Problems when revving :(

Printable Version

CBR Forum >> Past CBR Models >> CBR 900RR >> Problems when revving :(

Page: [1] 2 3   next >   >>

Login Message << Older Topic   Newer Topic >>

Problems when revving :( - 3/13/2008 7:28:52 AM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline I have a 98' blade When it start up it starts first time but there is a serious problem. I can ref it up to about 6000rpm and then I keep the throttle steady. It then keeps on going up and down between 2000rpm and 6000rpm without me even moving the throttle. So it it's kind of revving up and down by it self with me just keeping the throttle open.(its very freaky seeing the bike revving up and down by itself)  Keep in mind that all the time I'm still just keeping the throttle in the position where it would normally be running at 6000rpm. I thought diaphrames on the carbs but they all seem ok. The thing is when I got the bike I just started it and never revved it high. Then I stripped the carbs and cleaned them. So I don't know if it was doing this before I stripped the carbs(I didn't split them though). (maybe I messed up something) Any ideas ? _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! Post #: 1

RE: Problems when revving :( - 3/13/2008 7:50:46 AM    gixxereater   Posts: 1487 Joined: 5/23/2006 Status: offline Did you try new plugs? LOL _____________________________ Ambition is a poor excuse for not having enough sense to be lazy (in reply to gerharddvs) Post #: 2

RE: Problems when revving :( - 3/13/2008 7:51:58 AM    gixxereater   Posts: 1487 Joined: 5/23/2006 Status: offline Vacum leak? _____________________________ Ambition is a poor excuse for not having enough sense to be lazy (in reply to gixxereater) Post #: 3

RE: Problems when revving :( - 3/13/2008 10:53:31 AM    Manic Posts: 169 Joined: 2/22/2007 Status: offline You'll have to let us know what you find, when you pull the carbs back apart.  Make sure all the diaphrams are seated correctly, and all the springs are in place. (in reply to gixxereater) Post #: 4

RE: Problems when revving :( - 3/13/2008 1:09:33 PM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline I've got another 2nd hand set of plugs that came out of my 600 with the last service.I'll first try them and if it doesn't work I'll strip the carbs. Dont think it's anything series like valves _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! (in reply to Manic) Post #: 5

RE: Problems when revving :( - 3/16/2008 9:15:01 AM    Jarrod Franklin   Posts: 23 Joined: 1/15/2008 Status: offline sync your carbs (in reply to gerharddvs) Post #: 6

RE: Problems when revving :( - 3/16/2008 3:25:59 PM    DukeCBR Posts: 262 Joined: 3/1/2008 From: Cape Town, South Africa Status: offline yeah sync your carbs dude, seems like the carbs are fighting against each other in cycles _____________________________ 1993 Honda CBR 900RR Fireblade Steering Damper DynoJet Stage 1 Kit Twin Race Foam Filter Hindle pipe (in reply to Jarrod Franklin) Post #: 7

RE: Problems when revving :( - 4/2/2008 3:20:49 AM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline So I checked everything you guys mentioned. The diaphragms are fine and I changed the spark plugs but I still doesn't work. I checked the butterflies on the carbs (visually) and they seem to open more or less at the same rate when you pull the cable so if the sync is out, it's very little. It also seems very complicated to sync them cause there isn't vacume connections on all the inlet pipes If I ref the bike slides open together at the same width. What I did see is when you ref the bike and it starts hunting, the slides shudder up and down maybe this means something (all of them at the same rate)? PS. The bike only does this when you ref it and not when it idles < Message edited by gerharddvs -- 4/2/2008 3:28:04 AM > _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! (in reply to DukeCBR) Post #: 8

RE: Problems when revving :( - 4/2/2008 4:09:26 AM    DukeCBR Posts: 262 Joined: 3/1/2008 From: Cape Town, South Africa Status: offline Hi gerharddvs I have done some reading around on the net about your problem and what problems other people are having, and almost all of them have got the same conclusion. Check your rubber seals on your carbs, which is on your float diaphram cover. There might be a slit in the rubber somewhere that is causing air to leak into the diaphram section as it moves. Check all of your vacuum fittings that they are all secure, and check that your carbs are seated properly on your intake manifold. Since this is only happening at high revs and not low revs, it mostly points to a vacuum leak as the pressure increases in the carbs. Once you have found the vacuum leak (if that is the problem), you might have a little jumpy idle, syncing your carbs will be your next move. _____________________________ 1993 Honda CBR 900RR Fireblade Steering Damper DynoJet Stage 1 Kit Twin Race Foam Filter Hindle pipe (in reply to gerharddvs) Post #: 9

