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"Tight Quench" Triumph ride #768112 03/14/19 3:43 pm
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Hillbilly bike Online Content OP
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That would be my 79 T140D.. I milled the cylinders .022" and used a .008 copper shim base gasket to wind up with .032 quench using stock Triumph .020 pistons that have slightly bigger domes than the originals. I believe the actual static compression to be about 9,1-9.2...Stock T140 intake cam at 100 degrees lobe center, "3134" exhaust cam at 102 degrees....AMAL Mk2's with the "European Jetting"..NGK #7 plugs, Lucas Rita timed to 38 degrees total...Also had the valves done on a Newan single axis machine. The rings are NOS Riken.
Fuel is 90 US octane non ethanol..About 50 degrees F with high humidity.Caution needed as the roads are still messy with deicing sand..The Euro carb jetting is lean off idle, have to go back to #3 slides....The engine has only about 30 miles on it and took a fast ride up and down through the gears on the back roads., 6000 rpm max a few times...The engine does respond well and there were no signs of detonation. I even lugged it on purpose and heard and felt nothing...In hot weather there's more tendency to ping but considering the lean fuel mixture right now ,I don't expect any problems..
The 320MM Ducati brake disk and caliper is progressive and powerful..the 95 Honda 750 Interceptor front forks ride and track nicely.. I'm pleased with the modifications...


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
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Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768175 03/15/19 3:11 pm
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Much the same as I did with a 79 a couple of years ago, only I used an E3134 profile either side. I used the 7.9:1 pistons and ended up with a calculated 8.4:1
I used the USA carb settings it came with, except that the air correction jets at the carb mouths were removed already. The exhaust was standard pipes and Norton reverse cone mufflers.
It went so well I saw no reason to experiment with the settings.
Another 79 I worked on at the same time had the US specs but with the Euro needles... Timed the inlet to 100 LC (was 90) and it went pretty good too. Triumph straight thru mufflers.
I'm just saying that the US spec carbs seems to work well enough, at least for the fuel over here.

Hth
Stein Roger

Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768254 03/16/19 11:52 am
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When I got the bike it had the typical US EPA jetting. It ran ok...Then I switched to the Euro jetting and the engine had a hesitation just off idle and perhaps slightly less throttle response at mid range..I keep the 2A1 needle and 106 jet..Using #20 pilot jets made the idle more steady than the #15's...My bike has the stock T140D 2-1 exhaust but with a straight through muffler, that and the engine changes require some slight jetting changes...I believe the bike starts better with the repaired original Lucas Rita compared to the Pazon Surefire I was using...Better as in the Lucas ignition seems to fire the engine before the kicker is halfway down. The Pazon seemed not to fire until the lever was at full stroke...I have noticed this on several other bikes with Pazons..
I also think this engine could benefit from a faster ignition advance, full advance at let's say 3000 rpm instead of about 4500 rpm..But detonation could be a factor with lower octane gas.


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768257 03/16/19 1:03 pm
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Hillbilly bike,This is trumpet 650. I'm new to the forum but have been working & restoring british bikes for 30yrs. Denotation can be controlled by adding stronger springs in a stock advance unit. The electronic ignitions have an advance that is i believe is non adjustable as it is solid state. Please don't forget that any air cooled engine is sensitive to changes in , fuel ,weight and Modifications. Triumph engines were tuned with a certain amount of restriction or "back pressure" in the exhaust which changes how the engine reacts to carburation changes. As long as the timing , valve clearances & compression are within good specs , then carb tuning hesitation is usually a gust of air. There are 3 Main circuits in your carbs. 1 .idle 2nd,mid range 3rd ,Main jet. & of course the throttle cutaway, which affects just off idle ( the higher the number on the slide , the leaner the mixture) Also , check to make sure the throttle slides are opening The same. Hope this helps. & Ride on.

Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768262 03/16/19 2:18 pm
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Hi HB--trust that you are well and looking forward to some riding now that winter is (almost) over her in the North East.
REF the Lucas Rita vs Pazon Surefire comments.
I have used both and they both work fine.
However the Pazon Surefire is normally off and is actuated when it receives two signals from the trigger unit.
I think the Lucas Rita comes alive after one signal from the trigger unit.
So the Rita gives a spark before the Surefire.
I found this out when putting a Surefire onto a BSA B50 single.
It was extremely difficult to start.
I talked via e mail with Andy at Pazon and he told me that it is a "known fault" when used on the B50 which is of course a single cylinder engine and in addition has a very low geared kick starter.
The "cure" for the B50 is that Andy supplied me with a black box that comes alive after just one signal from the trigger unit.
Result: Starting much easier.
HTH

Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768268 03/16/19 3:36 pm
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TM, thanks for the explanation. ...Well, the winter is not over yet with below freezing temps and a bit of snow today...


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768269 03/16/19 3:47 pm
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Yes, we're looking forward to better weather- nothing in the near future tho. Tony helped me degree my cams on my '76 motor. Tried to take it for a ride but the chain broke ?!!? I have a Rita on my Norton-starts well. The Triumph has a Pazon. After the cam work and properly torquing the head it starts well...

Re: "Tight Quench" Triumph ride [Re: trumpet650] #768280 03/16/19 6:39 pm
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Originally Posted by trumpet650
Hillbilly bike,This is trumpet 650. I'm new to the forum but have been working & restoring british bikes for 30yrs. Denotation can be controlled by adding stronger springs in a stock advance unit. The electronic ignitions have an advance that is i believe is non adjustable as it is solid state. Please don't forget that any air cooled engine is sensitive to changes in , fuel ,weight and Modifications. Triumph engines were tuned with a certain amount of restriction or "back pressure" in the exhaust which changes how the engine reacts to carburation changes. As long as the timing , valve clearances & compression are within good specs , then carb tuning hesitation is usually a gust of air. There are 3 Main circuits in your carbs. 1 .idle 2nd,mid range 3rd ,Main jet. & of course the throttle cutaway, which affects just off idle ( the higher the number on the slide , the leaner the mixture) Also , check to make sure the throttle slides are opening The same. Hope this helps. & Ride on.

Hi trumpet!
Good info, but Hillbilly bike will have it covered, believe me... wink
Electronic ignitions advance more gradually (following a hyperbolic curve or something) while AAU's switch faster, so yes the EI will often help against detonation. Still, my 66 Bonnie with 4CA points and a very good AAU with stock springs doesn't ping even when severely provoked. This is on regular gas, 95 RON, which I believe corresponds with US 91 PON/AKI.

BTW, of all the bikes I have, and those I've worked on lately, this bike is the best starter of them all! Sure, the 4CA points are a pain to adjust but they stay in tune for a long time, once set.

Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768291 03/16/19 10:53 pm
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Originally Posted by Hillbilly bike
That would be my 79 T140D.. I milled the cylinders .022" and used a .008 copper shim base gasket to wind up with .032 quench using stock Triumph .020 pistons that have slightly bigger domes than the originals. I believe the actual static compression to be about 9,1-9.2...Stock T140 intake cam at 100 degrees lobe center, "3134" exhaust cam at 102 degrees....Amal Mk2's with the "European Jetting"..NGK #7 plugs, Lucas Rita timed to 38 degrees total...Also had the valves done on a Newan single axis machine. The rings are NOS Riken.


i need to look at your pistons more closely. my limitations come from valve-to-piston clearance before quench becomes an issue. i think the dualplugs compensate for what igive up in squish.


every day you do not take a chance is a day of your life that you will never get back.
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768301 03/17/19 12:11 am
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Hi Hillbilly, This is most interesting the way you did your motor. I'm all ears.

What is part # of pistons you used? May give a clue to their stated compression ratio.

What is your hot cranking compression? I understand dynamic compression well, but would be helpful to me to know cranking compression.

Timing is very much related to pinging. One reason Boyer works well is maximum advance is 3500rpm on the one I tested. Was very linear. Still set max to 36b as bikes will ping at 3500.

I got stiffer AAU springs to move full advance from 2000 to about 3500

Regarding 50f & ping. 50 is Triumphs favorite temperature. At 100f or 105-110f the whole motor changes. Sounds like it's falling apart & they will ping really bad when same hills at 50f no ping. But if you down shift, spin up motor to say 4400 & up they do very well in this heat & doesn't seem to hurt anything. They just sound very loose/worn. I always back off in this heat just to protect the pistons.

