VFR750FV Dyno

Had the 97 FV dyno'd

I knew there was a problem with the midrange due to over richness but makes slightly more poweer than the FK

 

Thanks for sharing that is an interesting chart, especially the big bucket in the torque curve.

What size pilot jets, main jets and needle/setting are you using to make it run rich? Any other mods to the bike?

 

Not sure whats wrong but its running very rich in the mid range and its on std jets. I've only removed the snorkel and washed the oil out of the K&N filter, it has a high level race pipe but thats it, which should make it weaker.

I need to strip the carbs and have a look.


Here is my 86 FG with and FK engine. This has more mods; No airbox lid, race pipe, Shortened carb bell mouths, heat shield between carbs and engine, HRC style air inlet duct above radiator. It only weighs 202kg with fuel.





Various bodywork choices





Just got the FK heads back from the porting shop, full radius valve job.

 

Looks like you're having fun and making some good mods with your toys.

i like the flatter torque curve on the 86 all the way up to 9k rpm, it would definitely be quicker than the 97 which has peaked at 8k and laying over. Makes you wonder what is happening...

 

It seem the after market headers are causing the richness following 3.5 hours on the dyno. Took out the Dynojet needles and put it back to std. mains are down to 120 from std 125's and its ok at the top end +3hp. dropped needles down and got +8hp at 6000rpm. Its still not great.

 

But what size are the pilot jets--that is feeding the transition ports. The dynojet kits i've seen put smaller mains, stepped needles, fatter pilots and drill the slides--and they run very rich...

 

The slides hadn't been drilled and all the jets are back to standard. The dynojet needles removed were shallow taper.

 

yes depends what you do to the jetting.

I have the snorkel removed which makes the mixture weaker but the FV is too rich, very strange.

My other VFR (1989) has no airbox lid, jetted 136mains and runs perfectly .

The RC30 has no airfilter at all and is also perfect.