RE: Problems when revving :( - 5/2/2008 11:48:50 AM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline So today I got some nerve together and had another look at my blade. I tried something and discovered something actually by accident. I had the tank of and filled the carbs with gas using a bottle. When there was no more gas running into the carbs, I removed the pipe from the bottle and blew into it to check if the floats were closing. I then started the engine and it was still doing that thing of only reffing up to 6000rpm. I decided to blow into the gas pipe going to the carbs. Suddenly I could redline the bike a couple of times(slides opening all the way so nothing wrong with diaphragms). It then started backfiring and went back to the way it was. I then filled up the carbs with gas again and repeated the test with the same result. My conclusion was that it aether wasn't getting enough gas or it was sakking in air somewhere. Once again I took of the carbs and cleaned them cleaned all the jets and the float levels. I checked the main jets and they are all 120 like the book says.I checked the rubbers where the carbs connect to the engine but nothing. I put everything together again but the bike is still doing the same.  With the same result when I blow on the pipe. I give up. Please help. At least now I know it isn't the CDI...Could it be something with the valves? _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! (in reply to DukeCBR) Post #: 10

RE: Problems when revving :( - 5/2/2008 7:22:56 PM    jabourdeau   Posts: 1 Joined: 5/2/2008 Status: offline I am no expert, but I did stay at a Holiday Inn Express last night.     I have had several cars that end up revving 1000k without throttle application.  It has usually been been correctly diagnosed as a vacuum leak, and I think one time it was an O2 sensor.   Good luck.  J  (in reply to gerharddvs) Post #: 11

RE: Problems when revving :( - 5/3/2008 5:56:51 AM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline So I did some more testing today and I discovered that when the bike becomes hot it starts blowing out the big puffs of white smoke out of the exhaust which files the whole garage not blue or black like when oil is burning. What could this be? _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! (in reply to jabourdeau) Post #: 12

RE: Problems when revving :( - 5/3/2008 7:41:46 AM    900FighterRR Posts: 47 Joined: 9/18/2005 Status: offline WHite smoke means water-specifially coolant, and possibly a head gasket failure.  Thats a big jump though.  You really need to start from the top here.  The shudder in your slides your experiencing is something I have seen; when my carbs were out of sync.  If you havn't done that yet your wasting your time.  First pull th carbs and go over ever jet port and fuel avenune with them.  If you never ran the bike before pulling the cabrs then who knows what the previous owner did prior to selling you the bike, you might be re-assembling them as you found them but that might be wrong.  Once the carbs are checked and cleaning and synced you can move onto the fuel pump and problems with it.  If the pump is not working fuel can still be pulled through it but it will run like shit because it is starving.  After that its a spark test, and not just the plugs you need to makes sure that your getting spark to all cylinder and that that the coils are shooting the proper voltage.  The only way to diagnose problems like this is to systematically go through each step until you've wittled it down to nothing.  If the carbs are still not synced then your skipping a major diagnostic step.  Good luck and keep us updated.   (in reply to gerharddvs) Post #: 13

RE: Problems when revving :( - 5/3/2008 8:14:17 AM    gerharddvs   Posts: 176 Joined: 5/10/2006 From: South Africa Status: offline Ok.So I have done everything U mention except for the sync cause dont have the equipment.I did measure the amount the butterflies open mechanicaly and they seem the same.If I open one by about 1mm the other are the same.Dont think that would cause white smoke though. I even changed the oil but no traces of water in it. Maybe your right about the gasket. Can U test the gasket without removing the head? _____________________________ 1995 CBR600F3 Drive it like you stole it! Here U see the F3 in it's natural habitat! (in reply to 900FighterRR) Post #: 14

RE: Problems when revving :( - 5/3/2008 11:04:27 AM    900FighterRR Posts: 47 Joined: 9/18/2005 Status: offline Ok, well you've got most of the bases covered.  The carb sync is not going to be accurate at all based on the measurments your relying on.  The sync is determined by measuring vaccumn because although everything may look even and the same there are a high degree of variations from carb to carb for various reasons.  When you sync them your nlooking for all the butterflies or slides to be equal to one another, your looking for all the vaccumn reading to be equal.  You use a base carb which in my ride is #3 because it is not adjustable and you bring the other three carbs up the #3 vaccumn level.  Its the only way to do it.  Now the head gasket is not doing to be easy and not seeing any water in the oil is really not telling you anything.  If you have a blown head gasket it may be leaking a very small amount of fluid that is being burned off instantly when it goes into the combustion chamber, its not like there is a huge amount of coolant flowing into the cylinders or you would notice your level dropping.  I'm still not convinced your carb sync isn't a problem.  Either buy a 4 guage sync setup or take it to a shop and have them look it over.  Wish there was more I could tell you but if I can't really see the smoke and hear your rev issue its hard to even know where to start.  What does this smoke smell like because its also possible that its unbirned fuel! Have patience and keep your head clear, take your time on each diagnostic step so you can rule each one out with certainty.  A video would be really helpful if you can get one up.   (in reply to gerharddvs) Post #: 15

Today's Posts
Most Active Topics
Make A Donation
Forum Rules & FAQ
RSS Feeds

Top 10 Posters
doncollins 6222 voodoochyl 6184 tahoe sc 5795 pitsvtec 5316 rrasco 4847 d2dgraphix_6 4673 blue fox 4259 vpsophmore 4140 havoc 3973 chainstretch 3853

New Vendors
Sport Bike GPS
AMSOIL - Performance Oil Technology
AMSOIL - Performance Oil Technology
K&N Engineering, Inc.