VFRDiscussion ARCHIVE / READ-ONLYREAD-ONLY

Throttle problem post-mods

9 posts Started 27 Mar 2017 Last recovered post 31 Mar 2017 Wayback Machine snapshot 5 Jul 2017

#1

Hi everyone;

Just joined and first post. I looked for an intro page but couldn't find one ..... I'll do it here.

I live in Vancouver, BC. I'm in adult education and have been married for 29 years, riding for 35 years. Dirt, sport, sport touring, adventure. Ridden solo and two-up into Alaska and down to Baja. Crashed multiple times, garnered my share of coupons from the police, broken bones and broken bikes.

In the garage right now is a street legal 2000 XR650R, a 1973 CB350/4 done as a mid-sixties GP tribute and a 2010 VFR1200F (non-DCT).

I bought the VFR last March and put about 10,000 km on it. I've always loved the V-fours and decided to get one when it became available at a really good price. It came with the Honda bags, a Sargent seat, the Akrapovic exhaust can and 4500 km. Driveshaft recall was done last summer. Winter came and modifications started.

Suspension was addressed with an Ohlins in the back and a re-spring and re-valve up front. A Stebel went on to get rid of the meep-meep.

Then things got serious. ECU went off to Guhl Motors for a re-flash. A PCV is under the seat, a K&N handling the air filtering and a Dan Kyle set of bock-off plates remove the PAIR system.

But things went awry. After the re-assembly I noticed the throttle butterflies weren't opening smoothly. Now, I didn't check to see how they operated before this work was done and this is the first time I've ever done work to a fly-by-wire system.

Using the PCV as a measuring tool, I see the butterflies open more or less smoothly to 24%. They then hold that position as I continue opening the twist grip. All of a sudden, they snap open to 100% when I am at pretty much the end of throttle travel. It will start and idle no issue on the work bench, and even revs cleanly to max RPM. But I can't tell if the butterflies are opening at a steady rate or not, as that run to redline and back is done pretty quick.

When installing the PCV, I used the included posi-tap to access power from the blue/black wire on the TPS. It appears the copper inside has not been cut, only accessed by the pin on the posi-tap. I've checked all through the linkages for any mechanical blockage but haven't found anything that it could be getting hung up on.

I'm really scratching my head here. I'm about to cut that blue/black TPS wire and solder in the power for the PCV, anyone have any thoughts as to what else it could be?

Thanks ahead of time.

#2

I would fire mine up and check, but there is no radiator, and valve covers are off for the 15K service......

[image: Valve Service1.jpg]

#3

Maybe ask Don Guhl, I would think they don't pop open all the way to help rideablilty, but I could be wrong. If you are revving it with an open airbox, that could be an issue as well. Mine ran like crap just swapping the K&N, then I disconnected the ECU, reconnected it, let it idle a bit, and it was perfect after that. I'm sure there is a load-based feedback loop......

#5
RC1237V, 3/27/2017 at 7:43 PM

I would fire mine up and check, but there is no radiator, and valve covers are off for the 15K service......

[image: Valve Service1.jpg]

Did you foil wrap your air box to match your handlebars?  Why is it gold?

#6

It was just a coincidence.........no one will ever see it once I button it up. I work at a machine shop, as do many of my colleagues, and some of them do aerospace and satellite work. It makes a nice heat shield, and the material was given to me so the price was right! Also making a titanium axle, another freebie. I will post pics when it's done. I know this bike will never be a lightweight racer and has way more power than I can ever use - don't really NEED any more, but it's fun for me to play around with it! I have a lot more changes to make, but we just lost a few employees here, so free time is rare.

#7

While you have the tank up, check the wiring harness where it runs along the frame just below the tank on the left side of the bike. The rough 'paint' on the frame may be wearing through the insulation on the harness. 

Back on topic. You may be able to reach out to VeeeFour (the guy who designed the electronic cruise control). He has tinkered with the bikes electronics and might have an answer for you. 

#8

crakerjac ...... thanks. Will do. And I've been dreaming of that cruise control. 

#9

Answered your question on another forum.

Stop dreaming and buy it  :wink:

End of thread · 9 posts recovered Wayback Machine snapshot 5 Jul 2017