Gearhead

Thanks!

Howdy folks. Quick question: do the Mk II's (87) also have the plastic water pump impeller from the factory?

Quick question: do the Mk II's (87) also have the plastic water pump impeller from the factory? Congrats Cap on the fix. Quite an adVenture you had!

Thanks. And I still have a bike... But it's finally only one bike! The VStrom keeps me entertained these days.

After finishing up this project in September as reported, the bike has been for sale on Craigs and FB Marketplace. Turns out it's not that easy to sell an old but nice, high mileage, full-dress touring bike in Autumn and Winter. Dang. Had several trade offers...no thanks, I trade for cash...until someone traded me an old, high-end Fender Stratocaster that tickled my fancy. Takes up much less space than the Venture! I watched my ol' friend ride off a week and a half ago. So, buyer-Charley is happy, I'm happy, and the ol' friend is back on the road daily like it should be...with a new friend. This community has been so soo awesome and helpful over the years. Holy cow, I joined in 2006 and made almost 1000 posts! Tempis fugit, as they say. Thanks to ALL for your kind participation. Special thanks to the tech gurus along the way, most recently Puc and Patch (and many others). And extra special thanks to Freebird for holding it all together and keeping this ship afloat. I am thankful to you all. God bless! Jeremy in Tucson

FINAL UPDATE: for anybody who’s still reading. I reached a 97% solution. Good enough. Pilot screws are still out too far, but once fairly warm the throttle response off idle is pretty good, and it feels good taking off with the clutch now. The bike is ALL BACK TOGETHER with all the plastic installed for the first time in 3.5 years, and it feels good! Key points: #155 Pilot Air Jet#2: This is an important aspect, down from stock 170. If I had a little smaller ones like 140, I’d try those, but I don’t. If I wanted to take the carbs apart again I’d try 42.5 pilot fuel jets (stock 37.5), but I DEFINITELY don’t want to do that! Aftermarket Slides: I realized that the aftermarket slides don’t quite clock the slide correctly with respect to the carburetor. The diaphragms are rotated a bit on the slide bodies. All 3 are the same, so they just seem to make them this way. I compared them to my 4th slide which is a low-mileage used OEM part. The lift hole is supposed to be straight down toward the throttle plate, and on the aftermarket ones it was off by maybe 15-20 degrees to one side. I trimmed the clocking tabs off the diaphragms and rotated them so the lift holes were straight down. I think this made a small difference in slide and throttle response. Pilot Screws: Patch, I followed your suggestion and tried riding the bike with all the screws set at 2 turns, 4 turns, and compared to the settings I came up with for best idle. The differences in throttle response were quite small, which is a little surprising to me. I left them at what seemed like the best for idle and throttle response: #1 – 4.5 turns, #2 – 3 turns, #3 – 3 turns, #4 – 3.5 turns. At all-2-turns it wasn’t bad. Idle speed was down maybe 100 rpm, throttle response off slightly. At all-4-turns it was almost the same as my optimal settings. Last Question: Does ANY fuel come out of the needle / needle jet at idle? If so, maybe replacing my old ovaled-out needle jets (with factory new) was the “big change”. Takeaways: - Just because I think I can understand everything doesn’t mean I actually will! - I still don’t understand what makes it different from before the teardown requiring a jetting change. That just feels wrong. So be it. - These Mikuni carbs are complex, more so than some of the other MC carbs I’ve worked on. - Aftermarket parts always carry some risk of being not totally right. - Choosing to forgo complete carb rebuild kits and piecemealing instead is risky, can cause much time and expense in the long haul. That said, this approach has worked fine a number of times in the past. - Thank God for this community who loves to help, particularly Puc and Patch! Jeremy

Today I replaced 8 tiny o-rings - 4 on the pilot screws, 4 under the diaphragm caps. They seemed OK and weren't high on the suspect list, and I don't think replacing them changed anything :-( Per Patch's suggestion, I removed the air filter and lid (airbox bottom in place) and observed the slide movements. It doesn't run right or take throttle well at all like this, but I remember that was always the case; I think it's normal for these bikes. I posted some videos, get 'em now before they go on Netflix None of the slides stick. The light reflects differently off #2 than the others which makes it look different already on the videos, but I think #2 consistently moves more vigorously and responds quicker than the other 3. What's interesting about that is that #2 IS different - it's a OEM part with limited use on it. The other 3 are all new aftermarket replacements that I just bought a couple months ago. I verified that the slide lift hole is the same size on the aftermarket units; I'll double check that it's oriented correctly. Tomorrow I plan to run it with pilot screws all at 2 then 4 turns and observe any difference, then take a look at the slides and needles. Maybe I'll shim the needles up .020 per Puc's suggestion. Jeremy

