cold starting a problem

[handsomejackuk]

Hi,

Currently finding my bike very difficult to start when cold turns over o.k. but never fires eventuall i flatten battery and have to jump start it fires after a while but takes a while. when warm runs great. I tend to turn the idle up as well when cold starting but when bike is warm idle is too high. any ideas its driving me mad.... May put original bsm can on as it used to start a lot better with that on last year.. Currently have bsm vampire open can on....

Alun

[DAVID THOMPSON]

i have used motorcycles in the cold for many years
in the winter i use one battery to crank the bike
and a extra one to run the ignition coil or cdi box and coil
this way the coil gets full power when it fires the plug
dave

started a r90s bmw at minus 22deg F once like that
damn that was a cold ride to work

[redland_doug]

Hi,

Blimey! That's exactly the experience I'm having with mine! New battery, fully charged, and the rotten thing still wont fire up when cold. Doesn't even have to be particularly cold. Bike is left in a dry workshop overnight. When it eventually starts it runs lumpy as anything until really warm. Increasing tick over is not the answer, and means it idles very fast once fully warmed up. It was suggested that I drain the carbs. Can only find what appears to be one drain screw, one the LHS carb at the bottom. Is that the chappy? Valve clearances have also been mentioned, but not sure how to go about this procedure and what the correct clearances should be. Looks like a bit of a strip down would be needed too. Any other suggestions? Wondered if it could be electical, but it was serviced quite recently, so newish plug in there.

All help gratefully received!!

Doug

[m4panther]

are you sure your petrol is any good? draining some gas out the screw always worked for me... are you using the choke? other things I've tried give two quarter throttle pulls then tapped the starter button once or twice then held it for a few seconds.. then repeat if I have to. it can be a cunt once in a while. how's your plug? are you using a maintenace free battery?

[redland_doug]

Hi,

Will try your suggestions. Plug is quite new (went in around Nov last year), but I've not looked at it yet. I hope the petrol is OK!! I've noticed that the air box does tend to get its share of water in, so its possible that there's water in the carb. I'll try a bleed to make sure the fuel is OK. Battery is bog standard vented type.

When it refused to start yesterday at work, and I thought that I'd just about exhausted the battery, in a kill or cure move I open the throttle all the way, and held the starter on ...... after quite a bit of spinning it fired .... and I shouted for joy. I've been told that this may indicated flooding, but I dunno.

Doug

[DAVID THOMPSON]

my rt125 will flat not start if the throttle is opened any
i think a lot of the problem is the carb settings to comply with the smog laws
and the fact that electrical systems are to weak
dave

[Bill Jurgenson]

my question: is cold starting the problem or starting after not having run a few days, more than two?
Starting in the cold has never ever been a problem with the XTZ engine. I have three of them and once had 4 at one time. The SZR is completely stock and never opened or cleaned (saving oil changes and filters of course) to my knowledge. Admittedly, continental winters ain't what they used to be and nowhere near as severe as in the northern US, but the Yamaha starts all year round and needs the choke only for about 30 seconds after. I twist the grip twice (accelerator pump), pull the choke and press the button, no gas until it starts. Maybe not after the first turn but quickly enuf. The MZs all have dual Mikuni flatslides and start easily.
BUT
If the beast has been standing unused for more than two days, it is a bitch to put it mildly.
There are several possible causes.
-Water in the gas tank; this is definitely a problem for bikes that stand outside uncovered or were used in heavy rain. Drain the tank entirely, including the that screw cap on the bottom of the petcock. Then drain the floatchamber - yes it is that large hex screw on the left carb half. The right half has no float, just a bowl that gets its gas thru that small rubber tube connecting the two. This works fine except for sidecar units where right turns tend to starve the right bowl.

-old gas. The content of the chamber is not very much. The chamber is vented, so the volatile parts of the gas evaporate easily when the bike left standing, leaving something approaching thin diesel oil with time. This is not easy to burn. On the Skorpion, closing the petcock and letting the thing run dry tends to help. That way, the floatchamber is flooded with fresh gas when the petcock is opened. Obviously this is no help where a fuel pump is installed and, in the case of the SZR, there is no petcock to shut off - or rather the one there can only be reached for service when the tank is being removed.

