Triumph 1970 T100

click said:

Appreciate all your patience with my ramblings!!!

Triton Thrasher & Bernhard; OK, so the opposite of what I was doing is true!!

So, I had, originally, a rich result on the plugs with the air screw 1 1/2 turns out, I could only get the bike to tickover well with the air screw 3 turns out which should have been leaning the heck out of the carburetion!!

I changed to a bigger PJ (from a 17 to a 15, correct me if I'm wrong but these new PJ's are measured in thousands of an inch so 15 is bigger than 17) which should richen the mixture but I had to re-adjust the air screw to 1 /1/2 turns to get a steady tickover, which should be creating a more rich running condition, my head hurts!!!

I wonder if originally the carb had an obstruction in one of the passageways, which would, I think, give a lean mixture and I compensated by turning the air screw out 3 turns?

When I changed the PJ from a 17 to a 15 I gave the carb another clean & maybe cleared the obstruction, hence the reason why the 15 seemed better! not because of the PJ change but because I cleared the obstruction.

Do I have the logic right hear regarding lean/rich, big/small, air screw in/out.

I always get this muddled in my mind, less air = rich, more air = lean, for some reason my brain always defaults to the other way around!!!

Once again I appreciate your patience and knowledge, I do/did know this stuff but I so rarely use the brain cells relating to carburetion they tend to, over time, go back to my incorrect default state!!!

OK, the plan is:

1. Remove PJ & airscrew to ensure passageway across carb is clear. Spray cleaner into the two small holes near the air intake, I'll use some guitar string to carefully poke around in the holes.

2. For my curiosity I'll put the 17 PJ back in & see how far I need to turn the airscrew out to get a steady tickover.

3. Consider using a hotter plug for the short, slow speed pottering around I'm doing & don't forget to change back if I plan on doing any high speed runs! (unlikely)

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Sorry I can’t follow that, but a 15 pilot jet is smaller than a17.

Click, a #15 pilot jet is smaller than a #17. The number refers to the size of the hole, and 17 thou hole is bigger than 15 thou hole.

I think you’re getting mixed up about what does what.

The pilot JET meters the fuel.

The AIR screw meters the air.

So a bigger pilot JET allows more fuel = richer.

Winding the AIR screw out allows more air = weaker (as TT already corrected).

And vice versa.

Fast Eddie said:

Click, a #15 pilot jet is smaller than a #17. The number refers to the size of the hole, and 17 thou is bigger than 15 thou.

I think you’re getting mixed up about what does what.

The pilot JET meters the fuel.

The AIR screw meters the air.

So a bigger pilot JET allows more fuel = richer.

Winding the AIR screw out allows more air = weaker.

And vice versa.

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This is turning into a Monty Python sketch or the Two Ronnies fork handles sketch (All my fault!!)

OK, I have it now, really appreciate the basic carb 101 lesson.

I'll now go away, have some whiskey and ponder all things carb related and do what I should have done at the beginning, read & understand all the info. I have on carb. tuning before I engage with making any changes!!! or asking any questions ;-)

I really appreciate you all sharing your knowledge with me.

Triton Thrasher said:

Sorry I can’t follow that, but a 15 pilot jet is smaller than a17.

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TT is correct .
I don't understand why you have become so confused, there is a recommended carb setting for your bike, in the Amal/Triumph bible.
Unless you have somehow laid your hands on a pilot jet that has been incorrectly marked, so get a couple of small drills to confirm this.

Bernhard said:

TT is correct .
I don't understand why you have become so confused, there is a recommended carb setting for your bike, in the Amal/Triumph bible.
Unless you have somehow laid your hands on a pilot jet that has been incorrectly marked, so get a couple of small drills to confirm this.

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You don’t understand why he’s confused ??

Perhaps part of the reason for Clicks confusion is that *someone* wrote this back in post #6:

”Over 2 turns, pilot jet is too small, less than 1 turn pilot jet is to big”

When they SHOULD have written:

“Over 2 turns, pilot jet is too BIG, less than 1 turn pilot jet is to SMALL”...