Gotcha, they are clean. Slides are new and move freely. Springs are stock, same as I pulled out. I need to run it and observe with the airbox lid removed. Needles look good. Emulsion tubes are NEW – so that’s a change from before I took it apart. They were worn oval, so were rich, now are not. I ordered factory parts from Yammy, so they should be good. Fuel level is good and consistent, and the bike pulls great under WOT. These two things make it unlikely that fuel supply to the carbs is insufficient. I tried replacing the Pilot Air Jets#2 this morning, out with the stock 170’s, in with 155’s. It did fatten the pilot mix just a bit. Throttle response is slightly better, but not quite perfect. Pilot screws are a little more reasonable, but still don’t behave like I am accustomed to. Remember that before all this nonsense I had them tuned to 2 turns or less. 1 – 3.5 2 – 2 3 – 2 4 – 3 If I screw them in more the idle degenerates and the throttle response gets worse. I haven’t tried yet to set them all to 2 and then to 4 turns, need to do that. BUT, lean pilot usually causes a hanging idle, and I don’t have that symptom! O-rings seemed fine. I will replace them. The screws look normal, same as when I first pulled them out. The tips look good to me. I didn’t connect a tach, was setting by ear for max rpm, so I don’t have a rpm drop figure. I can try to connect my tune-up tach, I think I’ve done it before. Jeremy

Thanks Patch. Looking for clarification on this. Are these tiny ports you are referring to in the jet block? If so, I cleaned them as well. If not, help me find them! Thanks! Jeremy

Just a little bump on my last question. Does 160 seem a good size to try for the pilot air jet 2? Also, I should know this, but are those the same jet type as the main jet?

Been doin other stuff, can't work on the Venture for a couple more weeks. I talked to Puc (thanks again) and have a couple things to try from him and Patch. Puc suggested raising my needles with one washer, just to see what happens, cuz it's pretty easy. Got me thinking. I've been approaching this not as a tuning issue, but rather a "something went wrong" issue. Which still seems like it must be the case, but I can't find it. At this point, what if I try a little smaller pilot air jet #2? They are easy to get to under the diaphragms, and I know that will richen the mix at idle and initial throttle response; remember when I plugged those jets with toothpicks? My pilot mix got WAY rich, makes sense. So I'm thinking about picking up a set of, hmmmm, maybe 160's to replace the stock 170's? Opinions? Does anyone know offhand what type of Mikuni jets those are, and the cheapest place to buy them? Thanks, Jeremy

Must be my old home number. Just pm'd you my cell!

I just wanted to offer an update on the particular question I posited about the Coasting Enricher system: "Are there any other side effects to disabling this system?" (Read OP for details.) I don't have a bulletproof conclusion due to the way everything has gone down, details in my main Carb Problem thread. https://www.venturerider.org/forum/s...67#post1062867 But at this point, my testing suggests that the answer is NO. If you block the vacuum ports to the Coasting Enricher diaphragms, I believe the carbs will work just fine with the exception of popping in the pipes on decel. I had not found much on this topic, so I wanted to offer my semi-substantiated conclusion to wrap this thread up. Take it for what it's worth!

