colder the better

[bhkfjr]

I've seen here on the forum that some folks have reported that their bikes run better when it's cold outside and some others like it hot. Some theorized the colder denser air made for a different fuel mixture and I've talked to a few riders that notice their bikes have more power at colder temps.

This has become a BIG issue for me on my bike. At colder temps my bike runs flawlessly. It runs so good it's almost spooky. Absolutely NO vibration at any speed at any rpm. It's tight, quiet, and turbine smooth. Hands on the bars and you can't tell its running. (cold temps are 60 and below).

As the temp rises the bike becomes increasingly rough running and sounding. I can feel it thru the bars and hear it in the exhaust note. It's noticeable at 70 degrees and really bad at 85-90. When this first started last year (25k on odo) I pulled into the next service station, convinced I had hole in one of my exhaust cans because that's exactly what it feels and sounds like. The hotter it is outside, the bigger the hole.

I've done the jumper mod. new ECU, and a pc111. None made any difference. Anybody else with this? Any thoughts? Any cures that I've missed?

 

[RadioHowie]

I've seen here on the forum that some folks have reported that their bikes run better when it's cold outside and some others like it hot. Some theorized the colder denser air made for a different fuel mixture and I've talked to a few riders that notice their bikes have more power at colder temps.

This has become a BIG issue for me on my bike. At colder temps my bike runs flawlessly. It runs so good it's almost spooky. Absolutely NO vibration at any speed at any rpm. It's tight, quiet, and turbine smooth. Hands on the bars and you can't tell its running. (cold temps are 60 and below).

As the temp rises the bike becomes increasingly rough running and sounding. I can feel it thru the bars and hear it in the exhaust note. It's noticeable at 70 degrees and really bad at 85-90. When this first started last year (25k on odo) I pulled into the next service station, convinced I had hole in one of my exhaust cans because that's exactly what it feels and sounds like. The hotter it is outside, the bigger the hole.

I've done the jumper mod. new ECU, and a pc111. None made any difference. Anybody else with this? Any thoughts? Any cures that I've missed?

I'd suggest entering the diagnostic mode on the LCD display and look for errors there, particulary error codes #21 or #22, coolant and/or intake air temperature faults. Either could indicate a fault with a temp sensor, sending misleading info to your ECU.

That's where I'd start.

 

[bigjimbiker]

Hey Howie...did you have to go to Bartow to get that "Certificate" or do they issue them in Winter Haven? :dribble:

I'm hopin' they maybe have an office in Lakeland...bigjimbiker

 

[RadioHowie]

Hey Howie...did you have to go to Bartow to get that "Certificate" or do they issue them in Winter Haven? :dribble:
I'm hopin' they maybe have an office in Lakeland...bigjimbiker

There's a satellite office in Waverly. No waiting.

 

[FJRMGM]

took my '05 FJR out today in 60 degree weather and it was running so strong it was almost scary. At 66k miles that is good.

Just wanted to jump every time I twisted the throttle.

Thank the internal combustion gods for cool weather.

 

[bigjimbiker]

Hey Howie...did you have to go to Bartow to get that "Certificate" or do they issue them in Winter Haven? :dribble:
I'm hopin' they maybe have an office in Lakeland...bigjimbiker

There's a satellite office in Waverly. No waiting.

Oh man, good news...if they had an office in Lakeland you'd have to take a number.

 

[not2shabby]

Just about any infernal combustion engine will run better in cooler conditions; more air/fuel in makes bigger bang! If your bike runs really badly above 80-85 degrees, I'd say it needs a tune up or something, maybe leaned out a little. Have you checked your air filter lately?

 

[professor]

Are you running on regular fuel? Regular burns with a quicker bang which may be the same result your getting when the air is colder/denser.

 

[bhkfjr]

Howie

Thanks for the reply. I'll have the dealer re-check for those faults and call Cypress for add'l thoughts. Is there a sensor that sends air temp readings to the ECU that affects air-fuel ratios?

