Unsure about carburetors!

[cs_05_hho]

Hello there guys! The bike with the possible issue is a Yamaha FZR 600R 4JH - 1994 - i have trouble starting it in cold weather! THE CHOKE IS OPEN AT MAXIMUM I crank the engine once - it starts up for 2-3seconds then it dies, i crank it again - 2-3 seconds - it dies - sometimes on the 3rd cranking it starts - it stays at about 1000rpm roughly - after which it raises to 4000 rpm (after 10 seconds or so i shut the choke and slightly open the throttle and maintain it at around 2000rpm)! Is this normal? I have to say that i bought the motorcycle in 30th oct 2011 - and since then i hadn't had the opportunity to do a carb sync!
When it'll warm up outside I'll change all the filters (air filter, oil filter) and the oil - bought for it Motul 5100 10W-40 (it runs now on Motorex 10W-40)! From the moment when i bought it until now i haven't ridden it to much - didn't pass 1000 km! I hope i posted correctly! I used the search function but nothing like this came up!

[M in KC]

Bro, mine exhibits the the exact same thing and always has. When the ambient temperatrues are elevated, the starting conditions are not as noticeable. In my case once everything is up to operating temp its all good. You can always check your carb sync to improve your cold starts if you wanted to.

[cs_05_hho]

M in KC - thanks for the info! Still i hope hearing from other members! I WILL SYNC THE CARBS!

[Nik]

M in KC - thanks for the info! Still i hope hearing from other members! I WILL SYNC THE CARBS!

Hi,
I know Y-G's fzr600 in the uk does this, with mine another 600 but in the West Indies it will do it on at dawn (a chilly 55 degrees ) but in the hot part of the day (80+ degrees) it is not so noticable. As has been said clean, synch'ed carbs help a great deal better starting , miles per gallon etc.

[cntryboy85]

this is my first winter with my 95 fzr 600 mine does kind of the same thing. one of the things i have found to help is either leave it on a trickle charge all night. cold weather zaps the small battery quick. put a relay on the coils to make them give a better spark. but it is mainly the carbs fuel gets thick at cold temps i rode mine the other day it was 35 degrees and it did not want to start at first but later that day at 65 it didnt have a problem.

[cs_05_hho]

Another thing that I realized is that the spark plugs are cold in their heat range - probably a hotter spark plug is more adequate for the winter! Thanks for the opinion guys Much appreciated!

[DonTZ125]

The problem with cold-weather starts is that the fuel doesn't want to evapourate. The colder it gets, even the "light ends" are staying as liquid. This becomes particularly annoying when the bike has sat since summer and all the light ends have boiled off in the autumn sun. "Winter" gas typically has a higher fraction of "light" compounds for easier starting. The old stories of Northern hunters urinating on their snowmobile carbs and intakes to raise the temperature and help start the engine aren't entirely false ...

A 'hotter' spark will do nothing extra to light off the fuel in cold weather, and a hotter plug does not mean a hotter spark. The heat range of the plug denotes how well heat is conducted away from the electrode, and thus what temperature it maintains for a given set of conditions in the cylinder - a 'hot' plug literally has a higher surface temperature than a 'cold' plug, allowing it to burn off carbon deposits and preventing fouling. If the conditions are correct to maintain the 'colder' plug in a clean condition, the 'hotter' plug will suffer heat damage and erosion, possibly causing pre-ignition now and poor running later as the electrode degrades.

[cntryboy85]

don is right on that you need atomaztion of the fuel to get the proper ignition of the air/fuel combo. cold weather the fuel almost gels up. think of oil does it flow better hot or cold?

[cs_05_hho]

DonTZ125 - what you say is true - i won't argue with that!
This is my first 600cc - and my first winter with a bike! I acumulate experience by each post I read from you guys on this topic!

[cowboi]

To add along with what don is saying also get some seafoam. You can get it at walmart or local parts house. Put some in the tank and it will help with cleaning and to give a better start up after the bikes been sitting.

[cs_05_hho]

Cowboi - i live in Romania - so no Walmart or local parts house here - could you be so kind to upload a photo of a similar product! What is that seafoam?

[cntryboy85]

http://www.seafoamsales.com is a link one of the websites. if you can get ahold of it this is some good stuff. but if it spills on your paint and you dont get it off it can eat to the plastic.

[reelrazor]

If you haven't done it already, change the spark plugs.

New ones will provide easier starts.

You can get an idea of whether it is running rich (too much fuel to air ratio) or running lean when you get the old ones out. You dont need any 'special' spark plugs. Over here the Autolite brand is cheap and quite functional.

Leave the throttle alone when it starts to rev up. Use the choke lever to modulate the rpms.

And, if you know that it will sit overnight, or long enough to cool down all the way.....right when you turn the key to 'off' or hit the kill switch to shut it off, try whacking the throttle wide-open. This will 'prime' the cylinders with fuel while they are hot-adding to what the "choke" provides on startup. (that's another old snowmobile trick)

[cs_05_hho]

changed the spark plugs! it works like a charm the main reason that i didn't change the spark plugs was that i couldn't find an appropriate spark plug key to change them!