Triumph Rat Motorcycle Forums banner

61 - 80 of 116 Posts

·
Registered
Joined
·
49 Posts
https://www.micromark.com/No-78-Drill-Bits-Pkg-of-6

6 off #78 drills $8.95

In the UK
https://www.chronos.ltd.uk/product/wire-gauge-drill-number-78/
90 p each

https://www.stringsdirect.co.uk/strings-c1/single-strings-c810/electric-guitar-c534/daddario-high-carbon-plain-steel-single-string-016-p6479

single string 0.016" £1.10 in UK.

Its cheaper and better to use a #78 drill, in order to break it in the jet use extreme sideways force after having a few drinks.
Or use the more expensive guitar string to blur the jet entry and poke the debris back into the jet passage so it can re block later at an inconvenient point. As a poor kid I poked jets clear with random bits of wire, nowadays my jets stay clear after a twirl with a #78 drill.
By all means spend more for an inferior job, YMMV.
if you like your bike randomly cutting out instead of idling smoothly, love tickling those carbs and kicking furiously for a reluctant start, and blipping the throttle at the traffic lights, stick with the more expensive guitar string poke and hope method.
 

·
Registered
Joined
·
297 Posts
Sorry to not agree with you here, Stuart, but a hardened steel drill bit to open a blocked hole in either aluminium or brass jets is an absolute last option, where everything else has failed. Any engineer will tell you that the risk of removing material from the jet is very real, unless you are somehow able to set your drill at exactly the same angle/pitch as the original machining and even then the blockage itself has the potential to "steer" the drill slightly off path.

I stand firm on my original advice of using an ultrasonic clean first. This will give the whole carb a good clean and very likely unblock the jet (it did on mine, as you know). If that does not work, use a carb cleaner aerosol with straw, then a correctly sized wire, ideally copper (I know that this is the most common fix employed). Then, and only after everything else has failed, reach for the drill. However, using the drill is definitely the fast-fix so I imagine dealers were quicker to reach for it than strip the carbs for a more cautious and sympathetic approach. 😉

Whatever method you use there is a risk of the dirt re-entering the jet. So, once the hole is clear, squirt some petrol or carb cleaner into the air screw hole, then use an airline (or aerosol carb cleaner) to blow the muck out backwards to the bottom of the float bowl, from where a brief flush of fuel with the bowl drain open, will get rid of it.

I am sorry you feel my point about the potential of breaking drills is "cobblers" but my advice stands. Tiny drills need great care as it does not take much to break them (been there more than a few times over the years). However, the new information you provided on using a straw, whilst potentially fiddly, is good advice as this would greatly limit the chances of breakage by absorbing any lateral force.

I appreciate you misunderstood this but I wasn't meaning to misquote you by not including all the text, I just didn't want to repeat your long response again and pad out this thread even more, so I just quoted the point I wanted to highlight. Apologies for any confusion caused.

Cheers,
Ian
 

·
Registered
Joined
·
1,364 Posts
How often do you guys need to clean the pilot jet? Once in a year?
 

·
Registered
Joined
·
1,650 Posts
Last time I did my Trident ones the hole [behind the air screw] was way bigger than a No.78 drill size. From memory I could use a 3/64th's drill bit and it was still loose, but a 3/32nd's bit was too big. The hole into the carbie venturi area was No.78. I never ever modified it so I'd say has always been that big and I've never really had any issues with idle or response etc. I can tilt the carbie's to the light and see the brass insert, and have measured the length so know I am through the idle jet and out the other side.

Are they different for a triple? Can't see why they should be?
 

·
Registered
Joined
·
297 Posts
Out of interest; what is the cause of these blockages? E.g. dirt, additive deposit buildups? On the latter point, I always run the carbs dry before putting the bike away as I hear that modern fuels are not to be left sitting in old carbs...

I have a number of classics one of which I have been running for 33 years without a single jet blockage issue, despite thousands of miles and various fuel quality (including pumped from drums in the outback).

One big difference is the lack of quality fuel filtration on these bikes. Relying solely upon a gauze mounted on the fuel taps and in the feed banjos is definitely a risk. I wonder what the mesh size of these gauzes are and what size particulates they allow through. Does the introduction of a good inline filter remove this issue? If so, one recommendations?

