Vaquero intake leaks

[brote]

No doubt in my mind moving the MAT / IAT will fatten up the mixture. Cold air is more dense and can use more gas. If we had a closed loop system, once the system went into closed loop the O2 sensor would handle the mixture trying to keep it at 14.7:1. I also believe that getting your TPS set correctly is very important . Now I wouldn't just run a specific resistor to replace the IAT but moving it works. Just my thinking, which may be faulty.

[ponch]

Originally Posted by brote

No doubt in my mind moving the MAT / IAT will fatten up the mixture. Cold air is more dense and can use more gas. If we had a closed loop system, once the system went into closed loop the O2 sensor would handle the mixture. I also believe that getting your TPS set correctly. Just my thinking, which may be faulty.

There are a lot of benefits to a closed loop system, like running on a lower grade of gas if necessary and better adaptability to changes. Considering Kawasaki has it on other models, they could build a cruiser with one.

[jp58]

Originally Posted by ponch

There are a lot of benefits to a closed loop system, like running on a lower grade of gas if necessary and better adaptability to changes. Considering Kawasaki has it on other models, they could build a cruiser with one.

From what i've read all the 1700's have an 02 sensor (closed loop) that are built for California. I read it in my owners manual somewhere.

[ponch]

Originally Posted by jp58

From what i've read all the 1700's have an 02 sensor (closed loop) that are built for California. I read it in my owners manual somewhere.

Probably so. BMW's are 50 state bikes and they have closed loop. That's a good thing if I wanted to move to CA. I heard if you have a 49 state vehicle, it sucks if you move to CA.

[RACNRAY]

This is the post from the member that tackled diagnosing his intake concerns (posted dec 2011)

QUOTE
"I checked my 1700 classic for intake leaks after seeing what Ray posted about his bike. The way he described how his bike was running sounded like how mine began to run. I found intake leaks between the throttle body and the intake as well as where the intake met the heads. I took it apart to find the same thing as his. The stand-offs on my throttle body were 14 thou tall where his were only 8 thou tall. And as though that wasnt enough, my intake manifold was warped 10 thou on both outside edges of the intake ports and the o-rings where the intake met the heads had small tears and chunks of the outer layer of rubber was missing. My friend has a machine shop so after removing the 14 thou stand-offs off we found the throttle body to still be 4 thou warped in the center. We machined the throttle body surface and trued up the intake by lots of wet sanding on a perfectly flat surface because there isnt a good way to mount it in a mill . I got it back together last night and on initial start up the engine seems much more stable. it comes off of high idle much faster and idles much smoother. The throttle seems much more crisp as well. The real test will be getting it out on the road but i woke up to snow this morning so i guess i will have to wait."
END QUOTE

I just spoke with him and he finally had the first chance the other day to ride his skoot. The results as he reported are a 50% reduction in decel popping, much better throttle response and the complete elimination of a hesitation he has had since new, even after the recall ECU was installed. He sounded very excited, he will post as soon as he can but this is just a brief description.

RACNRAY

[RACNRAY]

I now have close to 6000 more miles since the intake fix and the skoot is runnin flawlessly.
Since the map that was in the PCV was the map that was made during the last dyno session and there had to have been some small percentage of vacuum leaks at that time, i ended up having to lean out my idle and the lower throttle percentage/rpm rows as those are areas that were most affected by the vacuum leaks, the skoot was even happier after that.

There have been concerns about why the posts on the t/b's are there. Sticking with the "heat transfer" theory, reducing heat in the t/b assembly may have to do with lowering the operating temp of the servo motor which controls the butterflies. This is an electric motor device so it makes sense that we would want it to have the lowest temp for longevity. Besides the airbox the t/b is the part of the intake system that sits the furthest away from the heat of the engine. If the reduction of heat transfer is why the posts are there, then that consideration in design and manufacure has also compromised a good seal between the t/b and intake manifold. The amount of 0-ring compression on my skoot was nowhere as much as i see on other skoots that utilize an o-ring for sealing. When Mark bolted down my t/b he could, by "feel", sense the amount of o-ring compression was similar to what we feel is the norm. We find vacuum leaks are a problem, specially on bikes older than 5 years, as the o-rings (or the rubber lip molded onto the manifold) flatten out over time, allowing leaks. Most manifolds develop a "warp' in them and are no longer flat, needing surface correction.

I try not to overthink things, my experience in working on Jap skoots for over 35 years has allowed me to kinda "learn" their way of thinking.

Back in 1976 Kawi issued a "factory directed modification" on the KZ400's. They had a defective design in top end gaskets and o-rings that had some of those skoots leaking oil real bad. The replacement gasket kit was real neat in that it had new style gaskets and o-rings that replaced the original stuff. I did many of these kits and never had an oil leak after that. It did take Kawi about a year to come out with this FDM.

The HUGE tolearnces allowed in mass production has many affects on many aspects of our skoots. My dyno has proven that time and again. Being able to dyno stock bikes of the same model i have seen HUGE differences in power. Example: the 1999-2007 Hayabusa's average around 150-152 H.P., with 2 or 3 up around 157-158, and a couple down at 146-147! A 12 H.P. spread! Think of the THOUSANDS of machining operations it takes to make an engine! We do alot of cylinder head porting/polishing and i have seen, just in heads i have had apart, noticeable variations from head to head. I am currently doing a 2009 R1 head, and it's interesting to see how the ports match the valve seats on the #1 cylinder pretty good, but the match of port to seat gets worse on cyl's 2,3&4 being the worse!

I am waiting on Chris to finish the break-in on his Vaquero so we can document his power (and compare it to mine) and since he is having some funky running characteristics i wonder about vacuum leaks on his skoot. We shall see.

RACNRAY

[RACNRAY]

Thi is the post detailing the results/improvements after the intake leaks on his Vulcan were fixed.

"I finally got to ride my bike after i got home from work. What i have found is the overall smoothness of how the engine runs, idles, is better than the day i bought the bike. My decel popping has decreased by atleast 50 percent and im sure a good fuel processor will take care of the rest. Im not really thrilled with mt FI2000 due to lack of tuneability. The throttle response is very crisp compared to the way it was before. The bike also had what i refer to as a cough from the day i bought it. I had the ECM replaced under recall and in my opinion it actually ran worse than before i had it changed. The "cough" would happen at any given time when rolling on the throttle and would basicly pop back through the intake. From what i can tell by riding it the other day is its now gone after i made the repairs. The bike runs great. I didnt want to believe that my brand new bike had a vaccum leak but i definitely did after some simple testing. Anyone experiencing decreasing perfomance, poor idle quality, excessive decel popping backfing, i would recommend looking for vaccume leaks because they may be there just like Racnray and myself both have found. Its only a matter of time before more and more of these start showing up."

His performance/driveability improvements mirror mine. I know of a few other members that are planning to check their skoots for vacuum leaks, so we'll wait to hear their results.

RACNRAY