M600 carbs

[garryc]

Do all mikuni's come with the oil heating circuit?
If not what is the use of them on the 600?
Could i buy a set of float bowls without the oil inlets and cap off the pipes at the motor.
I have never opened the oil tap, should I and when
thanks
garryc

[Speeddog]

No, some have electric heaters.

If you ride in cold and humid conditions, it's possible for the carbs to ice up.

I've ridden my carbie M750 in cold and humid conditions,but it's California humidity.
It's got the electric heaters, but I've no idea if they still work.

IIRC, East-coast USA folks have some experience.

[motoxmann]

I have electric heaters in my m750, and they work, and I'm still riding even when it's in the 30's. it can get a little choppy sometimes when cruising at high speed, but thats just cuz the engine itsself is getting so darn cold, soon as I throttle it a little i smooths out. I'm jetted properly for this weather.
I've never tried riding with the heaters unplugged, so I don't know how big of a difference it would make. I would assume it can get fairly bad though if you run with no heaters in cold weather like this

[koko64]

I have had two 900 Monsters that were almost unridable in very cold weather due to carb freezing. In cool weather with high humidity they also gave trouble.

My mate's ZXR900 also had trouble with it's Keihin CV carbs freezing and it had coolant routed to the bowls! I remember when Harleys were given CV carbs and had the same trouble, the guys with straight butterfly carbs (Bendix and Keihin 38mm) had no trouble, but the guys with the new CV carbs were soon buying S&S carbs. A Mikuni 40mm flatslide also fixed my FXR.

My first Monster had the oil type heating kit fitted under warranty back in the day, but honestly it made little difference.
The electric heating kit came later so maybe it's an improvement. A customers Bonneville America cruiser has electric carb heating standard with it's oem CVs.

You know what I'm going to say next...
Since I've had FCR carbs there has been no carb icing, even at 0 C (32F). If only they had a choke.

[koko64]

Do all mikuni's come with the oil heating circuit?
If not what is the use of them on the 600?
Could i buy a set of float bowls without the oil inlets and cap off the pipes at the motor.
I have never opened the oil tap, should I and when
thanks
garryc

Garry, you up North Oz?
If you live in a warm climate you could put it back to regular oil lines. In Australia the oil heating kits were fitted under warranty. If you plan to ride in cold weather seek out the electric kit (or FCRs). Maybe the oil kit works with no oil cooler (in your case), or if you fit a oil cooler cover for winter.

[Howie]

Mine are electrically heated.  I only experienced freezing once. 

[koko64]

Hey Howie
What cold temps you ride in?  Gets pretty cold where you are.
The electric heaters must be better as Northern hemisphere cars had them too. Is that right?

[Howie]

If the road surface is clear and the voyage is worth putting on all the clothing I will ride.  Or used to.  Less likely since I am now retired and older.

Though carb icing has been a problem on cars here the more common reason for carb heating was emissions and you will even see intake heating on fuel injection.

Carbs don't ice in real cold temperatures.  Above freezing and humid is the perfect scenario.  Temperature drops in the venturi, you have ice.  IMO, the flat sides don't ice because of the slide rattling and because the slide is controlled directly by the throttle, not vacuum.  I think the oil heaters on the Mikunis don't work so good because the oil stays pretty cold at cruise.  Covering the oil cooler might help. 

[koko64]

Cold but "above freezing and humid" = Melbourne weather for much of the year .

[beethoven]

My 900 iced up once on west coast Fremantle. 6 deg C and 90pc humidity.  Only time in 7 yrs and I still don't use oil cooler. I believe the long intakes contribute as well. if you can eliminate easily I'd do it. it's just another unnecessary pain when working with carbs.