Constant on fan......

[leakyroof58]

Total newbie here, with a new-to-me '87 GL1200 Aspy...

Fan is running as soon as key is turned, I'm guessing previous
owner(s) didn't like 25-35 MPH heating problems. Haven't'
torn into it yet, but do the temp switches ever "short out"
as opposed to going "open" ? I think they have the fan wired
to run all the time - will know more when I replace the timing
belts this fall, 'cause I don't know when they were last done.
Right now temp guage never shows more than 3 bars......
Bike has 63K on it, but it's obvious it has been well cared for.
I'm a bit of a wrench-turner, so the timing belts don't scare me.
Everything works as it should otherwise. LOVE the bike !

Issue #2 - bike backfires thru exhaust when warm but only on
downshifts. It has a V&H aftermarket exhaust on it, and previous
owner said he didn't like the sound of the exhaust so he pulled
the baffles and welded in 2 washers to force exhaust gasses to
go where V&H didn't intend them to go. Am I looking at valve
damage in my future ?? I like the sound of the bike, but it's
not as quiet as a stock 'Wing. Any input on either issue would
be awesome.
Leakyroof.

[twocams]

leakyroof,
I guess my main concern would be burning up that little plastic 30 yr old fan motor. They weren't made to run full time all the time. Be a shame to overheat your engine cause the fan went out all together.
How big is the washer and hole? In exhaust.

twocams

[skier]

Hi from the Twin Cities.

Do you have any extra switches that the previous owner might have used to short out the fan sensor as desired?

[leakyroof58]

twocams - Yeah, the fan life has me concerned also. Probably a spendy part.
Have not seen the washer on exhaust baffle, but has me concerned as well.
Might be downing the bike earlier than I planned this fall to see what's up.

skier - no extra switches seen or present, but if I tear it down to replace
belts I might as well replace thermo-switch. Also could put in a by-pass
switch for a 'just-in-case' use if I get nervous about temp.

Thanks a ton for both of your responses......!!

[WingAdmin]

Have a look at the wire going to that thermo switch - if it gets pinched somewhere and shorted against the frame, the fan will run all the time.

As for the backfiring during deceleration, that's usually an indication of a too-lean mixture.

[leakyroof58]

Thanks Wingadmin.....awesome forum here, so much info.

Have only had the beast 3 weeks now but am convinced I
pretty much stole it for the price. Keep trying to find a major
fault because of the price, but so far it looks solid.
The seller drove it up here 150 miles to my house, so I guess
he thought is was trustworthy as well.

As for the exhaust, I'm certainly going to pull the baffles and
see what he did.....I can't imagine V&H selling an exhaust and
then thinking an owner would 'tamper' with the dynamics of
engine breathing, backpressure, etc. If V&H meant it to be
loud, well, then I guess it should be, based on their dynamics.
If loud means I won't burn out exhaust valves, then so be it.

Thanks for your most informed responses.....I'm sure to keep
an eye on these forums.....what a great resource !!!

[julimike54]

Great to have you here and with a new to you ride. If I was in your shoes I'd be taking it down for those timing belts, unless the PO told you when they were replaced. These engines are interference fit, belt breaks and you smack pistons and valves together. Not a good thing and they, or it, could break without warning. The mileage is around the point of need but as a mechanic friend told me it's not the miles it's the age, they get brittle and loose their teeth, just pop off. Good luck finding the wiring glitch with the fan!

[Rusty Bike]

If those pipes are leaking at the joint they may backfire. I would be looking for a good set of stock mufflers. Those Japs knew what they were doing. The OEM pipes will probably run better also.

[leakyroof58]

jullmike54 - thanks for the warm welcome. The timing belts concern
me but friends want me to go for rides.......and the PO couldn't tell
me when they were changed last. I DO love the bike, and so far no
weird noises/problems with it. I've had 30 years electronics experience,
so whatever was done to fan circuit I'll find out when I do the belts.
Thanks again !

[leakyroof58]

Rusty Belt -

I've read on some other forums that aftermarket exhausts often
will backfire on downshifts, but don't know the resolution. Other
than the downshifts, the bike runs absolutely flawless - no missing,
pinging, or other issues - it simply doesn't miss a beat.
(I changed plugs since I didn't know when they were last done.)

Don't know about exhaust leaks but the V&H exhaust was put on
by a local bike shop here in MN. I know I'll have to check out the
"slow air" valve per the Clymer manual at some point.
But right now......I'm having FUN! Can't believe the shape this bike
is in for it's age.....LOVE it.

Thanks for your input, Rusty Belt !

[leakyroof58]

Took the bike down for the timing belt change. Got the engine right where it
should be timing-wise, everything is lined up per Clymer manual, although the
right-hand belt is a little slack compared to the left. Now just waiting for
the belts to arrive. (You can't find squat in this town for this bike.....even had
to order the air cleaner on-line.)

