Hi All! Carburetor Rebuild Planned for This Weekend

[kmisterk]

Hey guys!

For starters, I think "Airheads" may actually need its own category, or at least the section of this forum should be renamed to something like "Other Platforms", as technically, my bike *is* an "R" series. Just an old, carbureted, airhead one :P 

Anyway, semantics, I suppose. 

 

Bike Details: 

 

1980 BMW R100T. Removed fairing, Naked Bike. 

This weekend, I am planning to do a Carb rebuild, but not quite a full one. 

I've been experiencing an issue where my right-cylinder spark plug is deteriorating quite rapidly, and I'm 90% certain it is due to the carb on that side running rich. 

 

Some of the symptoms: 

misfires, backfires, "wet" appearance on the plug, brand new plugs fouling up within 50-100 miles, poor cold performance and startup, poor idle (dies frequently at idle once warmed up). 

Hoping it was a relatively simple mechanical thing or electrical thing, I've performed various diagnostic steps (primarily logic driven, and not necessarily from a service manual or guide or other "standardized" method) such as: 

 

To troubleshoot the *specific* symptom at the time, misfiring, backfiring, on only the right cylinder. 

1. Swapping the spark plug cables (no change)

2. Swapping the position of the coils (No Change)
3. Testing Compression (the same and balanced on both sides, ~75 psi)

4. Swapped Spark plugs (Noticed the problem side was wet and soiled, while the "fine" side was "normal" as far as old and used spark plugs go.) (This caused the opposing side to start sputtering, but didn't *eliminate* the stuttering on the right side). 

5. *Replaced* the spark plugs (both) The bike ran really well, for about 25 miles. Then, at around 70MPH, it started sputtering, and has been expressing the same right-side-only symptoms that started this whole endeavor in the first place. 

My question for those willing to toss some insight my way is this: 

 

Are there any simple tests I can do to try and isolate whether or not the carbs *need* a rebuild? Adjustments I can make? I'm aware that I could try *readjusting* the fuel leanience using the fuel adjustment screw, but I don't really want to mess with that, as I don't have a *great* way to balance the carbs (will ultimately buy something to do so with the Rebuild kit, when I go that route). 

Logically, I don't really see another option, but I would love to hear anyone here's opinion on what I can do to try and further troubleshoot this without pulling the carbs off/apart. 

Thanks!
 

[Hosstage]

It points to a problem with the carb, like a bad float or needle and seat. Check for worn throttle plate and linkage. Check for proper cable operation and synch.

One more mechanical test would be to do a cylinder leak down test, but it sounds like you'll be pulling that carb apart. It's easier to repair a carb than bad valves or valve seals. At least for me.

Hopefully DR or another will chime in with more helpful info.

[kmisterk]

1 minute ago, Hosstage said:

It points to a problem with the carb, like a bad float or needle and seat. Check for worn throttle plate and linkage. Check for proper cable operation and synch.

One more mechanical test would be to do a cylinder leak down test, but it sounds like you'll be pulling that carb apart. It's easier to repair a carb than bad valves or valve seals. At least for me.

Hopefully DR or another will chime in with more helpful info.

 

Yeah. 

To be specific, I'll be replacing: 

Gaskets, O-Rings, Diaphragms, Floats, Float Pin, Main Jet Needle, said jet needle fastener. 

Then, after re-seal/re-gasket/rebuild of the carbs, and after remounting them, going through video-documented steps to tune and sync them, starting with fuel at full tightened, and turning back to the "recommended" 1.5 turns loosened (acording to Boxer2Valve's carb sync video. I'll be utilizing his videos and this guy's Balancing Video to get to an optimal place post rebuild. I was recommended on another forum to double-check that the Enrichers are actually being disengaged by the cable when the choke/enricher toggle is turned to the off position, as well. 

[Skywagon]

I had a 79 R100RT airhead.  The carbs were notorious for floats that were soaked but didn't show anything. You might try pulling the wired down, removing the bowl, and cleaning things up but I suspect a kit would serve you better.  You can go to the Bing Carb site and get new floats, needles, etc for just a few bucks.  The only real trick is getting the floats set so that they hold the same amount of fuel and meter it at the same rate.  You can buy a twin max to sync them or make your old device for nearly nothing.  Someone will come along shortly and show you how to make your own manometer and how to use it.   

