example in transferring that understanding to engine combustion cooling would be Exhaust valve material and Piston Rings and there BTU conduction / heat transfer to the engine mass. You can relate that then to the design and capacity's of fluid flows! On this engine there are 2, one liquid one air both mapped out thru assumed operating cycles.

Carbs V. injection: Well I have fun with both. Fuel injection still uses the same basic Stoichiometrics as carbs but with a different potential in the form of cheat sheets. Many of the older dyno guys are coming around to performance understandings thru hard numbers - on there tried and true American mule engines. Still today and when I peek into that world I see them still struggle with fluid flows and which of the 2 are producing these new to them numbers. But what most of us knew all the way back when we started was air filling has always been our biggest challenge on a naturally aspirated engine; the gas part is the easy stuff.

So that's where injection hedges ahead of carbonation. The injection system permits us to concentrate on fluid flows separately. The gains there are enormous, low turbulence, multiple opportunities for Venturie's, bypassing of Venturie's @ or near WOT.... Just those 2 provide increase in acceleration / torque and top end outputs... And as we see today we are achieving more out of smaller displacements because of this freedom to manipulate the fluids individually.

Carburetors on the other hand are much less complicated providing you accept there flow flaws. CV Carbs do appear to be complicated but not so, really. If we look at a CV (constant Velocity ) as an aperture Vs. a slide or piston and instead of light we view the opening as a fluid port or valve it begins to make sense then. This has more to do with air induction viewed as the fluid  then the second ingredient (the combustible fluid) we tend to mistakenly focus on. CV carbs start at the air induction port or the front of the air box. The complete air chamber is calibrated to the engine performance range. Velocity is a critical calibration within these carb setups. This is where old school thinking messes up the newbe when it comes to CV Carbs. "more air - more air"   NO not without velocity.

Rapping it up, assuming the carb is correctly jetted and in popper operation, the CV Carb to use an old term (runs like a Cadillac) its strong quiet and reliable, provides smooth acceleration and limits over lean or over rich fueling.

having some trouble with my english this morning hope this makes sense

   

[Patch]

4 minutes ago, Patch said:

You can also apply your heat sync experience to the compounding of the issue. Would you choose a passive or active cooling sync? We know greater mass for example will maintain a more even BTU exchange V. a lesser mass, then material densities, castings V. stamp will play an even greater role in conduction transfers... An example in transferring that understanding to engine combustion cooling would be Exhaust valve material and Piston Rings and there BTU conduction / heat transfer to the engine mass. You can relate that then to the design and capacity's of fluid flows! On this engine there are 2, one liquid one air both mapped out thru assumed operating cycles.

Carbs V. injection: Well I have fun with both. Fuel injection still uses the same basic Stoichiometrics as carbs but with a different potential in the form of cheat sheets. Many of the older dyno guys are coming around to performance understandings thru hard numbers - on there tried and true American muscle engines. Still today and when I peek into that world I see them still struggle with fluid flows and which of the 2 are producing these new to them numbers. But what most of us knew all the way back when we started was air filling has always been our biggest challenge on a naturally aspirated engine; the gas part is the easy stuff.

So that's where injection hedges ahead of carbonation. The injection system permits us to concentrate on fluid flows separately. The gains there are enormous, low turbulence, multiple opportunities for Venturie's, bypassing of Venturie's @ or near WOT.... Just those 2 provide increase in acceleration / torque and top end outputs... And as we see today we are achieving more out of smaller displacements because of this freedom to manipulate the fluids individually.

Carburetors on the other hand are much less complicated providing you accept there flow flaws. CV Carbs do appear to be complicated but not so, really. If we look at a CV (constant Velocity ) as an aperture Vs. a slide or piston and instead of light we view the opening as a fluid port or valve it begins to make sense then. This has more to do with air induction viewed as the fluid  then the second ingredient (the combustible fluid) we tend to mistakenly focus on. CV carbs start at the air induction port or the front of the air box. The complete air chamber is calibrated to the engine performance range. Velocity is a critical calibration within these carb setups. This is where old school thinking messes up the newbe when it comes to CV Carbs. "more air - more air"   NO not without velocity.

Rapping it up, assuming the carb is correctly jetted and in popper operation, the CV Carb to use an old term (runs like a Cadillac) its strong quiet and reliable, provides smooth acceleration and limits over lean or over rich fueling.

Just to scratch the surface of fueling

having some trouble with my english this morning hope this makes sense

   

 

[TheMasterMike]

On 1/14/2021 at 11:39 PM, circa1968 said:

Well, as a final wrap to my heat saga, the rebuilt carbs from Mike, the Diamond Cut Guy, has solved the issue.  While I learned a lot through this process, I can't begin to explain what the underlying root cause was (frustrating to me personally as I used to do root cause failure analysis on electronic stuff) and how/why the rebuilt carbs solved the issue.

But in the end, none of that matters.  My beautiful moto is finally running the way she should!!!!!!

Hats off and a big Thank You to everyone who helped and encouraged me along the way.  I was frustrated at times, but also found it fun and challenging. 

And now....its time for miles of smiles.

Maybe diamond cut guy will let you know something he finds, then you let us all know in case of similar situation.

[Patch]

1. Not sure why my post #87 shows as a quote but the context is there just expand it

[eusa1]

The carbs were dirty and had 1 diaphragm that was misaligned causing the machine to run very lean. 
that’s where the heat was coming from.

thanks to all. Mike

[PreachJohn]

3:20AM;, burning the midnight oil to read thro' the 4 pages of this thread. Really interesting stuff.
Some points made will stick somewhere in my noggin and come in handy on a rainy day for myself directly or for another fellow yokel needing a hand.