richard thomas
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| posted on 10/6/06 at 03:06 PM |
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Vapour lock??
Hi guys,
as per the post on SVA forum, past the MOT today. But had problems starting it when it was hot, and on the way home is was missing like hell around
5000, couldn't give it any more throttle to get through it..kangerood all the way home, quite embarrasing
I haven't got a lot of vents in the bonnet so i suppose seeing as it was a scorcher today the under bonnet temperature might have been quite
high! I'm thinking of cutting a hole above the filter to see if that helps...
The question is, are bike engines normally prone to hot starting problems? Or do i have a stinker on my hands??
All advice greatfully received.
Rich.
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ChrisGamlin
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| posted on 10/6/06 at 04:00 PM |
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Does the fuel line run past anything particularly hot, cos Id think something like that would more likely cause vapour lock than general hot weather
conditions. Also have you got a breather in your tank, otherwise it will be pulling a vacuum when pumping so will start to cause problems after a
certain time running, but not immediately.
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richard thomas
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| posted on 10/6/06 at 04:12 PM |
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Not really, but i do have a 1 litre fuel swirl pot under the bonnet which feeds the standard bike pump just under the throttle bodies. The swirl pot
is fed by and returns to the main tank at the back. I suppose the fuel in the pot could get warmish from under bonnet temp.
The other thing i'm thinkng - the airbox on a busa is fed by ram air ducts, so the engine never really has to deal with intake air as hot as it
must have been today...i am using a sausage filter. Do you think this could contribute??
Cheers, Rich.
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richard thomas
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| posted on 10/6/06 at 04:15 PM |
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Sorry, i should add that the main tank at the rear does have a vent...this feeds the swirl pot via a low pressure pump so the swirl pot is constantly
full, like a constantly recirculating system. It gives the bike pump a head of pressure.
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stevebubs
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| posted on 10/6/06 at 04:17 PM |
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standard underbonnt temps shouldn't cause vapour locks unless, as Chris has already mentioned, you're routing close to something you
shouldn't
When sat idling in full sunshine yesterday, my Fury was reading about 50C under the bonnet without any running problems, and I'm also running an
underbonnet swirlpot.
[Edited on 10/6/06 by stevebubs]
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richard thomas
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| posted on 10/6/06 at 04:22 PM |
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wonder if i should change the plugs...
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ChrisGamlin
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| posted on 10/6/06 at 04:30 PM |
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Loads of busa's run with sausage filters so I wouldnt have thought so, but if not running a PowerCommander I do believe they generally up the
fuel pressure a bit to compensate for the additional breathing of the sausage filter.
Also, I assume the LP pump can keep up with supply to the swirl pot can it, its not running low with sustained engine running?
Also maybe check each plug and see if one is running differently, maybe its a bit of crud got into an injector or something?
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richard thomas
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| posted on 10/6/06 at 04:49 PM |
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Thanks, i'll check that. The thing is, it was intermittent, did a couple of miles today and it was only the last 1 1/2 miles that it played
up!!
Even trying to hold 5000 in neutral had it missing down to 3000 and back up again, like it was hunting,you know - barp,barp,barp (sorry for crap
description of noise:-))...wonder if it is the plugs getting hot? If it was something more serious it would do it all the time surely?? Seems ok now
it's cooled down this afternoon.
Rich.
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ChrisGamlin
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| posted on 10/6/06 at 04:58 PM |
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One other thing Ive just thought of, have you got the air temp sensor connected up and in the right position, the one thats in the airbox on the bike?
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richard thomas
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| posted on 10/6/06 at 05:28 PM |
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Yup, i've got it on the base plate of the sausage. Now the thing is cold it's running sweet...
Just went out and gave the plugs a check - teeny bit sooty so have cleaned off - i've seen worse but they weren't " Haynes Manual
Brown" if you see what i mean. Think i'll change them in case they are breaking down with heat.
What grade is recommended?? any demon secrets?
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G.Man
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| posted on 11/6/06 at 06:51 AM |
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Sounds like your power commander needs mapping better to me...
Opinions are like backsides..
Everyone has one, nobody wants to hear it and only other peoples stink!
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richard thomas
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| posted on 11/6/06 at 08:55 AM |
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Uummm...i don't have a power commander - are they essential for bec installations??