Hello helpful fellow Venturers. I’m sad to report that I have done ALL the stuff and the bike runs the SAME. Seriously. After putting it together the first time 2 or 3 months ago, it ran great at anything mid range or top end. It was lean on the pilots, had pilot screws way out to help compensate, but it wasn’t right and wasn’t quite enough so it had a bit of a stumble off idle. And now it still does the exact same thing. Since that first time, as a recap, I’ve replaced stiff / sketchy slides, replaced and re-enabled the Coasting Enrichers, replaced the jet block gaskets and a few other things, fine-tuned the float levels, de-carboned the engine per the enclosed instructions, thoroughly checked out the spark and timing, and probably a few other things. And it runs EXACTLY THE SAME! I can’t remember a time I’ve been so frustratingly unsuccessful with an engine. That tells me the carbs aren’t really ALL THAT sensitive to minor stuff, but they’re sure sensitive to something I did. Before I took these apart way back I had the pilots set between 1.5 and 2.5 turns and off-idle response and power were fine. PATCH – COWPUC – MARCARL – ANYONE ELSE WITH CARB EXPERIENCE - I’m issuing one more call (beg?) for a great idea before I sell the bike as-is. In retrospect, I shoulda sold it 2.5 months ago. Actually, in better retro-retro-spect I shoulda sold it 3.5 years ago before taking it apart in the first place. Here’s my current stats / adjustments: PILOTS (turns): 1 – 4.5 2 – 2.25 3 – 2.5 4 – 3.25 So overall, they are a bit less “far out” than some of the previous iterations. But not normal. COMPRESSION (PSI, checked cold as before, 5 revs / 10 revs): 1 – 180 / 190 2 – 175 / 185 3 – 180 / 190 4 – 180 / 190 Just slightly less than before de-carboning. Very consistent, did each one 4+ times. I checked my gage with my shop air, and it’s quite accurate at 95 psi. FLOATS / FUEL LEVELS (idling, spec is -15.5 to -16.5mm): 1 - -16 2 - -16 3 - -15.5 4 - -16 I mentioned that sometimes #4 would change levels, dropping and sometimes rising rapidly. I think I figured out why. The engine was HOT at that point, burns on the backs of my fingers to prove it. I did #4 last. I think fuel boils in the tube right where it comes out of the bowl when I take too long and it has time to heat up. If I drained some fuel from the check tube and quickly checked again, it would be steady. There’s no way that a sticking float would cause the level to drop quickly…rise, yes, but not drop, because an idling engine doesn’t use fuel fast enough to do that. Anyway, all good now. SYNC: I did the bench sync, then small adjustments with mercury sticks while idling, maybe ¾ turn max. The work done this last time was de-carboning the engine according to Patch’s procedure (and yes, black stuff came out), new Coasting Enricher diaphragms, another thorough check of #3 pilot circuit, and adjust #3 and 4 floats. Lots of oil changes afterward, one more to come. A couple other observations: -- As before, the hotter it gets the better it is, consistent with lean. It’s ALMOST normal when good and hot, but a quick rev off idle, or taking off from a start with low revs reveals the hesitation. When only “warm” but not “hot” it is more pronounced. -- I checked for vacuum leaks with water, carb cleaner, and an unlit propane torch. Sprayed all 3 (separately of course) EVERYWHERE on and around the carbs, no effect on idle at all. -- It sure does act like it’s getting extra air from somewhere, or kinda like the airbox is not installed. The spray check shows no leaks, see above. -- If I shot propane into the airbox intake for a few seconds, it would start to die from lack of air. But if I shot it in there just for a second and revved the engine, it revved quickly and took throttle like it is supposed to. It needs that extra fuel. -- Regarding the pilot passages in the main carb bodies: there are 2 places the pilot mix comes out, at the adjustment screw and at a pattern of 3 tiny holes near the throttle plate. When I had them apart, I could SEE on all the carbs the spray flowing freely and equally from all those holes. This was when I had the jet blocks off and shot fuel in the appropriate port that leads to that area. -- I'll mention the pilot jets again. I've stuck a wire thru them, soaked them a bit, shot spray through them countless times, blew air, and looked at light thru them carefully with my reading glasses on. All 4 are (and always were) clear. The light visible through them is round and the same size on all 4 of them. I know these are the first suspect, but they are clean! Well, that’s all. Thanks for sticking with me through this trial. Special thanks to Patch who surely knows more about how the IC engine works than most of us have forgotten. Remember, I’m still looking for that one genius idea…. Jeremy