Cheers,
Ian
 

·
Registered
Joined
·
1,364 Posts
Last time I did my Trident ones the hole [behind the air screw] was way bigger than a No.78 drill size. From memory I could use a 3/64th's drill bit and it was still loose, but a 3/32nd's bit was too big. The hole into the carbie venturi area was No.78. I never ever modified it so I'd say has always been that big and I've never really had any issues with idle or response etc. I can tilt the carbie's to the light and see the brass insert, and have measured the length so know I am through the idle jet and out the other side.

Are they different for a triple? Can't see why they should be?
3/32 is .049....three times the recomended pilot jet size...I would say the bike would be grossly over rich just off idle...The pilot has a larger lead in to the small jet orfice, is it possible you didn't have the drill pushed in all way?
 

·
Registered
Joined
·
1,301 Posts
The jet sits in a gas part of the idle circuit, so closer to the plug closing a drilling on the opposite side of an air screw and behind a mixing chamber closed by a plug from the bottom.
You have to put this drill quite far to get to the jet.
I do not empty my carbs after every ride and check my pilot jets and small orifices under slides once a year, before first start in a spring.
 

·
Moderator
Joined
·
6,620 Posts
Hi Ian,

cause of these blockages?
Ime, in GB, moisture or condensation causing corrosion (Mk.1 Concentrics are made of a primarily-zinc alloy known as Mazak/Zamak) or, since the adulteration with ethanol, residues remaining after the volatile parts of the petrol have evaporated.

lack of quality fuel filtration on these bikes. Relying solely upon a gauze mounted on the fuel taps and in the feed banjos is definitely a risk.
Bar the T150, my Triumphs have BAP taps with a finer filter than standard taps' gauze. Nevertheless, ime standard tap or carb. filtration isn't any worse than any of the bikes I own made elsewhere in the world, nor has it ever caused a problem anywhere I've taken my bikes (GB and Western Europe). Occasionally found the odd small foreign body in a carb. banjo fed by standard taps, but that's the filter doing what it says on the tin.

Hth.

Regards,
 

·
Registered
Joined
·
297 Posts
Thanks Stuart,

Agreed. A number of people I respect have recommended not leaving the carbs with fuel in, for that reason. I now pretty much know the exact point in my approach to home where I shut the fuel supply off, so that the bike runs out of fuel as I pull up to the workshop door. 🙂

I guess as long as the gauze size is smaller than the smallest jet, there should be no blockage problems. However, I wonder if it might be worth considering the addition of one of these in each fuel line:

https://www.amazon.co.uk/Motorbike-Fuel-Filter-Anodised-Aluminium/dp/B07DW1M456/ref=mp_s_a_1_47?keywords=inline+fuel+filter&qid=1572446868&refinements=p_76:419158031,p_72:419153031&rnid=419152031&rps=1&sr=8-47

I have similar (replaceable paper filter) but larger versions on my Lotus 7 and Triumph TR3a and you might be surprised how dirty they get after only a few thousand miles. My only concern is that the fuel feed on the bike is gravity fed. Do you think the inclusion of a paper filter would impede delivery?

Ian

Cheers,
Ian
 

·
Registered
Joined
·
1,364 Posts
Question for you UK guys....I assume much of the gasoline sold is 10% ethanol? What do Brits use to distill ethanol, corn? If so, is it grown in the UK or imported? How much of your oil is imported? Just curious, not political..
 

·
Registered
Joined
·
1,228 Posts
Thanks Stuart,

Agreed. A number of people I respect have recommended not leaving the carbs with fuel in, for that reason. I now pretty much know the exact point in my approach to home where I shut the fuel supply off, so that the bike runs out of fuel as I pull up to the workshop door. 🙂

I guess as long as the gauze size is smaller than the smallest jet, there should be no blockage problems. However, I wonder if it might be worth considering the addition of one of these in each fuel line:

https://www.amazon.co.uk/Motorbike-Fuel-Filter-Anodised-Aluminium/dp/B07DW1M456/ref=mp_s_a_1_47?keywords=inline+fuel+filter&qid=1572446868&refinements=p_76:419158031,p_72:419153031&rnid=419152031&rps=1&sr=8-47

I have similar (replaceable paper filter) but larger versions on my Lotus 7 and Triumph TR3a and you might be surprised how dirty they get after only a few thousand miles. My only concern is that the fuel feed on the bike is gravity fed. Do you think the inclusion of a paper filter would impede delivery?

