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1Back to top Go down    1991 K75C - Overhaul. on Sun Apr 12, 2015 9:16 am

88

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So I finally got brave and dug the K75C out of storage yesterday. It doesn't need much to get sorted for summer so I will do that first and then tackle it more in the winter...

Unloaded beside big Brother...


Trying the comfort seat I scored on Ebay....Looks Nice, Feels good too!


First job is to sort a hole in the tank. Devcon putty and Aluminium Body repair mesh is my preferred formula.



After a few minutes cleaning....



Last edited by 88KE on Fri Nov 20, 2015 5:48 pm; edited 1 time in total


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88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

2Back to top Go down    Re: 1991 K75C - Overhaul. on Sun Apr 12, 2015 10:54 am

charlie99

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fantastic news Will

good riding to you

shes a sweet little girl that one


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cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

3Back to top Go down    Re: 1991 K75C - Overhaul. on Thu Apr 16, 2015 12:21 pm

88

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I was disappointed to see that the petrol which leaked for the hole in the tank dissolved the injector cover before my eyes and had attacked the plastics before I could wipe it away leaving it melted and with a rubbery texture. I can't believe it's so incompatible with petrol given it's function and location. I guess that's why so many bikes are missing them.






The P.O. was "gifted" but not in a Christmasy way.



Two connectors on one wire Rolling Eyes

The radiator cover - tank stud was broken off from a drop, someone had tried to glue something in it's place. Needless to say that didn't work and the piece is FUBAR.



I had purchased this piece off Ebay as a replacement....the metal bits have been stripped as they are rusted out but the plastics are in Nice condition..


The tank repair is done now just needs sanding and painting when fully cured...


__________________________________________________
88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

4Back to top Go down    Re: 1991 K75C - Overhaul. on Thu Apr 16, 2015 4:21 pm

92KK 84WW Olaf

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Its coming along nicely........better than mine. Looks like it will be TacKled in 6 weeks to the day!!

Is that a Frisbee holder? That's one up on a cappuccino machine.....

http://www.servimg.com/view/16818459/482


__________________________________________________
1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 58,645 now 60,500miles
    

5Back to top Go down    Re: 1991 K75C - Overhaul. on Thu Apr 16, 2015 4:39 pm

92KK 84WW Olaf

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That petrol vapour must have put you off track as you ended up with this...


__________________________________________________
1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 58,645 now 60,500miles
    

6Back to top Go down    Re: 1991 K75C - Overhaul. on Thu Apr 16, 2015 8:49 pm

88

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Thats a dual purpose frisbee...Used right way up it entertains the kids, use upside down it hold screws and washers and such for my K !


__________________________________________________
88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

7Back to top Go down    Re: 1991 K75C - Overhaul. on Fri Nov 20, 2015 7:39 am

88

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An update on the project.

At the end of last May Tackler arrived from Aus to take the K75 on a lap of France and the Alps (well documented elswhere in the forum)

In preparation for his visit the bike needed a bit of attention:

Steering/Head bearings shot - replaced.
Front calipers seized - Replaced.
Battery shot - Replaced
Fuel pump Kaput - Replaced with a known good one.
Broken Centre Stand - replaced.
Standard Bench seat was ripped - replaced with a comfort seat
New Tyres (Pirrelli Sport Demons fitted)
Panniers from the LT were fitted for the trip.
Windscreen and brackets acquired and fitted.





There was evidence of oil in the water and that was cleaned out as best we could at the campsite but the problem would return later due to the fan not working and the bike overheating.

Tackler's later trip was marred by a sticking sprag clutch thankfully he was in the mountains so had gravity on his side for bump starting.

Last week I returned to Rouffignac to collect the bike. It fired on the second go and just needed a top up of tyre pressures and fluids before I rode it back to Ireland. There was a tiny amount of oil foam in the header Tank. I reconed this might have come from rad fins after the last flush as we hadn't removed the rad.

The sticking Sprag clutch returned on day 2 or the ride to the ferry and is now well and truly stuck so it will have to come out.

