Still running hot, any advice?

[cowpuc]

9 minutes ago, circa1968 said:

Thank you Puc!  I'm looking forward to digging into the carbs more and learning how they work.  I looked on ebay for a used set, just to play around with and explore how they work.  Oh my, that's an expensive toy, $300+ for a set of used carbs!

@circa1968,,, I am almost positive that one of our club members actually offers a carb swap (you send him your carb bank and he sends you a completely rebuilt set ready to go) thing for club members here.  I cant imagine his prices being much lower than that 300 dollar range though as I know it is not cheap, just for parts, to go through for carbs BUT,, you might dig around and see if you could locate him just to find out if his service is still out there and the costs thereof. I am not sure if @skydoc_17 is the person I am thinking of,, for some reason I dont think so, but even if it is not Earl, he probably knows of whom I speak.  Also, @eusa1, the diamond cut guy just popped into my head, maybe he is who I am thinking of.. Either way,, I am sure one of these lop eared va,, fine gentlemen will be able to help you with my forgetful brain!!

I do know that buying used carbs off the internet can be a risky business and I would rather buy a rebuilt from a known source that risk a used one with the potential of having more problems that those you already have,, just a though..

[circa1968]

@Patch Heading to the garage now to work on the bench sync, have a couple hours free for the rest of afternoon.  Thanks for the read on the plugs.  I will focus on the bench sync 1st thing today and pull the plugs later.

@cowpuc I was just looking for a set for my own educational purposes to take apart, put back together again and try to learn more about what it does and how it does it.  I may get to the point of pulling and doing the swap, but not quite there yet.  I do recall seeing that post in some of my travels. 

[circa1968]

@Patch can you explain this to me further: “Set the # screw so that the throttle plate is just touching the shank of the bit,”

I thought you meant the sync screws but that is not it.  Which screw adjusts the throttle plate?

[Patch]

1 hour ago, circa1968 said:

@Patch can you explain this to me further: “Set the # screw so that the throttle plate is just touching the shank of the bit,”

I thought you meant the sync screws but that is not it.  Which screw adjusts the throttle plate?

The sync screws are the same you used when you synced the carbs the first time!

1 is the fat knob one that you tune the idle with, also has a phillips head. the other 3 are just screws, The are all linked together.

[circa1968]

Thanks.  That's what I thought you were referring to, but I saw no effect on the throttle plate, but now as I think about it, guessing I start w/ the fat knob & go from there?  I'll go fiddle around and see what else I can learn.

BTW, while poking around and doing more reading, etc found the brass caps for the pilot screws & removed them.  With the throttle plates fully open, I could see the needle tip sticking through into the carb body.  Each one protruded a different amount.  wth?  The two front ones were close to each other and the two back ones were close to each other, but I could visually see that all were different!   I threaded each one in until it gently seated then back out 2.5 turns, as I read somewhere else here.  Now they are all uniform.

I may have skipped a step ahead, but hey, you made me dangerous here!!  haha

Back to adjusting the throttle plates until my better half tells me to fire up the bbq for dinner!

[Patch]

Yes we can visualize what you are referring to. So your rears are set richer than your fronts, that is because of the rears getting hotter or harder to cool in traffic! As @CaseyJ955 was mentioning about the jetting being different for the rears... We'll be coming to that after you set your plates!

I am looking for the screw # to refer you to now but if someone has a pic or knows please chime in.

[Patch]

page 6-2 look at #5 and number and 13

[Patch]

https://www.venturerider.org/manuals/RSVservice.pdf

[circa1968]

@ Patch Yep, got it figured out!  I wasn't able to acheive more than a 2-3mm opening of the throttle plate though w/ the idle screw turned all the way in.  I do a lot of work on bicycles (much simpler machines!) and happened to have some steel braided brake cable that's ~1.5mm.  I used that for the feeler gauge and got them all set accordingly.  To fine tune it even more, I turned the idle screw down a bit and then used a 1mm shifter cable for a gauge.

That's a very cool process!  Thank you!

Ready for next step!! 

[Patch]

well you did well then. Should be ready for a startup now, get ready to dial it up or down with the idle screw, that the #5 only.

No throttle just hit the start button, maybe some choke.

Were they far apart?

[Patch]

Once its running and warm close one of the pilot screws in the rear, should be close to 1 turn as they are original setting (most likely) the front will likely show 7/8 of a turn.

As you back each off after you turned them in as above, you should see an increase in rpm, doing only one carb at a time. Stop the tune on each carb once it stops increasing rpm, then dial that one back in 1/8 th of a turn, and move to the next and repeat the process.

You'll notice a difference when you look down the barrel. 

Note: if any one carb tune does not increase in rpm as you back out, the that jet is plugged

[circa1968]

@Patch Got it.  They were not far off to begin with so it was fairly quick and easy to dial them in. 

That makes sense, the rears seated @ 1.5 turns.  

[Patch]

30 minutes ago, circa1968 said:

I wasn't able to acheive more than a 2-3mm opening of the throttle plate though w/ the idle screw turned all the way in. 

So remember the starting point lets say 3mm if you only showed a difference of 1mm that would be a 33% correction, right, that's huge

[circa1968]

On 11/16/2020 at 6:23 PM, Patch said:

Note: if any one carb tune does not increase in rpm as you back out, the that jet is plugged

Apparently I have at least two plugged jets.  Turning out the pilot screws on #1 & #3 had no effect.  When turned nearly all the way in, it would bog down the engine, but backing out from that point all the way to 4 turns made no difference on either of them.  I never even got to #2 & 4.

