Posted by Dave on July 3, 2005, 1:37 pm
I've got a '95 Intruder 800 w/25k mi.
After riding for an hr on a hot day, I heard the radiator boiling, and then
noticed radiator fluid came out of the overflow tube. The fan kicked on, but
didn't run excessively. The owner's manual says to mix the fluid 1/2 with
water, which I do, and I've always added Bar's Leak stuff, as recommended in
the manual. The engine oil level is perfect, so I don't think it overheated
due to low oil.
My questions are:
Is there anything I can do to prevent the radiator from boiling ?
Does Bar's Leak stuff gunk up the cooling system ?
Do I need to think about replacing the thermostat and the radiator cap ?
Any help is greatly appreciated.
Posted by krusty kritter on July 3, 2005, 3:20 pm
Dave wrote:
> Is there anything I can do to prevent the radiator from boiling ?
Ride faster, if your problem is occurring in slow traffic. Find
alternate routes where you don't have to sit at stop lights, idling for
long periods of time.
Part of the reason your engine runs hot is that the idle mixture is set
very lean to pass the EPA emissions tests. There is a way to make your
engine run cooler by drilling out the EPA anti-tamper plugs and
adjusting the idle mixture screw about 1 turn counterclockwise. If you
go to www.partsfish.com and look at the carburetor fiches, the plug is
#54 on the rear carb and #56 on the front carb. I have described how to
drill out the plugs many times. Google up "kaybearjr@aol +EPA"...
If you do this mod, you might notice the engine runs cooler but gets
slightly worse gas mileage. Your engine is cooled more than you think
by wasting gasoline. About half the gasoline that goes through your
engine is actually used to keep the pistons from melting, so I wouldn't
worry about wasting gas...
In the wintertime, turn the idle mixture screws back to other way to
avoid having the engine run too rich and too cool...
> Does Bar's Leak stuff gunk up the cooling system ?
Yes, it does. After a Suzuki race bike burned a hole in its piston and
broke the connecting rod, I tore the engine completely down for a
rebuild. It was a good thing that I removed the water pump for
inpection. The water pump impeller housing was FULL OF BARS LEAK, so
the pump couldn't circulate any water through the engine. The previous
owner had been silly enough to use Bars Leak when there was NO evidence
of leakage at all!
That particular engine's water pump had a vertical shaft and horizontal
impeller. It was underneath the engine and all the Bars Leak settled in
the pump, which was the low point of the system. Your pump is on the
lower left side of the engine and it has a horizontal shaft. The
impeller housing could still get filled up with Bars Leak if you've
used a pound or so of the stuff...
> Do I need to think about replacing the thermostat and the radiator cap ?
If you get ahold of a repair manual for that motorbike it will tell you
what the relief pressure is on the cap, and you could take the cap to a
Suzuki dealer and have it tested...
You can test the thermostat by immersing it in water and boiling the
water on the stove to see what temperature it opens at. You need an
accurate thermometer
(like a candy thermometer that you can buy in the supermarket or a drug
store).
While you have the thermostat out for cleaning, you can backflush the
cooling system with a garden hose. If you get a ton of Bars Leak out of
there, that might just correct the problem without drilling the EPA
plugs out...
Posted by Beav on July 3, 2005, 5:05 pm
> Dave wrote:
>> Is there anything I can do to prevent the radiator from boiling ?
> Ride faster, if your problem is occurring in slow traffic. Find
> alternate routes where you don't have to sit at stop lights, idling for
> long periods of time.
> Part of the reason your engine runs hot is that the idle mixture is set
> very lean to pass the EPA emissions tests. There is a way to make your
> engine run cooler by drilling out the EPA anti-tamper plugs and
> adjusting the idle mixture screw about 1 turn counterclockwise. If you
> go to www.partsfish.com and look at the carburetor fiches, the plug is
> #54 on the rear carb and #56 on the front carb. I have described how to
> drill out the plugs many times. Google up "kaybearjr@aol +EPA"...
Just a thought Krusty, but are the carbs on this bike different to those on
others in a quite fundamental way? The reason I ask is that every motorcycle
carb I've ever come across will run LEANER if you unscrew (anti-clock) the
idle mixture screw as its an air bleed rather than a fuel flow jet.
Unscrewing it allows even more air in than the preset.
> If you do this mod, you might notice the engine runs cooler but gets
> slightly worse gas mileage. Your engine is cooled more than you think
> by wasting gasoline. About half the gasoline that goes through your
> engine is actually used to keep the pistons from melting, so I wouldn't
> worry about wasting gas...
> In the wintertime, turn the idle mixture screws back to other way to
> avoid having the engine run too rich and too cool...
>> Does Bar's Leak stuff gunk up the cooling system ?
> Yes, it does. After a Suzuki race bike burned a hole in its piston and
> broke the connecting rod, I tore the engine completely down for a
> rebuild. It was a good thing that I removed the water pump for
> inpection. The water pump impeller housing was FULL OF BARS LEAK, so
> the pump couldn't circulate any water through the engine. The previous
> owner had been silly enough to use Bars Leak when there was NO evidence
> of leakage at all!