Ian

Cheers,
Ian
We don’t have to think the filter will impede delivery or won’t, because we test it.

There’s plenty flow on mine, with a typical inline paper filter and no gauzes in the tap or the carbs.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #73
thanks, gatornapper/ the more of you Amal purest I listen to the more I want to keep my bike that way it is. KUDUZT,, Wow sorry guy, meant no animosity toward you. I was joking about the bush in your seat(meant to be funny,ha!)and I wasn't being sarcastic about your knowledge of ser. #'s you are the smartest guy I know, Triumph ser.#'s wise(+more I'm sure) you were were so close to my ser# it sent chiils up my spine(knowing you were just guessing with out checking,seriously you know your s*** man) I have the utmost respect for you KUDUTZ, don't care what You Think Of Me, however, I have to thank you for explaining the center stand starting, very good point, I double checked with an expert on Triumphs(sorry) and he emphatically agreed with you SO,all of you OIF owners out there BEWARE!! (THANKS Kadutz for the warning to aall of us)I know you are another Triumph purest that thinks I'm bastardizing A perfectly good Tiger, same with all the others, but you brought to my attention that this a fairly scarce bike, which I had no idea of. Maybe I need to rethink this who thing, & yes KADUTZ the Major problem here is the Owner!(Buy the way KUDUTZ I'm 60yrs. old not 34yrs.) however I only take 75% of the blame This bike has issues. as far as me dissing everyone on there advice, not true. I have taken every grain of advice and plan on using most of it all. IS'NT That's what this forum is all about? the only reason I'm on this site is because,(15yrs.ago) I had had to have 2 full hip replacements and the Ortho. surgeon told me In Front of my Wife I had to SELL ALL of my motorcycles & could never ride one AGAIN!. i've owned &ridden motorcycles all my life&started riding with mini [email protected] .old.and ALWAYS owed a bikes/rode a bike All my life until THAT day(talk about getting nutted out!).Wife made me sell my DRZ400 & would not allow me to own or ride a bike, not even street. You know my wife & I always agreed that we would not not to Judge others. until you walked in there shoes for a month(I say yr.)maybe most of there life , Which is why we should Never judge, so please don't judge me.as I was about to say my wife of 35yrs. passed away a year & 9 months ago, which after reeling over that aftermath I realized I could own as many motorcycles as I want now ( I have 4 now, HA HA)stated earlier I have my own serious health conditions that make it hard to start my bike , so Kudutz can we bury the hatchet & be buds? will you friend me? I respect you very much just as I do everyone else on this site.
 

·
Registered
Joined
·
1,650 Posts
3/32 is .049....three times the recomended pilot jet size...I would say the bike would be grossly over rich just off idle...The pilot has a larger lead in to the small jet orfice, is it possible you didn't have the drill pushed in all way?
Nah, went right to the cross T on the carbie, marked the length with a texta and then laid it across the carbie to check. I was way past the brass plug and to the T. Bike has been fine and like it for over 40 years [I've owned it since '77, started with a T160 but realised my mistake hehehe]. TBH I never ever checked them before, then everyone gets on the webz and starts talking about No.78 drills and such like so about 2-3 years ago I did them and found the larger idle jets setup. I actually checked them again just the other week [was chasing a revs hanging up issue, but fixed it].

However, as I stated the small outlets in the venturi area are No.78 or slightly larger - yet to be checked, but if it ain't broke don't fix it, so one day maybe.

Or I might get them converted to removable ones by darbs aka Richard? No rush.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #75
clarification

my sonic cleaner is on it's way. thanks to Ian, I know what type a cleaner to use& how to operate the machine, etc. hopefully I won't have to poke Anything through any jets I hope(we'll see). unfinished business 1st, Kadutz no I'm not selling any parts I decide to replace, they're going in a box so if I decide to put it back to stock(or the next owner) can. Gavin I definitely agree on the drinks. as far as fuel i'm running now is 93 octane& 1/2 ethanol free, plan on running 100 octane or+ next yr. that's what the owners manual calls for. Oh, IAN T140E huh? electro as in electric start, correct? hows that working out for you? Kevin, i'll get back to you on the side panels, if I go with twin carbs(might be a while,though) thanks again for all the advice, wow I didn' know it was possible to ask 2 simple questions and get so much info(8 pgs.) did we break a record here? crazy, Your all fantastic, keep it up! and last but not least rancidpeg you are the most knowledgeable,(mechanical) women I have ever come across(+ your knowledge of Triumphs)you are absolutely amazing, you go girl! i'd fly to the UK just to hang out with you.
 