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zxrlocost
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| posted on 11/6/06 at 09:45 AM |
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so how did you get through the emissions mate at the MOT?
or didnt you do an emissions test
have you modded the engine in anyway
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richard thomas
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| posted on 11/6/06 at 10:03 AM |
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I have a westfield megabusa silencer which has the cat fitted. The figures came down to acceptable ones for a '99 in the opinion of the tester.
Maybe i should be recommending him to you all...as i said earlier, he was telling me that a kitcar doesn't have to meet emissions and i
wasn't about to correct him!! But i did ask him to check that it would pass and it did!!
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richard thomas
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| posted on 11/6/06 at 10:05 AM |
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Sorry, i should add that the engine is standard apart from megabusa exhaust system and sausage filter.
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zxrlocost
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| posted on 11/6/06 at 10:47 AM |
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mate hes talking shite
any bike engine kit car with an engine after 1995 must meet a standard CAT test at SVA
doesnt make any difference being 99 aFAIK
people have struggled with a CAT and a Power commander never mind just a standard engine with CAT
what readings did you get
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DIY Si
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| posted on 11/6/06 at 10:56 AM |
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Once registered, and assuming you have a Q plate, then you only have a visible smoke test, ie no emissions test. However, the sva man will do a full
cat test which you will have to pass to get the mac and therefore get registered.
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zxrlocost
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| posted on 11/6/06 at 11:00 AM |
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thats what I also meant for the SVA
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DIY Si
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| posted on 11/6/06 at 11:14 AM |
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That's one of the really stupid things about the sva. My car will have a q plate due to being a collection of bits., so once road legal I can do
what I like to the engine, but to get on the road in the first place I have to pass an emissions test! Welcome to the world of the men in grey and red
tape!
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richard thomas
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| posted on 11/6/06 at 11:25 AM |
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He ran me though the figures, there were 6 on the machine. He did say that there was a bit too much oxygen but put it down to the fact that he
couldn't get the probe into the tail pipe very far due to the bend!!! The rest fell in but took around 20 seconds after holding it at 4000rpm to
come in...
The only thing that is on the engine that might make all the difference on a busa is the PAIRS system - it injects clean air into the exhaust manifold
to help burn off excess unwanted gases before they hit the cat.
The thing is, westfield get their megabusa's through SVA using exactly the bits i'm using so i would have been shocked if it had been way
out anyway??
What should the readings be for a cat test?? I meant to write them down at the time but......
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richard thomas
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| posted on 11/6/06 at 11:53 AM |
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quote
'mate hes talking shite
any bike engine kit car with an engine after 1995 must meet a standard CAT test at SVA '
sorry, i should clarify, he was talking about the mot, not the sva.
Rich.
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zxrlocost
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| posted on 11/6/06 at 01:50 PM |
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well the test will be done at idle and at 2500rpm-3000rpm better for you if you hold it at 2500rpm
motorbike emissions are sky high due to the power of the small engine and other things
but in the bike it wouldnt have had an emission test
your CAT will bring down the CO it wont affect the HC or lamda that much
I know of two people who have had cats on there hayabusa engine and had the power commander set on best for emissions and still struggled
If you pass the things then thats wicked but just expect it to be a pain in the ass with emissions and noise especially with a sausage filter
I think you need to get some more readings on your emissions
one at idle then one at 2500rpm
I thinks its only the CO reading at idle but all three readings at 2500rpm not 4000rpm
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zxrlocost
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| posted on 11/6/06 at 01:56 PM |
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readings should be
tickover
CO 0.3 max (he told me 0.5 on the phone when i was setting up but Im just looking at my result sheet and it says 0.3 max) I got 0.00 for that
fast idle
CO 0.2 max on this result sheet(he told me 0.3 again when i was setting up)
I got 0.00 again
HC max 200 I got 106
LAmda 0.97-1.03
I got 1.03 fewwww!!!!!!
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zxrlocost
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| posted on 11/6/06 at 01:59 PM |
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PS If the SVA bloke cant get the probe up the exhaust properly youll put him in a mardy PAP straight away
dont give them anything to feed off or they will they think there special and start being petty
I had the same problem
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richard thomas
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| posted on 11/6/06 at 03:56 PM |
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I remember that the lambda was 1.02...but that was at idle after holding at 4000 for a bit. If the lambda is in should the rest of the readings be
close? Think i've got the idle set a bit high too.
I seem to remember that the hotter the cat is the better it works?
Rich.
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