-the vacuum operated fuel pump. If you are talking Skorpion, throw out the fuel pump entirely. The SZR needs a pump as did the XTZ and I think the Baggi, too, 'cause the petcock is lower than the floatvalve. If the tank is full, it's alright, but nearing empty, the gas no longer flows by gravity. The Skorpion tank is much higher than the carb. The Skorpion only has a fuel pump cause MZ order the XTZ engine as is or perhaps could only get it from Yamaha that way. Anyway, the pump is a membrane pump that acts on the intake vacuum, so that means it pulses and doe this only once every other turn around. When the system has drained, which happens when it has been standing, it takes a lot of turns to get anything back to the carb. That is the reason why Belgarda (they actually built the SZR, not Yamaha, and they build the MT03, too; this is not a Yamaha development) put an electric fuel pump (same one as on the FZR) on the the later SZRs.

- use a hotter plug in the winter, a DPR8 or even a DPR7 if you actually tend to drive US style. Personally, I never use the recommended DPR9xxx anytime of the year. Colder plugs tend to foul more easily. Be sure the outside of the plug is clean and dry. It is a good idea to use a bit of electric terminal grease on the plug connector threads.

- Use a decent battery.

- Before you run down the battery, use a cold start spray. On the Skorpion, just pull off the crankcase vent tube at the bottom of the airbox and spray into there. I am not a Baggi user, but there will be a comparable place on that airbox, too. Or just thru the airfilter if that is easily gotten to. On the SZR, you have to unscrew the tank to get to the airbox nozzle.

[redland_doug]

Hi,

Thanks for the tips. It was a complete bugger to start again after work yesterday - and it wasn't a very cold day at all. Quite mild in fact. The Baggie has always been a temperamental so-and-so if its been stood around for a while, so I've taken to switching off the petcock, and letting it run the carbs dry before storing for anything longer than a weekend. This problem I'm having now is every day, in the morning and evening after the bike's been sitting around for 8-12 hours (inside overnight, and outside during the day). When I leave it overnight I also put the battery conditioner on it, to ensure its tip-top charged. Usual starting procedure that has worked for years has been full choke (half in summer), push starter with slight crack of gas for about 2 secs. Usually takes three or four stabs, then she fires. Immediately to 1/2 choke if not already there, and ride off. Choke off by the end of the road. But no more ... the Baggie has other ideas now! I ride this thing everyday, and depend on it. Its a real pain!

Bike seems a bit gutless at the moment too, which may be related.

Good news is that I'm off for a week and half next week, and my local bike shop have agreed to take it in while I'm away and try to figure out what's wrong. Chap there said it could be tight valves or water in gas. Anyway, he's got plenty of time to tinker while I'm away. No worries about him being able to reproduce the problem - he's just got to leave it outside the shop all day and then try! Fingers crossed it'll be all fixed when I get back. If not, the old girl has to go, and its death-by-moped for me! Oh the shame of it.....

Cheers,

Doug

[redland_doug]

Hi again,

A further update - I had to go on a trip for a couple of weeks, so I left the bike with my local bike shop with instructions to try and fix it. They said they would check stuff like valve clearances, fuel etc. When I got back, I popped along to pick it up. They said they checked the battery, which they replaced under warranty (the 'old' one was about a month old!!), drained the carbs, and cleaned a 'load of muck' out of the starter motor itself. They claimed it wasn't worth checking the valves, and that it now started OK for them. I made them try it in front of me. Guess what -no change!! It did finally start, but it was a struggle. Reluctantly I paid up their labour charges and left, vowing not to return.

In the spirit of investigation, I've just got a can of 'Easy Start' spray - basically ether. It claims to be able to start anything. So today when it refused to start, I duly squirted a load into the air box and tried again .... nothing. Aha! So this tells me that its electrical - right? If there was any sort of spark, it would have caught the ether. Interestingly, I then managed to immediately bump start it (with the help of mate). So this makes me ask a few questions (apart from why the shop didn't do this!)

• I should be looking for an electrical problem, not a fuel one, right?
• Is it possible that the 1st attempt to start flooded the motor, so not even the ether would catch?
• If so, then why did bumping do the trick? (I know the ether caught then, 'cos the engine surged!!)
• Should I be looking at coil, CDI, plug or something else?
• Whilst the engine is cold and warming up, it won't idle and runs rough at low revs (idles very slowly, seems to be 'missing a beat' as revs are increased at first).
• Once warmed up, it idles fine, and starts fine.

Next steps in diagnosis are going to be done by me, not the shop, so all opinions sought please! Anyone one know what coil it uses, and is it easy to change?