[kmisterk]

19 minutes ago, Skywagon said:

I had a 79 R100RT airhead.  The carbs were notorious for floats that were soaked but didn't show anything. You might try pulling the wired down, removing the bowl, and cleaning things up but I suspect a kit would serve you better.  You can go to the Bing Carb site and get new floats, needles, etc for just a few bucks.  The only real trick is getting the floats set so that they hold the same amount of fuel and meter it at the same rate.  You can buy a twin max to sync them or make your old device for nearly nothing.  Someone will come along shortly and show you how to make your own manometer and how to use it.   

 

Ha, thanks! I appreciate the tips! Looking forward to hearing from the manometer masters.

[szurszewski]

You don't need us to tell you how to make a manometer - just google "homemade manometer" or "diy manometer" ad in the word "airhead" and you might find pics of exactly your kind of bike hooked up to one. 

 

I have one in the garage made with jelly jars - it's easier to cart around than really large tubes but with the same fluid volume; overall though I prefer the long tube versions. 

 

sample image search:

https://www.google.com/search?q=homemade+manometer+airhead&safe=off&sxsrf=ALeKk00Tfs6wADwcqIfaARjhGUuUcA5lzQ:1623963382632&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiL17KEx5_xAhWUt54KHbiaCHwQ_AUoAnoECAEQBA&biw=1179&bih=596

 

 

[kmisterk]

18 minutes ago, szurszewski said:

You don't need us to tell you how to make a manometer - just google "homemade manometer" or "diy manometer" ad in the word "airhead" and you might find pics of exactly your kind of bike hooked up to one. 

 

I have one in the garage made with jelly jars - it's easier to cart around than really large tubes but with the same fluid volume; overall though I prefer the long tube versions. 

 

sample image search:

https://www.google.com/search?q=homemade+manometer+airhead&safe=off&sxsrf=ALeKk00Tfs6wADwcqIfaARjhGUuUcA5lzQ:1623963382632&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiL17KEx5_xAhWUt54KHbiaCHwQ_AUoAnoECAEQBA&biw=1179&bih=596

 

 

 

Thanks! Also found out about a tool called the Harmonizer, as well as another called the Twinmax. Do these tools perform the same function?

[dirtrider]

Evening  kmisterk

 

You are getting good advise so I will pretty well stay out of the way here.

 

I just have a basic suggestion BEFORE you tear the carbs apart.  You really are just guessing about that side running rich (might be a good guess but personally I like to verify as much as possible before just tearing into things)

 

It's been a while since I have been into those R100T carbs but a trick I used to use was---

 

Before doing anything on the carbs I would get the motorcycle level, then with petcocks (on) start the engine & run it, I would then turn the petcocks to (off)  & continue running the engine until it either stalls or starts to falter (basically run the carbs out of fuel).

 

I would then allow the engine to cool off for a while, then I would turn the petcocks back on for about 5 minutes or so (that should re-fill the float bowls & give them a time to sit with a fuel head).

 

Next, I would carefully move the float bowl clip then carefully remove the float bowl from each side (without spilling) then set them level on my bench.

 

Then either by eyeball or better yet with a MM scale measure the fluid heights in the center of the float bowls.

 

If you have a leaking needle or have a fuel logged float the side with the needle leak or bad float should show a higher fuel level.   

 

If the fuel levels look pretty equal then check the slide diaphragm for leaking on the rich side. 

 

You might also do a quick spark plug short out on each side  at 3500 RPM's while watching the tac to see if you get about the same RPM drop from each side being shorted (caution, only short the plugs to ground DO NOT just pull the spark plug wire cap off the spark plug  as that can damage your coils)  

 

 

[kmisterk]

30 minutes ago, dirtrider said:

Evening  kmisterk

 

You are getting good advise so I will pretty well stay out of the way here.

 

I just have a basic suggestion BEFORE you tear the carbs apart.  You really are just guessing about that side running rich (might be a good guess but personally I like to verify as much as possible before just tearing into things)

 

It's been a while since I have been into those R100T carbs but a trick I used to use was---

 

Before doing anything on the carbs I would get the motorcycle level, then with petcocks (on) start the engine & run it, I would then turn the petcocks to (off)  & continue running the engine until it either stalls or starts to falter (basically run the carbs out of fuel).

