UK Riders - how does your bike run since the change to E10 petrol

[GuyGraham]

My S model with BSR carb has always run spot on (apart from carb icing, but that was cured by the optional carb heater)

Bike has the 3x3 with a DJ jet kit needle on 3rd groove from top, 22.5 pilot, pilot screw at 2.5 turns out and 140 main

It started fine on full choke, then I would put in on half choke after about 20secs, then pull off and turn the choke off after about another 20 secs. Bike would run great from that point onwards, with no hesitation and fully responsive to the throttle, with that instant torque as soon as you twisted the throttle

Since we went over to E10 petrol last Sept in the UK, things have changed

Bike starts and idles fine as above, and pulls off fine, but then it goes flat at anything above about 1/8 throttle and prob about 2.5/3k rpm. Exhaust note sounds hollow, and it has no power and feels really flat, and produces no more power even if throttle opened more and more. Can't even get it to accelerate by slipping the clutch to get revs up and then feeding it back in as it hasn't got the power to keep the revs up. There is a transition point at about 6K rpm where it feels like an old school non powervalve two stroke hitting the power band where it suddenly feels like its old self again and it takes off with full power and exhaust note changes to normal. As the bike gets hotter and hotter over the next four miles of road riding this transition  point moves lower and lower in the rev range until it is fully gone (and exhaust note also changes sound to a normal sound at same point) and it is completely normal again. Its more pronounced on cold days (say -2°C to 5°C) than on warmer days say 10°C as the bike gets fully hot quicker on the warmer days obviously.

Initially I thought the thermostat was stuck open and bike was over cooling, but thermostat is fine and works as it should opening and closing at about 70°C. Rads are hot to touch after less than a mile. Even blocked the one rad off fully, and half of the other with cardboard so it heats up quicker but no change

Next thought was lean mixture, so lifted the needle to 4th and then the 5th groove - still the same but on 5th groove it has the cough / hiccup off idle that indicative of a rich mixture, so went back to the 4th groove.

Next I started increasing the main jet size, first up to 142.5, then 145, 147.5, 150, and finally 160 but still no improvement (mpg has gone down though!)

Have had the needle jet out to ensure not partially blocked but it is clear

Have tried leaving the choke on but again no improvement.

Have tried different brands of petrol but again no change

Emptied tank to ensure no water

Plug is a NGK CR8EIX and is fine - doesn't sound or feel like a misfire though

Strange thing is, this only happens for the first ride each day. If I ride the bike, then stop and ride it again say an hour later even if engine is cold to the touch and it requires choke to start it again, it doesn't do it and is fully responsive straight away with no flat feeling, and exhaust note sounds normal in affected rev range.

 

I've run out of ideas now

Anybody experienced anything similar to this and if so what was your cure for it

 

 

 

 

Edited April 3, 2022 by GuyGraham

[Oregon lightweight moto]

I had similar problems with my 650 after trying to mess with the jetting, I  just switched to non ethanol fuel and my issues went away.

I’m assuming they make it very difficult to get real fuel over there?

 

[GuyGraham]

1 hour ago, The Science Cow said:

I had similar problems with my 650 after trying to mess with the jetting, I  just switched to non ethanol fuel and my issues went away.

I’m assuming they make it very difficult to get real fuel over there?

 

Can't buy Ethanol Free fuel that I'm aware

Standard grade 95 RON unleaded in 10% and super unleaded (high octane) 97RON is 5%, but its about 15p litre more expensive so trying my best not to have to use it as engine doesn't need the 97 Octane of the super unleaded

[DrzDick]

Esso Synergy Supreme +99 has zero Ethanol in it but only in certain parts of the country, so you could try a tank full of that just to see if it really is the E10 fuel.

My DRZ is running well on E10 btw, but has suffered from a slight off idle hesitation for years now. I've been told that a worn emulsion tube is the likely candidate (it a FCR39 carb) but TBH it doesn't really bother me how & where I ride so I haven't done anything about it yet. 

Below is a snippet from the Esso website.

Although our pumps have E5 labels on them, our Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, the Teesside area, Scotland and NW England). Legislation requires us to place these E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps.

[bumtarder]

Theoretically you'd need to go about 3% richer on the jetting with 10% ethanol blend. The pilot jet can stay at 22.5 but the fuel screw adjusted to about 3 turns, and the needle perhaps one clip richer and main jet from 140 to about 144. This assumes that you haven't developed any mechanical issues such as a worn DJ needle, carb needle jet or a worn emulsion tube which can all have an effect on the fueling. As a test you could also try taping off 1/3 of the 3x3 to richen up the main.

Edited April 3, 2022 by bumtarder

[GuyGraham]

19 hours ago, bumtarder said:

Theoretically you'd need to go about 3% richer on the jetting with 10% ethanol blend. The pilot jet can stay at 22.5 but the fuel screw adjusted to about 3 turns, and the needle perhaps one clip richer and main jet from 140 to about 144. This assumes that you haven't developed any mechanical issues such as a worn DJ needle, carb needle jet or a worn emulsion tube which can all have an effect on the fueling. As a test you could also try taping off 1/3 of the 3x3 to richen up the main.

