Wierd problem, please help!

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Wierd problem, please help!

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CBR Forum >> Past CBR Models >> CBR 954RR >> Wierd problem, please help!

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Wierd problem, please help! - 6/30/2008 8:04:39 PM

GR8TSCT

Posts: 9
Joined: 3/30/2008
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I spent some time looking for this problem on different threads and could not find it; I apologize if it is a repeat. I put my bike on the dyno, and there was a "V" dip in the power. It dropped around 6000 RMPs. You can notice it when you are riding down the freeway; it bucks like it is going to stall, but if you give it some gas it takes off. It is just around when the engine is around those RPM, when it acts up. I replaced the spark plugs, and put in the injector cleaner. I am not sure what it could be, maybe fuel pump? Or fuel filter? If anyone has any suggestions, I would greatly appreciate it. Thanks

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RE: Wierd problem, please help! - 6/30/2008 8:50:12 PM

SurfnSCal

Posts: 179
Joined: 1/30/2008
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are you running a pipe and PC3 i assume? If this thing has the same problem as my buddies 929. There is a nasty flat spot around there. With the PC3 we were able to smooth it out, but could never really get rid of it. I guess we just didn''t have enough adjustability from the PC3 to correct it. But if it is truely bucking badly then you might have a fuel delivery problem. Hook up a fuel pressure gauge and watch it as you are doing a dyno run. And drop in FP while running would mean either pump or filter. If nothing then your problem is else where.

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Post #: 2

RE: Wierd problem, please help! - 6/30/2008 9:33:21 PM

Hcstreetriding

Posts: 994
Joined: 3/16/2008
Status: online

isnt 6000 rpm supposed to be the flapper opening spot? maybe a faulty servo, not opening the flapper, going way rich and losing power? Just taking an alternative guess. Getting any error code??

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Post #: 3

RE: Wierd problem, please help! - 6/30/2008 10:07:19 PM

TK954RR

Posts: 4966
Joined: 12/3/2006
From: Green Bay WI
Status: online

I think the flapper is at 4k.

Sorry dont have anything more to add atm, but i would run with Surfin''s idea.

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RE: Wierd problem, please help! - 7/1/2008 7:42:08 AM

Hcstreetriding

Posts: 994
Joined: 3/16/2008
Status: online

The flapper does its thing twice, I know once at 3000 and again at 6 or 7, cant remember, sorry, will try to look around for some answers.

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RE: Wierd problem, please help! - 7/1/2008 12:17:37 PM

Nealio240z

Posts: 167
Joined: 5/12/2008
Status: offline

mine did this also- it was the fuel pump...

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RE: Wierd problem, please help! - 7/1/2008 1:08:43 PM

Hcstreetriding

Posts: 994
Joined: 3/16/2008
Status: online

Nealio might be on to something. If you gun it(above half throttle) does it cut out on ya?

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Post #: 7

RE: Wierd problem, please help! - 7/1/2008 5:18:18 PM

GR8TSCT

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Joined: 3/30/2008
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I dont have a Power Commander, The Dyno put out a 134.1 HP stoke (which is actually good acording to records), and the pickup after the 6000 rpm is just fine. The pickup from 2k to 6k could be better. It wont pick up the front end to save its life even if you give it all its got. But after the 7000 RPM it runs great!!!! So I am leaning toward something other then the fuel dilivery system. But it is still in my mind. I put a bolt on can (Yana Shiki). It flattened out the "V", but it still bucks all kinds. The exaust valve was replaced, and adjusted by the dealership. The FI light is NOT on (no codes). If anything the exaust smells like it is running a little ritch. I believe these bikes have a flat spot around 6k to 7k but not this bad. Thanks for all your help, If you have any other ideas I am all ears.

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Post #: 8

RE: Wierd problem, please help! - 7/1/2008 5:30:26 PM

Hcstreetriding

Posts: 994
Joined: 3/16/2008
Status: online

heh as a side note doesnt that Yana Shiki sound pretty sweet for, well for what it is, thats what i have on my bike and everyone says it sounds great but they have never heard of it.

hmmmm you have me stumped at the moment, but i would not rule out the fuel pump just yet............ a power commander could deff help a lot, but its not going to fix something thats broken. i keep thinking about it. Mine picks up hard right around 6000-7000 so i dont think its normal.

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RE: Wierd problem, please help! - 7/1/2008 6:39:36 PM

GR8TSCT

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Joined: 3/30/2008
Status: offline

Ya same here. everyone I know tells me it sounds awesome, and no one has heard about it either. I am very happy with it! Thanks for all the info, I am stumped as well. I asked different mechanics at different dealers and they all came back with different ideas, all to get you to buy things... one even said to replace the chain and sprockets.......

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RE: Wierd problem, please help! - 7/1/2008 9:34:22 PM

CBRinPDX

Posts: 282
Joined: 11/12/2006
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The EGCV valve turns 90 deg to TDC @ ~3000 RPM then moves 180 deg to BDC @ ~8000 RPM.

If you want to really "wake the bike up", install a full exhaust system (Arata), remove the flapper and swap out the velocity stacks, install a PC III EX and have a race shop tune the bike. Try to find a shop that has experience with the 954, I''ve been told the 954 is a pain in the ass to tune properly.

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Post #: 11