Whilst I was in there, I checked the fan switch. unplugged it and ohmmeter
shows it is shorted. So, now have to find one of those Geo metro switches.
No wiring kludges found, so I guess the switch will fix it. Would like to find
one about 180 degrees or so for in-town driving. The I-net shows quite a few
choices for fan switches with 18x1.5 threads....

Thanks to all for your help !!!

[leakyroof58]

While I'm in here, what does everyone think of the
stock hose clamps used on the rad hoses..?? They seem
sturdy enough, but are they OK for re-use ??? I intend to
get this area of the bike ready for another 20-40K miles
without having to do all this again. Thoughts ????????
(I'll put new hoses on now, while I'm in here....)
Thanks in advance....

[twocams]

I bought some new stock hose clamps and put them on.. I had some regular hose clamps on at first but they didnt look right. So if yours aren't all rusted and work good I would reuse them.
Just my .02 worth

twocams

[leakyroof58]

Might as well be fixin this thing on the moon. Nobody in town
has metric o-rings, like 46x2 for water pump cover, including
Honda dealer. Didn't have the fan switch ($95 !) either.
Only thing I found was the NAPA 7733 hose. I found a 1 7/8 x
3/32 o-ring that should work but will have to stretch it a tiny
bit for it to fit in the groove. Problem will be making it stay
there while I tighten the cover up. Ordered fan switch from
E-bay, exact-fit replacement so I won't have to fudge wires.

Guess I'll be doing yard work this week.

[leakyroof58]

Don't timing belts stretch ?? Honda owners manual only
goes up to 24,000 miles, with no mention of timing belt
re-tensioning. Odd.

My belts HAD been changed, as they were NAPA part numbers.
Sounds like the tensioning is a little tricky....I don't have a
scale built into my arms, so will err on the too-tight side
if anything. Lots of stuff to learn here - hopefully not the
hard way.

Also changing t-stat...does anyone recommend a silicone
sealer and not rely totally on the o-rings.? (I'll be waiting
a WEEK for the 54x2 t-stat cover o-ring.) Old one was
flattened out. Local dealer stocks nothing.

[twocams]

I have never put any sealers on parts that have O-rings. Make sure the parts are clean. I have used sand paper on some type of flat surface to make sure the part is as flat as possible.

twocams

[leakyroof58]

OK twocams - advice taken. I don't much like the messy
sealers anyway, and it looks like you've had enough bikes
to know. (But really - a Honda 50 ??? LOL!.) Actually, I
wish I still had one.They were popular when I was a kid,
45-50 years ago. And the "trail 90".
I'm replacing any o-rings I come across because they are
all pretty flat looking. Just frustrating that nobody in my
town carries much for o-rings.

It will be a nervous turn of the key after replacing timing
belts, but rolled the engine over a couple times and all
lines up nicely. Fingers crossed.

Also put in a "fan on" LED indicator so I know if the fan
kicks in. I'll be watching the temp bars closely the first
couple rides. I'm only used to seeing 2-3 bars.

[Rusty Bike]

I am in the process of going thru an 86 SEi. I have been able to get most rubber parts thru Honda OEM parts houses on line. Metric O-rings should be on line also. I have found a few parts at the local dealer but they were NOS and the dealer opened in the late 60's. These old bikes take a lot of commitment and patiences to keep running. Often you must use substitute parts and/or fab your own stuff. Good luck...Rusty Bike

[SilverDave]

LR 58:

I am glad you are getting rid of the " Constant on " fan system ... LOL
Thats rather hard on the cheap little fan motor, and probably also cools your engine way too much .

Hot Rodders have been designing cooling systems for years . Here is one very informative article :

http://www.hotrod.com/articles/ccrp-070 ... ng-system/

------------------------------------
Firstly note that his last paragraph indicates the most efficient gasoline engine operating temp is from 195° to 200°
( see his very last paragraph )

On your engine (and mine) this translates to 5 bars or so ( maybe low 6's ), if your "bars " are accurate .
5 bars = 185° , 6 bars = 202°
but not as low as three !
---------------------------------------
Secondly , if we were to start all over again , and re- design the cooling system for the 1200 :

Jeff Smith says ( in this article ):

"three basic parameters that determine cooling efficiency:
radiator surface area,
coolant speed through the system,
and the amount of airflow through the radiator."

Hmmmm..............

Surface area is sorta limited by the frame and fairing (hard to make it much bigger )
Coolant speed is controlled by a gear driven water pump (hard to change without total rebuild )
and Airflow ?
Well the1200 rad has good airflow at higher cruising speeds, unless you live in Osoyoos ( or Death Valley )
and at parade speeds the fan system is hard to improve upon,
unless we go for a well fitted shroud, twin fans , 11/42 clearance to shroud ,
and maybe a larger ( faster) fan motor , with more efficient blades .

-------------------------------------
I think we've reached the practical engineering limits for this system. If its clean, with fresh antifreeze, new thermostat ,
good fan ground, and electrical connection, and with a tested and working fan switch, then it will work .....
just as the 1984 - 87 engineers designed it to .

-------------------------------------------
Mine does :
Cruising all day in summer at 5 bars, and in fall at 4 bars.
Parade speeds : fan on at 7 bars, and off when its cooled to 6 bars .

