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Author: Subject: 93 Carbed Blade won't start when hot
andyfiggy2002

posted on 18/7/14 at 10:46 AM Reply With Quote
93 Carbed Blade won't start when hot

Runs & started fine hot or cold last 10 years, in April replaced Pipercross open air filter with pipercross air box/ filter combi to get induction DBs down for spa & the ring. Gave it the beans & Engine behaved flawlessly at spa/ ring where temp got up to sunny 17 degrees.....however ever since I've been having hot start problems? Have I overcooked something I ask??

Symptons...when engine is hot like after I've filled up with fuel or I've left it standing for 10 mins after a blat it's a real bitch to get going, sometimes will catch & fire up really reluctantly using plenty of right foot peddling or if battery exhausted I have to get out & bump start. Starts fine if I let it cool down for a couple of hours or when it's cold then it just needs a little choke in this hot weather to start 1st time. Fitted new battery, coils, HT leads, plugs....battery charging ok. Honda Fuel pump seems to prime & run ok. Fan kicks in as normal & gauge indicates nothing abnormal. No hiss when I open up fuel cap indicating breathing ok. Carb bowls drain ok, only thing is it is a bit lumpy on idle which I suspect carbs need synchro. Oil press seems lower than normal so maybe I have over cooked it but no excessive smoke of any kind out of exhaust & engine still pulls like a train, oil consumption still frugal, plugs normal tan colour however when cold I pulled all ht leads & turned engine over I expected to see wet plugs but didn't?? Fitted leads again & started ok???? ... I now dread filling up for petrol....Plse help anyone

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johnnybizzle1986

posted on 18/7/14 at 11:50 AM Reply With Quote
Hi,

Ive got an 89 cbr1000F engine in my haynes roadster, and I had the same problem, I'm putting it down the the engine been old/tired and having low compression (about 25k miles on the engine) I put a MotoBatt battery on it with a bit more cranking power and trimmed the ends of the HT lead as mine were a bit knackered and it seems to work for now.

have you tried going back to your old air filter/airbox setup, might be abit lean at tickover or something?

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teegray19

posted on 18/7/14 at 12:15 PM Reply With Quote
Regulator/rectifier problems? Seems to be a common Honda fault..





Built Formular 27 with 1600cc crossflow, 1700cc 0 miles crossflow, Kawasaki ZZR1100

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andyfiggy2002

posted on 18/7/14 at 12:36 PM Reply With Quote
Dynojetted so carbs have been up jetted, motobatt is fitted & did oil & plug change when got back to UK, would burnt valves make it difficult to start when hot? But no smoke or noise, oil & fuel & coolant consumption ok

& has PC fan blowing on cbr1000 reg/rec, battery is charging, fuel pump runs ok & starts from cold ok?

andy bates, where are u....lol




[Edited on 18/7/14 by andyfiggy2002]

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teegray19

posted on 18/7/14 at 01:00 PM Reply With Quote
Have you done a compression test?

Haynes manual will tell you the limits, do the test WOT rules out valve cylinder problems then? Halfrauds normally have the kits in for 20/30 quid





Built Formular 27 with 1600cc crossflow, 1700cc 0 miles crossflow, Kawasaki ZZR1100

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40inches

posted on 18/7/14 at 01:02 PM Reply With Quote
Mine does almost exactly the same thing, but switching the ignition off then on, it fires up straight away






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andyfiggy2002

posted on 18/7/14 at 01:10 PM Reply With Quote
Would low compression make it hard to start from hot but not affect performance or cold starting?
& I assume ignition switching trick is turning fuel pump on/off therefore giving a bit more pressure?

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40inches

posted on 18/7/14 at 01:15 PM Reply With Quote
quote:
Originally posted by andyfiggy2002
Would low compression make it hard to start from hot but not affect performance or cold starting?
& I assume ignition switching trick is turning fuel pump on/off therefore giving a bit more pressure?


If I keep trying to start it, there is a strong smell of petrol, switch ignition on/off it fires with a bang in the exhaust
If it doesn't fire first time, ignition trick and it fires immediately. Weird!






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andyfiggy2002

posted on 18/7/14 at 01:57 PM Reply With Quote
No smell of fuel but sometimes I get a backfire when I've struggled to start it hot, self regulating fuel pump on its last legs maybe?
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teegray19

posted on 18/7/14 at 03:49 PM Reply With Quote
I bet it's the fueling being thrown out by the new induction set up.

Return to old set up, if it's sorted get the carbs set up again.

You could try a pump and igintion switch but nothing's been changed there so seems strange.

Mine was running mega ritch with a differ t air box on, rejetting and correct air correctors sorted all starting running issues.

And more power! Worth a try.... Might be running leaner with differnt airbox. Running hotter, harder to start?

My ten pennies worth.





Built Formular 27 with 1600cc crossflow, 1700cc 0 miles crossflow, Kawasaki ZZR1100

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mark chandler

posted on 18/7/14 at 04:49 PM Reply With Quote
When I removed the original filter on my 893 it ran badly, doing the exhaust just made it worse until I fitted a dynojet kit which resolved things.

They can be very temperamental to start, filling the gap on the plugs helped mine, have a google you file the tang so it only covers half the electrode which provides a less shrouded spark.

Duff plugs will stop them dead.

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andyfiggy2002

posted on 18/7/14 at 06:26 PM Reply With Quote
That's annoying, I stuck pipercross air filter back on & it has cured the problem I guess a bit like having a winter & summer setting on your air filter on an ordinary production car, spa/ ring in April was 1 degree at night & 17 degrees during day so not as hot as it is here in UK this humid summers day. oil press gone up to which is a bonus. So any ideas how I can use this air box in summer to quieten down induction noise considering I've got 132 jets in already or can I only use it during winter?
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40inches

posted on 18/7/14 at 06:55 PM Reply With Quote
quote:
Originally posted by andyfiggy2002
That's annoying, I stuck pipercross air filter back on & it has cured the problem I guess a bit like having a winter & summer setting on your air filter on an ordinary production car, spa/ ring in April was 1 degree at night & 17 degrees during day so not as hot as it is here in UK this humid summers day. oil press gone up to which is a bonus. So any ideas how I can use this air box in summer to quieten down induction noise considering I've got 132 jets in already or can I only use it during winter?


A rolling road session will sort it out. Bike carbs can be very sensitive to any change, it needs setting up for your new induction.
Mine won't start without a silencer fitted






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rick1962uk

posted on 18/7/14 at 07:04 PM Reply With Quote
have you checked the valve clearance
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andyfiggy2002

posted on 18/7/14 at 09:50 PM Reply With Quote
Ok comments noted & appreciated guys
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