And Click has Premier carbs, he‘s unlikely to have a 15 thou and 17 thou drill bit lying around...

Fast Eddie said:

You don’t understand why he’s confused ??

Perhaps part of the reason for Clicks confusion is that *someone* wrote this back in post #6:

”Over 2 turns, pilot jet is too small, less than 1 turn pilot jet is to big”

When they SHOULD have written:

“Over 2 turns, pilot jet is too BIG, less than 1 turn pilot jet is to SMALL”...

And Click has Premier carbs, he‘s unlikely to have a 15 thou and 17 thou drill bit lying around...

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Yep, you do everything back to front when using Amal carbs. . . .

IMHO, with Amal’s, all you have to do is remember that the jets control the fuel, and the AIR screw and slide cutaway control the air.

That’s why I’ve got on my soap box before in previous threads when people have called it the idle screw / tickover screw / pilot screw / mixture screw / etc.

Amal call it the ’pilot air screw’ cos it controls the AIR in the PILOT circuit. Quite straight forward of them really, and not ‘back to front’ at all !

Call it the pilot air screw folks, then it’s easy to remember what it’s doing, and therefore easy to work out what you’re doing when you fiddle with it.

Fast Eddie said:

IMHO, with Amal’s, all you have to do is remember that the jets control the fuel, and the AIR screw and slide cutaway control the air.

That’s why I’ve got on my soap box before in previous threads when people have called it the idle screw / tickover screw / pilot screw / mixture screw / etc.

Amal call it the ’pilot air screw’ cos it controls the AIR in the PILOT circuit. Quite straight forward of them really, and not ‘back to front’ at all !

Call it the pilot air screw folks, then it’s easy to remember what it’s doing, and therefore easy to work out what you’re doing when you fiddle with it.

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Thanks again for the info.

In practice I can tune Amals quite well but when it comes to explaining what I'm doing, that's when the grey matter gets muddled!!

I had the T100 out again yesterday & it ran like a clock, tickover was fine, steady & solid. I still think it's a bit rich on the low end but I'll try a hotter plug for the type of short, slow trips I'm doing. I'll also pull the carb & double check all the passageways.

Hi Lassies & Lads,

I know you all like pictures

I had the Triumph out today for a costal spin around where I live, probably no more than 30 miles, just pottering around between 30-55mph.

Really lovely day, one of the best we've had in a while, long may it last.

Bike is running well, I still think the carb is a bit 'fluffy', rich on the idle circuit but everywhere else is fine. Tickover was good but once the engine got hot it would stall if I let go of the throttle, I did try & raise the idle but I was enjoying the spin so much I was not in the humour of 'tinkering'.


SKERRIES for a coffee.


LOUGHSHINNY


LUSK (You can just make out Lambay Island in the misty background)


MALAHIDE


PORTMARNOCK


HILL of HOWTH (Normally a very picturesque spot but mist at the top was blocking the lovely view of Dublin Bay!)


HOWTH (With Irelands Eye in the background)

OK, confession time!!!! Hopefully it might help somebody else.

I had the Triumph out yesterday, did the usual, checked the PJ (It's a premiere Amal MK1), new fuel, general check around the bike etc.

I noticed the choke lever was loose & tightened the big main screw at the top (more of this later)

Started the bike up & when I came off choke it was spitting through the carb!
Once warmed up the spitting was a lot less so I decided to go for a spin, overall the bike was great but low down, 1/4 throttle of less, it would spit now & then!!

Then a lightbulb went off!!!! I was chasing a rich carb issue on low throttle. I had changed my pilot jet from a standard 17 to a 15 (yes, smaller to lean out the idle/low throttle circuit) I even put the needle clip on the top ring, lowering the needle & leaning out the low end even more.

I had the bike out this time last year & it ran great, but I felt it was still a bit 'fluffy'/rich on the low end. (see pics above)

My air screw was only out about a 1/4 turn out with these settings, which is very rich but it ticked over well & overall the bike ran fine.