OK, cylinder fogging / soaking in progress. Carbs in work...again. Coasting Enrichers, new diaphragms installed, restored to normal functionality. Carb#3 - verified once more that all pilot passages are PERFECTLY clean. Addressing float levels on #3 and 4. Reminder, checked per the book with the engine idling, spec is -16 +-.5 mm, #3 was at -17mm (1 mm low), and #4 moved around from -17 to -20mm, mostly between -18 to -19. There's a couple things weird about these. First, the moving around of #4 is obviously weird. FP is producing plenty of flow, evidenced by key on open flow, and also the fact that the bike runs great while hard on the gas in an acceleration run. Other 3 carbs are rock steady. Seems like float must be sticking, but I seen no evidence of that, or any reason why it would stick that I can tell by looking in there. That said, it's difficult to tell for sure because it might be hanging up on the fuel bowl which is removed for inspection. Another thing, looking back in my records, I checked the fuel levels a couple times before. #4 has always run a little low, and not super consistent, so this is an old and persistent condition. Ideas? Second, the levels I'm measuring 1) on the bike idling, 2) wet on the bench while tapping carbs, and 3) dry on the bench aren't consistent. I'm assuming method 1 should be the trump method, the one method to rule them all The others are in-process indicators. When I bench checked them (method 2) over a month ago I found #3 and #4 to be spot on, but then on the bike they ran low as indicated above. And using method 3, these two floats have to be set quite high compared to how others set their carbs, as if my floats are super buoyant. Refer to the following thread about bench testing, post #4 , my floats #3 and 4 are now set to 25.5mm by the measurement shown in those photos: https://www.venturerider.org/forum/showthread.php?138114-When-Bench-Testing-Carb-Float-Levels-Should-Fuel-Be-Added-Under-Pressure&highlight=float+adjustment One thing that just occurred to me is to be very careful about making sure the carbs are very level when checking this wet. I'll put a level across my intake boots to verify that the bike is level on the center stand, and I'll do the same on these carbs when I bench test them wet again. Jeremy

OK. So the carb cleaner isn't for decarbonizing, but rather for a starting aid? The Deep Creep does the decarbonizing?

Ok, it sounds like you are recommending another oil rinse But do I have the steps right otherwise? And which first... the carb cleaner or the Deep Creep?

OK, just to clarify on the de-carbonizing. One thread says do Deep Creep first, then carb cleaner. The other says carb cleaner first, then Deep Creep. What do you recommend in this case? So the process is basically: Fill chambers and intake ports, let soak for a day Blow out with air Fill again, turn motor a little Repeat the above with carb cleaner AND Deep Creep, 2x each? After last blow-out, drain and refill oil Reassemble bike and start, warm up, tune carbs Shut off Check compression Change oil and filter Done. Do I have that right? Thanks, Jeremy

So Patch, the Service Manual says to fine tune the carb sync with the merc sticks. Do you recommend that as well, after starting with the bench sync?

Ok...OK...I'll do it! I have the Deep Creep, extra motor oil, and need to go review the fogging procedure. I may write back with another question or two on that. I also ordered 4, count 'em, four, new Coasting Enricher diaphragms (I have them out again and they're all shot). Oh, before I split the carb rack, I inspected the sync of the throttle plates. I visually compared them to the pattern of 3 holes that are more or less covered by the edge of the plates at idle, and I also used a feeler gage. The 4 carbs were VERY close to the same as each other by those criteria. I think the carbs were sync'd. More to come

Patch, thanks again for all the time you are putting into this. I've let it sit while I tend to the rest of life. Just to 'splain briefly, the "toothpicks in the Idle Air Jet #2 " was not intended to be a mod, just a test. I was trying to characterize the contribution of those air jets to the idle mixture, to help possibly understand the Coasting Enricher system behavior. Jeremy

