Throttle Body Size

[Dool]

According to @Sasa 36mm is the optimum size for our much loved Himalayan, so I ordered a 37 a 36 and a 40, 37 was a pain to install but works and even got an electric Cold Start.
36mm is still in Transit as is the TPS/MAP sensor that fits the 40mm which I have already, I have started making an adaptor to fit it to the Himalayan Manifold, then I willl have a go with mounting straight to the Head with the 36 which incorporates the Injector .
This will save the Air about 100mm of travel so it might get into the Engine Quicker

 

[Dool]

Just arrived, (Not from Italy!) a 36mm Throttle body with injector mount attached, will be an interesting progect, again it has no IAC Valve so a Manual adjuster has been ordered to suit, MAP and TPS are combined.
It may need some adapting to fit the Inlet Port of the Himalayan but I have a Dremmel

 

[Dool]

It could time to revive this also, I've had this TB for more than a few months now, as you can see it is somewhat shorter that the set up on our beloved EFI Himalayans and incorporates the Injector ( and the Hole is different! Challenge ) this could have a an impact on the air flow

This Length difference could be a result of many things but what if is just because the TB shown is from a Watercooled Head which is thicker?

So guessing that is not the answer I thought more.


This is a Carby Manifold ( Carby heads have only one difference and that is the ECT Oil temp sender!) it bolts on to the Head and holds the Carby

I dont have a Carby just the Manifold so you need to use your imagination as to where the Butterfly Valve of the Carby sits as opposed to the Throttle Body Butterfly, but you get the picture!



So let me say it is 60mm further back than a Carby, multiply that by 5000 times and its a big number.
I don't know if it makes any difference, I didn't design the engine
But someone did and I think they did not design it as an EFI bike!

You only have to look at the connection between the Air Box and the Throttle Body to see that EFI was ( in the Case of the Bs4 ) not addressed in the original design The Throttle body is hardly a bespoke unit, the Manifold looks to be an adaptor to hold both the Throttle Body and the Injector with the Slack being taken up in the shitty air box hose,( so they could keep the airbox ) unless I am mistaken and it is some improvement like the restriction at the end of the Exhaust system

Got to have an answer so perhaps it is this,





The Bolt holes nearly match up so I am in with a Chance.

 

[Dool]

34mm seems to be a good upgrade, Conti throttle bodies are hard to get, with the RB not using MAP I can modify this one to drive just a TPS so it should work fine, if I do not lose the parts!

 

[Dool]

Milled down the side I will mount the TPS to, gives me more shaft to reshape.

 

[Sasa]

Will this 34 adapt to the stock manifold or require further mods?

I wonder if this could be made as a viable alternative to the Conti as a performance upgrade part!

 

[RCruiser]

Sasa FYI, I can get/send you a Conti TB if you'd like. It fits onto the OEM Himmi Manifold. I forget what I paid for mine but I thought it was reasonable.
R

 

[Sasa]

Sasa FYI, I can get/send you a Conti TB if you'd like. It fits onto the OEM Himmi Manifold. I forget what I paid for mine but I thought it was reasonable.
R

Thanks a bunch @RCruiser, I already had an arrangement with @Dool about buying his when he no longer needs it.

Anyhow if he decides to keep it I'll contact you and we'll arrange things up!

Prices for a Conti here in EU are insane!

 

[Csx355]

Hi all - I have a 477 kit on the way and it strikes me that with an increase in capacity then an increase in fuel delivery would make sense. I have zero knowledge of FI systems having always played about with carbs. So where do I start? From what I’ve read a bigger throttle body is the way to go, Perhaps coupled with some head porting. Where do people get these? Dool suggest a 36mm TB is optimal and appears to have done the legwork (and machine work) to make this happen. Is there a plug and play option? Does anyone have one for sale? Many thanks Steve

 

[Dool]

