I just fixed a leak from the Orings on pipe going into rear cylinders. Filling up with colant and I now have a major leak on RHS from the tell tale hole below the big bridge pipe!
I didn’t have a leak there before. From what I can see there shouldn’t be a way for coolant to get through to that tell tale hole? see pic below
Any ideas?
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Assuming the cyl head coolant connector tube O-rings are ok… #25 in the pic below, the only way for coolant to be coming out of the drain hole under the “bridge pipe” is either one of the O-rings on the bridge pipe or “shaped” O-rings in the two end fittings are leaking. #21 or #22 in the pic below. Check them all, if they’re the originals, they’ll be 40 years old.
Smithy.
Hi Smithy,
thanks for the quick reply. I had all this off before refitting carbs a while back, and had fitted new Orings on the connector pipe, and the alloy caps. What is very puzzling is that even if it was leaking at either of those places, the coolant would leak or weep outside of the pipe, or alloy junction, not flow out of the weep hole? There is no direct connection between the large coolant gallery with the link pipe, and the weep hole. No sign of corrosion, or crack etc. that the coolant could run through to exit the weep hole below?
I have another R motor in bits on a bench. I’ll check it out now. In years of VF ownership I have never had this happen?
I reckon you’re right Smithy,
checked the spare motor, and the weep hole just carries through underneath on both sides, so it drains any leakage from that crossover pipe.
Despite replacing the Orings, I must have had a leek on one side that I couldn’t see. this would have filled the little void below, and then drained out of the RHS weep hole, as it was designed to.
Back into it now, will carefully replace the 2 crossover pipe Orings, and also the ones in the alloy housing just to be sure. I had all sorts of terrible thoughts of a cracked liner…
Thanks again
How is the leak solving going?
Hah, lots of fun sealing the leaks in cylinder pipes which join up to the thermostat housing. The slight leaks were running down around that link pipe and out of the weep holes.
All water issues fixed and then fuel leaks manifested.
I’m certain this bike had been raced as a production bike back in the day. The tank had been raised on spacers, and seems to have been blown out with compressed air to increase capacity. When I knocked the underneath back into shape so it would sit back on without spacers, it leaked badly.
Fixed leaks with epoxy, and then had a lot of trouble getting fuel to flow properly, as the in tank pick up screens seemed to be totally blocked!
Forced speedo cable wire up both pipes and fuel flowed.
After a couple of other faults I left the R in the ‘naughty corner’ of the shed, and decided to fix the FF. It had been making nasty noises from the front head.
Swapped the motor today for a spare with the help of great mate Mike.
Hopefully the FF will be running in time for VJMC rally/ Xmas party next weekend.
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Cheers for the info.
Completed the transplant on FF yesterday and test rode. Started up almost instantly, sounds quite different with original exhaust collector and gutted pipes, rather than Lazer 4/1 that is now on RE.
Motor pulled strong, I should have set valve clearances before installing, slight noise there but doesn’t sound like the nasty cam/rocker lunch time.
After a hard suburban workout I noticed it getting hot, and boiled just as I got home.
Left if overnight. Today, checked all hose clamps, tightened a couple, refilled reserve overflow tank, changed rad cap.
Started and ran bike stationary. Felt upper hoses get hot as thermostat opened, and system cooled slightly.
A bonus was a small weep on the lower rear cyl cooling pipe sealed up with some stop leak additive. I’ll change coolant once I’m sure it’s all going well, but so far so good.
Will ride again soon to check, and ensure fans are cutting in- all that side of it is standard.
Confirmed that fans aren’t cutting in, and it’s the thermo switch on top rad at fault. Couldn’t find a good one in my stash, or buy one to suit, so fitted a manual toggle switch.
Tomorrow off on a 3 day ride and mini rally ride with the Vintage Japanese Motorcycle Club riding some of best roads around the Illawarra region of NSW. Hopefully the old girl will behave herself. Carrying some coolant and basic tools just in case. You know how it is- if you bring them you won’t need them, if you don’t …