Running issues, increased mpg & eating spark plugs

[drix]

Hi guys

Been having a few running issues and think I have an idea as to where to start but events & symptoms are little odd (or new) to me and thought I'd get expert views first. Anyways, here's the summary:

Setup:
FCR41 - straight out of the box
2-1 Projection Components big bore exhaust with Scorpion can - no baffle
Dynacoils with Taylor leads
Ignitech - straight out of the box

Events:

August 2016 - 48000kms: Valve clearance check and ran the bike on dyno, 74bhp at the wheel and running rich low down but fine after 3700rpm. Riding it feels fine and pulls well from low in the revs. Tank range - 210kms to reserve.

April 2016: weekend out with the boys and trashing it the country side. Bike not pulling clean from low down in the revs & tank range decreased to 175kms to reserve.

August 2017 - 52500kms: Runs on one cylinder due to a spark plug failure, plugs were prob a year old or so, serviced the bike and fitted new NGK Iridium plugs.

September 2017 - 52500kms: Ran the bike on the dyno and power dropped to 71bhp at the wheel. Needles lowered from clip 4 to 3, mixtures screw set to 2 1/4 turn, float height at 1mm, accelerator pump - wheel lock wired to rod. Power back to 76bhp at the wheel, runs richer low down than in August 2016 but then fine after 3700rpm. Riding it feels fine and pulls well from low in the revs. Tank range - 190kms to reserve.

April 2018 - 55000kms: Spark plug failure so replaced them with NGK Iridiums again.

Bit concerned by the spark plug failure after barely 2500kms and the tank range which still isn't as it used to be. Spark plugs do show the bike running quite rich. So I'm thinking that I should start looking at replacing the needles (carbs have done approx 15000kms), perhaps different jets and look at modifying the Ignitech map.

Would I be going down the right path here? Any other suggestions?

Cheers guys
Adrien

[cobbadiggabuddyblooo]

Drop down to a 145 main jet.
Buy another clean set of plugs and Use std 5k resistor DPR8EA-9 copper core plugs.
Ditch the Taylor leads and use a copper core lead and remove the 10k resistors from the spark plug caps.
While at it check your battery voltage. You can see this via your IGNITECH too.

Leave your needle set where you have it now and there should be no reason to replace it with very little Km’s work. I refurbished my FCR’s after 60,000km from new and replaced the needles, tubes and float seats but wasn’t really needed.
Std float height 9mm

Sort your fueling issues first before changing timing.
Are you running the std airbox or bell mouths???
Is the TPS turned on and calibrated on your IGNITECH??

Alex had a similar set up with the Kayla exhaust / Acrapovic 60mm can and FCR’s with bellmouths / ramair twinsock and I advised him to do the same and tidied things up nicely.
It’s the nature of the beast with 2-1 exhausts on TRX’s.
You’ll find running like a tea strainer in the end of the can will give you good gains down low too ( like 3-5hp ) under 4000rpm with minimal losses from (1 hp ) over 7500 rpm.
It’s not a slip in baffle as such, just an end cap on the tail pipe with perforated holes.

Once you sort your fueling, I’ll touch base on timing with FCR’s

[drix]

Ha Cobba, thanks for the info! Bike is running with the usual blue bellmouths & ramair filter. Ignitech is litteraly out of the box, not played with it yet

Will start 145 main jets in this case and swap the leads, plugs and non resistor plug caps!

What baffles me a little is the sudden change in mpg/drop in power for no apparent reasons other than following a good trashing.

[cobbadiggabuddyblooo]

More than likely fouling of the plugs. From main jet and needle position.
If you haven’t set up the TPS you miss on gains with extra advance and response on lower throttle % too which will help initiate a better burn.
The iridium plugs are good to help keep the plugs a little cleaner so if your fouling them it’s either way too rich or weak spark.

[Tarwetijger]

175 - 190 km to reserve, that must be something like 12-13 km/l?!
My (original) bike does about 22 km/l now.
Also when I had TDMR flatslides with bellmouths fitted and the Akra headers it was healthy with fuel consumption.
And definitely more power than 74bhp. Are you sure the carbs are not insanely rich?