 

I would then allow the engine to cool off for a while, then I would turn the petcocks back on for about 5 minutes or so (that should re-fill the float bowls & give them a time to sit with a fuel head).

 

Next, I would carefully move the float bowl clip then carefully remove the float bowl from each side (without spilling) then set them level on my bench.

 

Then either by eyeball or better yet with a MM scale measure the fluid heights in the center of the float bowls.

 

If you have a leaking needle or have a fuel logged float the side with the needle leak or bad float should show a higher fuel level.   

 

If the fuel levels look pretty equal then check the slide diaphragm for leaking on the rich side. 

 

You might also do a quick spark plug short out on each side  at 3500 RPM's while watching the tac to see if you get about the same RPM drop from each side being shorted (caution, only short the plugs to ground DO NOT just pull the spark plug wire cap off the spark plug  as that can damage your coils)  

 

 

 

Ahh, thank you! 

Having little to no history of what recent work has been done to the carbs (and, it had been sitting in storage for over 3 years, so I'm not exactly super hopeful on it being in ideal shape, regardless of what kind of maintenance had been performed prior to that), it's been a desire for some time to get the carbs apart anyway and clean them out, replacing any pieces that may be needed. 

That said, I definitely can appreciate the simplicity of this test! Exactly the kind of options for specific tuning I was looking for! So thank you for that, and I'll be sure to do this! Between here and another forum I'm active on, I'm far more reassured about getting my bike up and running well again before the weekend is out. 

Assuming the right-bowl is over-filling, could that cause similar issues to what I'm experiencing (sputtering, the back firing/misfiring, the wet, fuel-smelling fouled plug, etc)?

[dirtrider]

2 minutes ago, kmisterk said:

Assuming the right-bowl is over-filling, could that cause similar issues to what I'm experiencing (sputtering, the back firing/misfiring, the wet, fuel-smelling fouled plug, etc)?

Evening  kmisterk

 

It sort of could, not so much the over-filling or rich running as that usually doesn't cause backfiring or misfiring but once the spark plug fouls THAT could cause the backfiring or misfiring.

 

Are you getting black smoke out of the exhaust? That is usually a giveaway on running rich. 

 

Have you checked the air filter for restriction or mouse nest, or full of nuts, corn, or XXX?  

[kmisterk]

4 minutes ago, dirtrider said:

Are you getting black smoke out of the exhaust? That is usually a giveaway on running rich. 

 

Yeeeep. usually right after a small stretch of misfiring, it then kicks in and spits out a good cloud of black smoke. 

4 minutes ago, dirtrider said:

Have you checked the air filter for restriction or mouse nest, or full of nuts, corn, or XXX? 

 

Sure haven't! Man, it's crazy the little things that seem obvious but are so easy to miss when looking at these things. I'll be sure to pop the filter off and inspect, make sure it's not clogged or overly dirty. If a bad air filter was causing a rich fuel mixture, would it not equally affect both sides though?

[dirtrider]

3 minutes ago, kmisterk said:

 

Sure haven't! Man, it's crazy the little things that seem obvious but are so easy to miss when looking at these things. I'll be sure to pop the filter off and inspect, make sure it's not clogged or overly dirty. If a bad air filter was causing a rich fuel mixture, would it not equally affect both sides though?

Evening  kmisterk

 

Yes, but that assumes that both sides are running equal air intake & equal power. It might be effecting both sides but one side is more critical.  Just take a quick look to eliminate an air filter possibility. 

[kmisterk]

Just now, dirtrider said:

Evening  kmisterk

 

Yes, but that assumes that both sides are running equal air intake & equal power. It might be effecting both sides but one side is more critical.  Just take a quick look to eliminate an air filter possibility. 

 

Understood. I will absolutely do so. I've got a little laundry list of tasks to test tonight, none of which require me to do any sort of disassembling of anything. I am hopeful that I can make this thing run smooth by the time the weekend is over. Would be *really* nice.

I suppose in a position where the carbs aren't "Synced" or "balanced", one could be hogging more air or less air, etc. Is it possible, then, that the left carb is running lean, while the right carb is running rich? 

[dirtrider]

3 minutes ago, kmisterk said:

 

Understood. I will absolutely do so. I've got a little laundry list of tasks to test tonight, none of which require me to do any sort of disassembling of anything. I am hopeful that I can make this thing run smooth by the time the weekend is over. Would be *really* nice.

