Reversible Intake Manifolds On Yer T140V?

[Lordmac]

I do not like those stock intake manifolds on my T140V. Why? Well, here's why: you can't EASILY take off yer intake rocker box because of that bulging metal casting that protrudes on the top of the manifold unless you first remove the carbs and manifolds and all the other related stuff which takes FOREVER!. Unless there is some strange and weird wrench that I have never seen or heard of made just for that purpose, those rocker box nuts are a reeel pain to get off because there is no room to get tools in there. That's my opinion and I'm sticking to it.
I decided to do something about said problem, and here is my zoo-looshun: I purchased a second set of manifolds to experiment with so as not to maybe ruin my originals. I then cut and ground and filed and sanded those casting bulges off as if they were never there and polished the remaining metal so they look reeel neat.
I can now EASILY remove the intake rocker box with a small wrench and the carbs stay put!

Below are photos of the manifolds pre and post alteration.

 

[solomon]

Just checked mine. I've not only got the bulges, one has a lump so big it virtually touches rocker box.

Maybe I'll get grinding. Can't think why it's there.

Ps. You've got nice shiny cylinder head. How did you do that?

 

[Greyfell]

Wow, nice job. I'm thankful, however, I don't have worry about that on my Thunderbird.

 

[Lordmac]

The manifolds aren't made as right and left but rather, single castings, and are drilled and tapped for the respective side to be used and mounted up or down. Unfortunately, this creates that waste metal chunk sticking up on the right side while on the left it is used as the mount for the choke lever on the bottom. The balance tube holes and threads are treated the same way. Cheese monster of Triumph to do that.

I used a hack saw to cut most of that chunk off, then proceeded with various fine flat files and Dremel tool and then degrees of sandpaper and polish. It is a bit of work, but then, so is messing around getting those rocker box nuts on and off a few times. But hey, it shore-nuff looks WAY cooler than those chunks of metal sticking out for no reason!

How did I get my engine metal so shiny? I used soft brass brushs - you know, those inexpensive little ones you get from the hardware stores. Works great. Beat the heck out of 'em. You can cut them down to fit between the fins and the wood or plastic handles don't mar the aluminum at all. The metal shines up rather quickly too. Whooda thunk it?

I like your thick gasket tween your carb and manifold. Is that a purchased item, and if so, where? I use the 'O' rings but they smash down too much even with mild pressure. Something to look into. Carbs need that insulation factor.

 

[Lordmac]

Wow, nice job. I'm thankful, however, I don't have worry about that on my Thunderbird.

Yeah, it's a big deal owning the big and POWUFUL Bonneville!

 

[solomon]

I used soft brass brushs - you know, those inexpensive little ones you get from the hardware stores

Can you post a pic? Don't they scratch the softer aluminium?

I like your thick gasket tween your carb and manifold. Is that a purchased item, and if so, where?

https://www.ebay.co.uk/itm/27581501...vMlBMwqTL-&var=&widget_ver=artemis&media=COPY
As you say, to keep carbs from getting too hot.

 

[Rudie]

soft brass brushs

post a pic?

Enter "brass brush" into either Ebay or your internet browser.

Don't they scratch the softer aluminium?

The soft brass bristles collapse easily under even mild pressure. Up to a point, these brushes can continue to be used. However, eventually the bristles compact into a solid mass; heavy pressure on these compacted bristles could scratch aluminium.

Also avoid wire brushes with brass-plated steel wire.

 

[Rudie]

View attachment 54435

thick gasket tween your carb and manifold.

Reverses the modification Triumph made to 650's from 70, carried on to the 750 twins. Triumph modified the 70 on carb mounting to fit the carb between rubber washers in steel cup washers on one side, as in your View attachment 54434 photo, and a thick O ring between carb and manifold. Triumph made the modification because the increasing power and vibration on 650 twins was frothing the fuel in 650 carbs mounted rigidly, causing holed pistons.

I use the 'O' rings but they smash down too much even with mild pressure.

O rings between Amal carbs and manifolds are correct on any old British bike, the trick is knowing you have fitted the correct O rings ...

Most old British bikes that mount a carb. rigidly against a manifold use a thin O ring - Amal 622/101 - for sealing between carb and manifold; at least all Amal carbs. have an O ring groove machined around the carb. outlet to the engine, the Amal O ring fits in this groove. If a carb is mounted rigidly against a manifold, it also requires a spacer of insulating material to prevent heat transfer from cylinder head to carb.

