Idle speed changed with oil change

[Scab]

After a couple of oil changes, I had switched to running Castrol 10w40 in my '05 fjr. During the January weather warm-up, I switched back to the yammy-lube 20w40. Immediately after, the idle dropped by approximately 300 rpm's and required readjustment. If this viscosity change could effect engine idle to this extreme, is there any information or investigating done about a possible correlation between oil viscosity and the dreaded "tick"? If the yammy 20w40 is that hard to push through the engine, is it even making it to the vavle guides?

This may have been addressed prior to my membership, but it is difficult to search and find the oil/idle combination. If this is a dead horse I'm beating, let the slings and arrows begin...

 

[SkooterG]

IMHO:

The change in viscosity of oil did NOT change your idle speed. As Spock would say, "That is illogical."

 

[Scab]

I assure you it did. There were no other changes to the bike. And from other experiences with motor oil and previously owned motorcycles, I have noticed gas mileage differences with viscosity changes. I kid you not.

 

[SkooterG]

More on this..........

I recently changed from 5W-40 synthetic to 20W-40. Interpolating from your claims, my idle should of decreased by 1200 rpm! Well, as you might have guessed there was no change.

You didn't provide details? Was your rpm drop during the fast idle or after warm up? I am ASSuming after warm up. Now remember, once the oil has come up to normal operating temperature, both of the oils you have used are basically the same - both 40 weights. The 10W and 20W are relative viscositys at cold temps.

And I still assert that a 10 weight oil and a 20 weight oil will have negligable change on something like idle speed.

As for your gas mileage claim, any changes there will be very small, most likely unnoticeable. IOW, other factors will hide any changes from different oils. And once again, unless you only run the engine for extremely short periods before it properly warms up, the two oils you mention are exactly the same and there would be no difference - in friction, heat, gas mileage, blah, blah, blah....

And another thing - Did you idle increase by 300 rpm when initially went from the 20W-40 to the 10W-40? If not, how do you explain the discrepancy?

 

[Scab]

Okay, in more detail: Prior to oil draining, I warmed engine fully (two bars on temp gauge). After immediate refill, I started engine and checked for leaks, etc. There was no fast idle at this point, engine was still warm and idle speed is obviously not set to oil temp. Granted, the oil was cold but even after the oil had ample time to reach normal operating temperature, the idle did not return to pre-oil change numbers. The variance, though now not the initial 300 rpm's, still required adjustment.

As for the idle change when I initially switched from the yammy 20w40 to the Castrol 10w40: This occured early in ownership and during many idle adjustments. The bike idled high upon delivery and after adjustments, would "creap" and require readjustment. This last for a few thousand miles before it settled in and accepted adjustments on a somewhat more permanent basis.

And while all this is interesting, I guess I should have phrased my inquiry better. The real point I was getting at is could the oil viscosity be a contributing factor in the "tickers"? Obviously, even to Spock, it will require more work from the engine with a thicker viscosity. This could be a cold-start issue, or climate issue. It may not have a darn thing to do with the "tickers". All I was wondering was if the "tickers" could possibly be oil viscosity related. Has anyone even checked? Viscosity definately makes a difference. Was the FJR designed around yammy 20w40? I doubt it. Have the machining techniques improved in manufacturing? Probably. Have the tollerences in manufacturing this engine been reduced to such a point that viscosity is now a contributing factor? That is my question.

As for viscosity and mileage, my last ride was an '85 GL1200. An oil change from 20w50 to 10w40 netted a 9% increase in fuel mileage. That's noticeable.

 

[Ignacio]

......holding back......urge.......to.......move........thread...... :trinibob:

....oil......ticking.........lot's of paragraphs devolving...... :dribble:

 

[SkooterG]

......holding back......urge.......to.......move........thread......  :trinibob:
....oil......ticking.........lot's of paragraphs devolving......  :dribble:

They do this to you on purpose.

[SIZE=7pt](Including me)[/SIZE]

 

[Ignacio]

There are a few nuggets in here though.

Hadn't heard idle-speed and oil viscocity connection before. I'm still a bit skeptical that there isn't another variable in that one.

I'm holding my tongue on the tick and viscocity connection just in case the tick actually turns out to be tight seal design. If it is....I guess it's possibly plausabile that higher viscocity could be related more to tickers.... :blink:

 

[Windjammer]

It's odd that oil viscosity differences are affecting your bikes in such noticable ways, and with such easily measurable results. I've never experienced such changes, but I'm not knocking your observations. Like you said, it's not your main point anyway.

The cause of Ticking has been so hard to track down because it's been known to happen to users of different oils, who live in different climates, with bikes from different model years, using different octane fuel, different riding habits, and on and on and on and on. A huge amount of discussion has yet to yield any answer, except that once the ticker is repaired, it tends to stay that way. There have been very few "double tickers" reported, where the problem actually came back. While it's not conclusive, this does tend to rule out "user defined" elements like fuel and oil as the culprits, otherwise those same culprits would tend to make the problem come back again. Since changing parts for different parts fixes the problem, then it's logical to say the parts were the problem, not an outside influnce.