Plug and Play options in this game are few and far between.
Your Big Bore will Suck more, as you would imagine, with the stock head the Compression will be high.
IMO all EFI Himalayans run on the Lean side as a Sacrifice to the Gods ( Whomever They are ?) now it will presumably be even Leaner.
Depending on Ex and Inlet mods you will be needing, at the Very least a US$200 FuelX Pro ( mentioned for a Reference point not for consideration) up the Top shelf PC 5 at US$500.
Powertronic will cost about 350. Not including the Laptop!
Red Box here will cost you about the same as the powertronic, either way you need a Laptop to change the Jets and adjust the Mixture now.
Red Box is actually the Biggest of the Units but take into consideration that it replaces the OEM ECU and does not come with Multiple Plugs and sockets to Wire into the various sensors, it is fitted in minutes the others take hours.

Okay so the Good news is that Bigger Throttle Bodies are not expensive !

 

[Csx355]

Hi Dool, many thanks for the reply. I have the Red Box en route with the 477 kit. And that’s where I’m beginning to step outside of my comfort zone! However given that the decision to modify has been made it seems sensible to go all in whilst the head and barrel is off. Do you have a suggestion regarding what body I need and where to get it? Regards Steve.

 

[Dool]

I would recommend you make a Throttle Position indicator. the disc style is easier to read.
With the Software you will see the importance of knowing the throttle position, and when and if you need help you can state the throttle position with a degree of accuracy.
Saying my Bike does this or that when you do this or that is pretty much useless without the Datum that others can follow.
By knowing where the throttle is in relation to the Software you can start to get an idea of what changes to make.

Also I would sit the head upside down and place the new Barrel on it and Scribe a line around inside the barrel to mark the head then shape the combustion Chamber to suit.

I would install a Delkovic header and cut off the last 70mm that has the restriction then fit a slip on muffler and then I would think about the Larger Throttle Body.
.

 

[Sasa]

Hi Dool, many thanks for the reply. I have the Red Box en route with the 477 kit. And that’s where I’m beginning to step outside of my comfort zone! However given that the decision to modify has been made it seems sensible to go all in whilst the head and barrel is off. Do you have a suggestion regarding what body I need and where to get it? Regards Steve.

If I may, once you have that head in your hands, you might want to replace valves either with bigger ones or with stronger ones (Hitchcock comes to mind), rework the combustion chamber as @Dool suggested and deshroud the chamber near the valves for good measure. Some porting also would be nice but it has to be done properly.

TB comes as last mod and it isn't overly necessary. A good plug&play solution is the 34mm TB from the Conti 535GT, but it's hard to come by and possibly costs a kidney.

I would assume a cam is on its way with the kit right?

 

[Dool]

Depending on the Budget, there are a few parts out there that are just "nice" to have, like for example the HMC sexy Valves, they are great if you do the extra work on the Seats, and if you do that work on the Seats to OEM Valves you get a benefit also! just not so sexy its called "Undercutting"
Just removing the Dags in the Ports has to be Better than leaving them. Going all out on the Head with CNC Porting and Bigger Valves is not that expensive, Sam can get you a Head cw big valves and sized combustion chamber at a fraction of what the work would cost in the west.

These Bikes are Great for upgrading, they start pretty Low

 

[Sasa]

These Bikes are Great for upgrading, they start pretty Low

Then they become a money black hole in no time!

 

[sam2019]

Sam can get you a Head cw big valves and sized combustion chamber at a fraction of what the work would cost in the west.

Before you make promises on my behalf remember that RE has risen some prices to extremes, cylinders are now 50% more and frames over 100%. its nauseating the greed.
when a head at the old price even with my markup and shipping and customs was still cheap - it may not be so anymore. I have not bought a head for a long time so I dont know the actual price.
Work would still be cheap but remember quality of head work here is not like in the west, its all done by hand with a dremel and according to Indian quality standards.

 

[sam2019]

Then they become a money black hole in no time!

so true

 

[Csx355]

Go on then Sam - tease me with the cost of a flowed head!

 

[sam2019]

Go on then Sam - tease me with the cost of a flowed head!

you have PM