We don't get Bars Leak over here, (actually, it MAY be here, I've just never
seen it) but we have a similar product called Radweld. Does the same job,
but once it's done the job of sealing a hole, the system can then be drained
and re-filled with clean coolant without it "cleaning out" the repaired
hole. I've been forced to use it recently on my Z1000 when I picked up a
stone with the rad, but I drained and re-filled as soon as I got back home.
you're dead right about that stuff being good at gunging up the cooling
system, but it's good at doing what it says on the tin too. My rad hasn't
leaked a drop since.
> That particular engine's water pump had a vertical shaft and horizontal
> impeller. It was underneath the engine and all the Bars Leak settled in
> the pump, which was the low point of the system. Your pump is on the
> lower left side of the engine and it has a horizontal shaft. The
> impeller housing could still get filled up with Bars Leak if you've
> used a pound or so of the stuff...
>> Do I need to think about replacing the thermostat and the radiator cap ?
> If you get ahold of a repair manual for that motorbike it will tell you
> what the relief pressure is on the cap, and you could take the cap to a
> Suzuki dealer and have it tested...
> You can test the thermostat by immersing it in water and boiling the
> water on the stove to see what temperature it opens at. You need an
> accurate thermometer
> (like a candy thermometer that you can buy in the supermarket or a drug
> store).
> While you have the thermostat out for cleaning, you can backflush the
> cooling system with a garden hose. If you get a ton of Bars Leak out of
> there, that might just correct the problem without drilling the EPA
> plugs out...
And that's the first thing I'd do, for one reason alone, that being once a
fine running engine has had it's jets played with, it's a crap shoot if it
ever runs as well again unless the repairman REALLY knows his carbs, and
those guys are getting rarer than rocking horse shit these days.
--
Beav
Reply to "beavis dot original at ntlworld dot com" (with the obvious
changes)
Posted by krusty kritter on July 4, 2005, 12:30 am
Beav wrote:
> > There is a way to make your
> > engine run cooler by drilling out the EPA anti-tamper plugs and
> > adjusting the idle mixture screw about 1 turn counterclockwise.
> Just a thought Krusty, but are the carbs on this bike different to those on
> others in a quite fundamental way? The reason I ask is that every motorcycle
> carb I've ever come across will run LEANER if you unscrew (anti-clock) the
> idle mixture screw as its an air bleed rather than a fuel flow jet.
> Unscrewing it allows even more air in than the preset.
That is true of the older slide valve carburetors. But CV carb idle
mixture screws work the opposite way. Clockwise is leaner,
counterclockwise is richer.
> And that's the first thing I'd do, for one reason alone, that being once a
> fine running engine has had it's jets played with, it's a crap shoot if it
> ever runs as well again unless the repairman REALLY knows his carbs, and
> those guys are getting rarer than rocking horse shit these days.
Problem is, most amateur CV carb tuners haven't got a clue about the
jet sizing numbers. Tuners who may have tinkered with the hexagonal
jets found in old style slide valve carbs just *assume* that round jets
work the same way...
Say you had a #100 hex jet and you wanted to flow 10% more fuel.
Simple. Use a #110 hex jet in a slide valve carb...
But if you installed a #110 round jet in place of a #100 round jet,
you'd get 20% more fuel flow. A #100 round main jet has an orifice hole
that's exactly 1.0 millimeters in diameter. The next size round main
jet is a #102.5 if it's a Mikuni jet, or a #102 if it's a Keihin jet.
But tuners that are used to the hex jets think they need to go four
sizes up, to a #110 round jet to get the 10% additional fuel flow...
The #110 round main jet has 21% more orifice area, so if the engine has
enough vacuum at high RPM to suck up all that extra fuel, it *might*
work OK...
But the amateur tuners, lacking all clues about round jet sizing might
abitrarily install #120's. The orifice size in that case is a whopping
44% larger, and the engine may be absolutely drowning in gasoline at
full throttle...
You can see that since the area of the orifice hole increases as to pi
times the square of the radius, the orifice area increases
exponentially and fuel flow increases radically as the size numbers
increase...
Idle jets are sized in fractions of a millimeter. The orifice hole in a
#40 idle jet is 0.4 millimeters in diameter.
And, remember that CV carbs are running mostly on their idle jets from
closed throttle to 1/8th throttle, so when you're cruising along at
highway speed you're only using a tiny amount of throttle and you're
running on the idle jets.
That's why opening the idle mixture screws about 1/2 to 1 full turn has
so much effect on the running temperature of the engine...
Posted by Dean Hoffman on July 3, 2005, 3:40 pm
On 7/3/05 12:37 PM, in article 7N2dnRU7Ob_tv1XfRVn-3Q@comcast.com, "Dave"
> I've got a '95 Intruder 800 w/25k mi.
> After riding for an hr on a hot day, I heard the radiator boiling, and then
> noticed radiator fluid came out of the overflow tube. The fan kicked on, but
> didn't run excessively. The owner's manual says to mix the fluid 1/2 with
> water, which I do, and I've always added Bar's Leak stuff, as recommended in
> the manual. The engine oil level is perfect, so I don't think it overheated
> due to low oil.
> My questions are:
> Is there anything I can do to prevent the radiator from boiling ?
> Does Bar's Leak stuff gunk up the cooling system ?
> Do I need to think about replacing the thermostat and the radiator cap ?
>
> Any help is greatly appreciated.
>
>
In addition to KK's suggestions, have you cleaned the bugs and such out
of the radiator fins recently? An air gun at a few inches from the backside
of the radiator would probably do the trick.
Dean
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