Am I correct in thinking your cams will flow better under wider throttle openings & raise the dynamic compression? How about say 60mph, you approach hill & roll on throttle to climb it. How does the cylinder pressure differ if you had original cams, ignition, carbs etc.? Wouldn't it take the same cylinder pressure to move bike same speed?
That's the part that throws me. The 2 bikes that got low compression pistons, 7.1 on 650 & 7.4 on T140. Neither bike will ping now no matter what. But if it takes same clyl pressure to move bike up same hill, same speed, why doesn't it ping or detonate?

When I do my next tear down I'm going to measure qinch space. Head was skimmed about .009". Motorcycle magazines made mention of the squish band & how good it was. But I still had bad ping. 170# compression. Put in .070 thick head gasket replacing .050". This dropped compression to about 151#. Of course this took away .020 squish. But dramatically reduced ping. It also effects rocker geometry. So I was thinking of going back to .050 thick gasket & 7.4 pistons.

I was very pleased to hear about your good success.
Don



1973 Tiger 750
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768311 03/17/19 1:17 am
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reverb Offline
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...hey Tony, regarding the Pazon, a buddy here possibly fried one in his 750, then another buddy that is a car mechanic, adapted a 4 cylinder EI using one coil and the engine runs BETTER. I mentioned this to Andy (Pazon)
So I am really thinking that this surefire is not cooperating with my dual plugs head.

Re: "Tight Quench" Triumph ride [Re: TR7RVMan] #768325 03/17/19 6:25 am
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Originally Posted by TR7RVMan
Am I correct in thinking your cams will flow better under wider throttle openings & raise the dynamic compression? How about say 60mph, you approach hill & roll on throttle to climb it. How does the cylinder pressure differ if you had original cams, ignition, carbs etc.? Wouldn't it take the same cylinder pressure to move bike same speed?
That's the part that throws me. The 2 bikes that got low compression pistons, 7.1 on 650 & 7.4 on T140. Neither bike will ping now no matter what. But if it takes same clyl pressure to move bike up same hill, same speed, why doesn't it ping or detonate?

Because you are running the engines like they want it! Pinging is induced primarily by opening the throttle at too far and too fast at low rpm, filling the cylinders with a lean mixture that won't burn evenly and then detonate. It's the combination of circumstances that's the killer. At higher rpm the engine will ingest an air and fuel mixture with the correct ratio (or close), and burn it at the correct time an speed. It won't matter much if you have a 7:1 or 10:1 calculated compression when the engine is spinning, except it'll make more power with the latter.
As a rule, slow cams fill the cylinders well at lower rpm, not so well at higher rpm, while faster cams are the opposite.

Last edited by Stein Roger; 03/17/19 6:55 am.
Re: "Tight Quench" Triumph ride [Re: TR7RVMan] #768336 03/17/19 11:07 am
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Originally Posted by TR7RVMan
Hi Hillbilly, This is most interesting the way you did your motor. I'm all ears.

What is part # of pistons you used? May give a clue to their stated compression ratio.

What is your hot cranking compression? I understand dynamic compression well, but would be helpful to me to know cranking compression.

Timing is very much related to pinging. One reason Boyer works well is maximum advance is 3500rpm on the one I tested. Was very linear. Still set max to 36b as bikes will ping at 3500.

I got stiffer AAU springs to move full advance from 2000 to about 3500

Regarding 50f & ping. 50 is Triumphs favorite temperature. At 100f or 105-110f the whole motor changes. Sounds like it's falling apart & they will ping really bad when same hills at 50f no ping. But if you down shift, spin up motor to say 4400 & up they do very well in this heat & doesn't seem to hurt anything. They just sound very loose/worn. I always back off in this heat just to protect the pistons.

Am I correct in thinking your cams will flow better under wider throttle openings & raise the dynamic compression? How about say 60mph, you approach hill & roll on throttle to climb it. How does the cylinder pressure differ if you had original cams, ignition, carbs etc.? Wouldn't it take the same cylinder pressure to move bike same speed?
That's the part that throws me. The 2 bikes that got low compression pistons, 7.1 on 650 & 7.4 on T140. Neither bike will ping now no matter what. But if it takes same clyl pressure to move bike up same hill, same speed, why doesn't it ping or detonate?

