Josh?s bigger throttle bodies project

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I've generally seen shops charge anywhere from $60 to $100 to strap down the bike and do runs with a/f.

I've been to many dyno shops over the last 20 years and I usually pay cash, and tip (keep the change)...they all have been very receptive to my coming back, and most have charged less for repeat customers...so figure higher end of scale to start, less usually if you come back after other mods or tuning.

You will want to bring a USB thumb drive so you can get a copy of the dyno run files (literally has the extension .DRF)

Every pull they make will generate one, and they save them to a folder that they typically will ask your name, and what the bike is.

You can load these files into the Dynojet run viewer at home and compare them. Very useful.
 
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Modifying my spare stock airbox to fit the larger stacks for the bigger throttlebody’s. So far so good.

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Looking good, PD. It’s a big difference.
 
Very detailed and interesting project PowerD.

Keep in mind Honda engineered the stacks to meet their [whatever] requirements were. That is, be it a specific power delivery behaviour, emissions, fuel economy, other product line business reasons, etc.
 
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Yea- well aware they built to requirements- some that I don't have to worry about.

Noise & emissions being the big ones. No cat, add fuel. :)
 
Just wanted to say that I am really enjoying this thread. You guys are venturing into areas of tuning that I would never consider doing myself. The biggest engine mod I have ever done to a bike was boring my 1976 CB750F from 736cc to 836cc, installing K&N air filters, and adding an aftermarket exhaust. The power gain was impressive, but I could never get the carburetor jetting perfect (close, but no cigar). I just don't have the time, or the skills to perform engine mods to any of my newer bikes - ie fuel injection, ECU, electronic sensors all over the place. I really miss the good-old-days when bikes were so much easier to work on. I am looking forward to see how Josh's project ends up.
 
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It’s actually much much quicker and easier as well as really more precise to tune the fuel injection then carburetors ever were.

Especially with the auto tune box, I just give it a target table of air fuel on the chart and it takes care of everything automatically for me


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Ok- some more interesting stuff to report today.

As mentioned before, I noticed that the stacks on the 36mm Tb sit on the upper lip and although our 32mm Tb have the same lip- our stock stacks go all the way down the throat of the Tb and effectively make them 26mm.


So I decided to cut off the long portion, bore out the center similar to what I had done before- but also cut them short at the same height as the lip and then heat them up and shove a socket inside to stretch it wider to mate with the lip.


Cut-

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Bored-


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Hard to tell in pictures, but here are more-

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Compared to-

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So this took quite a bit of time as I needed to measure for it to sit right on the lip correctly. Although they would probably work quite well, I was still thinking there is room for improvement.

Since Honda uses very similar throttlebody design on most of its modern bikes, I started searching to see if they used 32 mm on any other bikes and then once I found those bikes I looked at their intake horn design.

Sure enough I found factory parts to fit the same 32 mm throttlebody housing and actually sit on the inside lip instead of choking off all the way down the bore to 26mm

It is my belief these will work better than the bored out stockers, and even my shortened and stretched stockers that I have not tested yet.

In fact due to the plug-and-play nature of these and the cheap cost I would think they now make the TSR pieces obsolete.

Stock on the left, new ones on the right.

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So I will be installing these which will drop right in, and then re-dyno in the spring.

Based on whatever results seen then, I will decide if I will move forward with fitting the 36 mm throttle bodies.


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No. 919 has 36mm TB.

I have a set of the 919 stacks though to go with my cb1000r 36mm Tb.

The 32mm stacks on the right are from a CB650R


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Thanks for the info PD,people have been -tinkering- for more power from day one. I'm doing cosmetic changes over the winter but at some point I'll be looking for more power and your digging for power here is greatly appreciated.
 
PD forgive my perhaps naive query, but in my head more horsepower equals more heat, so I'm wondering if you are looking into that?

'14 CB1100 STD 5 speed
 
tod.branko_imp said:
PD forgive my perhaps naive query, but in my head more horsepower equals more heat, so I'm wondering if you are looking into that?

'14 CB1100 STD 5 speed
More heat is the easiest part for to solve.
 
FLYTYM_imp said:
tod.branko_imp said:
PD forgive my perhaps naive query, but in my head more horsepower equals more heat, so I'm wondering if you are looking into that?

'14 CB1100 STD 5 speed
More heat is the easiest part for to solve.
More heat is the easiest part for to solve.
Add water-jackets? :-/

Add block fans? :(

Go faster? :D
 
PowerDubs_imp said:
No. 919 has 36mm TB.

I have a set of the 919 stacks though to go with my cb1000r 36mm Tb.

The 32mm stacks on the right are from a CB650R


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Dear PowerDubs,

I have to disassemble the airbox to replace the IACV.
Could it be a good idea to replace the stock stacks (26mm) with those of the CB650R (with hole 32mm)?
Are they plug and play?
Consider that my bike is completely stock.

Thanks for your reply
 
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No- I would say wait- and see what results I get soon with my dual stacked custom made stacks.

They should give better results- but are NOT for a stock bike.

At the very least- you will need to add more fuel.

But also- there are many other ways to uncork the bike first- exhaust being the main one- get at least a slip on muffler, if not a full exhaust to get rid of the cat.

But no matter what- ANY change to the factory velocity stacks- you should add fuel.
 
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