Rad Fan and rough idle - '02 Vmax

[zippo6]

Ok, time to throw my dignity out the window and ask the questions....
Let me start here. I'm a PROUD new Vmax owner!! Purchased my Max about 3 weeks ago, it's an '02 Carbon Fiber....

Anyway....

Question 1: At what point does the rad fan kick in? My first day out on the bike, I was sitting in traffic dieing to roll on the throttle and noticed the temp gauge 'close' enough to the 'hot' zone to cause me to pay attention to it.... I never noticed or heard the fan and thought I would ask the question.

Question 2: rough idle.... once my bike is at a normal operating temp (halfway through the temp gauge, or more) It tends to idle a little rough, which clears itself with a twist of the throttle, however it also almost seems to miss fire when pulling away from a dead stop, but only while low in the rev range. Bike idles at about 1000rpm.

Not sure what other info I should provide. Oil and filter were just changed about 400km's ago. Yamaha oil filter and Yamaha 20w50 oil. Next I plan to replace the plugs and possibly the fuel filter.... If it still continues, I'll take it to the shop and have the carbs cleaned and synced.

I would love some feedback from anyone with thoughts or suggestions.


Thanks,
Shane


'02 Vmax

 

[4gasem]

Welcome Shane!

The Vmax tends to always run towards the red when warm. Most of us put in a bypass switch to turn the fans on manually while sitting in traffic.

Rough idle is probably caused from the bike loading up while idling. The bike probably needs the carbs adjusted and sync'd.

20W50 IMO in the great white North is over kill. 10W40 is MORE than fine. Remember the first number is the cold viscosity and the higher it is the more viscous the oil is. Meaning the longer it takes to pump through the bike. On a water cooled bike in the Northern climates 10 or 15 is fine.

Good luck! Do a search for more info. There are great threads on carb adjustments and such.

Chris

 

[zippo6]

Thanks Chris, I'll look into installing a bypass for the fan as well as working on the carbs.
As for the oil, I had 10w40 in hand but it was suggested that I use the 20w50 due to the temperatures we experience here in the summer months (maybe that should read month!). Anywho, I'll do some more digging on suggested oils, the last thing I want is a premature wear or failure due to oil.

Shane

 

[4gasem]

Just DO NOT use car oil and you'll be fine. I as well as others use Diesel oils. I use Shell Rotella 5W40 myself but others run the 15W40. They are high in zinc which is good for the transmission.

Chris

 

[naughtyG]

ya I use Shell Rotella-T (non synthetic) 15W50 in Florida and it's going great.

 

[grimmie]

I had the same issue when I bought my 2000 Max. I changed the plugs and wires and it fixed the problem. I really believe it was the wires. They were the original wires that came on the bike. The bike had about 9000 miles on it when I bought it, and when it got to operating temp it would start to idle rough, spit-spudder, and stumble when I went to take off.

On a side note, I changed my wires over to regular auto plug wires. I bought high performance plug wires and cut them to length. I don't recal the plug numbers, but they don't come with the screw-on ferrels on the end of the plug. You will just have the threads to screw it on to. This is the way the stock boots connect to the plugs. I bought a set of the cheapest plugs I could find - just to get the ferrels off of them. I put the ferrels on the new plugs and I have not had any issues at all. Because the plug wires come for V8's I still have the 4 extra wires for my next tune-up.

I also put a clear/glass fuel filter on it and ran a can of seafoam through it. Runs like a top ever since. I still have the Dale Walker jet kit that I need to install, but that's another story.:biglaugh:

Let us know if you have any questions! Some of these guys are really good with these bikes and will give you the no BS answer you're gonna be looking for. They have good short cut idea's and what-not.

Anyway, hope this helps.

Shane

 

[Knight]

Zippo as I am having similar issues can you let me know if you got problem sorted

 

[jfeagins]

Knight, define "similar" please.

If you are having a miss @ idle speeds only, and it disappears as you apply throttle, it could be the all-to-common charging issue with these bikes. If the charging voltage falls below around 13v, the CDI box gets finicky and don't want to fire. This would be especially noticeable if the problem gets worse as the motor warms, and the fan has already kicked on. Reason being; as the fan comes on, it uses more of the available charging voltage, and causes the CDI box to become unstable. Easy check for this is to put a volt meter across the battery with the bike idling. Idle speed should produce at least 13.25v and slowly increase closer to 14.75 as you rev the engine. Be sure to check it with the fan on too. Same voltages should be present. If not............could be the voltage regulator. Could be connections. Could be stator.

Lots of existing threads under electrical dealing with these issues, and any other you may encounter..

 

[PATMAX]

Dang, this thread is 6 years old!
Sounds like it is rich but the possibility of an electrical issue is possible.
I seem to have found that R/R causes more issues than just an occasional rough idle.
Carb sync would be where I start, ideally I'd check the CO2 from the tailpipe but that requires a "sniffer "'which most do not have but electric such as the R/R and battery would be my next check list items.

 

[alorio1]

Knight, define "similar" please.

If you are having a miss @ idle speeds only, and it disappears as you apply throttle, it could be the all-to-common charging issue with these bikes. If the charging voltage falls below around 13v, the CDI box gets finicky and don't want to fire. This would be especially noticeable if the problem gets worse as the motor warms, and the fan has already kicked on. Reason being; as the fan comes on, it uses more of the available charging voltage, and causes the CDI box to become unstable. Easy check for this is to put a volt meter across the battery with the bike idling. Idle speed should produce at least 13.25v and slowly increase closer to 14.75 as you rev the engine. Be sure to check it with the fan on too. Same voltages should be present. If not............could be the voltage regulator. Could be connections. Could be stator.

Lots of existing threads under electrical dealing with these issues, and any other you may encounter..

You are spot on jf, There has been a lot of carb tear downs because of an un-healthy charging system.....so you guys with what seems to be carb issues, get your volt meter out and check your charging system first before tearing into your carbs..........

 

[Miles Long]

You are spot on jf, There has been a lot of carb tear downs because of an un-healthy charging system.....so you guys with what seems to be carb issues, get your volt meter out and check your charging system first before tearing into your carbs.........

Couldn't agree more! My bike was behaving like yours - stumbling at idle, sometimes to the point of stalling, but ran great once the engine spooled up some. A meter check showed less than 12 volts when idling.
Be certain it's not the charging system at fault, before digging into more involved systems (can you say CARBURETORS, boys and girls?).
If it is your charging system, the very first thing to check is the battery. Most any auto parts supplier will load-test it, no charge.
Cheers!

 

[Fastatv]

My 95 was acting similar to yours, and as many have said, a new battery and the "charging mod" took care of the issues for a while. Then, started having low RPM misses again. Checked battery and charging..all was good. This time it was the plug wires as someone else mentioned on this thread. Cut the corroded ends off, re-installed, been good ever since.

 

[Biker Dash]

If it is your charging system, the very first thing to check is the battery.

YES!!! Especially important if you have bought the bike used, and the only way anyone nowdays is getting a new Max is if it is a 2nd gen bike.

When I bought my 03, it was VERY rough idling, and was badly out of tune. It also was running what looked like was probably the battery that was in it when she came out of the factory.

The new battery DID help a lot, but I also had rough idling, and it would at times want to stay up around 2k rpm when at a light, ect.

The tubes from the plenum to the carbs were lose at the plenum. Plenty of silicone fixed that. Final tuning and syncing got the bike so she runs PERFECT.