circa1968

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!

Thank you for that Patch. I mostly followed you on that explanation. Not to toot my own horn, but back in my day I was very good and well known for my troubleshooting skills of computer/electronic systems (I worked in both Mfg & Development). I like challenges and, when faced with a new one, I always try to first obtain some basic knowledge of how the thing is supposed to work before I can figure out why the thing does not currently work. Hence my frustration here and grasping at straws (definitely not my normal approach). I think I was hoping to get lucky with a quick and simple action. Thanks for getting me on track and the education. I think I'm on day 2 of school here but loving the learning. I'm slowly getting over my fear of screwing something up too. And we're heading into cooler/wetter weather so I guess even if I do, I have more time to unscrew it. haha Attached is a pic of the plugs I removed, but failed to track from which cylinder.

Hi Puc, Up until this last ride, and maybe one other time, the two back pipes did not read the same. I am able to take the exact same reading (directly on the pip, same angle, etc) on both of them. #1 is always ~400+ and #3 was reading the same (~200) as I got on the #1 & #2 flanges. I guess I made a bad assumption there on those readings (pipe vs. flange). Part of my learning/education process. I guess I see now the difference in thermal mass, but not sure why I was seeing such a difference, directly on the #1 & #3 pipes before. And for what its worth, #1 gets to that temperature within minutes. From what I'm learning from all you zen masters, that sounds like it is running lean and now maybe the same for #3. I'm going to follow Patch's bench sync advice and see what comes next. @bpate4home Yeah, I hear you and having an EE background that was my first instinct also. I hooked up 12 v to the fan connector and confirmed it came on and then also got her warm & let it sit until the fan kicked on to confirm all the other sensor & control circuitry works. If it makes small sparks, I understand it. Its all this big, controlled explosion stuff that's outside of my wheelhouse!

Thank you Patch. I understood your procedure perfectly and will follow it. Unfortunately, I did not track the plugs when I removed them, but have a few miles on the new plugs, so will pull them & get pics to see if that is of any use. I will also take pics of the old plugs, for what that's worth. I'm pretty mechanically inclined and have an engineering degree and a quick study of most things that come along. I like challenges, just have zero experience working on engines or carbs and don't want to screw anything up. But that said, I've learned a lot already and each new step leaves me wanting to learn/do more. Fascinating stuff. I did get out for a ride yesterday. the cooling issue seems to be much better. I noticed it getting warm a couple times when in traffic, but out on the twisty road had no issues. Of course it was also in the 60's vs. 90's when I first got the bike and noticed the heat. At the end of my ride, the radiator was reading ~200F, a little warm, but seems mostly normal. #1 & #3 (two back) were reading 400+ on the exhaust pipe (#3 was not this high previously). #2 & 4 were reading ~200ish but I can only check those on the mounting flange, not the pipe itself. For what its worth, when I check the mounting flange on #1 & #3, instead of the exhaust pipe, they are also 200ish. Again, I sincerely appreciate the help and information!

Clearly I'm in the right place....

Sorry, couldn't resist... I'm one of the newest members here and have quickly grown to appreciate this site and group. Love my Venture and couldn't wait to make a little bike art with her to share with y'all. Enjoy!

Ragtop, not sure if you are getting my PM replies but I sent you photos of what I have to confirm its correct and you can have it for the shipping cost. I don't plan to use it and if it helps you out I'm happy to send it your way!

Thank you for this video and info on the NAPA filter. I spent the better part of an hour repositioning the myriad hoses in that area from the rats nest they were (drove me crazy every time I looked at that) to make them more cleanly routed, freeing up enough space to put the filter in the hose area. See attached photos. A couple of key things to make this work: Remove the u-shaped hard rubber tube on the hose from the filter to the pump, this makes it easier to reroute it. Rotate that little black can, held on by the white p-clamp w/ the PIA screw/cap nut, ~45 degrees towards where the filter used to reside. loosen the hose clamp & rotate the pump hose going to filter ~180 degrees. Its preformed to go down from the pump and you want it to go up and back. I had a good bit of extra hose length going from the tank to the filter and did not want to cut it, so basically had to snake it around a bit under the tank, making sure not to have any kinks. Its not currently secured in position w/ any zip ties but just a tight friction fit and the hoses sorta holding it in position. I may take a second look at ensuring it cannot move and add some zip ties to be safe.

I did not adjust the mixture screws. Are those the ones behind the plug that has to be drilled out? I will wait to see if a clean filter and clean tank with fresh gas helps before jumping into that.

