Gergely
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| posted on 16/11/09 at 08:57 AM |
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R1 revs not dropping quickly enough?
Hi,
Got the 5VY (2005) R1 engine back in tha car again... it had its valves replaced, since the originals were faulty ones.
Anyway, test driven the car this weekend, the engine is sweet, runs very nicely.
But when I take my foot off the accelerator pedal, and depress the clutch, the engine spins up and only drops back to idle quite slowly. Each
gearchange (with the clutch - when cruising) whenever I depress the clutch, the same thing.
I checked the pedal, it is not sticking, and returning nicely... the same thing with the accelerator cable.
What can it be? Any ideas? It surely wasn't the case before the engine has been taken out...
Thanks!
Gergely
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ko_racer
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| posted on 16/11/09 at 09:11 AM |
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Sounds like the idle is set too high (most likely), or you have an air leak between engine and tb's
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Peteff
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| posted on 16/11/09 at 10:01 AM |
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Have you got a return spring at the engine end ? I had to fit one to my ZX9 engine even though it looked to return quickly without, it was not enough
in practise so I had to rig a bracket and spring to stop it from staying about 3000 rpm
[Edited on 16/11/09 by Peteff]
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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smart51
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| posted on 16/11/09 at 10:22 AM |
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Too much air or fuel getting into the engine, holding the revs up. Check the throttle butterflies close quickly and fully when you take your foot off
the pedal. Check for air leaks on the inlet tracts.
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Dangle_kt
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| posted on 16/11/09 at 10:43 AM |
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quote:
Originally posted by Peteff
Have you got a return spring at the engine end ? I had to fit one to my ZX9 engine even though it looked to return quickly without, it was not enough
in practise so I had to rig a bracket and spring to stop it from staying about 3000 rpm
[Edited on 16/11/09 by Peteff]
that was it exactly on mine, all semmed well, but I swapped the spring for a more heavy duty one and had no problems since. Easy to sort to, so best
try there irst before checking for air leaks which isn't easy.
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Gergely
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| posted on 16/11/09 at 11:25 AM |
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Cheers guys, I will have a good look.
The idle should not be the issue, if anything, it is set lower than it was before.
Anyway, I will check the return spring and the air leaks, too, and will let you know - but it won't before the weekend.
Cheers!
Gergely
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Chippy
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| posted on 16/11/09 at 11:41 AM |
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If you need to check for air leaks, with the engine ticking over, spray some carb cleaner, or easystart around the inlet tracts, if you have a leak
the rev's will rise as it sucks in the spray. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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ReMan
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| posted on 16/11/09 at 12:38 PM |
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As above, the standard carb return spring was not designed to pul back a larger heavy cable and the weight/resistance of the pedal setup
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smart51
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| posted on 16/11/09 at 01:03 PM |
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Just remembered - I had this once and it turned out to be a frayed accelerator cable. It was just a bit too sticky to close the throttle quickly.
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road warrior
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| posted on 16/11/09 at 01:14 PM |
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Hi Gergely
There is a small plunger near the bottom of the throttle bodies on each side. These are attached via a linkage to the thermowax. The thermowax ports
tend to get corroded up or it may have a air lock.
If it is idling high and not returning very quickly this is most likely your cause.
It won't need adjusting just a clean. Email me if you need more info.
Cheers
Sonja
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mad-butcher
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| posted on 17/11/09 at 08:23 PM |
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If it didn't do it before,then it points to an air leak or possibly the throttle cable hasn't been routed in exactly the same position ie
a tighter bend in it
tony
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Gergely
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| posted on 30/11/09 at 11:24 AM |
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Thanks guys for all the responses. We tried to rev the engine in neutral to see if this happens, and the revs dropped fairly slowly again. It turned
out after some fiddling that when we installed the throttle cable, we have tightened it too much, without leaving enough free play in it. The last mm
or half of return travel was slow and it didn't allow the engine to go back to idle quickly enough...
It seems fine now in neutral, but the stupid rain and fog means I couldn't test drive it yet... Maybe tonight!
Thanks again all!
Gergely
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Gergely
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| posted on 1/12/09 at 08:17 AM |
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Got out for a half an hour blast last night - I didn't realise that the roads are this empty at night...
Something to keep in mind from now on I guess...
The revs drop nicely back to normal, so it seems that it really was only the stupid mistake of not allowing enough free play in the throttle cable.
Thanks all!!
Gergely
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