Otoh, 70 on 650 and 750 twins' carbs are mounted correctly with a small gap between carb and manifold, it is this gap that prevents heat transfer from cylinder head (manifold) to carb. This gap is sealed with a thick O ring - Triumph 70-9711; the thick Triumph O ring does not fit in the standard Amal outlet O ring groove.

The difference between the two carb mounting types is the correct 70 on parts also isolate the carb from at least some of the engine vibration.

I use the 'O' rings but they smash down too much even with mild pressure.

Your View attachment 54434 photo appears to show your have not fitted the correct O rings, you have fitted thin Amal 622/101 between carb and manifold.

However, this might not be your fault, some dealers are still confused ...

The confusion arises mainly because: Meriden put supplier part numbers in 76 on parts books, they incorrectly equated 622/101 with 70-9711, they left the error in for several years. Mind, this is nearly fifty years ago, it really is about time the dealers who still supply incorrect O rings read the memo?

Otoh, if you have fitted correct 70-9711 thick O rings, you should check the length of the 5/16" o.d. parts of the carbs mounting studs and the lengths of the components mounted on them.

You should be able to tighten carb mounting nuts until the cup washers are against the 'steps' between studs' 1/4" thread and 5/16" o.d. and there is still the small gap between each carb and manifold and the thick Triumph 70-9711 O rings are visible in the gaps between carbs and manifolds and sealing those gaps.

 

[Lordmac]

Reverses the modification Triumph made to 650's from 70, carried on to the 750 twins. Triumph modified the 70 on carb mounting to fit the carb between rubber washers in steel cup washers on one side, as in your View attachment 54434 photo, and a thick O ring between carb and manifold. Triumph made the modification because the increasing power and vibration on 650 twins was frothing the fuel in 650 carbs mounted rigidly, causing holed pistons.


O rings between Amal carbs and manifolds are correct on any old British bike, the trick is knowing you have fitted the correct O rings ...

Most old British bikes that mount a carb. rigidly against a manifold use a thin O ring - Amal 622/101 - for sealing between carb and manifold; at least all Amal carbs. have an O ring groove machined around the carb. outlet to the engine, the Amal O ring fits in this groove. If a carb is mounted rigidly against a manifold, it also requires a spacer of insulating material to prevent heat transfer from cylinder head to carb.

Otoh, 70 on 650 and 750 twins' carbs are mounted correctly with a small gap between carb and manifold, it is this gap that prevents heat transfer from cylinder head (manifold) to carb. This gap is sealed with a thick O ring - Triumph 70-9711; the thick Triumph O ring does not fit in the standard Amal outlet O ring groove.

The difference between the two carb mounting types is the correct 70 on parts also isolate the carb from at least some of the engine vibration.


Your View attachment 54434 photo appears to show your have not fitted the correct O rings, you have fitted thin Amal 622/101 between carb and manifold.

However, this might not be your fault, some dealers are still confused ...

The confusion arises mainly because: Meriden put supplier part numbers in 76 on parts books, they incorrectly equated 622/101 with 70-9711, they left the error in for several years. Mind, this is nearly fifty years ago, it really is about time the dealers who still supply incorrect O rings read the memo?

Otoh, if you have fitted correct 70-9711 thick O rings, you should check the length of the 5/16" o.d. parts of the carbs mounting studs and the lengths of the components mounted on them.

You should be able to tighten carb mounting nuts until the cup washers are against the 'steps' between studs' 1/4" thread and 5/16" o.d. and there is still the small gap between each carb and manifold and the thick Triumph 70-9711 O rings are visible in the gaps between carbs and manifolds and sealing those gaps.

You are right again, Rudie, and I knew there were different O rings called for in the manuals and that the fat ones are the correct ones and make complete sense, but SOMEHOW, last time I installed new ones, (which was when I put those fancy new Amal Premier carbs on) I ended up using the skinny ones. I must have my Triumph be RIGHT! Therefore, I am ordering a set (or two) of those 70-9711 O rings post haste. Maybe first, though, I should check my bag-o-'O'-rings and see if I got any of those hiding in there . . .

 

[Lordmac]

Can you post a pic? Don't they scratch the softer aluminium?

https://www.ebay.co.uk/itm/27581501...vMlBMwqTL-&var=&widget_ver=artemis&media=COPY
As you say, to keep carbs from getting too hot.

Here is s picture. And no, the brass bristles are reeel soft and don't scratch unless you're really rough. So be gentle. Just rub lightly. These can be got at places like Harbor Freight (fright?) for a dollar, or other places too. Brass bottle/Pipe brushes actually work better to get into the cooling fin areas. Just make sure they are soft ones.

