Hi everyone,

I've had a K100 RS for a couple of months now, and I drive it to work and back every day (about 45 km roundtrip). It's needs to be driven after having been stored for many years. Some oil seeps and sweating is starting to show up, nothing unusual for a 30 year old bike that is being put back into use.

One thing puzzles me though : It seems to be taking longer to start the bike on cold-start now compared to the first week.
I use the fuel enrich lever ("the choke") but I still have to insist quite a bit on the starter-button and giving it some gas before it responds and fires up.

What could be the cause ? Or am I just paranoid ?
Couple of parameters have changed :
1) I always disconnect the battery when I park her for the night (as I have been told she drains battery when parked and the relay is sensitive to battery voltage)
2) It's slightly colder in my garage (current temp around 15-17 degC / 60degF
3) I have changed oil, oil filter, and coolant since then

Would disconnecting the battery have any impact on startup ?
How careful are you guys to have a top-charged battery at all times ?

Your input is as always highly valued.
Best regards,
Einar.

When the weather gets colder in the winter, the refineries change to a more easily vaporized fuel mix.  It often takes some time to get the "summer" blend out of the system.  Thie summer blend will start a bit more reluctantly than the winter blend when the temperatures start to drop.

ERasberg wrote:Would disconnecting the battery have any impact on startup ?
How careful are you guys to have a top-charged battery at all times ?

Disconnecting the battery will slow its discharging, so that's good.

I keep my battery charged by riding it every day. The first two years of ownership,  I removed the battery from the bike in winter, stored the battery in a heated room indoors and charged it once a month.

Now when winter comes, I store the bike in an unheated workshop with the battery's transmission ground cable disconnected then fully charge the battery just before I start riding the bike in spring. The results have been similar. It starts and I ride away. It's an AGM battery—the only battery the bike has used for the last five years.
 

I also have experienced this time to time

the battery voltage whilst decaying , ie drained some what ..makes a huge difference to firing up quickly
the best batteries don't seem to do this quite so regularly ...but the cheapy versions do exhibit  poor starting after just a few months of , "occasional riding "

perhaps it might be an idea to measure the drain on the battery whilst in the off state ?

constant draining can ruin an other wise good battery ,as in many cases the run time to recharge is no where near long enough to fully recharge it

point 2
is the "choke " ahem indicator light coming on at the instruments ?

could the switch signal to the ficu - ecu not be happening ?  meaning its not enriching the mixture  at first start correctly , because its not getting the correct signals ?

3rd point

have you checked the high tension leads (both ends )  for any corrosion between the coils . and plug tops

don't forget that the plugs require a ferule on top , not just the 3mm thread of some versions of spark plugs , and now arcing between leads and plugs reducing ignition pulse strength ?

just a few thoughts

.75, Laitch, Charlie99, thank you for the very useful input. Great help. Follow-up questions !

1) I most likely have a "cheap" battery, so I'll try to measure the drain in off-state. Any particular way i should do that ? Also possible I don't achieve full charge riding to work. What is a healthy on-state charge Voltage, say at 3000RPM ?
Laitch, a battery lasting 5 years is very good for any bike, I would say, so that's encouraging.

2) Could this be a sign of weak injection/fuel pump pressure ? (I very occasionally feel a "surge" when driving, I was pretty sure it was electrical contact, in the process of cleaning all with CRC)

3) 10-4 on the HT leads arching, I will inspect for corrosion. Highly possible they have not been attended to in a long time.
What is a ferule ? (apologies, my english lacks a lot of technical vocabulary, Google translate didn't really clarify) 

4) The "choke" light comes on, yes. I'm fairly certain it works correctly, both in the "Constant"-enrich position as well as the "Boost"-position (in lack of better words). 

5) Regarding winter/summer blend, I have not heard about this difference before. I'll investigate.
In France winter/summer blends are usually discussions around what alcohols to drink !

ERasberg wrote:.75, Laitch, Charlie99, thank you for the very useful input. Great help. Follow-up questions !

1) I most likely have a "cheap" battery, so I'll try to measure the drain in off-state. Any particular way i should do that ? Also possible I don't achieve full charge riding to work. What is a healthy on-state charge Voltage, say at 3000RPM ?

2) Could this be a sign of weak injection/fuel pump pressure ? (I very occasionally feel a "surge" when driving, I was pretty sure it was electrical contact, in the process of cleaning all with CRC)

3) 10-4 on the HT leads arching, I will inspect for corrosion. Highly possible they have not been attended to in a long time.
What is a ferule ? (apologies, my english lacks a lot of technical vocabulary, Google translate didn't really clarify) 

 
the issue isn't the charge voltage whilst running , but certainly that should be tested at 3000 revs ....after a half hour of running is when maybe the voltage should be measured , as this will be well away from the recharge needed after starting , should be up near 13.8 .volts  ...(but we have seen exchange regulators installed and could be as much as 14.1 volts )

what is important is the time of charge ...a battery needs a good time to charge properly  , I use a trickle type charger , capable of 4 amps ...but drops back quickly usually , but I leave it on for at least 5 hours ...and 8 preferably after it has been sitting for a month or so ..

you can pull the negative lead off the battery and connect in series with the earth point and the earth lead a multimeter  red wire towards the battery negative lead , set on 200 milliamps  and the black lead to the earth point ...you can pull fuses to help identify which group ofcomponents is drawing current , usually the clock will draw current ...maybe 5 milliamps , but idf it indicates more than pull other fuses to identify the lossy electronics ?