Just as its supposed to !!
( Check the thick line at the edge of the bars reading for acceptable operating range )

SilverDave

[CrystalPistol]

Total newbie here, with a new-to-me '87 GL1200 Aspy...

Fan is running as soon as key is turned, I'm guessing previous
owner(s) didn't like 25-35 MPH heating problems. ... etc ...

I've had my '85 since 1995, never yet experienced .... or heard of .... a 25-30 mph heating problem.

There is a possibility that the fan temp switch is just bad. It shorts the negative side of fan to ground to operate fan. I did once wire a jumper from the negative side of fan to a switch and then switch to ground to activate thefan if needed, that was shortly after I got it and read of the mod and thought it might come in handy. So far, never needed it "switched" yet. Typically on hot days I see 5 bars moving and maybe 6 bars if at a light long, in cooler weather usually 4 bars moving and 5, maybe 6 at a long stop light.

Don't timing belts stretch ?? Honda owners manual only
goes up to 24,000 miles, with no mention of timing belt
re-tensioning. Odd.

My belts HAD been changed, as they were NAPA part numbers.
Sounds like the tensioning is a little tricky....I don't have a
scale built into my arms, so will err on the too-tight side
if anything.

They deteriorate but don't really stretch, they have very stout cord inside the rubber to maintain length. Not unusual to see them over 100K miles but most will replace based on age .... even though they live a pretty sheltered low stress life. I R&Rd mine's a few years ago when they were about 20 years old but had only about 70K ..... they hang in the basement still ..... looking near new.
Too loose they'll slap a little, too tight they'll sing out. Not tricky, just meticulous will do.

Also changing t-stat...does anyone recommend a silicone
sealer and not rely totally on the o-rings.?

OEM sealing method only for mine.

[PAPete]

Issue #2 - bike backfires thru exhaust when warm but only on
downshifts.

In my experience, this is typically due to problems with the diaphragms in the air cut-off valves. Just a thought....

[leakyroof58]

Wow - once again impressed with the enormous amount
of informed feedback on this forum..Thanks to all who have
responded - I really appreciate it !!

A thought occurred to me as I had the water pump cover
off - should I replace it now, or wait till a problem. From
what I have read, if it has metal impeller blades, it has
been replaced. Mine has metal. Just wondering if I should
order a new one from Mother Honda NOW, in case she
runs out of them or it is no longer carried. Pump SEEMS
OK now, and as I have stated before this bike seems to
have had ultimate care. If I ever sell it, I can say 'spare
water pump' and use it as a selling point. But, at 61, I
don't ever see selling this magnificent piece of Honda
engineering. The way it runs, handles, drives - Yeah baby!

[leakyroof58]

It lives again !!!

Finally got the 54x2 o-ring for t-stat cover and
put it all back together today. So far, no leaks.
When I ran it, waited for the bars to come up...
sometime during 4 bars, the fan came on, and so
did my little LED light. So, all is well so far.
Short rides will be the real test.

If you're thinking of doing this job (timing belts),
I would say round up your parts ahead of time, not
wait like I did for a week. You need -
NAPA 7733 rad hose (Does upper & lower)
46x2 O-ring (water pump cover)
54x2 O-ring (T-stat cover)
2 new 1/2 inch hose clamps for rad siphon line
4 new 1 1/4 hose clamps for upper/lower hoses.
T-stat - I used Autozone 15868 t-stat,but I know
many others will work. You want 180 degrees.

As for timing belts, I settled on Gates T070,
because I know Gates makes good stuff and because
the "T" designation in their part number indicates
to me that this belt is specifically designed for
timing applications, IE low stretch.

Life is good again ................

[CrystalPistol]

sometime during 4 bars, the fan came on, and so
did my little LED light. So, all is well so far.
Short rides will be the real test.

I don't recall my 1200's fan ever coming on at just 4 bars, usually when I do hear it it's when I've left it idling after a ride when it's thoroughly warmed before stopping ... it's idling as I get off, de-helmet, de-glove, and un-lock the side door to outer shop and open my 2 sets of big doors in to my shop & basement and then ride in and usually it's up to 6 bars then .... at least. Same with sitting at traffic lights in warm weather, usually up about 6 bars anyway before the fan comes on though it does go off after temp is back down in the 5 bar range.

[leakyroof58]

Thanks to all who replied....these threads are golden....

Several trips and 200+ miles after all the changes - no leaks,
and no fan running. Running in garage I purposely got it hot
enough for the fan to kick in - new switch was the fix.
As for anti-freeze, looked at lots of brands in the big-box
stores.....most said "low silicates". Well, how low is 'low' ?
Found one - Havoline Xtended life anti-freeze, said "silicate-free
and phosphate free". They claim a 5-year 150,000 mile life, so
that's what I put in. It's orange, but who cares ??
Used only new O-rings without sealer on all joints - no leaks.
I think this old girl has lots of miles left.....
Again, I thank you all !!!