Hi @solomon
Both the seals and the gasket were identical. I didn't place the top o rings on the tubes when testing the crush. Could that be it?
Cheers
T140V 1976 Composite Gasket
- Thread starter Migsan
- Start date
Help Support Triumph Motorcycle Forum:
Both the seals and the gasket were identical. I didn't place the top o rings on the tubes when testing the crush. Could that be it?
Cheers
Ok. To recap.
The top end was rebuilt?
The bike ran, but plugs got oily.
So removed head again.
You have now straightened the head.
You have not touched the tappet blocks this second time?
The translucent seal is identical thickness to first time?
The gasket thickness is identical thickness to first time?
But now there is no crush distance under head and pushrod tubes don't contact seals?
If the head has been straightened there would be more pressure on identical seals using identical gasket.
Something must have changed...
I will go over it all again! But was I supose to measure the crush with or without the black o rings from the top of the tubes? Because I did it without!
So, as far as I remember top oring pushes down on pushrod tube. So makes sense to fit it.
Here's a video explaining crush very well. It's not measured, it's "judged". I'm NOT recommending anyone does this, although it is my method.
View: https://m.youtube.com/watch?v=EaLarrD9rjk
Thank you very much @solomon
So I fitted the head with the top black o ring and forced the head by hand until the black o ring felt in place. Now I have a gap but I believe it's bigger than 0.04. My feeler gauge only goes 0.035 but the gap is slightly thicker than the gasket!
I checked the white/transparent square seal used was 70-4752 and the black o ring is 71-1283
I understand not only the seal at the bottow will be crushed but also the black o ring correct?
Plus forgot to mention there is no longer any play in the tubes!
Cheers
It's highly tricky measuring the crush. How do you know if the head is exactly level? Pushing something in there will just exasperate things.
That's an advantage of the above video method. I'm also suspicious the seals aren't definitely and absolutely the same density as the original Meriden seals. That's to say, they might be softer or harder.
There's the double gasket method.
0.04" is 1mm, so if a gasket or other material is to hand 0.75mm to 1.0mm and put over gasket to use, seals should be in contact with pushrod tubes. Not slightly crushed, no rocking of head.
Rechecked with doble gasket @Rudie technique and I believe we are good to go! Won't spare on the hylomar
The oring doesn't, I think, play a significant part in any overall crush height.
Not sure thicker is better with Hylomar?Rechecked with doble gasket @Rudie technique and I believe we are good to go! Won't spare on the hylomar
View attachment 54012
I will just smear a thin film on the gasket but I was planing on putting some on the center bolts as well to avvoid any oil leaks!
So just to give and update!
Assembled the head following all the recomendations center bolts 16 foot pounds and the remaining 18 foot ponds. All followi g the sequency and doing approximately half a turn.
Took the bike for the 5 mile ride no issues runned very well!
Let it cold down overnight and today retorqued all the bolts moving each one slightly anticlockwise before retorquing.
The previous day placed a new pair of plugs and noticed they were allready pretty dirty. Cleaned them and went on another 5 miles rides for gas.
Couldn't restart the bike at the gas station and had to replace the fouled plugs for another pair. Barely made it home with the bike misfiring!
Here is a picture of the pair.
Could it be residual oil? Is it still burning oil?
I have no white smoke but at start up there was a slight dark smoke. Even opened the mixture screw a 1/4 turn!
Can't seem to get this right!
Can't see that clearly, but looks sooty rather than oily to me.
Where would "residual" oil lurk? Don't think that would be it?
Could be running rich.
Did you adjust idle when engine had heated up,? Will be tio rich if done cold.
Mixture screw is for low throttle adjustment. Once throttle is open a lot the other jets determine richness.
Maybe put new plugs in, go for a fast ride for a few miles, no idle or low speeds, throttle open a lot. Stop, don't idle, and inspect plugs, take a picture of them.
Thanks @solomon
I shall try that tomorrow! Wich plugs would you recomend?
I believe my mixture screw is is near 2 complete turns!
Cheers
Miguel
Champion NC3 are the recommended, and what many use. I swapped to an equivalent, NGK B8ES which I think runs better (just my opinion for my bike). NGK B7ES runs hotter, could try them.
Did you tune the carbs for idle? The 1.5 turns out is a starting point. Could be more. Do you want a link to carb tuning?
Did you tune the carbs for idle? The 1.5 turns out is a starting point. Could be more. Do you want a link to carb tuning?
Thanks @solomon
I have a pair of NKG B7ES I will run them.tomorrow. yes I had the carbs tunned for idle around 1100 rpm.
Please if you don't mind would love the carb tunning link in case I missed something!
I shall show you the plugs afterwards.
Cheers
This is considered authorative...
https://www.ntnoa.org/pdf/Bushmans Carb Tuning Secrets.pdf
For starters, see under
SYNCHRONIZING TWIN CARBS FOR IDLE AND SLOW SPEED RUNNING
Mixture screw should be used to get engine at point any more in or out reduces revs. Stop screw sets idle speed in conjunction with mixture screw. So both need tweaking to tune. So it's done by ear with mixture screw, using tacho with stop screw.
... and engine should sound balanced from both pipes.