Professor

Regular gas burns faster than premium? I'll have to try that! Been running mid-grade always.

So far so good. Any other ideas to bring up to service dept. They are almost clueless when it comes to this this bike. FJR? yeah, we got another guy with one of those.

 

[RadioHowie]

HowieThanks for the reply. I'll have the dealer re-check for those faults and call Cypress for add'l thoughts. Is there a sensor that sends air temp readings to the ECU that affects air-fuel ratios?

Coolant temp sensor is located in the right-end of the coolant crossover pipe living upstairs of the valve cover.

Intake air temp sensor is located in the rear of the airbox, under the seat, tool tray and ECU.

A bad intake air sensor, open circuit or short circuit would give you a fault #22 as I mentioned in my earlier post. If there is an error in that particular system, the bike would still run, but would run in "failsafe" mode, basically a preset "map" depending on the fault code generated by the ECU.

A bad coolant temp sensor would throw a #21 fault and would also put the ECU into "failsafe" mode. If either sensor is bad, the bike would run at preset settings not necessarily ideal for the current ambient temp, but at least it would run.

A bad air temperature sensor would throw a #22 fault and the ECU would default to a pre-designed injection map that would let the motor run, but would run as if the temperature were 68 degree, even if it was 32 degrees or 105 degrees. So if it was below 68 degrees, it's running lean. If it's over 68 degrees, it' running rich. You probably wouldn't notice if the air temp sensor was bad and the bike was just being cranked, since the fast idle circuit would provide the extra fuel the motor needed.

If the coolant temp sensor was bad, the ECU default's to a present coolant temp of 140 degrees would be feeding the motor the fuel amount that would be correct IF the coolant temp was 140, but if it's up around 230, which would be normal for an up-to-temp motor, it would be running hella-rich, since the ECU is providing fuel to what it's told itself is a cold motor.

'Howie

 

[Bearly Flying]

We look forward to all you Southerners visiting in Late January to late February, to experience REAL HORSEPOWER when it drops to -40 deg F or better. I got lotsa room, If you wanna come up........... :cold:

 

[bhkfjr]

Update

Bike is not throwing any codes.

Dealer has no thoughts on issues as to remedial action. (no codes-no problem) No blame intended, thats just the way it is. One would have to ride the bike at 60 degrees in the A.M and then again at 85 in the afternoon to compare.

Frustrated in the heat

 

[rocketdoc]

No question the FJR runs a whole lot stronger in the cooler, damp weather, as do most other internal combustion motors. Cooler denser air contains more O2 more for the firebreathing dragon to gobble. The first time I noticed this was the fall of '03, I had been riding the FJR since I picked it up in July. I was on one of my regular routes that involves a very tight left, I always drop down into first heading in, and roll off in first exiting the corner. As I did the front wheel came up so easily it caught me by suprise. The fall is particularly fun in this regard, and just shows another dimension to the bike.

 

[boomerang]

HowieThanks for the reply. I'll have the dealer re-check for those faults and call Cypress for add'l thoughts. Is there a sensor that sends air temp readings to the ECU that affects air-fuel ratios?

Professor

Regular gas burns faster than premium? I'll have to try that! Been running mid-grade always.

So far so good. Any other ideas to bring up to service dept. They are almost clueless when it comes to this this bike. FJR? yeah, we got another guy with one of those.

If you are running mid grade fuel make sure it's not "enhanced" with ethanol. Some gas stations like BP uses ethanol in there mid grade fuel.

It's pure crap ! My bike does not like it at all. Crazy as it sounds, it runs best on regular.

 

[worldbound4now]

Regular fuel. Cooler temperatures. Happy pilot. I LOVE the weather here from around September through April because the Feej just runs so damn well.

 

[FJRScorpion]

+1 on the cold running = better performance. It's pretty well known to be true with "air cooled engines" like my KZ650C, but I suspect for additional reasons.