When I do my next tear down I'm going to measure qinch space. Head was skimmed about .009". Motorcycle magazines made mention of the squish band & how good it was. But I still had bad ping. 170# compression. Put in .070 thick head gasket replacing .050". This dropped compression to about 151#. Of course this took away .020 squish. But dramatically reduced ping. It also effects rocker geometry. So I was thinking of going back to .050 thick gasket & 7.4 pistons.

I was very pleased to hear about your good success.
Don



Don,one problem with me is I don't write anything down to keep track... grin I don't remember the piston numbers but placed side by side on the same pin centers with the original 7.9 compression pistons they had slightly higher domes...The compression I listed, 9.1-9.2, is based on my actual measurements from checking cylinder head volume and piston dome displacement..
Part of this deal relies on the better port velocity of the T140E head..
Retarding the intake cam timing lobe center from 92 to 100 will decrease cylinder pressure at lower speeds while increasing it at mid and higher speeds.The engine feels the same at lower speeds and stronger above 3500 rpm..Keep in mind almost all my riding is on two lane rural roads with little traffic. And I usually accelerate before climbing up a grade...
.

I have never tested the cranking compression on any Triumph...Too many variables like kicking speed and and how many kicks before you record the reading?
Cylinder pressure is the key to good engine performance and economy. Manufacturers spare no expense getting compression as high as practical. The 1930's technology Triumph head design has limitations but improvements can be made using know techniques..And just as important as compression ratio is intake cam timing..I would be checking that before putting in thick head gaskets which is really the wrong way to lower compression...Sometimes reading your posts I get the impression you a reluctant to use higher rpm's because of vibration that goes along with it?







79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
Re: "Tight Quench" Triumph ride [Re: NickL] #768337 03/17/19 11:21 am
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Originally Posted by NickL
The Rita unit fires on the first detected impulse from the reluctor.
Both Boyer and pazon process the signal differently and require
a second impulse to time the initial spark.

Tony, the Rita can be modified to advance more quickly if so required,
one of the advantages of those old units is their discrete components
and non potted construction.

I have on my bench at present a new ignition i've been messing about with,
i designed it years ago but only ever built one for my own use. This device
has an adjustable advance/retard slope with a fixed retard maximum value of 22 degs.
You can vary the maximum advance between 2-5000 rpm engine. The slope is linear,
so it starts at 300 rpm and finishes where set. It uses a wasted spark output.
I built it with b44/b50's in mind, it uses a hall effect sensor as a trigger as
i prefer them, but could be changed to suit points or reluctor if wanted.
I really should get a life i suppose but i still like fiddling with these things, i am going
to make a batch of 10 and see what people think, cost around $200 aus.target.
The expensive part for me is the mechanical side, tapered sleeve and rotor etc.
If someone wanted to just buy the electronics part it would be around $110
The technology is PLL analog/digital so quite old fashioned but very accurate and reliable.
I'll post some detail when done.


Nick , The Lucas Rita works well enough as it, I was just talking... I am interested in your ignition...Is it a stand alone unit or used i with an existing trigger like a Boyer or whatever?


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768338 03/17/19 11:25 am
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They are probably 8.6:1 pistons, Hillbilly. This is the next comp ratio up from 7.9:1 as far as I know (though you see a lot of eBay sellers calling them 8.5:1 for some reason). With the cranking compression testing, it shouldn't matter as long as you have the throttle wide open, as long as you kick it over with a least some energy, as the needle won't go any higher once it has reached the 'true' reading (hence on electric start engines like cars, the engine can be cranked over a lot more and a lot faster than kicking a Bonnie over, but the gauges still work)


If anything other than a blank space is visible here, something's wrong.
Re: "Tight Quench" Triumph ride [Re: Hillbilly bike] #768415 03/18/19 5:48 am
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Hi Hillbilly, I agree thick head gasket is not the best way to lower compression. It does work & does reduce ping. At the time I didn't know nearly what I know now. Still at 29k miles doesn't use oil so I'd like to get another 5-10k miles out of it if possible... Big if! I also don't want to spend the $$ on it now. I have some home improvement projects that are taking precedent.

Regarding mid to higher RPM, what do you consider mid to higher RPM?

