Gen 1 high revs from start up
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Category: RSV / RSVR / FACTORY
Forum Name: Technical Chat
Forum Description: Any technical problems or useful advise for other owners, remember this is just advice posted here, if you make something go BANG in a big way don't take anyone to court about it.
URL: http://www.rsvr.net/forum_posts.asp?TID=30009
Printed Date: 27 Mar 2026 at 02:25
Software Version: Web Wiz Forums 12.07 - https://www.webwizforums.com
Topic: Gen 1 high revs from start up
Posted By: Steve750
Subject: Gen 1 high revs from start up
Date Posted: 26 Aug 2023 at 18:37
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Hi all, As soon as i start the bike, the revs go to about 2k rpm.I've tried adjusting the idle control screw but this makes no difference at all. The choke doesn't make any difference whatsoever either. Could it be a stuck choke cable or stuck throttle cable...although the throttle goes back to its seating point when it's let go. Obviously I don't want the bike revving it's nuts off from cold.whilst I try to figure out what's wrong somewhere. Thanks guys
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Replies:
Posted By: Bladerunner919
Date Posted: 26 Aug 2023 at 18:46
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Does the choke lever have any effect - ie, can you increase the revs with it and then reduce back to 2k? |
Posted By: Steve750
Date Posted: 26 Aug 2023 at 18:48
| No mate, no effect at all |
Posted By: camngetit
Date Posted: 26 Aug 2023 at 19:36
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Do the revs drop when warm or is it always at 2000rpm You need to take the airbox off and see whats happening with the gast idle and throttle mechanism, ------------- its twins for me !!!! www.apriliaperformance.co.uk www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
Posted By: Steve750
Date Posted: 26 Aug 2023 at 20:24
| I'll take it apart tomorrow and have a look....didn't get it up to temp |
Posted By: Spoonz
Date Posted: 26 Aug 2023 at 20:54
| There is no choke it’s just a fast idle lever that holds the throttle partially open. If the lever has no effect, it probably means that the throttle is already partially open. Most likely a cable issue |
Posted By: redratbike
Date Posted: 26 Aug 2023 at 21:56
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yep tank up airbox off take a look at that fast idle mech -------------  |
Posted By: Steve750
Date Posted: 26 Aug 2023 at 22:16
| Wicked...thanks for the help guys!....I'll whip it off in the morning and have a look! |
Posted By: Steve750
Date Posted: 27 Aug 2023 at 15:17
| When the fast idle lever is used, shouldn't he butterflies in the airbox open slightly? Them obviously do when the throttle lever is pulled |
Posted By: Spoonz
Date Posted: 27 Aug 2023 at 15:58
| Not checked the butterfly position to say for sure but idle systems usually uses bypass ports which don’t require the butterflies to move as the amount of air required to adjust idle is tiny compared to when your accelerating. I suspect it’s 2 stage, so depending on the throttle plate position it starts using the bypass circuit and at a certain throttle position it opens the butterflies. |
Posted By: Steve750
Date Posted: 27 Aug 2023 at 16:01
| Yes....that would make sense mate. I've removed the upper air box half and undone the lower...just need to pull the thing off carefully now....does the airboat come away with the lower box? |
Posted By: Stevex
Date Posted: 27 Aug 2023 at 19:04
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The air boot is held onto the bottom of the air box by a large jubilee clip, it's easier to undo the clip and remove the lower airbox, then the air boot. From what I remember, the idle adjustment rotary knob under the right of the tank adjusts the idle stop. The fast idle lever merely raises the throttle mechanism slightly and when knocked off the mechanism returns onto the idle stop. The throttle obviously has full control over the mechanism and when shut, returns the mechanism to the idle stop. Should all be fairly obvious once you've gained access to the mechanism. When you get access to the throttle body, it's worth checking the small hoses carefully for cracks or splits.