 

[triumph david]

VERY INTERESTING, riding season is here, soon as it gets to hot to ride this is my next project!!! Thanks for the info!!!!

 

[solomon]

I had the fat orings before fitting the thick insulation spacers.
Carb bowls stay cooler with spacers. Also, because the air box is removed on my oif bike, it leaves nothing supporting the end of the carbs. The spacers add better rigidity than fat orings.

 

[Lordmac]

I had the fat orings before fitting the thick insulation spacers.
Carb bowls stay cooler with spacers. Also, because the air box is removed on my oif bike, it leaves nothing supporting the end of the carbs. The spacers add better rigidity than fat orings.

That is some good-to-know-info. If I do that to my Bonnie, will I get thrown into "not-original-modifier" jail?
All mods aside; getting rid of those useless metal chunks on the manifolds is totally legal cuz it's still an original part.
Don't tell anybody, but I don't have the original fuel lines installed either . . . yikes!

 

[solomon]

. If I do that to my Bonnie, will I get thrown into "not-original-modifier" jail

Yes. And the rivet counters will throw away the key.
That said, my understanding Concours d'Elegance is NOT original, but as good as original or better.
Your manifolds are clearly better.
Fat spacer? Well, I had very hot carb bowls when riding very slowly for long time. Now not. That's better innit?

 

[Rudie]

because the air box is removed on my oif bike, it leaves nothing supporting the end of the carbs.

Triumph introduced the carb mounting update on 70 650's, that did not have anything supporting the carbs' inlet ends.

Described on another forum, 70 onwards carb mounted with 70-9711 thick O ring, the gap between carb and manifold should be about the thickness of a business card.

the air box is removed on my oif bike

That is some good-to-know-info.

Be aware the the thick spacers @solomon has fitted cannot be fitted without removing (not fitting) the o.i.f. airbox(es); box fitted, insufficient horizontal space between box and manifold for carb and thick spacer (and the accompanying gasket).

The spacers add better rigidity than fat orings.

Triumph modified the 70 on carb mounting to fit the carb between rubber washers in steel cup washers on one side
and a thick O ring between carb and manifold. Triumph made the modification because the increasing power and vibration on 650 twins was frothing the fuel in 650 carbs mounted rigidly, causing holed pistons

... I suppose if an owner does not ride his or her Triumph 650 or 750 twin very fast, he or she will not encounter the problem Triumph was trying to fix, but possibly insufficient cooling air passes over the carbs?

 

[Lordmac]

... I suppose if an owner does not ride his or her Triumph 650 or 750 twin very fast, he or she will not encounter the problem Triumph was trying to fix, but possibly insufficient cooling air passes over the carbs?

I ride fast enough to keep everything cool. Ain't that why we ride Triumphs? I love my Triumph!

After taking all the info into account, I have decided to stick with original Triumph engineering where carb O rings are concerned. I figure those guys knew enough about what they were doing to satisfy my needs. And, I am nearly certain that I can fit the big O rings without removing the carbs, what?
Besides, I don't want to void my warranty and have my bike go nook-yoo-ler . . .

 

[solomon]

I ride fast enough to keep everything cool. Ain't that why we ride Triumphs

I might be a repressed Harley owner. I like slow riding, pulling away low down. Don't tell anyone though.

My problem occurred on a charity ride. Most of the 1,000 Father Christmases had water-cooled bikes, could spend a couple of hours idling or in first or second. I think my carb bowls got so hot fuel evaporation became a problem. That was in the winter.

 

[solomon]

How did I get my engine metal so shiny? I used soft brass brushs - you know, those inexpensive little ones

Thanks! Got my brushes, like a brass toothbrush. Head getting shiny.

Only problem is, I've got poor self-control. I'm flirting with doing the crankcase.


Ps. Before someone says something, header pipe is not fixed in place, swapping them.

 

[Lordmac]

Thanks! Got my brushes, like a brass toothbrush. Head getting shiny.

View attachment 54545

Only problem is, I've got poor self-control. I'm flirting with doing the crankcase.


Ps. Before someone says something, header pipe is not fixed in place, swapping them.

Well yeah, one cannot go on living with dull crankcases. Chiny chiny chine. The brass brush offers just the right amount of beautiful chinyness!

 

[solomon]

Well yeah, one cannot go on living with dull crankcases. Chiny chiny chine. The brass brush offers just the right amount of beautiful chinyness!

Oh, no. Even your nuts are shiny.
I'll get brushing. I've noticed it leaves a brassy tint, doesn't matter.