I know you guys asked if I had checked if the choke slide was fully retracting & I said yes, I had checked it's operation by holding the slide in my hand & pulling the choke lever to off & I could not see any obstruction to the slide so I thought that's working fine!!!

What I think was happening last year is that I would take the choke off by pulling the choke slide up with the lever but because it was loose the choke slide was dropping a bit back down.

I was then chasing my tail leaning out the idle/low throttle circuit because the choke was partially on!!!!!!!

I put the clip on the needle back to the middle & ran the bike up to temp and changed the PJ from 15 to a 17 (richer)
This allowed me to adjust the air screw to approx. 1 turn out.
I decided, since I had it, to put in a 19 PJ (richer again) and this allowed me to adjust the air screw to 1 1/4 turn out.

Bike is running well, no spits and no 'fluffy' feel on the low end.

Moral of the story, don't allow me to tune your carbs!! or pay more attention to the small details, all this was caused by a loose screw . . . . . . . . .
no not the one in my head

Well you aren't going to get off that easily....WHERE are the pix like last time? Come on now....!
Nice bike!
Wait: is that a chronometric you have on it? What is the story with that?

Onder said:

Well you aren't going to get off that easily....WHERE are the pix like last time? Come on now....!
Nice bike!
Wait: is that a chronometric you have on it? What is the story with that?

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Maybe ex Police bike as chronometrics were fitted to them.

trident sam said:

Maybe ex Police bike as chronometrics were fitted to them.

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Hi,

Spot on, it's an ex. Garda bike (Irish police), never really thought about the speedo!! it works so I didn't pay much attention to it, I'll have to give it a good look some day!

Onder said:

Well you aren't going to get off that easily....WHERE are the pix like last time? Come on now....!
Nice bike!
Wait: is that a chronometric you have on it? What is the story with that?

Click to expand...

Hi Onder ,

I was enjoying being out on the bike so much I forgot to take any pictures
Hopefully I'll get out & about soon & take a few snaps just for you

click said:

Hi,

Spot on, it's an ex. Garda bike (Irish police), never really thought about the speedo!! it works so I didn't pay much attention to it, I'll have to give it a good look some day!

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Been around Ireland many times on my Trident, Galway is one of my favourite places ever.

V N ice motorcycle . Be wary of To Hot a plug if ou do go W F O .

Ah sure, everywhere is Ireland is great. Galway for sure is beautiful, the West of Ireland is beautiful, so is the South, East & North

In any country, I've been on a bike, I've really enjoyed myself

Matt Spencer said:

V N ice motorcycle . Be wary of To Hot a plug if ou do go W F O .

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Thanks Matt, did some plug chops at above 3/4 throttle & all was good

Just found this , not really relevant , tho a friend had a early frame ex ' P R ' 500 with long intakes & 30 concentrics with alledgedly 40 over 650 pistons - 72 bore .
Good at 90 on dirt roads , where the Jappers'd back off at 70 .

Onder said:

Well you aren't going to get off that easily....WHERE are the pix like last time? Come on now....!
Nice bike!
Wait: is that a chronometric you have on it? What is the story with that?

Click to expand...

OK Onder, just for you.

I decided to take a few snaps outside my house, hope the butler has my whiskey ready & walked the hounds while I was out for a spin on the Triumph . . . . . . . . . . . . .

It's Howth Castle, not mine!, it's over 800 years old, well parts of it are, and it's one of Europe's longest continuously-inhabited private homes.

Did about 30 miles pottering around with slow moving traffic, it was a 'soft' day, slit mist of rain so great for an air cooled engine. Had a few spits through the carb at the beginning, dialled the air screw in a bit & all seemed fine, tickover perfect & pickup from traffic lights crisp with no hesitation, happy camper

click said:

Hi,

Spot on, it's an ex. Garda bike (Irish police), never really thought about the speedo!! it works so I didn't pay much attention to it, I'll have to give it a good look some day!

Click to expand...

Hi trident sam.

Good eye, yes it is a chronometric.