·
Registered
Joined
·
1,364 Posts
Nah, went right to the cross T on the carbie, marked the length with a texta and then laid it across the carbie to check. I was way past the brass plug and to the T. Bike has been fine and like it for over 40 years [I've owned it since '77, started with a T160 but realised my mistake hehehe]. TBH I never ever checked them before, then everyone gets on the webz and starts talking about No.78 drills and such like so about 2-3 years ago I did them and found the larger idle jets setup. I actually checked them again just the other week [was chasing a revs hanging up issue, but fixed it].

However, as I stated the small outlets in the venturi area are No.78 or slightly larger - yet to be checked, but if it ain't broke don't fix it, so one day maybe.

Or I might get them converted to removable ones by darbs aka Richard? No rush.
What do you mean by small outlets on the venturi side? The drilled holes in the throttle bore? Well, so everyone is chasing their tails with the .016 drills? And Amal pilot jet size makes no difference? Interesting...I'll stick with Mikunis that never need fussing with..:wink2:
 

·
Registered
Joined
·
297 Posts
oops, I meant Boggie on the T140E
No problem, Ian or Boggie; either will do 🙂

Good luck with the cleaner. I had fuelling issues too and the cleaning process I detailed above addressed the issues as well as making my Amals look like new 🙂

I use the cleaner for everything now. Every time I unbolt something from the bike, in it goes! Even my wife's jewellery goes in and it does a great job on rejuvenating spark plugs.

🙂
 

·
Registered
Joined
·
42 Posts
Discussion Starter #79
so,Boggie you never told about your electric start, i'm very curious how it's done for you. got the sonic cleaner today, you said pure condensed water would that be equivalent to reverse osmosis?(which I have on tap)10:1 would be 10 parts water? I have a electric oil heater(radiator)in my barn office can I just put the carb on it? not crazy about putting it in my oven,(I know it'll be clean)afraid anything I bake after might taste like Amal. thanks for all the advice.
 

·
Moderator
Joined
·
6,620 Posts
Hi Brian,

fuel i'm running now is 93 octane& 1/2 ethanol free, plan on running 100 octane or+ next yr. that's what the owners manual calls for.
Uh-uh, some confusion:-

. Octane is measured three different ways in different parts of the world - RON (Research Octane Number), MON (Motor Octane Number) and (RON + MON) / 2. For a given gallon of British petrol (= US "gas"), RON's the highest, MON's the lowest and obviously (RON + MON) / 2 is half-way between.

. I'm intrigued where this "100 octane or+ ... that's what the owners manual calls for" actually appears in the '78 Triumph Owner's Handbook (manual)? http://classicbike.biz/Triumph/OwnersManuals/1970s/1978-Bonneville-750-T140E-Owners-Handbook.pdf, manual page 7, .pdf page 9:-

FUEL
Octane Rating (minimum) ... 97
Premium grade
. To be clear, GB uses RON, US uses one of the lower ratings; in 1978, 97 (RON) was the highest octane rating widely available in GB, higher was available but owners had to search it out; iirc from a thread some time ago, "93" in the US is equivalent to 97RON in GB.

IAN T140E
electro as in electric start,
Don't believe so; iirc from his early posts, Ian's bike is a '79, Triumph didn't fit twins with electric-starters 'til '81. The "E" model code suffix was first used in '78 to designate models fitted with parts to meet the lower EPA-mandated emissions limits from 1st January 1978; originally these were parallel-inlet-port cylinder head, Amal Mk.2 carburettors and revised crankcase and oil tank (frame spine) venting; from '79, electronic ignition, 3-phase alternator and 'negative ground' electrics were added; later the carbs. were changed for Bing CV. Otoh, T140's with factory-fitted electric starters were designated T140ES.

Hth.

Regards,
 
61 - 80 of 116 Posts
Top