Triumphrat

JT95945 · 07-31-2009, 05:07 PM

Have Issues Here That I Need Some Guidance On. I Had Prob Lem Fouling Left Cylinder. I Had 120 Psi Compression On Both Cylinders At Tahat Time. I Just Did A Top End New Pistons,rings, Lapped The Valves. However I Did Not Do Valve Guides They Seemed O.k.we Put It All Back Together With Standard Pistons And Rings And Bamm Same Symptoms. We Have Good Ignition,120 Psi Compression Fires Rite Up But Fouls Plug Within Minutes With Smoking Left Pipe Not Real Bad Though. Carbs Have Been Rebuilt May Have Been Running A Little Fat. At First It Seemed Left Cylinder Was Fule Fouled Now The Plug Seems To Be Oil Fouled. Are There Any Ways To Eliminate Valve Guides Without Removing Head? What Am I Missing?

delrazor · 08-03-2009, 03:19 AM

I just sorted timing, carbs , pipes etc etc and have the same symptoms.
Checked my oil last night and it took 1.2 litres after maybe 800 miles (since oil change). after topping up I fouled 2 plugs in as many minutes - both left cylinder.

Help me through this folks, because (as I alway state) I am a 2-stroke guy up till recently.
causes of smokey exhaust....

1) rings - if both cylinders are holding around 140 psi can this be the cause of one smokey pipe?

2) wet sumping - likely to be the left side only? I only use the centre stand but it does hang left a bit on he centre.

3) valve guides - Would this be a symptom likely to show after parking then go away on the open road?

4) super rich mix??? dreaming.

5) anything else?

thanks a million in advance
derek

ps. I am currently applying to go off to study MC mechanics with the youngens. MId life crisis? OR to broken for steelwork?

epynt1050 · 08-03-2009, 04:21 AM

If you have oiling on one cylinder only but good compression the most probable cause is valve guides.
If oil (not petrol?) is getting into the combustion chamber, the it can only come down the guides or up past the rings. If you have good compression, it cannot be the rings.

JT95945 · 08-03-2009, 07:08 PM

we tore down the top end again to find that rings did no seat. so we have decided to throw in another set. is there any sucessfull advice into seating these rings. one shop says start dry do not pre oil when putting it back together.

jimmy bush · 08-03-2009, 09:11 PM

When I rebuilt my 68, I had smoking issues and plug fouling too. I talked to a local Triumph mechanic with 30 or 40 years experience and he said not to worry about it smoking until I put at least 1000 miles on it. He said sometimes it takes that long to seat the rings. I've got nearly 1000 miles on it now and it has nearly stopped smoking. He also told me to run Champion plugs and that stopped the plug fouling.

JT95945 · 08-03-2009, 09:41 PM

thanks for the replys. my issue is that the left cylinder looses fire once the plug fouls, i cant even get 50 miles let alone 1000 miles i would expect minor smoke during break end but loosing fire is getting fustrating. what is a simple way to test valve guides without removing valves?

Plewsy · 08-04-2009, 08:40 AM

If the valve guides seemed ok, they probably where
as they would have to be pretty bad to stop a cylinder.
When you fitted the rings did you gap them?
For now I would work on that side carb, got to extremes for leaness for float setting
and needle position.
What size jets are you running?
Have you tried swapping coils, to see if symtoms change?

JT95945 · 08-08-2009, 02:05 PM

we have swapped coils no diiferent, the jets are stock, not to lean if anything a little fat,rings were gapped at 12 and those were standard replacements we also staggered the gaps.

Caulky · 08-09-2009, 05:28 AM

Smokey exhaust? I had this very bad before this latest rebuild.
One day, no wind...the street was like a thick fog.
Neighbours didn`t approve

The left cylinder was worse than the right.
No matter what I did with the mixture settings, it smoked.
And it was losing (burning) oil.
I bought new barrel, pistons, rings and oil pump.
(the old barrels were already + .040" and the threads were knackered).
I decided that it had to be fixed.
1. the valves were sloppy in the guides.
2. the barrels were tapered.
3. the ring gaps varied depending on where I checked.
4. the valves were seating gas tight...WD40 did not leak through them.
5. black plugs and spark failure.
On this evidence, new valve guides were essential. Having consulted the
workshop manual, I didn`t fancy the DIY method.
I bought the removal tool but didn`t relish cutting the seats, so I sent the head away, with new valves.
They fitted new guides and seats for unleaded fuel, and gas-flowed the head.
I bought new springs. I fitted new small ends.
Now there`s no smoke

I`m not suggesting you should do the same, but maybe its food for thought.

RetroRod · 08-09-2009, 06:10 AM

You've not stated what method you followed to bed the first set of rings, but I have just completed this exercise myself.

Get on the thing and pull it to 5k through the gears a couple of times, then get out and ride it at ordinary highway speeds, varying RPM here and there. No continuous loud noise for awhile, and do not lug the thing up grades.

Install the rings dry, with a smear of oil on the thrust sides of the piston

The combustion pressure that is developed during the initial run helps to expand the rings onto the cylinder walls, thus assisting in the bedding process.

I used a running-in oil for the first 300 miles to assist the rings sealing in the bore.

I agree with a previous comment that you ignore some engine smoke during the initial stages until the rings have sealed.

If you are using the correct heat range plug, then plug fouling should not occur. Good luck the second time around. RR