5th gen running rough

its from idle or cruise....if i accel slowly it is ok....maybe struggle a little mayb not but when i hit it hard it like kills the rpm....then i give the throttle lttle fast twists n it starts reving correctly....

 

ill try cleaning injectors

 

I have very similar problem with my 5th gen. 20k miles, lovely bike just running like a pig. new plugs, air filter and oil and filter just changed.

 

inspect plugs after a run to see if you can find a misfire in just one cylinder.

 

will do, been doing some googling and came across this,
'get an aftermarket fuel pressure regulator and remove the EGO sensors'
what is this about? is it removing the 02 sensors> my bike doesn't have them.

https://www.gtamotorcycle.com/xf/threads/power-commander-on-5th-gen-vfr.155334/

 

Just been checking the coils and I think the front left coil is arcing towards the frame, the other 3 coils seem ok, wonder would I be better off buying a new coil or buying a used set of plug caps and coils of ebay for the price of a new single coil, either way hoping this will solve the poor running issue.

 

dija try running it in the dark to watch for arching ?

 

yes that's what I said, it looks like it's the front left coil that could be the issue, hoping that's all it is, it's an easy bolt on fix.

 

I bought a used set set of coils and plug caps off ebay, taking a chance but hopefully it will work out ok, one of them is bound to be good you'd think.

 

Problem is still there, I checked the battery with a voltmeter,
she is showing;
13.8 volts idling no lights on
13.95 lights on full heads idling
13,15 volts at 5000rpm full heads on,

is the battery bad or the reg/rec and could this be causing the poor running/ bogging?

 

Its not charging at 5000 rippems. Should be higher

 

If it's not charging at 5000 rpms would this cause the rough running? the bike is still starting etc ok.

 

it's definitely charging but slightly low, so try cleaning contacts wherever you find them. probably not the cause of poor running.

 

Wondering if you should check starter valve sync if you don't know where it's at.... see post #11 and it should become much better at idle and low speed.
Agree you need to address the charging system........

https://vfrworld.com/threads/starter-valve-synch-revisited.53524/#post-617905

 

Anywhere between 13.2 and 14.4 is fine for a lead acid battery no matter if it’s on a bike or a car

Resting voltage of about 12.6 is a fully charged battery

My brother used to work for Exide,


VF1000F2 a work in progress

 

Compared with a mates 98 vfr today, checked both batteries with the voltmeter at the various settings, both seemed roughly the same so as was said this isn't the cause of the slight misfire/rough running or whatever is going on,
one thing I can confirm is it definitely is not running as good as my mates bike, his bike felt so free revving and pulled like a train, lovely clean throttle, mine feels like someone is trying to choke her!!
it isn't terrible but it's there and it's very frustrating, I will have to get the starter valves synced as a starting point, I'm not able to sort this myself and finding a good mechanic who wants to tackle the job isn't easy either.

 

I have read somewhere here the spark plug boots can develop a bad resistor...... then the other day on the FJR forum, a guy says the resistor itself doesn't go bad but the spring inside can corrode, which he cleaned up..... maybe wanna check your plug boots for resistance??

 

Thanks, I will check out the plug caps and coils, first going to try and get the starter valves synced. I'd love to get this bike running as it should, it's near perfect in every other way, was very well looked after by the the first owner for 20 years.

 

Nice - What about AGM batteries from Chi-nah? I was a believer in them until I had an issue where the negative terminal leaked acid when new. I ended up getting a Yuasa replacement battery for my Gen3 bike - YTX12BS? not sure without looking. I used to get these AGM batteries out of the mail box (Chrome Battery and Western Powersports) fully charged ready to rock and roll at 13.0 volts.

My Yuasa stays at 12.6 resting and starts bike without any fan fair, guess time will tell. I had one of those chinese batteries go over three years and have one on my Ninja500 that is close or over 3 years old.

I like being able to speak to an actual engineer on a product and it is nice they (Yuasa) are made in the USA! so there, more information than you really want to know. PEacE

 

There are a few exceptions to that as you have pointed out, including lithium Ion
In that as well


VF1000F2F, in bits