[cobbadiggabuddyblooo]

Quite a few inconsistencies in dyno readings from 1 to another.
dynotek / Dyno dynamics are a brake dyno and hence the lower reading but a dynojet are an inertia dyno and always read around 10% more.
Plus some give at the crank and some at the wheel.
But like if I put my bike on a dynajet I’d be pushing close to 120 for a penis extension..

I know I would easily get 270km before reserve on the std motor/ fcr.

Even now I’m about 200-220km to reserve with 167 mains.

[drix]

All dyno runs were done at the same shop who use a Dyna Pro dyno who seem to retail both inertia & brake dyno... will ask next time which type it is.

Seems like I have some tinkering on the cards and started ordering a few Bits’n’Bobs

[drix]

Changes finally done.. main jet down from 160 to 145, copper HT leads, cap resistors removed & new plugs. Bike feels more responsive but I still do 190km to reserve and fuelled up circa 17liters at the pump this morn.

Could go down on main jets a little more as it doesn’t sound to run very lean but not sure if it’ll make a big difference. As for eating plugs for breakfast, time will tell I guess.. maybe I should invest in BP & NGK shares

Still confused with this one

[cobbadiggabuddyblooo]

Lack of back pressure will rob you of 5 hp in the lower midrange area and if your riding a lot under 6000rpm, put a baffle in place.
Similar result when I changed from a 50mm akrapovic can on the akra system to the current 57mm Megacycle can. Lost 5 down low but gained 3 hp up high.
When I dynoed the Nojima system with 50mm free flowing can, it was much the same as the Akra with 50mm free flowing can got my 5hp back but lost 3 up top again.

With the Over system minus cans I’ve had stashed away oddly enough the Over 60mm titanium cans arrived today and the first task is making baffles because it’s 60mm free flowing and i’m sure if they where telescopes, I’d see green cheese on the moon...
There is always a compromise so look where you want to make your power and make sure things compliment each other.

Moral of the story..
If your riding a lot around 4 -5,000rpm baffle it as this may give you a little more power and fuel economy but if still lacking economy ( and robbing you of power) I’d look at power to the coils and earth to make sure you getting full potential.
Rule of thumb, needle clip 9x out of ten will never need to move the clip down past the middle position and most times the clip will live 1 position above middle position dropping the needle deeper into the main restricting flow.
The acc pump on the trx is the longest duration option in fcr’s so in that 1/4-3/4 throttle that effects needle position and mostly around that midrange area you gobble lots of fuel from the pump too.

Plus if your using the dyno A/F snuffer down the tail pipe, make sure you use a sealant on the headers, mid section and can joins otherwise you’ll get a false lean reading and can easily influence the A/f from 12.5 to reading 14.

[drix]

Hi guys

Bit of an update after a long time.. after replacing the leads, removing resistors in the plug caps and fitting new plugs and approx. 1000km later, the rh plug went pop.

Replaced the plugs and rode for a bit before deciding to revert back to stock coils last weekend just to try out. Started the bike after the change and it ticked over fine but I didn’t go for a ride. Decided to go for a ride yesterday eve, on start-up a pop from the exhaust and here we go, plug gone again!

Plugs are a little on the black side rather than the brown side, I have a 2-1 Akra that I'm cleaning so I'll be fitting that on and see but based on the current experiences, I'm thinking that this is more of an electrical problem so the fun begins on tracing it back to its source… I’m not a fan of electrics and so not looking forward to the fun times ahead of me on this issue!

[PrfctChaos]

Swapping the coils over and then seeing if the problem moves to LH with the coil would be worth a shot I guess.

[cobbadiggabuddyblooo]

Old school copper core style plugs or iridium???
Had 3 iridium plugs die on me now.

[drix]

Iridium plugs but moving to standard copper ones now

Will try swapping coils over too to test

[drix]

Bit of a delayed reply here but thought I'd post for repository info.

Swapped the coils over but that popped a plug pretty much straight on start-up. I have fitted the Dyna coils ones back and re-earthed them to the frame properly. I haven't been riding the bike much this year due to having a new toy but so far, the re-earthing seems to have solved the plug popping issue. I haven't really had a good chance to check on the mpg though, guess I'll get round to that in the new year now.

Lesson learnt - do the basics right first time!