scrappy600 Posted March 7, 2011 Report Share Posted March 7, 2011 Came across a wee problem with the new racebike at Mondello yesterday, someone might recognise it and shed some light on the cause. Basically it won't tickover when hot, it'll tickover in the paddock fine before a session and sitting in pitlane no issues at all. During a session it drives on fine, no issues at all, temps go to about 90º - ish when on track, it's when i come back into the paddocks after the session and pull in the clutch to coast to the garage then the revs fall to tickover and it seems to just smother itself. It will turn over grand and catch if i try start it again but if i let the revs drop to tickover it dies again. Don't know if its related or it just needs to be adjusted to suit me but i thought in around the paddock cold or hot the clutch was quite 'grabby' and very prone to stalling easily compared to the road bike. Bike is an 03 /cbr 600rr, only extras are slip on and bmc air filter, no power commanders or quick shifters or anything. Link to comment Share on other sites More sharing options...
scrappy600 Posted March 8, 2011 Author Report Share Posted March 8, 2011 It's mostly in neutral and sitting after comin in from a session when it won't idle. Gears engage fine, didnt notice any issues with them at all. Its only got a slip on and filter could that cause fuelling to run rich? Is then, a pc111 the only way to rectify it? Link to comment Share on other sites More sharing options...
lorenzo Posted March 8, 2011 Report Share Posted March 8, 2011 If it was lean it'd raise the revs, not drop them. The fact that it happens only when it's hot is what's confusing me. What sort of temps are we talking, do you have a guage on your bike? It might, and this is a real long shot, be due to the increased pressure when your coolant's close to boiling? I'm guessing you don't run a fan as it's a race bike? Link to comment Share on other sites More sharing options...
cagimaha Posted March 8, 2011 Report Share Posted March 8, 2011 I'd be tempted to suggest either an air leak between the carbs and the head (either the intake rubbers or possible a cracked head) or valve clearances being too tight so when it gets hot there isn't actually a clearance and the valve isn't closing causing a loss of compression. To check for the air leak get the bike hot enough for the symptoms to happen and spray something mildly flammable (WD40 is a good one) around the intake rubbers and see if the revs change. To check for the valve clearance issue the easiest way would be to whip the cam cover off and check them with a feeler gauge but I guess you could also try a compression check when it's hot and see if it shows anything untoward. Link to comment Share on other sites More sharing options...
Evilchicken0 Posted March 8, 2011 Report Share Posted March 8, 2011 If it's an 03 CBR RR then isn't it an injection bike ???? If so it could be a sensor that changes the mixture due to the hot / thin air ... or maybe the fuel's evapourating before getting to the engine. I'd have a look at maybe getting the bike to run hot on a dyno so it can be plugged into a dyognostic. After that maybe you need to do some heat management http://cgi.ebay.co.uk/Fairing-Panel-Exhaus...=item2c5b488640 Stick this under the bodywork and also to the ecu to keep the heat out of it. Link to comment Share on other sites More sharing options...
banoffee Posted March 8, 2011 Report Share Posted March 8, 2011 my gsxr had this exact same problem only when hot. turned out to be a cracked spark plug cap that would arc out only when hot and expanded... Link to comment Share on other sites More sharing options...
scrappy600 Posted March 9, 2011 Author Report Share Posted March 9, 2011 Thanks for the replies guys, i've checked the owners manual and it's idling at 1100 revs, manual says it should be 1300 +/- 100 so will raise it but i dont think that would cause it to idle fine when cold but not when hot. I'll change out the plugs as banoffee suggested and might remove the PAIR system also to see if itll smooth it out. Will do a track day after that and see if the problem persists, after that i'll have to get the valve clearances done and see if thats got anything to do with it. Only 15'000 on the clock though and its only seen a years track use, didnt think the clearances would be that badly out so soon.......... Link to comment Share on other sites More sharing options...
banoffee Posted March 9, 2011 Report Share Posted March 9, 2011 for me it was the plug caps (part of the HT leads) not the plugs themselves... though new plugs are always nice Link to comment Share on other sites More sharing options...
scrappy600 Posted March 10, 2011 Author Report Share Posted March 10, 2011 But it will cause problems.... Until the engine coolant is good and hot the idle fueling will be chucking loads of extra fuel in to allow it to idle, as the coolant temp rises it will lean out. If the amount of fuel going in won't support a steady idle with the amount of air going in due to the throttle opening you've got then it will stall because the crank inertia won't be enough to overcome 2 cylinder's compression, end of. If you raise the idle speed the crank has more inertia and it will idle. If it's a track bike then a higher idle rpm is a good thing anyway. Don't forget that the idle speed should normally be set with the engine coolant good and hot - if you've got the fan still fitted let it come on and off a couple of times. Thanks for the advice, makes sense to me now that i've read it a couple of times, you can tell i'm new to this can't you!!! The idle control knob on the side is turning but with no resistance and the revs aren't moving so its either been disconected by the previous owner or its become loose itself so ill have to strip her down and see where it connects to, hopefully raising the tickover will solve it! Link to comment Share on other sites More sharing options...
scrappy600 Posted October 24, 2011 Author Report Share Posted October 24, 2011 Just to put this to bed, the idle/mixture control screw was wound fully out and once returned to standard settings plus a few extra revs for the track she's ticking over sweet as a nut and is now popping and rumbling nicely on the over run too! Thanks all for the help! Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 24, 2011 Report Share Posted October 24, 2011 Just seen this... What rpm is your tick over set to at the moment? You're lucky enough to have a manual knob to adjust it, on mine you need a HRC ECU & Loom plus the PGMFi setting cable... You'll want it set a fair bit higher than standard for track focused riding. Link to comment Share on other sites More sharing options...
scrappy600 Posted October 25, 2011 Author Report Share Posted October 25, 2011 Just seen this... What rpm is your tick over set to at the moment? You're lucky enough to have a manual knob to adjust it, on mine you need a HRC ECU & Loom plus the PGMFi setting cable... You'll want it set a fair bit higher than standard for track focused riding. Eh, I'm not 100% certain what it's at and I've the bike stripped for next season at the mo, but I'm aaaalmost certain I brought it to just under 2000 rpm at hot tickover. Works fine for me anyway, to be honest I'm not setting fast enough lap times to need anything more than standard so it'll remain that way for me at least with this bike anyway. Link to comment Share on other sites More sharing options...
Cibbersicks Posted October 25, 2011 Report Share Posted October 25, 2011 You'll want a higher tickover for slower corners, especially with a 600, to keep the thing spinning a little more, to get on the gas closer to the sweet spot on the way out of the turn. Ten Kate set their 600rr's to 2200rpm - see HERE Link to comment Share on other sites More sharing options...
scrappy600 Posted October 25, 2011 Author Report Share Posted October 25, 2011 Is there any issue in having tick over that high on a bone stock engine with stock management? Link to comment Share on other sites More sharing options...
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