SV650.org - SV650 & Gladius 650 Forum



SV Talk, Tuning & Tweaking Discussion and chat on all topics and technical stuff related to the SV650 and SV1000
Need Help: Try Searching before posting

Reply
 
Thread Tools
Old 15-02-19, 01:28 PM   #11
Craig380
Member
 
Join Date: May 2015
Posts: 772
Default Re: 650 twin spark - tough starting the morning after

Quote:
Originally Posted by embee View Post
I know my (old) Yaris can suffer from this if I start it when just part warm and stop it again, the next cold start can be a pig.
A lot of cars get this, especially those with hydraulic tappets. The tappets can pump up and keep the valves off their seats, so there's not very much compression when trying to restart. My old Mondeo did it.

It's called 'lawnmower syndrome' (people starting their cars so they can get the lawnmower out of the garage)
Craig380 is offline   Reply With Quote
Old 17-02-19, 04:48 PM   #12
aesmith
Member
 
Join Date: Mar 2013
Location: Aberdeenshire
Posts: 918
Default Re: 650 twin spark - tough starting the morning after

Cheers. I'm surprised that a couple of weeks out of use is long enough to require special handling before startup. My bike's normally used every weekday, but is out of use for a couple of weeks at a time when we're off work, or most recently because our track was impassible.

The plug fouling theory sounds plausible. I would have though over fueling would have dispersed overnight.

So the question is how warm is warm enough to avoid these issues? Typically it would arise for me if the bike needs to be moved from the shed to the garage and I can't face pushing it up the slope. Or running a few minutes to check the Scottoiler is working.

Hope the answer isn't "until the fan runs", I don't think I've ever got the bike that hot either in the shop or when riding.
aesmith is offline   Reply With Quote
Old 20-02-19, 12:00 PM   #13
embee
Member
Mega Poster
 
embee's Avatar
 
Join Date: Jul 2003
Location: Warwickshire
Posts: 2,671
Default Re: 650 twin spark - tough starting the morning after

If you do get soft carbon build up on the plugs it will "dry" but it's like a sponge so as soon as it next fires up from cold it soaks up the condensation and is way more prone to foul. To self clean effectively the plugs need to be up to something like 300C and running in a non-rich mixture regime, best achieved by allowing the engine to warm for at least a couple of minutes then holding the speed steady at around 3000rpm typically for another 30sec or so. That should be enough to be sure of avoiding repeated cold foul issues. It's not the rich fuelling per se, although that is what produces the carbon/soot, but the condensation of the water from combustion mixed with the soot which is the problem.

With any modern engine it is usually best practice to do starts "un-assisted", i.e. don't touch the throttle, and wait for something like 10sec after starting before using the throttle at all. Sure it isn't always essential, but that's usually the best way to avoid issues.
No need to run it until the fan starts, just until the plugs are hot enough, and rpm is the primary factor here.
__________________
"Artificial Intelligence is no match for natural stupidity"
embee is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
WTD: Twin Spark 650 Engine Markos_46 Stuff Wanted 0 11-08-15 08:06 AM
SV650 K7 Twin Spark Bibio For Sale - SV's and SV related items 11 26-06-14 02:18 PM
Sv k8 engine twin spark 500 payner123 For Sale - SV's and SV related items 0 08-11-13 10:01 PM
pic of a twin spark sv 650? suzuki139 SV Talk, Tuning & Tweaking 6 28-07-11 08:32 AM
tough starting in the morning svinjected SV Talk, Tuning & Tweaking 13 14-07-11 07:10 AM


All times are GMT. The time now is 12:56 AM.


Powered by vBulletin® - Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.