throttle body balance

[Lampie]

After a few Suzuki's , which all needed a throttlebalance, I was wondering if our engine needs a balance check .

Any advice how to...on the crossrunner

I have a Morgan carbtune 4 cilinder
(http://www.carbtune.com/)

[Skids]

Originally Posted by Lampie

After a few Suzuki's , which all needed a throttlebalance, I was wondering if our engine needs a balance check .

Any advice how to...on the crossrunner

I have a Morgan carbtune 4 cilinder
(http://www.carbtune.com/)

I admit to being unsure on the new 800F/X engine. On my previous VFRs, a '98 Fi and '08 Vtec, both benefitted massively from regular (4000 mile) Starter Valve balancing (and I have the same Carbtune as you do). The procedure was very similar for both older models, though the SV adjusters were in a different place and the values of the adjustment were different but the principal was the same.

So I don't know of any reason why the new model wouldn't benefit from regular SV balancing. My X is due it's 8000 mile service next week and I will be requesting the garage balance them.

Does anyone have sight of the Honda Service Manual for the X or F? The procedure, if required, should be in there as it is certainly in the Vtec manual (though not in the service schedule).

HTH

[stubax]

Do you need to do this with fuel injection??? 

[Skids]

Originally Posted by stubax

Do you need to do this with fuel injection??? 

On the design of the Fi & Vtec, yes. Unsure if they've changed the F/X engine so it's not required but it's absolutely the done thing on the older fuel injected models.

[Skids]

Taken from another site:

What the Starter Valves (SVs) Do?

The starter valves have a few functions:

1. They allow sufficient air past the throttle butterflies to allow the engine to idle because the throttle butterflies are a pretty good seal on the throttle bodies when closed.
2. They also allow the engine idle speed to increase when cold. The fuel injected engine in the VFR doesn't have a choke in the traditional sense of having an extra butterfly to act as a restriction in the inlet tract, fuel enrichment is taken care of by the FI ECM and the fast idle by the starter valves moving to allow more air past the throttle butterflies. In the FiW and FiX models the starter valves are moved when you move the "choke" lever, on the FiY and Fi1 models the starter valves are moved automatically by the Fast Idle Wax Unit.
3. The starter valves allow the air flow to each cylinder to be balanced at the closed throttle position and low throttle opening - less than 5%.

The Symptoms

The symptoms of the SV’s being out of adjustment include:

1. Lumpy idle - not to be confused with the already off-beat idle due to the uneven spacing of the firing pulses of the V4 engine.
2. Hesitant throttle response when opening the throttle from closed.
3. Increased vibration - check the chain/sprocket condition and tension first as the VFR can be quite fussy about an over-tight or too loose chain.

[Skids]

And if you check the VFR800 02-09 Honda Service Manual, starting page 5-75 (downloadable on VFRD website) there is the full procedure.   

[Skids]

I've never looked beneath the tank of the X, but here is a very good guide to SV balancing on the 02-13 Vtec engine, which the F/X is a derivative of. Don't know if it will help but it's there.

Download page for 02-09 Honda Service Manual (see page 5-75).