Quick update. I think (hope) good news on the running hot issue! I took it out for a short run today and it subjectively felt much better, so when I pulled back in, took a few quick measurements while it was still running. The radiator was measuring 178F top & bottom. I went back through some notes and found I had measured 220F a few weeks ago! For what its worth, it was in the 90's first reading and in the 60's today. Here's what I did yesterday: 1) Drained coolant. 2) Removed fins & emptied the cyclinder cooling jackets. 3) Refilled w/ distilled water & bled all the air out of the system. 4) Repeated steps 1-3. Yes, two flushes w/ distilled water. 5) After completely draining the system of water, I used some red-neck engineering to apply air pressure @ the radiator cap with one cylinder jacket plug removed at a time. This blew out more than what was simply drained. 6) Removed the water pump cover. A bit more water drained out and I did not see any thing abnormal there, so buttoned it back up. 7) Refilled w/ 50/50 mix, bled out all air pockets and wrapped it all up. During this process, there were small bits of black gunk, maybe slime or degraded rubber. I'm not sure what it was, but not a lot and very small bits. Also saw 2-3 small white pcs of what looked like calcium buildup, but not much of that either and they were quite small. The one thing that surprised me was behind cylinder plug #3, I saw a small pc of something with a tan color. Using a pick and tweezers was able to retrieve a small pce of what looked like thin plastic. It was a bit chewed up and deformed (see attached). I have no idea what this is, but its no longer in my cooling system! I can't say if this unidentified object, an air pocket in the system or something else was causing the heat issue, but it seems to be behind me now (hopefully)! I synced the carbs and still getting a high temp reading on exhaust #1. Also, idle is all over the place but that could also just be the cheap ebay tach I'm using. It does idle rough/low until thoroughly warmed up. I will be changing the fuel filter next, and then completely drain the gas tank, make sure it is clean and go down to home depot to buy an insanely expensive gallon of REAL gasoline, with no ethanol. The latter is just to start with a baseline of ruling out crappy gas. Question for the gurus here: @ 21k miles & 13 years old, should I take it in for a valve adjustment? I know it can't hurt, but in your opinions is it worth it? Thank you all again for your ideas, support and encouragement!

I just took the CB unit off my bike. PM me and we can work out the details to get mine to you.

So, after syncing the carbs, both back exhaust (#1 & 3) are now running 200 deg hotter than the front. wth? Normal? I'm going to buy a small hand vacuum pump to test the gauges and verify they are all consistent. Idle is bouncing around within a 100-150 rpm range. Normal? Also, the bike still runs hot, its like riding a weber bbq grill. I checked the tank temp, right where my legs touch and it was 105 degrees - with a nearly full tank of gas. I've been thinking of ways to check the whole system to verify coolant is working its way all the way through. I suspect either blockage or an air gap somewhere, although I did "bleed" it when changing coolant.

My sync gauges showed up at the end of the day today, a day late. So much for Amazon Prime. I will be doing my very first carb sync tomorrow. Sorry to hear you are having same issue, but I feel a bit better now knowing this may be a more common, & easily solvable issue, than I thought. Still hoping this is the root cause of my heat issue (my heat issue being me boiling in short order).

I wondered about that too. I have been checking top & bottom of radiator, I don't have the #'s off the top of my head, but did not seem out of the ordinary. In the range of 200 deg, IIRC. I just put in iridium plugs and will get a pic of the old plugs.

Puc, I went down the air flow thing as my first attempt to solve the heat issue. The previous owner put a shiny chrome piece over the radiator. Took that off away, didn't like the look of it (yes, there can be too much chrome) and didn't see the point of blocking even a little airflow. I have had the tank, seat, etc off several times and no signs of anything out of place that would restrict airflow. Today, I measured the heat diff on #1 within two minutes of a cold start, but I didn't log anything in terms of specific times or temps. I'm running 87 octane fuel. I ordered the Alpha Moto guages from Amazon: https://www.amazon.com/gp/product/B004MSE9JO/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1 I decided to soak the float bowl in SeaFoam overnight, clear it out tomorrow morning and be ready (hopefully) for the sync. To fill the bowl w/ Seafoam, I first drained it then closed the tank petcock and disconnected the fuel line from the tank. Next, with the drain screw closed, I simply turned the key to ON (didn't start the bike) which triggered the fuel pump to run and refill the bowl with residual gas in the line. Rinse & repeat until there's no more gasoline in the line, pump or bowl. Now I used a nice little squirt bottle from the kitchen (hehe, don't tell my wife!) to put straight SeaFoam into the fuel line, turn the key to ON and let the fuel pump fill up the bowl. I was pretty damn proud of myself for coming up with that! You guys are making me dangerous but I'm sure others who are much smarter figured this out long before me. My plan is to repeat the process tomorrow with a 50/50 mix of seafoam/gas before firing it up. I've seen some youtube videos of others professing to have had success with this approach. I'm captiously optimistic this, along with a sync will bring success. Or perhaps its just wishful thinking and I'm about to learn a whole lot more about carbs than I ever intended to... Grateful as always for your input!!

BlueSky, I think I did a cheap version of the sotgun method that just involved squirting some Seafoam down the pilot jet and air jet. Now I found a better description of what I think you are referring to that involves pulling the slide and mixture screw. That may be more involved than I'm comfortable with at this point, but desperation has taken me down riskier paths before.