The issue that exercises my mind most however is the oil in the waterway. We had concluded that the previous owner being a truck mechanic and not having had a bike since the 70's put oil in the cooler expansion bottle, mistaking it for an oil resevoir. It appears to have gotten no worse during Tacklers 2 odd k miles in the alps.

Not being able to shut the bike down at the ferry post (it was too flat for me to contemplate bumping it!) and with a sticking fan motor it overheated again and a fair amount of foam blew out the top of the bottle (The cap had been conveniently nibble away by some French mice for that Volcanic effect!).

I have to suspect the head casket is toast but the bike runs beatifully smoothly and economically and has given no impression otherwise ovevr the past 4 k miles.

So I need some advice please:

Is it possible the heat is opening up the gasket between oil and waterways when getting too hot?

Is there another possibility I'm overlooking.

I will check the head torque values and failing that may have to remove the head for a new gasket.

Could the bike run so well for so long with plenty of fast motorway work with such a head gasket issue?

All input appreciated



Last edited by 88KE on Fri Nov 20, 2015 5:48 pm; edited 1 time in total


__________________________________________________
88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

8Back to top Go down    Re: 1991 K75C - Overhaul. on Fri Nov 20, 2015 8:03 am

mike d


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Sounds like you need to perform a compression and leak down test to see if it is from the head gasket.

Mike

    

9Back to top Go down    Re: 1991 K75C - Overhaul. on Fri Nov 20, 2015 8:12 am

92KK 84WW Olaf

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Will

The only place to relieve the excess pressure from overheating is through the expansion tank. My recollection is that you did not have to keep topping up, remembered as I read this post about another one dealing with sticky radiator caps. If the cap is bunged up couldit cause over pressure that suddenly releases into the expansion reservoir as steam instead of hot coolant if temperature is above the boiling point? Maybe swap with the LT one and see what happens?

I did have a car one time did this but it was a head gasket and it was drinking coolant. The K75 doesn't seem to be losing coolant?


__________________________________________________
1992 K100LT 0193214 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 58,645 now 60,500miles
    

10Back to top Go down    Re: 1991 K75C - Overhaul. on Fri Nov 20, 2015 7:57 pm

K75cster

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Perhaps the impeller is spinning but not flowing the fluid, and that there, is a good place for oil and water to mix too, after thecompressiontest maybe consider the pumps


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Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

11Back to top Go down    Re: 1991 K75C - Overhaul. on Sat Nov 21, 2015 3:57 pm

88

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We considered the pump Keith, then dismissed it as there's nothing showing at the weep hole. I'll run the compression test first.


__________________________________________________
88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

12Back to top Go down    Re: 1991 K75C - Overhaul. on Sun Nov 22, 2015 4:24 am

K75cster

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I've not pulled the pumps apart before, so cant say if they can leak between the two and not out the weep hole, I guess there is only two places for the oil to catch up with the water and that would be the head gasket and the pumps, so if its the head gasket would it not be boosting the pressure in the water? maybe a pressure test of the water may help it pass into the combustion chamber and by removing the plugs maybe have some water mist out when cranked over under pressure??? Anyone know of a safe pressure that might be done at??


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

13Back to top Go down    Re: 1991 K75C - Overhaul. on Sun Nov 22, 2015 5:27 am

charlie99

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Will don't discount the pump assembly

we have seen before that the weep hole can get blocked ...additional oil through the pump seal could accumulate further blocking the weep hole completely

next thing to happen is the pressure from the pump far exceeds the water pressure and might bleed into the impeller assembly

my best guess is to replace the pump seals and see what happens after

during this process ...a fair bet might be that the weep hole WILL be blocked

hope it gets resolved simply Will

good luck mate


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

14Back to top Go down    Re: 1991 K75C - Overhaul. on Sun Nov 22, 2015 6:42 am

RicK G

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+1 on what Charlie said.
If that weep hole is blocked and it is easy to happen when the oil seal leaks the easy path is into the coolant. I have fixed 3 or 4 like that over the last few years.
When fixed put a teaspoon of soluable oil in the coolant (just water) and run for a few days then drain, flush and refill with the green stuff or whatever you usually use.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

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