Indeed above 4k vibration starts in. At 5k it turns into a buzz. 6k is horrendous vibration. I'll not do 7k. I took bike to 112mph once. Never again. I'll do 80 while passing. I generally cruise at 60-62. Vibration is tolerable. 70 is a good buzz, but actually smoother. But the wind is more & I'm just old & slow.

What I don't like is using 4th gear so much. In the lower hills I need to run 4th until I'm up around 62-65. If hills are a little steeper I go 70 as motor is spinning much freer. The killer is the smaller hills at speeds of 50-55. 4th gear is around 5k ish. That's awful. Motor isn't working very hard, spinning very freely, but will ping in 5th. This is right where all the guys melt pistons either 650 or 750. Even going from 8.6 to 7.9 pistons is a help. Backing timing 4-5d is a big help. Going up hwy 50 or 88 in the Sierra mountains the road will not allow 70 due to curves. Traffic often moves 60-65. My bike is reving silly then. Yet slowing you'll get pressured by following cars to speed up. I've ran the motor an hour solid at a time 55-60 in 4th several times.

Back in the days of 100 octane I could pull 5th easily. With 110 leaded race gas I pull in 5th easily, but not with 91. 110 or 101 unleaded race gas is not the same. May still ping at times. Very good, but doesn't seem to give the power of 110 leaded. The motor cannot be made to ping with 110 leaded. Problem is you must buy it bulk from speed shop. Around town not a problem, but I was done with the 100 mile leash. I was so happy to be able to use 91 & go for a 300 mile ride I almost cried.

Regarding why vibrates so much, my feeling is the dynamic balance is not very close. I've ridden worse 650& 750, also much smoother. I think I'd stay with same factor. On the '69 Bonnie the improvement after dynamic was amazing. Like a completely different motorcycle. Of course it still vibrates, but 55-60 is almost dead smooth. 60-70 is still very smooth. Light flywheel. 7.1 pistons.

My long term plan is virtually blue print the entire motor. Deck the cases & all. For sure will use 7.4 pistons. Check quench & decide what to do with that.

Use the best of everything, cost is what it is. Then see what I get. Truth be told, I don't know it would actually be much better than well assembled non blue printed motor. I've never set cam timing on Triumph, so I'd learn & decide what to do with that. I don't know what cams I'd use. I'm quite happy with the power I have now for my riding style. I really don't want a modern bike at this time.

I've been learning a lot from you. Has given me some new insight on this. I may need to rethink some of my plans.

If possible, please pacifiy me & check compression hot. I use full throttle. Count kicks until gauge won't read higher. I find the cyl washes down quickly. I put plugs in finger tight. Start motor briefly to re oil rings. The test the other side.

Keep up the good work & thanks!
Don



1973 Tiger 750
Re: "Tight Quench" Triumph ride [Re: TR7RVMan] #768429 03/18/19 11:19 am
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Don, I consider 5000 rpm to be higher mid speed range. Mine is smooth for a Triumph at those RPM's.I do use 6000 through the gears with full throttle during sporting rides. It was like that when I bought it and is still the same after the engine work.. I use VP C-12 in my race Triumphs,it's 108 MOT octane leaded...What's left over I use in my street bikes but never noticed a change in performance other than the nice exhaust smell and white lead oxide deposits in the exhaust pipe pipes.But race gas is more than just octane...And cam timing may be more of an influence over detonation than actual static compression ratio...
I don't take long rides at steady speeds so to speak and never on expressways for more than a few miles...Although my Triumph is smoothest I experienced, it's not in the same league as my several Ducatis...A hour of fast riding feels like mechanical bugs crawling over my butt .....What I do may not be for everyone but it is for me..A few years ago I built a 750 long rod T120 with 9.5 compression MAP forged "tight quench" pistons and similar cams and cam timing..After some tuning the engine ran well on 91 octane fuel....But the balance factor I chose may have been wrong and the bike had a nasty vibration right around 3500-4000 rpm. 55-65 MPH..Rather than redo the crank I sold the bike .....Looking back I should have changed the gearing...

I will check the compression but it'll be a week or two..I have the bike back on the work platform for rear brake modifications..and it snowed last night.....Tony


79 T140D, 96 900M Ducati ....On a bike you can out run the demons..

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