Author Topic: High RPM problem 5th and 6th gear (Read 6005 times)

andrewsw · « **Reply #15 on:** September 21, 2006, 05:31:26 PM »

well, yup, that sounds rich. as I said before, in my limited experience, stumbling is a sign of richness as well, whereas when you're lean, it just won't pull well and will tend to pop when you come off the gas.

PitterB4 · « **Reply #16 on:** September 21, 2006, 09:42:25 PM »

It's possible that the VV is way different than non-Vs but I find it hard to believe that you're rich with 100s and that Yosh.

Before you start screwing around with the carbs, try this... pull the filter out, put the tank back on and take it for a spin. If it gets better, you are rich. I'm going to bet it's nearly unrideable meaning you are lean.

devilears · « **Reply #17 on:** September 22, 2006, 06:36:55 AM »

So I just took out the air filter and took it for a spin. Definitely better than with the filter, still not perfect, but definitely better. Still starts to stutter a bit when over 8k rpm on full throttle in the higher gears, but I at least I got it to rev through to 10 k in 5th and 6th. Guess this means I must be getting smaller main jets?

andrewsw · « **Reply #18 on:** September 22, 2006, 12:10:04 PM »

well despite all of our collected wisdom and generally miguided shots-in-the-dark it is clear that you are rich. And because of where it shows up in the rev's it must tbe the main jet. amazing.

you are on the right track. just remember to only change 1 thing at a time so you know what is actually working.

devilears · « **Reply #19 on:** October 07, 2006, 04:51:35 PM »

At last I got round to change my jets today. Went down from 100 to 90 which is supposed to be standard on the vv models, and it was the only ones I could get hold of. But to my despair that still did not fix my problem, when I get to 8-10 k rpm in the higher gears on full throttle I still have no power. In the lower gears I can feel a bit of hesitation between 8k and 10k, but nothing serious and once past 10k it pulls fine again.

I'm starting to wonder now if this isn't maybe somehow conected to the vv system, because this is supposed to change at about 8k. If anybody with the vv model has had similar problems, I would really appreciate it if you could give me any advice or suggestions, this is really driveng me craz

As far as I know the vv system is somehow activated through oil pressure. I`m wondering if maybe there isn`t something wrong with the oil I have which causes it to not have enough pressure to properly activate the vv system at 8k rpm. I have also figured out that this problem is not so bad when the bike is a bit colder. So I thought mayne as the bike warms up the oil becomes to thin and the switching doesn`t take place as it should. I am currently running a semi synthetic 10w-40 oil, can anybody with the vv model please tell me what specification oil they are running.

Thanks

devilears · « **Reply #20 on:** October 08, 2006, 11:22:51 AM »

So I checked my oil again to day to see if this could be the problem. I saw that there was a bit too much and drained some of it. To my srprise the oil was very thin, much thinner than I expected and smelled like petrol. Is this normal? I don't think so. What is the main cause of fuel in the engine mixing with oil? Maybe if I can figure this out, correct it and put in some new oil my problems will go away. I really hope this is my problem.

Can anyone please give me suggestions as to what might be causing the petrol in my oil?

Thanks

gsxr400 racer · « **Reply #21 on:** October 08, 2006, 11:43:36 AM »

bad petcock , bad orings to the floats , bad float needles, cracked floats,ect...

Thief400 · « **Reply #22 on:** October 08, 2006, 12:54:31 PM »

Just a thought here I remember some post from another board about the VV models not switching over to their high rpm cam lobes .... have you check this out yet? I seem to remember its a problem with the accumulator and actuator. There was on guy who install a light on his dash so he know if the ignition module was sending the proper signal to switch the cams over.

devilears · « **Reply #23 on:** October 08, 2006, 03:11:21 PM »

Thanks for the advice guys. I`ll try the light thing for the vv system. Can anyone maybe tell me what the sizes are for the o-rings, I've checked in the manual but cant find anything there. I found these sizes in a previous topic, are they correct?

Needle jet (emulsion tube): 10 x 1.5
Pilot air screw: 3 x 1
Float: 5.5 x 1.5 and 7.5 x 1.5
Membrane cover: 4 x 1

Thanks again for all the valuable info.

devilears · « **Reply #24 on:** October 11, 2006, 05:39:15 PM »

I`m starting to go crazy now. I just don't know what to do. I`ve tried everything. I`ve now changed my oil as well and replaced the o-rings in the carbs seeing as my oil was full of fuel and checked the valve clearances. Still does the same thing. When I get to 8k rpm in the high gears and open the throttle fully nothing happens.

I'm wondering now if maybe I`ve got a fuel delivery problem causing the bike not to get enough fuel when running at high rpm`s. Is it possible that a wrong float setup could cause fuel starvation at high rpm`s. Or maybe the filter inside the tank on the petcock is blocked causing it to not get enough fuel through?

How does one check and adjust the float heights? As this together with cleaning the petcock filter seems to be my next step.

The only thing that bothers me about this is that when over 10k rpm it runs fine again. If I rev it to 12k in each gear so that when I switch to 5th or 6th its already past 8k it will run a lot better, only feeling a little hesitant every now and then?

Is it possible that it will behave in this manner if the main jets I got now are too small? It did the same thing with #100 mains, I now have #90 mains as it was the only I could get hold of. It doesn`t seem that the problem got worse, it still feels exactly the same, so if # 100 was too small it would definitely have gotten worse when I put the #90 mains in?

Any advice and ideas will be very much appreciated.

Thanks

gsxr400 racer · « **Reply #25 on:** October 11, 2006, 11:42:30 PM »

adjust your needles

andrewsw · « **Reply #26 on:** October 12, 2006, 12:22:08 PM »

have you read this: cv carb tuning

you really should. It helps a lot and includes all kinds of information including how to adjust the floats and all that.