Josh’s bigger throttle bodies project

[PowerDubs_imp]

What is your question?

An engine is simply an air pump- get more air in, get more air out, and fuel to match.

So- every part of the system is a potential restriction- some maybe more so than others- but that can change at any time.

Not to confuse you- but for others following along- what I mean by that as example-the custom cams didn't gain much *at that time*- but that only means they weren't a large bottleneck- *at that time*.... so if I enlarge the ITB's and get a great gain- some of that may be due to already having better breathing cams, intake or exhaust in place...

There is no way to say a single part is worth a certain value- unless compared to an exact same configuration.

The Staintune muffler on a stock bike might be worth X- but if I were to test it compared to a stock muffler- right now- on my bike with the other mods- it will likely make a bigger difference.

[PowerDubs_imp]

So I now have this set of 36mm TB and a spare set of stock 32mm to compare, measure, swap pieces if I need to....

.... and what I found out right away is causing me to put these 36mm on a shelf for now- as there is a very easy way to get more power- uncorking / derestricting the stock setup.

If you look closely at the furthest TB- under the main lip your eye first is drawn to- there is another, thinner lip in the bore.







On the 36mm TB- the velocity stacks sit on this ledge- for a nice smooth unobstructed flow- using all of the 36mm.








Hard to see in a picture- but on our 32mm- our horns insert almost all the way down the throat- effectively making our TB nowhere near 32mm.








It’s no wonder boring the center out makes power- the entire lower 2/3 of the stack itself is a complete restriction!! From the factory they are choked to something like 26mm if memory serves.

So- I need to take some time to think about this and bounce some ideas in my head- but the answer should be an easy cheap plug and play stack swap (compared to swapping the 36mm on)...

I’ll probably do those as well- the cb900 (919) and the cb1000r both use 36mm TB- so they should work well on our 1140


Sent from my iPhone using Tapatalk

[tommymck]

Hi Josh,

It's been ages since I've been on the forum, but last I recall, you had a bit of a spill and were thinking of hanging it up. Glad to see that you're educating the rest of us as you always did!

[PowerDubs_imp]

Thanks Tommy.

I’m not much of a teacher - but always like hearing someone appreciates what I am doing.


Sent from my iPhone using Tapatalk

[teamvisegrip_imp]

PowerDubs... First off I love your work and always looking forward to the next up-date.

I think you need to look a the TSR Intakes again. I installed them on mine. Call me stupid but I cannot shrink the pictures to post here but could load to Photo Bucket and give a link below.

I remember you opening up the stock set on this project... But if you look a the pictures you see there is no way to open the stock Funnels to the size of the TSR Units. In the next photo you see the the TSR Funnels are a direct shot into the Throttle Body. No restriction pure access to them. The bike runs great with the mods and like you I think more can be had. But this is where I will stop. I think you should move ahead with the 36s.

Hope this helps in some small way.

Here is the link.

https://app.photobucket.com/u/teamvisegr...02638c3597

[pekingduck]

PowerDubs... First off I love your work and always looking forward to the next up-date.

I think you need to look a the TSR Intakes again. I installed them on mine. Call me stupid but I cannot shrink the pictures to post here but could load to Photo Bucket and give a link below.

I remember you opening up the stock set on this project... But if you look a the pictures you see there is no way to open the stock Funnels to the size of the TSR Units. In the next photo you see the the TSR Funnels are a direct shot into the Throttle Body. No restriction pure access to them. The bike runs great with the mods and like you I think more can be had. But this is where I will stop. I think you should move ahead with the 36s.

Hope this helps in some small way.

Here is the link.

https://app.photobucket.com/u/teamvisegr...02638c3597

I took the liberty of posting your pictures here, but I think Josh's point is that the air horns from the CB1000R would simply drop into the stock TBs and offer an enlarged opening.

[PowerDubs_imp]

Vicegrip- thanks for the pictures. What else have you done to your bike? Fueling? Dyno?

Duck- nah, the CB1000R horns definitely won't drop in- they are too large, and also staggered length.

I just bought a used set of CB900 (919) horns off Ebay- they are also for 36mmTB, but same equal length as ours.

The TSR bits are just too much (if I remember, weren't they many many hundreds?)..when there are so many other Honda that use the same mounting and of various sizes....as an example both the CBR500 and some honda scooter use 34mm TB basically the same design as ours...so an in between option.

[teamvisegrip_imp]

PowerDubs... What I have done to the engine is below
TSR Air Funnel Kit to Throttle Bodies
TSR Air Intake Funnel replacing Snorkel
K&N Air Filter
Air Plates to block secondary air
Yoshimura full exhaust
ECU done by Guhl Removed speed limiter, up redline by 500 rpm and remap for mods The ECU was sent to them only. No dyno was done so I have no idea what I gained.

I absolutely love the bike now. Funny you said it was loud with the Air Filter mod and you changed yours back. I do not hear any real difference but working in an engine room my whole career has made me a little deaf! LOL!

As I said this is where I get off the mod train! No more mods it is perfect the way it is now. There was a very noticeable improvement in power throughout the rev range. It now feels like an 1100.

Pekingduck thanks for posting the pictures. I am computer stupid. LOL!

[PowerDubs_imp]

Yea- you’ve pretty much covered everything.

Would be interesting to see some dyno runs to see the results with a/f.

Could be wrong, but I’d guess the file Don uses was made on a bike with stock snorkel and almost certainly stock velocity stacks.

There is a dyno locater on Dynojets website. If you are interested, I’d chip in to help.


Sent from my iPhone using Tapatalk

[teamvisegrip_imp]

When I contacted Gulh they asked all I did to the engine. When I mentioned Par-Plates, the plate to cancel the Secondary air, they questioned that one. But I am not sure if they compensated for everything. I do know the bike runs way different and OH so much fun now. Can more be had with a proper tuning? Good question. One thing is for sure the bike is not fuel efficient now. LOL!

I am on the ship till the end of December., my last run then I retire. I went to the Dyno-Jet site but our internet is way to slow to figure out where the closest Dyno Tuner is. I have taken some of my bikes to a place in Minneapolis call Power Sports, if I remember right. I think he has a Dyno machine but I never get any read-outs from the jobs, only that the bikes run AMAZING when done! Once I finish my 85 Honda XL600, it will go to them for final tuning. Unless the Dynojet kit I bought for it hits the mark right off the bat. Lots of work on that one by the way.

But these guys are 2 ½ hours away and with it being the middle of winter in northern Wisconsin there is no way I can get the bike down there and back anytime soon. The bike is laid-up for the winter.

So lets get back on topic here... yeah send me the closest Dyno to me... Superior Wisconsin same as Duluth Minnesota as we are next to each other. I will contact the shop and see what it costs to put the bike on the Dyno. If I can help you out I will see what I can do. Just need to see if I can afford it. LOL! I have a lot on the list right now... the XL600, my Kawasaki H2 Denco project and a possible CZ 175 Trail Port for low end power project.