Thanks,

Doug

[kendo]

Hi,
I have the same problems with my MZ and my train of thought goes like this,there is an initial weak spark at the plug when a cold bike is turned over with the choke fully on,this allows the plug to get flooded and no amount of cranking will get the bike to fire (even with easi-start) until the fuel had evaporated from the plug electrodes (that is why the bike started with a bump because the ignition system , not the starter motor ,had the batteries full attention).My bike will eventually start from cold if i try it once then leave it for 10 --15 mins (to allow the plug to dry out ) and it always starts when warm as there is no requirement for the choke which in turn does not foul the plug.I don`t think the starting problem is tied down to a single cause ,but to a combination of causes.

1 -- When a big single tries to start there is a massive power draw on the battery, this leaves little in reserve to run the ignition system. This is why the battery should be kept in tip-top condition (especially in the winter)

2 -- There may be an issue with the choke setting on the primary carb causing an exess of fuel when starting from cold.

3 -- The factory coil may not be as good as it should be giving a weak spark when there is a drain on the already weakened power supply (during starting).

My next move will be to buy a higher aH battery and fit an aftermarket coil to see if that cures the problem that is spoiling an otherwise great bike.

Hope this helps,
Kenny

[redland_doug]

Hi Kenny,

Thanks for taking the time to reply. Sounds like a very plausible theory. I need to check what battery the shop supplied. The book says Baggies are shipped with a 'premium' 9Ah unit. I wonder what they've put in. Perhaps I should try cranking with 1/2 or even no choke from cold, to see if thats any better. Does anyone happen to know if it possible to extract the plug easily (without removing the tank, rads etc)? It looks like a bugger to get at. I'd love to take a look at the plug when it in one of these 'foul' moods. Any idea what would be a suitable after market coil, and are they easy to fit? I'm really starting to consider ditching the bike, which would be a complete shame, because in all other respects its a hoot.

Cheers,

Doug

[handsomejackuk]

Same problem here, i started this thread off. I still getting the same problem here. Decided today to change air filter as air filter is now 5 year old replaced with new but not got round to starting it as i have totally removed rear subframe for repaint and a bit of TLC to rear end of bike. Now that i got the rear stripped down may have a crack at stripping carbs looks fairly east now that all the rest of the rear is off..

With #regard to plug changing, I have managed to change it o.k. with a short plug spanner not sure if it was the one that came with the tool kit no panels to remove just a bit of fiddling. need to hold the top of the spark plug and slowly withdraw the spanner while holding on to the plug with a bit of practice becomes quite easy....

took off my choke assembly today and cable did seem a little stiff I thought it was always fairly stiff. will investigate this when i reassemlbe bike. also removed side over on carb that i held on with two screw small diaphragm in there hope i got this in the right way any ideas ?

Will keep you posted

Jack

[handsomejackuk]

can anyone with access to a multimeter confirm to me /us what is the voltage drop when cold cranking mz bagira. voltage before pressing starter and voltage when turning over at battery....I am wondering whether my battery is on its way out again !!! 3rd battery in 3 years of ownership currently getting through a battery every year. bike seems to start better when I jump it with vehicle starter.

Got my subframe off last night and painted today looking a lot better now i must say. Thinking of relocating my indicators at same time and changing my number plate light for l.e.d. type. Got a small problem with my led brake light they don't last very long either. Indicators are possibly going to be located on rear footpeg holes. will post some pic's when I get it sorted.

I am still looking to clean my rear end up a bit more still to much crap on it.. Removal of chain guard for nice stainless one and would liike to modify / possibly remove the lower chain guide but not sure whether it is a good idea.... would also be nice to remove airbox for something a bit smaller and the little mudflap thingy.....

rear pegs usually off bike as not ever used....

Anyone know of nice chainguards for baghira ?

[redland_doug]

Hi,

Did another test today - from cold, removed plug cap, put in a spare, and held against casing to watch the spark when cranking on the starter. To my uneducated eye it seems to be a very poor spark. Sounds like the theory that cranking the motor doesn't leave much for the spark may be true. Any idea what could be the culprit? Coil, CDI unit, something else....? How easy to change these things?

Cheers,

Doug

[DAVID THOMPSON]

most bikes suffer from the fact the coil runs from the same battery as the starter motor
all the years i road in cold weather i ran an extra battery to crank the motor and regular one ran the bike

even did that to the old 6volt vw cars
dave