a ferule is the screw on caps that make the terminal end of the spark plug  from 3 mm thread on ngk type plugs to the normal 5mm or so that is required inside the spark plug leads connection end cap
please do not use crc anything like wd40 or water displacement anything to clean electronic parts , it leaves a foul residue that hardens over time and as it dries out , causing insulating effects commonly ,,, crc do make a good contact cleaner that may well dissolve a lot of gunk of  the metal connector parts and I have used it extensively over many years to clean critical connections . with great success (leaves 0 residue usually )

a good place top look for a lossy - low feed and pressure fuel pump is the under seal tank connector ...which expand and become intermittent over time  often causing the pump not to work at all , many have replaced them for something better



hope that helps

Charlie99, great info, thank you for taking the time to provide these additional (important) details.
This helps me greatly to understand what I need to do and what I need to look for.

I'll pull the tank (again) and check that seal tank connector. Should have done that when I changed coolant fluid. Lesson learned.
To clarify, this would be the tube inside the fuel tank that plugs into the fuel pump ?

A question ERasberg , when you are starting the bike does it crank over normally but does not fire or is it cranking slowly ?

John Re

Melbourne Australia

Hi John Re

It's cranks normally without firing so it led me to believe the battery has sufficient charge and that there is no excessive friction in the piston rings, however I'l measure the battery voltage tonight to be sure.

I did change oil to a 15-40W (don't know what was in it when I bought the bike) so maybe it has had an impact ?

Hmmm ok , I have a similar problem with my bike when the weather gets very cold , spoke to my mechanic about it , he suggested to switch to a lower octane fuel , I normally run 98RON and so tried 91RON , it started much easier , something to do with all of the extra additives in higher octane fuel , less fuel etc etc , give it a go , it can't hurt

John Re

Melbourne Australia

Higher octane fuels have additives that raise the ignition temperature to prevent pre-ignition(engine knock).  So yes, lower octane fuels should start easier in cold weather.

I put 98 in the K in France in the summer to avoid the darn ethanol E85 and E10, eventually started running badly on it. Went back to 95 and a rapid improvement in running and less consumption too. Even the 95E10 was better. Maybe all the E95 there is E10 but any of the E95 was better than the 98.

Parked it up a week after coming back........the 97 K1100LT arrived.

Switch to a good quality AGM battery I've had 3 batteries in twenty years. First Deka went 8 years second Deka went 5 years current AGM battery has been going for 6 years and isn't a Deka but is no longer available in Brick sizes.
You can now buy smart battery chargers which will keep your battery charged with out overcharging it. Mine is attached to the garage door motor on the ceiling and the cable just plugs into the merit plug already built into the bike.
Regards Martin.

ERasberg wrote:Charlie99, great info, thank you for taking the time to provide these additional (important) details.
This helps me greatly to understand what I need to do and what I need to look for.

I'll pull the tank (again) and check that seal tank connector. Should have done that when I changed coolant fluid. Lesson learned.
To clarify, this would be the tube inside the fuel tank that plugs into the fuel pump ?

no, the under right hand side cover 4 pin plug- socket  well  on after 85 models

On earlier models its at the front left of the tank. If your tank is bolted down its the earlier model and that plug is well prone to problems. If contact is poor no petrol coming through.

Before you go changing the battery or anything else, try giving the start button a quick jab before you hold it down to start the bike. You will hear the fuel pump running for a few seconds. This brings the fuel system up to pressure. I have found that the bike starts faster when cold after doing this.

Thank you to everyone! Much appreciated. I will apply all your advise.

I was not aware of the octane issue. I will try 95 octane on next occasion.

For the frenchies or others using 95, the 95E10 mix is to be avoided for all vehicles before 2002 due to the "dryness" of the biofuel ethanol (the E10) that eats up carburetor/injector seals. I have already destroyed 2 carbus that way and my mechanic told me it was the fuel. Many gas stations sell regular 95 octane as well so it's not that hard to find.

Regarding the battery, it was bougth in July, and measures ok at the moment, so I will monitor it and see how it holds up. 

@Avenger GT : thanks for the tip, i will follow your instructions on next start up.

@Charlie99 : the 4 pin socket has been cleaned and is (I hope) in decent condition. I did manage to reproduce the "surge effect" by touching the wire-bundle on the right side while driving. It was however difficult to identify at speed exactly which wire was suspect, so I cleaned up all of them.

AvengerGT : your technique sorted me out. Quick push to run the fuel pump, then a second attempt and it started right up.

I'm still a bit confused though as the temperature hasn't change much on startup as I park in a heated garage.

I don't think temperature has a lot to do with it. When the bike has been standing overnight, the fuel pressure in the system drops. All fuel injected cars, and more modern fuel injected bikes run the fuel pump when you turn on the key. The 8 valve Ks don't, so a quick poke of the button brings the fuel pressure up before you start. Makes life easier for the battery and the starter.

I totally agree with Avenger GT, to  " prime the system"

My bike has always taken a few spins to start .

During the summer I leave the " choke " off,  , press the starter , she starts , then I bring the " choke " on to keep the revs up

Now its winter, " Choke " off, press the starter to prime the system, then " choke " on,  press the starter and she fires straight up .

Bob