Hey Guys,
I’ve got a f4i stuntbike that’s been modded/screwed around with a bit… It bogs pretty bad under 2k rpm, attempting a throttle body sync in hopes of fixing that.
I got stuck though, not sure which hoses I’m supposed to use…

It looks like the 2 hose’s that are supposed to go to the air box have been plugged (with screws)… Can’t imagine this is an issue because they get blocked at the air box end anyway… Can I be safe to assume they are hoses No.1 and No.4?



In the manual it sounds like the hoses that are connected to the fuel pressure regulator (3 hose junction) are 2 and 3, can anyone confirm this?


And finally, my Motion Pro 'Syncpro', requires calibration, unsure which hose to use for calibration? (guessing the odd one in the 5 hose junction).
Also, should i be connecting the hoses from the sync tool straight to the throttle body, I've seen guys using the existing hoses with connectors, seems a fair bit easier.

Looks like this guy did a great write up, but sadly the images are gone: https://cbrforum.com/forum/f4i-main-...-04-f4i-42143/
Hopefully this mostly makes sense, Any help appreciated

 

I've not messed with that part of the bike too much but will be shortly (in the midst of replacing more than a few valve shims!). I'm inclined to say you are spot on but not 100% sure. Do you have access to a service manual? There is a section towards the front that should give you a decent visual of what goes where...

 

Here is a link for the manual if you are interested - https://www.carlsalter.com/download.asp?p=1918

 

Thanks Doc, and yeah i have a copy of the service manual.
It seems a little ambiguous, but i'm confident that vacuum hoses 2 and 3 are connected to the pressure regulator in the 3 way junction

Even if that's correct i'm still unsure where to connect my Sync tool to calibrate it, the instructions say to attach it to the "non-adjustable master carburetor or throttle body"

 

Hmmm. I'm pretty sure you are correct re: the "t" being hoses #2 and 3. I had thought that tb #1 was the non-adjustable master but, again, those directions are clear as mud... to me, anyway!

 

Did you ever get around to syncing yours doc?
I attempted it again, but when i was trying to calibrate my Syncpro my bike would suck up the fluid and didn't show any signs of settling. Fluid just went straight up the tube once i started the bike.
I reckon either I was doing something wrong, or my bikes VERY out of sync. Sent it to the mechanic, hopefully he can sort it.

Here's a picture of how i had my Syncpro connected to the No.1 vacuum hose. I am using an adapter to connect the Syncpro hose up, wasn't 100% sure if this made a difference or not, but it looked WAY to fiddly to get in to connect it directly

 

Sorry to hear that. I've had a few jobs that I was able to get 97.3% done myself and then had to bring in outside help because I ran out of skill or patience. Frustrating as hell, I know...

Yes, I managed it. Bike was apart a total of 6 weeks but last weekend, with the wife's help, I got my timing set and synced the TBs. Strangely enough, I only had to do some very minor adjustment to #2 as #'s 3 & 4 were where they needed to be. So, lots of tube fiddlin' for nothing, really!