As per the original post, I have lifted the needle 1 and then 2 notches, and gone from a 140 main to a 160 but all to no avail

BTW, Mikuni slotted main jets are sized according to their diameter, so a 140 measures 1.40mm dia (not withstanding the manufacturing tolerance). I have confirmed this measuring the hole size using a shadowgraph

A 140 main has a CSA of 1.5393mm² and a 142.5 has a CSA of 1.5948mm² (a 3.61% incrase in area),

A 160 main jet has an area of 2.0106mm² which is 30% larger than the orginal 140 I had in

All this is mkaing me think its not carburation

Put a new plug in it and cleaned the air filter but still doing it this morning but not as bad as it was but then again it was about 8°C this morning (and this is with the 142.5 main jet refitted)

Its almost as though the fuel is not atomizing properly in cold weather and so doesn't burn fully until engine and oil is fully hot

Edited April 4, 2022 by GuyGraham

[SC_lurker]

Welcome to California! 10% Ethanol fuel is standard here, has been for decades. Thank goodness for our water supply that the old MTBE is long gone. Jetting wise, most here have figured out what works with what is available at pumps. Alcohol is hydroscopic so to combat that and clean, I use a PEA additive $10 per liter sold by Gumout (multi system tuneup, similar to Seafoam) that provides a year of stability for extended storage. Tablespoon per gallon. No issues with e10 untreated, on extended rides where fuel is consumed rapidly. 

[Marshy UK]

When E10 came in I tried a couple of tanks on it and didn't like it. On advice from a tecchie, I've switched to super unleaded now and despite tne increase in price, it seems to be more efficient than when on the E10. It'll be interesting to see how this pans out and if I am getting more milage to compensate for the price. From what I've read E10 gives around 10% less mileage.

[GuyGraham]

Think I may have found the issue - 3 pin holes in the CV carb diaphragm

Was able to replicate the feeling, even when it was running normally by holding the throttle open about a 1/3 in  3rd or 4th gear and just letting it accelerate down hill til it wouldn't go any faster (without moving the throttle) and it felt & sounded exactly the same

Kinda got me thinking that the slide wasn't lifting enough to how fast the engine was going and wanted/needed the slide to lift

Close examination of the diaphragm against a light source revealed 3 holes in the creases of the rubber

New diaphragm fitted but yet to test as its been snowing here today.

[GuyGraham]

So, can report that the new carb diaphragm has fixed this issue

Must have been suffering from this long before the introduction of E10 fuel here as its transformed the bike. Cant remember it being this responsive to the throttle for a long time. Its like the throttle was connected to the carb with rubber bands and now its connected directly. Instant torque and response as soon as throttle is twisted...no more lag or flat feeling. 

Its much better even when cold than it was when it was hot before  and I thought it was running OK.

The gradual decline in performance has not been noticeable until this issue arose but I reckon the carb diaphragm has been holed since well before the E10 fuel was introduced here in the UK, and I didnt notice it as it was such a gradual decline in performance

Bike is fun to ride again

So it seems life of the CV carb diaphragm is 18ys / 60K miles

Edited December 12, 2022 by GuyGraham

[tarka]

Mine doesnt run as well on the new fuel. Definitely flatter, not as crisp and snappy. I only use shell vpower 99 now and it runs great!!! It costs more but I feel the difference in performance is well worth it,

[SC_lurker]

My preferred fix for a leaky cv diaphragm is a Keihin FCR! Takes throttle response to a whole other dimension.

[GuyGraham]

13 hours ago, SC_lurker said:

My preferred fix for a leaky cv diaphragm is a Keihin FCR! Takes throttle response to a whole other dimension.

Not worth it for me with an 18yr old bike and 60K miles. £28 Vs £600 is a no brainer.

An FCR would be totally worn out at 60K.....I had a WR450 and the slide wheels had dug into the body by 10K miles so much so the slide rubbed on the body

 

I have a 2016 WR250F (much better than the drz off road, and makes more power) and an SV1000S for speed. The DRZ is just my winter hack for commuting now so as long as it runs properly I am happy with it and its 55/60mpg

Edited December 18, 2022 by GuyGraham

[SC_lurker]

On 12/18/2022 at 4:06 AM, GuyGraham said:

Not worth it for me with an 18yr old bike and 60K miles. £28 Vs £600 is a no brainer.

An FCR would be totally worn out at 60K.....I had a WR450 and the slide wheels had dug into the body by 10K miles so much so the slide rubbed on the body

 

I have a 2016 WR250F (much better than the drz off road, and makes more power) and an SV1000S for speed. The DRZ is just my winter hack for commuting now so as long as it runs properly I am happy with it and its 55/60mpg

My 2007 DRZ is what 16 years old? Has 14,683 miles now. I ride it less now as I also own other street bikes, one Suzuki makes 135 hp, 90 lb. Ft. on a dyno with air/oil cooled 1157cc.

The slant FCR I run has untold miles but has been solid since 2018 or so. Slide is same as I bought it for around $100. Rebuilt the head and a big bore piston and cylinder around the same time (9,000 miles) with OSHC 2003’s. No practical way to get a license plate on a 2016 (or any) WR here in CA. The DRZ is a great winter commuter. I have heated grips. This bike will outperform any 4 stroke 250-300 that has legit CA street registration and I still pass the (<96 db) sound test at OHV parks.

Around here (CA) there are so many vendors that won’t ship cams, pistons, programmers, exhausts, etc.. to CA. There are workarounds but very inconvenient.

A 60k mile DRZ might be ran hard and put away wet, your mileage may vary. 

[38super]

Shoe Goo will fix your diaphram

[bumtarder]

28 minutes ago, 38super said:

Shoe Goo will fix your diaphram

Why?? You can get new ones for about $13 on ebay.

[GuyGraham]

7 hours ago, 38super said:

Shoe Goo will fix your diaphram

It was hard and shiny in comparasion...nothing like the soft and flexible rubber of its replacement. It would have split again in due course that I am sure

Replacement with a new one was the best option