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starting from cold, in a hot climate

Posted: Mon Jul 13, 2009 7:51 pm
by jag
Hi all,

Been a while since I last posted on this forum - in fact I think the last time must have been on the old forum over a year ago before I moved down here to hot and sunny Seville in Spain. Although no posts since the move I have been checking out the site whilst I've been here which has been a source of inspiration at times.

Without boring you all with details suffice to say it's been one problem after another - I suppose a symptom of pay cheap pay twice?! Now that it looks the RVF is working fine my question is regarding cold starting, bearing in mind the summer temperatures of 30-40ºC down here.

This morning I pulled the choke out, pressed the button and it started well. Gradually put the choke it as I rode it and all seems fine. The morning ride was only for about 10 mins. After about 7 hours of it standing in the sunshine, I went to start it and based on it being a bit reluctant to start on choke in the morning I just pressed the button without the choke pulled out and it started and idled fine. At this time the ambient temperature would have been around 35ºC...

So my question is whether starting the bike the second time round in the heat we have here constitutes a cold start? If so, does that mean I should always have the bike starting with the choke out regardless of the ambient temp (assuming the bike has been left standing for a few hours) and therefore that it shouldn't have started without the choke?

I am a bit concerned that whilst the fuelling and carbs issued were apparently resolved recently, nevertheless there is still an underlying issue. The idle is around 1200-1300 rpm (with it slightly higher after a high speed motorway trip).

My newly found local Spanish (ex-Honda) mechanic seems confident that I have the bike running as good as it's ever been but as he has never worked on a NC35 in his life I am a bit cautious...

Cheers,

Jag

Re: starting from cold, in a hot climate

Posted: Mon Jul 13, 2009 8:25 pm
by mrdidlydingo
jag wrote: So my question is whether starting the bike the second time round in the heat we have here constitutes a cold start? If so, does that mean I should always have the bike starting with the choke out regardless of the ambient temp (assuming the bike has been left standing for a few hours) and therefore that it shouldn't have started without the choke?

I am a bit concerned that whilst the fuelling and carbs issued were apparently resolved recently, nevertheless there is still an underlying issue. The idle is around 1200-1300 rpm (with it slightly higher after a high speed motorway trip).
Jag
Cold starting refers (in my mind) to the temperature of the engine components and circulating oil and not to the ambient air temperature, living in England its a tad tricky to comment on the effects of regularly starting a bike in 40 degree heat, so rather than considering the ambient temperature look at the bikes temp gauge as you start and a few moments afterwards once the coolant has circulated I would have thought this will be more accurate way to gauge wether the bike is 'cold'

The choke is merely a mechanical device to richen the mixture and make the bike easier to start by reducing the airflow through the carbs, in that sort of heat without knowing anything about the relative humidity I would suggest there is already reduced air flow as the air (very broadly speaking) is much less dense at high temperature therefore the bike if it hasn't been reset for the heat will run richer anyhow !

Re: starting from cold, in a hot climate

Posted: Mon Jul 13, 2009 8:37 pm
by Keysie
I would try starting the bike without the choke even in the morning as it must be pretty hot even early on, if it doesn't want to start then it needs the choke ie: the bike will let you know if its cold or not

Re: starting from cold, in a hot climate

Posted: Mon Jul 13, 2009 10:08 pm
by challymo
To be honest with you I very rarely bother with the choke, only using it when the bike refuses outright to start without it. To be honest it sounds like you bike is running fine.

Re: starting from cold, in a hot climate

Posted: Mon Jul 13, 2009 10:34 pm
by Cammo
In the hot Aussie summer I always use choke when starting for the first time of the day, but usually not again after this first start.

Re: starting from cold, in a hot climate

Posted: Tue Jul 14, 2009 1:05 am
by jag
Thanks very much for the replies guys.

It sounds like the bike starts along the lines described by Stickshift; I think we also have similar hot weather here. Hopefully my local mechanic has indeed given me the bike in a good state for use over the summer.

By the way, the couple of guys I have spoken to in Seville regarding my bike and the hot weather have suggested that I use 15W 50 grade oil instead of the stuff recommended in the Haynes manual and after having done about 500km after the oil change there doesn't appear to be any problems...

Cheers,

Jag

Re: starting from cold, in a hot climate

Posted: Fri Jul 17, 2009 2:16 pm
by Neosophist
15W50 doesn't thin down as much when its warm. Probably a good suggestion if your riding in 40+ weather.

When im doing long trackdays I use either Motul 15w50 or Repsol 10w50 as the bike runs hoooot...

otherwise I tend to stick with Honda's Ultra S9 10w40 :)