I suppose in a position where the carbs aren't "Synced" or "balanced", one could be hogging more air or less air, etc. Is it possible, then, that the left carb is running lean, while the right carb is running rich? 

Evening  kmisterk

 

That 3500 RPM cylinder shorting test should give you a rough idea on the (above idle)  balance (just be sure the engine has good clean spark plugs in it for the test).  

 

I just popped  in here to give you a way to tell float bowl fuel level & quick cylinder balance power before any disassembly,  you have others working with you on your carbs.      

[kmisterk]

20 minutes ago, dirtrider said:

Evening  kmisterk

 

That 3500 RPM cylinder shorting test should give you a rough idea on the (above idle)  balance (just be sure the engine has good clean spark plugs in it for the test).  

 

I just popped  in here to give you a way to tell float bowl fuel level & quick cylinder balance power before any disassembly,  you have others working with you on your carbs.      

Well, thank you for your insight! 

[kmisterk]

Okay, gonna do a quick followup with what went down today!

 

Thanks to all who helped with recommendations, I feel like the bike is in a *much* better place now, even if she still needs a bit of carb work. 

 

Whelp, here we are: 

 

1. Adjusted the floats.

 

as many have suggested both here and elsewhere, the floats were not closing the fuel inlet when they should, allowing for float bowl overfilling and leaking when sitting. I'm not 100% sure if/how this would affect the symptoms above, but hey. I was able to fix it after carefully bending the float arms to an angle that was, and I quote "Parallel to the bottom of the carb where the float bowl connects."

 

2. Tested the float levels. 

 

Running the engine with the petcocks off for a while let me drain the carbs. Then, with the engine off once more, I let the carbs fill back up again. I didn't have any measuring device with a millimeter scale on it, so I just visually compared the two on a level surface, and as best I could tell, they were the same. 

 

3. Enricher Lever and Cable inspection

 

It was recommended that I ensure that the enricher/choke cable, lever, and controls were all actually performing their tasks as designed. I had to adjust a bit of slack out of the cable and tighten down the lock nut, but even before doing this, the levers on both carbs were actuating as expected per the relevant position of the adjuster control on the handlebar. 

 

4. Airbox and Air Filter Inspection (shudder)

 

This one was a doozy. I actually managed to grab a couple of pictures of this. 

 

Here's an album of the state of the airbox when I removed the filter. https://imgur.com/a/VNAyU0T

 

Basically, the filter itself seemed fine, if only a bit dirty. Nothing worth replacing yet, but I'm exceptionally glad I checked it; The entire airbox below the filter was covered in a good amount of slime of some kind. Liquid, gross, consistency of oil, but colored weird. I couldn't tell what it was, but my best bet was that it was a mixture of oil and ... who knows what else. Is there somehow a way that oil can leak into the airbox like this? Also, what is the red/black tube cutting through the airbox? is it at all responsible for the liquid build-up?

 

5. Throttle Cable Rerouting and Adjustment

 

Lastly, inspired by the recommendation for checking the cables and function of the enricher, I performed similar inspections and adjustments on the throttle. I noticed both throttle cables were not properly seated in the rubber mounting fixture that hugs the main tube on the frame, so I remedied that, and then proceeded to adjust the slack/play on the cables. Eliminating all but a slight amount of slack/play in the cable, I tightened the lock nuts down, which were not at all tightened before, and freely rotating on the spindle. 

 

After all this, the bike is now idling better, and, despite still sputtering a bit while revving (will probably be worse under a load), it is definitively running better than it was when I started. 

A quick video to demonstrate its most recent running state can be seen below. Any hints as to what may still be up? I plan to replace the spark plugs once more when I can tomorrow (Friday the 18th) and assess once more. 

 

 

[dirtrider]

Quote

 

4. Airbox and Air Filter Inspection (shudder)

 

This one was a doozy. I actually managed to grab a couple of pictures of this. 

 

Here's an album of the state of the airbox when I removed the filter. https://imgur.com/a/VNAyU0T

 

Basically, the filter itself seemed fine, if only a bit dirty. Nothing worth replacing yet, but I'm exceptionally glad I checked it; The entire airbox below the filter was covered in a good amount of slime of some kind. Liquid, gross, consistency of oil, but colored weird. I couldn't tell what it was, but my best bet was that it was a mixture of oil and ... who knows what else. Is there somehow a way that oil can leak into the airbox like this? Also, what is the red/black tube cutting through the airbox? is it at all responsible for the liquid build-up?