Thanks for all the input Patch. TROUBLESHOOTING UPDATE: IGNITION: - Verified all connections - Removed wire caps and snipped a bit off the wires - Spark check - I don't have a checker for this. Cranked motor with a screwdriver in the cap and held near the engine. All four produced a healthy spark that would jump about 1/4" plus. Also checked a spark plug in a wire, grounded the threads, and cranked engine, producing a consistent spark. - Timing - verified two things. 1) the rotor has not rotated, verified #1 TDC with a rod in the spark plug hole. 2) Ignition timing for #1 at idle is in the specified range, and advances when revved. - Finally, with engine idling and warm, pulled each plug wire, one at a time. Each cylinder cutting out dropped the idle from ~950 down to ~800 rpm. Each cylinder seems to be contributing the idle approximately equally. CARBS: - Double checked pilots. Made small adjustments, but still pretty much need to be out too much - 2 to 4.5 turns. I did notice one other anomaly: #3 pilot didn't affect idle nearly as much as the others, even when totally screwed in. - Double checked fuel levels. Came out about the same, #1 and 2 on spec, #3 - 1mm low, #4 - 2 to 3mm low. Clearly this needs small adjustment. - Symptom the same - idles fine, but doesn't take throttle quite like it should, slight hesitation. - Checked for vacuum leaks while idling again, this time with unlit propane torch. Nuthin'. - Plugged Idle Air Jet #2 with pieces of toothpick, see pic. This is the #170 jet under the slide which gets closed off under high engine vacuum by the Coasting Enrichers, which I disabled. This produced marked results. -----Engine clearly idles rich. It actually idles best with pilots screwed all the way in. Had to adjust main idle screw. -----With the pilots set at 1/2 or 1 turn out, the engine took throttle MOST EXCELLENTLY off idle. This was encouraging. DISCUSSION IDLE AIR JET #2 AND COASTING ENRICHERS: I had thought of the Coasting Enrichers as a binary thing - on or off. Maybe not. Perhaps it engages and blocks off the Idle Air 2 passage gradually, and partially at idle? My bike is too lean on the pilots with them totally disabled, but too rich with Idle Air 2 blocked off. Make sense? See attached diagram from Service Manual p5-2. Idle Air Jet 2 is part number 5, and the air flows through it as shown in red until it meets up with the rest of the pilot circuit. With the Coasting Enricher in its normal, at-rest position, the valve center piston (labeled "A" in the diagram) is down as shown, and the air passes through that gap as shown. Under high vacuum, the valve piston is pulled upward as shown by the red arrow, blocking the gap and thus the airflow from Idle Air Jet 2. That's how it "enriches" - by blocking off that air source to the pilot circuit. The engine vacuum gets above the diaphragm through that passage on the upper right, which I blocked off in one of my genius moments. As I said before, I did this because one or two of the diaphragms are compromised, they are spendy, and my research seems to indicate this feature is ONLY operational under the throttle chop condition, and otherwise that gap is completely open and air flows freely from Idle Air Jet 2. But now that the potential sources for my problem are dwindling, and with what I found in my experiment, I have to wonder if that's not true. Maybe idle vacuum pulls the pistons part way up and meters a lesser amount of air through. There is also the possibility that the carbon buildup on the pistons is doing this to me. I believe that it could. But it didn't have this problem before I tore it down, and the carbon buildup didn't change with the bike sitting in the garage, did it? Maybe low compression can happen under those conditions from the rings getting stuck, but not more carbon buildup? And I've had a lot of old engines in worse shape than this one, never had this symptom before due to carbon buildup. So I'm thinking the carbs come back off. First thing, I'll visually check the throttle plates for their state of synchronization (bench sync). I will then adjust the two errant floats and re-enable and repair the Coasting Enricher system. I'm reluctant to do the combustion chamber soak because I'm not convinced it needs it, and due to the mess and fine grit tradeoff, but still considering that. Patch? Puc? Anybody? Whaddya think? Are there any more tests that should be done before disassembly? One more thing: You're right about having the parts on hand saving effort. If you've worked on these carbs you know that parts ain't cheap, and everything is x4, and (true confession) MY NAME IS JEREMY, AND I'M CHEAP! So I cheaped out. I've done this many times in the past and it worked out OK, particularly with bike carbs - clean up the old parts, make the adjustments, and everything is fine! But this bike IS 32 years old, the others probably weren't. Actually, the last other one I worked on was an 80's Gold Wing belonging to a friend, and he had to buy quite a few of these parts also...but it was his money, not mine!!! But I will say, those carbs 1) didn't have Coasting Enrichers, and 2) the slide / diaphragms were fine, so either they had been replaced or Honda slides are better built than Yammy slides. Oh well. Jeremy

So Patch, on the Coasting Enrichers, do you agree with the majority opinion out there that they only "enrich" momentarily under throttle chop conditions, and NOT at idle? Now if you can't maintain idle then how are you balancing? You can't be running the enricher? I didn't say it won't idle. It idles pretty smooth with the pilots out 3 to 5 turns. But it hesitates taking throttle off idle, pretty much every time. Jeremy

Thanks, will keep you posted.

Yes I have read it. Lots of good stuff. Fogging would have been a good idea for me, but of course I did not intend to take a 3 year hiatus on the project! But given my indoor, mild temp storage environment and good compression readings today, I think I'm OK there. Stuck rings would tend to lower compression, yes? And usually not evenly across the cylinders? Compression test by the book is to be done hot; I did mine cold. Not sure if they read higher or lower when done cold, I can see arguments both ways but have not tried it to find out. Anyway, the manual lists the following: - Min - 142 psi - Std - 171 - Max - 199 I'm right in the range between Std and Max. (I have not had my gage calibrated, so that's a variable.) I guess that probably indicates a little carbon build-up, which is fairly common I'd say, but shouldn't be problematic...do you agree?