Josh’s bigger throttle bodies project

[PowerDubs_imp]

So far I’ve done the easy mods to the bike. And have made good gains.

Where we stand so far, my bike vs a stock ‘17 CB1100 - both on a Dynojet, measured at the wheel.









While the results are good, and enjoyable to ride- I’m not done yet. I think she has more left in her.

Next obvious bottleneck is the throttle bodies. The bike has 32mm.

I started to look around - knowing that a lot of motorcycles (and cars) use partsbin engineering to save cost.

Sure enough- a similar vintage CB1000 has TB that look the same in all the pictures, but are 36mm.

My guess is that Honda used the same casting with a different ID bore.

So I bought a set.






Came complete with everything- injectors, fuel rail, TPS sensor, other sensor, hoses....


So I went to the garage, grabbed my spare airbox, and sure enough- the housing/flange are the exact same and fit the mating groove perfectly.




The only issue I see so far is the spacing between the pair is a little further apart on our bike.

So I went back on EBay and found a guy selling a dirty but complete set of CB1100 TB for $99 or best offer. Got them for $40 shipped.

I can use them for measurement, and hoping the spacers in between just interchange. I could use my stock parts of course- but this will allow me to leave my stock parts alone, and get the ‘1000’ Tb ready and just swap them on.

This is just the start. I need to look up specs to decide which injectors to run, check the part numbers for the rubber boots to head, etc.

Wheeee!!!


Sent from my iPhone using Tapatalk

[GoldOxide_imp]

Going to be one of the quickest CB1100s around.

[Houtman_imp]

Very interesting !

[dave]

That's a pretty substantial improvement! Can you please clarify exactly what mods you have done to your bike? You must be extremely knowledgeable when it comes to these EFI systems - I don't even think about altering mine!

[Bheezy27403_imp]

Popcorn emoji

[Cormanus]

Go Josh!

[PowerDubs_imp]

That's a pretty substantial improvement! Can you please clarify exactly what mods you have done to your bike? You must be extremely knowledgeable when it comes to these EFI systems - I don't even think about altering mine!

It's a noticeable gain, and even at part throttle, or low rpm runs better than stock. No complaints.

The mods are listed in that pic. Nothing fancy there- intake, cams, exhaust, fuel and ign. Hotrod 101.

I'm not the smart person- those accolades would be Dynojet, Don Guhl, Web cams, Arrow exhaust, and Staintune. I just put together what they sell.

I have a rudimentary understanding of how everything works, what to do, and what not to do. Ask me to build what they did however and I couldn't do it.

The actual programming, and cam grinding is light years beyond my scope of knowledge.

But it is more convenient to plug in a laptop VS jetting carbs, and bolting in cams compared to grinding 2 stroke cyl ports.

...more to come.

[bflint]

Wow

[Aussieflyer]

Way to go PD, hats off to you sir. Looking forward to your write up on this project.

[j3gq_imp]

@ PD
I see the list of changes under the picture, but do not understand every single one.
And which ones do contribute to power increase and how much. If you find the time and energy, could you explain ? Or is this explained already in a different blog ?
Thanks