Puc, I had been checking after a ride, ~10-20 minutes, enough to get the bike thoroughly warmed up. Today, for whatever reason, I decided to check it before warmed up. After about 2 minutes, the #1 exhaust was already @ 400deg. I think this firmly affirms what you and BlueSky are telling me & trying to get through my thick skull - its running too lean on that cylinder. Thanks BlueSky. I will give that a try today. I saw a VMax video of someone doing it w/ gumout & getting good results. All I had on hand was Seafoam, so used that. I will pick up some gumout, try that. If still no luck, will then go to carb cleaner. Sync gauges are due tomorrow. Again, my appreciation for the education and encouragement. You guys are awesome!

Puc, I'm using an IR thermometer to measure the header pipe as it comes out engine. There is a ~1" gap between the heat shroud & the engine. I've attached a few photos showing the two rear exhaust. Is there a better method? I've gotten consistently high readings off the 1 cylinder exhaust, tried different angles, distance, etc and still the same results. I can get to the two front ones as well. Three cylinders are consistent & #1 is always ~200 deg higher.

Quick update: I tried Cowpuc's propane method of looking for a vacuum leak and did not notice any change in idle while doing so. I also drained the carb on that hot cylinder and did not see any gunk or discoloration. After a little research on BlueSky's shotgun method suggestion, I did that using straight Seafoam. I put it all back together and went out for a quick test ride. Very subjective to my feel & memory, but it ran and accelerated much smoother. However....that exhaust header on #1 is still running 200 degrees hotter than the others. I also dumped a full can of SeaFoam into the full tank, in addition to the 1/2 can that was already in there. I just ordered a set of vacuum gauges to sync the carbs. They are due tomorrow. Also ordered a new radiator cap (likely has nothing to do with it, but why not). When that comes in I'm going to give the coolant drain/flush one more shot, including pulling the cooling fins and draining the cylinder jackets. Is it possible, or perhaps even a good idea, to try to use some low air pressure applied to the cylinder drain to blow out any possible clogs in the system? Thanks again for all the advice and encouragement!

You two are gentlemen of the highest order! Thank you very much. And big thanks to Don for putting this site together, best $12 I ever spent! Just as soon as I'm ready to throw in the towel, you two give me new hope and motivation to keep trying! BlueSky, I added a can of seafoam to a full tank the other day but haven't put more than 20 miles on since. How long do you think it would take to work its magic? The background on the bike is I bought it in Sept from original owner (this is my 2nd time around w/ the RSV, having owned a '99, pre-parenting). It's a 2007 w/ 21k miles, so obviously a lot of sitting without riding on the bike over the years. I don't know what the most recent history of how long it sat w/ gas, etc but tank was nearly empty when I purchased it so if there was bad gas in it (likely), there wasn't much, if that matters (I'm guessing not). Cowpuc, I do follow your logic, so from one twisted mind to another.... 😉 A couple other thoughts: 1) Could this recall have any bearing on my heat issue or is it more about oil/coolant possibly mixing? 2) Is it worthwhile doing another drain/flush of the coolant system? I previously drained, filled w/ distilled water and ran til hot, let it cool & then drained/refilled w/ 50/50. I did not pull the fins and drain the cylinder cooling jackets. Could I have a plug in the system keeping coolant out of that cylinder jacket causing the problem? You are both leaning towards fuel/combustion issue, which makes sense. I'm just reaching for straws of what else I could do w/ my limited mechanic skills/knowledge before paying the dealer - and holding out hope. Thanks again!!!!!!!

Thanks Cowpuc. I'm reading the temp on the header pipe. I checked the plug, it is clean and gapped correctly (.9mm) I spoke w/ a mechanic today and he echoed much of what you said, lean mix, vacuum leak, carb sync or stuck float. He also mentioned possibility of a stuck exhaust valve. I like your idea of unlit propane. At least if I can rule one thing out, its a start. I'm ready to throw in the towel and take it to the yama dealer & let their seasoned mechanics fix it. I was hoping for something obvious and simple, but it rarely goes that way. The things you are talking about are out of my skill range/knowledge base and I'm getting depressed not being able to ride my new baby. I just want it fixed so I can go ride.

Thanks BlueSky.

Yeah, the two front cylinders are harder to get a reading on due to the airboxes, but the back two have about a 1" gap right before it mounts to the exhaust port. Not too hard to get a reading on those two. A little trickier in the front, but doable. If the #1 plug isnt firing, for whatever reason, would this cause the excessive temperature on the exhaust header? I did attach a trail tech tach to that plug wire today and getting a tach reading so I know the wire is at least getting electrons to it. Was going to pull the plug tonight, but getting late enough I'll wait until tomorrow.

California, SF Bay Area. Temps in the 90's when I first got it and did a few rides, but 70's-80's now. Yeah, I had a '99 years ago and never had this issue. Thanks, will be pulling the plug after dinner.