Bottom line, I'm now armed and dangerous with more information than I probably should be allowed to have.  I'm going to pull the carbs & open them up to clean the pilot jets!!!!

Wish me luck! 

[Patch]

Use a little spay lube on the bottom where they enter the black intake pipes. The Throttle cable I find to be the worst of the job...

I think many of us would change the rubber bits while there just do to age. 

Have fun and you know where to find a 4 leave clover if needed

[circa1968]

8 minutes ago, Patch said:

Use a little spay lube on the bottom where they enter the black intake pipes. The Throttle cable I find to be the worst of the job...

I think many of us would change the rubber bits while there just do to age. 

Have fun and you know where to find a 4 leave clover if needed

That was timely!  I just got everything loosened & ready to pull, but no go.  Figured I missed a step in the process and came to the computer to review.  Yeah, that throttle cable....

[Patch]

Make sure you use good drivers on those screws, a small impact driver makes short work of taking them apart.  If you need to touch up a flat screwdriver to remove the jets then its money well spent, nothing worse then stripping the head off a jet.

Take your time and don't skip past the inricher or costing circuits... Read the position sensor its on in the book. Note your jet sizes down..

While your carbs are off, and even tho this is a relatively new engine, it would be a good idea to check your compression, for stuck rings or leaky valves. Just takes some of the guess work out of things. 

 

[circa1968]

Well, since you've pushed me to become divorced from my comfort zone and we now live in separate states (thank you!), I will be doing all those things you mention.  The float bowl o-rings are pretty gunked up and new ones will not arrive until Friday, so I now have time to fiddle and see how much more trouble I can get myself into.

Question:  I've been studying the service manual, and I have a clymer manual as well now, and have been able to identify and understand pretty much everything so far.  But, in the attached picture there is a rubber hose connected to two diagonal float bowls via a T &  the T goes off to the some abyss under the battery.  I cannot find anything which identifies this.  What the heck is it and what does it do?

[Patch]

I am thinking those to have to do with the air induction system? pg. 6-16

[circa1968]

Found it!  You were close:  "Evaporative Emission Control (California Models)...captures fumes that are created in the fuel tank and stores them in a charcoal canister.  While the motorcycle is parked or when it is operated at low engine speeds, the fuel vapors remain in the charcoal canister.  When the motorcycle is ridden at high speed, the vapors pass through a hose to the carburetor and are burned..."

I call it a PITA!

[Patch]

Yah I did see mention of that in the book.

[circa1968]

Well, at long last, the replacement float bowl gaskets and needle valves came in, I've managed to get everything back together.  In the process, I shimmed out the needle by moving the washer to other side of c-clip and made a slight adjustment to the float bowls, using the method found on the site here.

Much to my amazement, it doesn't appear that I've totally screwed anything up (but perhaps that verdict is still out).  The bike fired up and I took it out for a quick 5-minute ride.  Its definitely got more zip to it but I suspect its now running on the rich side of the spectrum as I'm getting some backfire I did not have before.

I still need to check sync on the carbs, even though I did the bench sync, will still check again w/ vacuum gauges.  Also need to dial in the idle mixture but I'm about as tone deaf as they come (In 9th grade, Sister Denise spent the entire year trying to teach me how to tune a guitar by ear - it never happened and my Rock & Roll dreams came to an abrupt end), so I'm looking for a proper tach to help with that or may just take it to a shop that has an exhaust gas analyzer.

@cowpuc@BlueSky@Patch and so many others here who have encouraged and taught me, I am in awe and in sincere gratitude for all of you.  I've actually enjoyed working on all of this along with the learning process.  I have much to learn and many mistakes to make to assist me in that process but nice to know that there are so many here willing to help me through. 

Thank you all!

Dean

[Patch]

In theory if after a bench sync IF the compression is equal'ish the carbs are synced.

Of course theory and practice are 2 moods at times.

Personally I prefer a a leaner setup. You can also use your vacuum gauges to tweak the idle circuit, tho usually the ear picks up the rpm.

Congratulations on the accomplishment  

[circa1968]

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.

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.

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.

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.

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.

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

 

[eusa1]

On 11/16/2020 at 4:07 PM, cowpuc said:

@circa1968,,, I am almost positive that one of our club members actually offers a carb swap (you send him your carb bank and he sends you a completely rebuilt set ready to go) thing for club members here.  I cant imagine his prices being much lower than that 300 dollar range though as I know it is not cheap, just for parts, to go through for carbs BUT,, you might dig around and see if you could locate him just to find out if his service is still out there and the costs thereof. I am not sure if @skydoc_17 is the person I am thinking of,, for some reason I dont think so, but even if it is not Earl, he probably knows of whom I speak.  Also, @eusa1, the diamond cut guy just popped into my head, maybe he is who I am thinking of.. Either way,, I am sure one of these lop eared va,, fine gentlemen will be able to help you with my forgetful brain!!

I do know that buying used carbs off the internet can be a risky business and I would rather buy a rebuilt from a known source that risk a used one with the potential of having more problems that those you already have,, just a though..

Thanks for the plug, yes he reached out to me, my carbs are still available.