------------- People say I don't know Jack Sh1t; but I do, he lives next door. |
Posted By: Spoonz
Date Posted: 27 Aug 2023 at 21:11
Update. Checked with af1 guys. The idle air is bypass. The idle adjustment screw and the fast idle lever open the throttle slightly if the bypass amount cannot hold idle. ( cold start etc) He did say that if the bypass screws are set far enough off it can create a high idle that the idle screw won’t be able to adjust down as it has no control over bypass. So if the cable operation seems normal, note the current bypass screw positions by seeing how far out they are set. Then see if they are set oddly. You can see the bypass holes above the butterflies which look closed on this tb. Bypass screws are on the other side of the tb)  |
Posted By: Steve750
Date Posted: 28 Aug 2023 at 11:53
| Morning....so, I've accessed the TB's and no movement can been seen at all when moving the FI lever. I've also noticed that the idle adjuster isn't touching anything so no adjustment can be made...I'll see if I can get a picture. Next to the idle adjuster is a blew screw which I won't play. |
Posted By: Prsv
Date Posted: 28 Aug 2023 at 13:19
This. Check cables are moving freely lubed and there's no binding in the body linkage.
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Spoonz wrote:Posted By: redratbike
Date Posted: 28 Aug 2023 at 13:44
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whilst there make sure the butterfly’s are secure , re-locktite if needed as the screws are known to come loose ------------- |
Posted By: Steve750
Date Posted: 28 Aug 2023 at 18:38
| Apologies for being not very clever, but where does the cable run to on the TB's? I'll remove the cable and make sure it's well lubed but first I need to see where it attaches...I just can't figure where it goes 🤦 Good old Haynes doesn't exactly help either. |
Posted By: camngetit
Date Posted: 29 Aug 2023 at 19:15
This is interesting as mine is fine on fast idle on the lever ie cold start but for a long time i cant get the idle when warm down below approx 1000rpm as the idle screw doesnt touch the stop so maybe i need to tweek the bypass screws ,although i normally have it set abit high so not that fussed if not ------------- its twins for me !!!! www.apriliaperformance.co.uk www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
Posted By: Steve750
Date Posted: 29 Aug 2023 at 19:26
| That's the same as mine....it doesn't touch anything to adjust. |
Posted By: Spoonz
Date Posted: 29 Aug 2023 at 22:21
| The idle speed ls meant to be 1250 +/- 100rpm. Hence why you may not get it below 1000rpm without strangling the bypass air. big lumpy twin, they don’t like low idle speeds. |
Posted By: legend88
Date Posted: 30 Aug 2023 at 13:40
I was about to say this, mine idles at about 1300rpm and suits it fine.
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Posted By: Steve750
Date Posted: 30 Aug 2023 at 20:17
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Any pics of where the fast idle cable runs to guys? |
Posted By: camngetit
Date Posted: 30 Aug 2023 at 21:46
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I'll leave it then that was easy lol ------------- its twins for me !!!! www.apriliaperformance.co.uk www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
Posted By: Spoonz
Date Posted: 30 Aug 2023 at 22:38
I presume you mean where it goes to at the tb? Where the big red arrow is.  |
Posted By: redratbike
Date Posted: 30 Aug 2023 at 23:43
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surely you can see where the cable runs or see it move when the lever is pulled ------------- |
Posted By: Steve750
Date Posted: 31 Aug 2023 at 21:46
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Thanks Red....nothing moved at all when lever was pushed back and forth so that pic really did help! Stripped lever assembly apart and the cable was fine until I pulled it myself...and then it snapped....it was rusted so that's why it did nothing. I slackened the cold start assembly at the TB end and the butterflies closed ever so slightly so I'm in hope it'll run gently when I start it tomorrow morning.....a little too late tonight! Thanks all 👍🏻
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Posted By: redratbike
Date Posted: 31 Aug 2023 at 23:00
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well i suppose after all these years something is bound to break/corrode etc hopefully now you have found this t should sort your issues ------------- |
Posted By: Steve750
Date Posted: 06 Mar 2024 at 15:07
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Hi all, Just to keep you updated in case someone else has this issue with an old bike that's been standing a while. The fast idle cable was rusted complete in the sleeve so a new one was fitted and it now starts good as gold and ticks over beautifully. The Arrow can that's fitted about blew my shelves off the wall though 😏
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