BTW, I didn't notice much idle variance on mine when new, perhaps you should synch the TB's and do the break in tune up to make sure all is well. Also, are you setting the idle to the factory setting, or raising/lowering it to some level you prefer?

 

[Scab]

I bought this bike in Atlanta, about a two hour drive from where I live. After getting home (no test drive) I noticed the idle running about 1300 rpm's. I went to the manual for reference. I don't even remember now if I found the info there or not. I am not real impressed with the tech info in there (or lack of). I think I may have found the info on this forum, can't really remember where. Anyway, I then went to set the idle at 1050 (as best I could). Now, keep in mind, this is before I found the thread about the hidden adjustment knob. You don't even want to know... It is a sad story of a 6mm socket being used like a morris-taper fitment. It was ugly, but effective. That might explain the creep though, considering there was an adjustment knob on the other end of what I was adjusting.

After I was enlightened to adjustment knob location, 2 adjustments then done.

 

[Scab]

As for TB sync, I did check. All well within specs. Using analog gauges, within a needle-width of each other. I did find this thread before attempting. What a breeze.

 

[shuswaper]

Scab...I concur! When I switched from the Yammi 20-40 to Castrol Syntec 5-40 in the fall of `04, I noticed my machine was idling faster. I let it fully warm up to be sure and yep, it was idling faster alright. That was the first and last time I have ever adjusted the idle. The fact of the matter is, the syntec 5-40 is thinner and it flows better period. The stuff simply offers less resistance to mechanical motion...you can take that to the bank! :assasin:

 

[SkooterG]

Scab...I concur! When I switched from the Yammi 20-40 to Castrol Syntec 5-40 in the fall of `04, I noticed my machine was idling faster. I let it fully warm up to be sure and yep, it was idling faster alright. That was the first and last time I have ever adjusted the idle. The fact of the matter is, the syntec 5-40 is thinner and it flows better period. The stuff simply offers less resistance to mechanical motion...you can take that to the bank! :assasin:

Well I still ain't buying it. And won't be heading to no bank.

Am I supposed to believe everything I read on the internet? Hell, one time on the EZboard, an fjr owner tried like hell to convince me and everyone else that the Fitch Fuel Catalyst truly does work! It had worked for him and he had documented blankety-blank percent increase in fuel mileage. Whatever!

Voo-doo.

Black Magic

Smoke and mirrors.

I am sure you guys are pure in your intentions and truly believe what you are saying, but I don't know you, your methods, and any other variables you may be encountering.

The fact is, in both your examples, when properly warmed up, all the oils are 40 weight and therefore NOT ANY THINNER.

Go find me some objective research - a technical article or SAE paper or something that correlates a change in oil viscosity to changes in idle speed and significant changes in fuel economy. If you guys are right, somewhere out there will be documentation saying so.

 

[Scab]

Greg, I am not disputing the differences of warmed-up oil. How fast did your cold 20w get the top of the engine vs. 5w synthetic?

 

[Scab]

If cold oil moved as well, we could all go back to straight 30w and call it done. As for research, if I had it I wouldn't have asked. Where's the research otherwise?

 

[Scab]

And while all this may sound strange, the science is sound. Example: I have a late-model automobile that requires 5w20 oil. The information with the vehicle clearly states: Under NO circumstance use 10s40! Why? Engine destruction. There is simply not enough room in the tollerances of the engine to move the oil and the engine will not lubricate. And because I don't have the study in hand or a link to web address don't make it any less true.

If it makes no difference, put 90w gear oil in your crankcase and tell how long she lasts.

 

[Geezer]

Intuitively I would agree that a 5W 40 oil would have less mechanical resistance than a 20W 40. That could allow for a higher idle speed. Some of the super high MPG cars now use 0W oils, which don't hold up well under stress but allow for better gas mileage under ideal circumstances.

I also wonder if the quantity of oil may account for some of the difference in idle speed. Putting a little more of the heavy oil than what there was in there of the thinner stuff might cause a bit more back pressure.

I wonder if Jestal will chime in with some factual information to settle this before it gets moved to that other place.

 

[Scab]

Besides, I am not trying to convice anyone of anything. I was just asking a question based on reasonable science. Heck, if I knew for sure I would be making a heck of lot more money in my new position as Technical Advisor for Yamaha!

I admit I don't know. But, it sounds possible. I was just wondering if anyone had done any serious research or testing of oil viscosity in this engine.

 

[sportryder]

FWIW, just because 2 bars are showing on your coolant temp gage it is NOT a sign the engine and the oil inside it are up to full running temperature. If you doubt this previous statement, start your FJR up and wait until 2 bars are showing on the temp gage. Then, feel the clutch cover on the engine and see if it is warm. It'll still be cool to the touch and especially during the colder winter months.

When the oil is cold, 20w40 oil vs 10 or 5w40 oil there will be a difference in viscosity until the engine cases are fully warmed.