 

Morning  kmisterk

 

That looks like it might be transmission gear oil in the bottom of your air box. Is the air box secured to the transmission correctly ( I think that the airbox to transmission securing  bolt hole goes all the way through into the inside of the transmission?)  

 

 I see a loose bolt in that oily goo so it's very possible that is the air box securing bolt???? 

 

It also looks like your crankcase venting system has been modified as the hose entering the air box is (was anyhow) supposed to vent into the air horns going out to each carb (through a centered vent tube in each outlet).

 

There is also a duckbill type drain on the air box so make sure that is not plugged and/or the lips are not stuck together.    

 

 

 

 

[kmisterk]

3 hours ago, dirtrider said:

That looks like it might be transmission gear oil in the bottom of your air box. Is the air box secured to the transmission correctly ( I think that the airbox to transmission securing  bolt hole goes all the way through into the inside of the transmission?)   

 

Yep, I can basically assume that's what it was, now, as you're the second one to say so. The bolt was indeed the bottom-bolt, which I replaced and made sure to tighten down securely. I'll be checking this periodically to make sure it doesn't get loose again. 

 

3 hours ago, dirtrider said:

It also looks like your crankcase venting system has been modified as the hose entering the air box is (was anyhow) supposed to vent into the air horns going out to each carb (through a centered vent tube in each outlet).

 

There is also a duckbill type drain on the air box so make sure that is not plugged and/or the lips are not stuck together.     

 

I did think it was odd that the vent tube exited out the back like this. It feels like a modification designed to avoid feeding bad air into the airbox. In any case, I'm wondering if this is cuasing any adverse effects. I don't *think* it would, but I don't know much about these style bikes to begin with. Learning as I go!

Where is that drain usually located? I didn't immediately spot anywhere for liquids to drain by default, but that could have just been an "i don't know where to look for it" type situation. 

[dirtrider]

25 minutes ago, kmisterk said:

I did think it was odd that the vent tube exited out the back like this. It feels like a modification designed to avoid feeding bad air into the airbox. In any case, I'm wondering if this is causing any adverse effects. I don't *think* it would, but I don't know much about these style bikes to begin with. Learning as I go!

Where is that drain usually located? I didn't immediately spot anywhere for liquids to drain by default, but that could have just been an "i don't know where to look for it" type situation. 

Afternoon kmisterk

 

I can't tell you exactly where the duckbill drain is as there are a few different versions of the R100 series air boxes.   Below is a picture of a BMW R100 air box but I'm not sure that it matches yours, but it shows what you are looking for.

 

A lot of BMW airhead riders modified their vent system (most in their own way as it was pre internet) as they didn't  want oil venting directly into  the carb intakes. Some even added an emptiable container to catch the oil, then emptied them occasionally.   

 

I haven't kept up with the current "best practice" R100 venting mods so a dedicated (educated posters) airhead forum would probably be your best bet at finding the best way to configure your venting. 

 

I can't tell from your original pictures but it looks like possibly someone might have routed your vent hose out through that drain hole. 

 

 

[dirtrider]

More__

 

Here is what your original inside airbox venting looked like. Those plastic tubes (red arrows) went inside the air horns that exit your air box, the hoses with the 90° bends connected to those centered plastic tubes inside the air outlets.  (you can see one of the passthrough holes in your above earlier posted picture)

 

 

[kmisterk]

47 minutes ago, dirtrider said:

I can't tell from your original pictures but it looks like possibly someone might have routed your vent hose out through that drain hole. 

 

Pretty sure this is exactly what happened. Could be problematic. I am unsure how I want to proceed at this point. Gonna think on the venting situation and get some ideas from some of the more airhead-specific forums I cross-posted this to. 

Thank you for all your help, you've been fantastic!

[Hosstage]

It is common in the Harley world to reroute those breathers away from the air box and vent to the outside world. Pulling oil mist and water vapor back into the carb or throttle body makes for a mess long term, and can add to the build up of carbon on the piston and head.

[kmisterk]

3 hours ago, Hosstage said:

It is common in the Harley world to reroute those breathers away from the air box and vent to the outside world. Pulling oil mist and water vapor back into the carb or throttle body makes for a mess long term, and can add to the build up of carbon on the piston and head.

 

Yeah, that makes a lot of sense. Why would it be routed into the airbox to begin with? That doesn't make sense to me. Emissions? Maybe?

[dirtrider]

1 hour ago, kmisterk said:

 

Yeah, that makes a lot of sense. Why would it be routed into the airbox to begin with? That doesn't make sense to me. Emissions? Maybe?

Evening kmisterk

 

I'm sure part of it was due to tightening emission restrictions but not all of the reason.  

 

For one reason you don't want a slug of oil to end up on your rear tire.  No problem if it just puffs out some oil fumes but a shot of oil out the vent onto your rear tire is not something that you want to happen when leaned over at speed.

 

My one complaint of external venting is drops of oil on my shop or garage floor after parking the motorcycle after riding. 

 

I always allowed my R100 airheads to just vent into the intakes but I kept my engines in good shape so they didn't vent much of any oil out. 

 

Some removed the intake path venting as they believed (possibly correctly) that those plastic tubes with centering fins restricted air flow through the intake.

 

On the later BMW oilhead motorcycles BMW vented the crankcase into the air box but added a bottom chamber below the air intake section to catch & hold any vented oil. There was also a drain on that bottom chamber so the rider could drain that lower air box once in while if they  thought about it. 

 

Some played with venting changes on the R100 airheads & others just allowed the thing to vent as BMW designed it (I was one of those). As mentioned the  later 1100/1150 oilheads  vent into the air box & nobody (that I know of anyhow)  ever fools with trying to vent externally. 

 

See what the present trend is with venting the BMW R100  airheads as maybe someone has come up with an elegant way to do it without oil spots on your garage floor.

 

Personally, if I was going to do something other than stock  I would probably add a catch tray (or catch container) inside the air box, then terminate the vent hose into that, then I would add a small tube drain to that internal tray coming out through the rear of the air box with a valve that I could open once in a while to drain that internal tray.   (at least it works in my mind at the moment)

 

That venting issue is not something that I would even be worried about at the moment if that vent hose just passes through the air box & vents out the rear. It should run fine like that so first thing is to get it running & riding good then get all the other things found & repaired. 

 

That venting thing can be updated or changed at about any time in the future so it isn't something that needs doing right now.   

[Skywagon]

In the catch basin DR mentioned, I used a small plastic container stuffed with Brillo Pads before… if you decide to go that way. The Brillo Pads help absorb and if you get much oil over a year or so it keeps it from sloshing around. Following to see what ultimately turns out to be your tune issue 

[kmisterk]

4 hours ago, Skywagon said:

In the catch basin DR mentioned, I used a small plastic container stuffed with Brillo Pads before… if you decide to go that way. The Brillo Pads help absorb and if you get much oil over a year or so it keeps it from sloshing around. Following to see what ultimately turns out to be your tune issue 

loooove the idea featuring the Brillo pads in a container. May use that idea. 
 

So, I went on that “25-30 mile ride” I was talking about after finally swapping plugs in for new, non-fouled ones (a paltry 30-40 miles into riding with them, bah), and I ended up going on a much longer ride than intended. I didn’t want to stop, the bike was running *so* incredibly well. 
 

In any case, I’m thinking that closing up the screw hole once more in the bottom of the air box paired with tightening up all the cabling and fasteners related to them got the bike back to a fairly healthy state. She was pulling harder than I feel like I’ve felt before, but that may also just be a sort of placebo effect. 
 

All this considered, I’m postponing rebuilding the carbs for now. I did buy the components to do a rebuild today, for when I want to end up doing it, 

 

6 hours ago, dirtrider said:

That venting issue is not something that I would even be worried about at the moment if that vent hose just passes through the air box & vents out the rear. It should run fine like that so first thing is to get it running & riding good then get all the other things found & repaired. 

 

That venting thing can be updated or changed at about any time in the future so it isn't something that needs doing right now.   

 

Yep! Makes sense. I do want to reintroduce a method of venting that allows for proper draining of fluids from the lower air box by design, as well as feed the vent tubes elsewhere. 
 

All in all, I’m super happy with the results of the fine tuning, adjustments, and tightening of various nuts and bolts. 

[kmisterk]

Oh! Forgot to post the video I took most recently of the engine and how it's running *now*. It's *So* nice.