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Motorcycles => Venox 250 => Topic started by: ChaosMagnum on June 14, 2014, 11:20:12 PM
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Hi there I bought an 08 Venox last year. I'm guessing its been sitting for quite some time because the Odometer only read 25km. The issue i've been having with it is that it seems to be very weak when starting from a stop. I have to ride the clutch for a good 3 seconds to get going, otherwise it'll just bog down/die. It feels like it revs up from idle a little slow as well. I'm wondering on what some possibilities are for this problem.
I just checked out the carburetors and they look good n' clean. I'm planning on checking out the plugs. But I can't imagine they're bad since the bike has such low miles. Same goes for the air filter. Any other suggestions on what I can test out?
Thanks!
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The bike has never been broken in according to what you posted. That means it is still tight.
Have you ever owned a clutched bike before? It takes at least 2-3 seconds to release the clutch, and get under power on every bike I have been on.
You will have to go thru the entire bike if it has sat. These are not light switches that come on at the well... flip of a switch.
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I apologize. I forgot to mention that it now has around 3300km on it. And it still feels a little sluggish starting from a stand still. And yes I have other clutched bikes. Honda Valkyrie and a Honda rebel. I know the valkyrie is in a totally different league, but the rebel even seems to rev up and get off the line fairly easily and quickly compared to the venox.
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The first thing I would do is a Compression test. See what you get there. It should read over 120 psi to be in good enough shape to go further. It could be the valves are out of adjustment... or the carbs out of sync... or lots of other maybe's.
Compression test it first.
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WAIT! 08 bike... if it had the same air filter since than that is expired! its paper, does not matter how much km, 2 years on a fresh one will be good to throw out! possible running too rich and miss fire on one cylinder due to a old obstructed air filter... your plugs should tell you if that is true. running rich on low rpm will be like this too but my best guess you are only running on one cylinder in idle.
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Lot's of maybe's on this... Good Idea max to check the plugs.
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Alright I'll give the compression test a shot. I've already synced the carbs. Seemed to help a little but not much. I'll let y'all know what I find out
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My money is on a valve adjustment. The problem could be anywhere but we'll figure it out w/ you.
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Well I checked the compression. Tested out good. Checked the plugs. They looked fine. I guess I should probably order a new air filter. I will check out the valve clearances possibly tomorrow if i get the chance. Thanks all for your support on this ^.^
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;)
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Ok will I checked the valve clearances. They were a little tight. So I got that squared away. Although the bike is doing a weird thing now. When I burp the throttle the revs drop super low then slowly climb back up
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just let me know... did you change the air filter yet?
And carbs being clean... did you open it up and clean every orifice with carb cleaner and compressed air?
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didnt do the filter yet. Looking for a replacement right now. And I didn't use compressed air for the carbs, but I did use carb cleaner
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Try pullin off the plug wires one at a time (while the bike is running). That will tell you if both cylinders are firing correctly. I'd turn the idle up to 1600 ish, and see if the rpm drop when you pull either plug.
I would also get a new set of plugs, and run the bike for a few minutes to compare the plugs, and see if one cylinder is flooding or too lean
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I did try the plug wire test. it pretty much wanted to die when I pulled either one of the plugs. So i'm guessing they are both firing. The plugs look fine too. No excess fouling or burning. I have one question though. I just pulled the carbs again because I feel I didn't do a good enough cleaning job the first time. But why is it that they put a 110 main jet in the front and a 108 main jet in the back?? I would think the cylinder in the back should have the 110 since it would run hotter than the front cylinder o.o
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It has to do with Intake manifold, and exhaust length. The shorter intake, and exhaust side of a V twin engine will run richer if jetted the same as the longer side. I believe your intake is split 50/50 but which ever cylinder has the longer exhaust pipe gets the leaner jet.
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Well the front cylinder definitely has the longer exhaust pipe. But that's the one that's jetted to 110. while the shorter rear one is jetted to 108. Shouldn't they be flipped around then? Also Another question. I tried fitting a higher flow air filter on it. But with the extra flow, the bike does not want to accelerate at all. I'm lucky to get it past 30 mph, and if i pin it, the bike just bogs down and slowly drops in rpm. Is that just because the extra air is causing it to run too lean?
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Yes tooooooo lean. Try the original air box, and flip the jets around. Someone may have confused them in a prior cleaning.
Pay REAL close attention to the ports under the pilot jets. That is where your main issue most likely is. Have you tried adjusting the MIX screws to induce a stall? That will tell you those circuits are clear.
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I looked in a pdf service manual for the venox. And it says under the carb specifications that main jet sizes are: FR:#110 and RR:#108 ( any thoughts on that?? ) I have not tried to do the mix screws to induce a stall. I'll try that when I throw the carbs back together So I'm curious with the higher flow air filter then. IF I wanted to use a higher flow air filter. How many sizes up do you think I should do the main and slow jets?
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Then I got the pipe size backwards...
Too re-jet I'd get a set of 5. They go up in steps of two at a time. I would start w/ the RICHEST, and work backwards if you have too. It's better than thinking it is right, and being too lean. Rich won't really hurt anything but lean can end this thread in a few hundred yards.
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air filter 1st buddy! get the stock! the airbox/filter actually is a little tricky! its made to give enough flow of air to make the engine run clean and slightly lean on low end and restricts the air flow on high end to make the mixture richer for more power and keep the bike from over heating, there is also the idle close valve that gives a extra flow of fuel when you are closing the throttle on engine breaking!
the jetting about the 110 and 108, follow the manual! its because of the water circulating rear 1st then front so front is fitted with 110. reversing the jets will definitely make one cylinder run richer and the other leaner, if both colors are the same then you are good, if they are slightly off then use the idle mixture screw to compensate.
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Ok i got a big problem. I think in my last cleaning of the carbs, the float bowls got out of spec. The service manual I have says that the float bowl height should be 17.5mm in the front and 19mm in the back. Problem is that the floats don't even get close to that measurement nor are they physically capable of doing so. So does anyone have the proper spec numbers? Or someone point me in the right direction?
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they are adjustable but i never touched them... when i measured them they were not according to the manual either. so if you have not touched them and they seem not been worked on before then dont fiddle with it.
played with my nsr floats before and had serious problems.
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I don't suppose you remember what those measurements were do you? Cause it smells like it's running rich and it won't hold an idle anymore
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Forget the specs. The float center line should be parallel to the body of the carb when inverted. Since you have to remove them again... Double check the seats, and be sure there is nothing up in there. With the carb inverted you should NOT be able to blow air thru the fuel inlet.
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old air filter can cause smelly running and impossible idle. check the exhaust pip and see if both are with a lot of carbon build up, one float being faulty possible... 2 at the same time.. not likely.
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Hey guys. Sorry ive been inactive. Transmission in my car exploded and I've been dealing with that fun stuff. But I'm back to takling the venox now. Zombie, In regards to what you said about the center line of the float. Which line are you referring to? Cause I'm not seeing any lines that I can line up with the carb body
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You have to make an imaginary line. ( bear w/ me) Split the surface area of the float in half, and use that as a guide. It may help you to remove the float, and scribe a line.
Something else that may help is filling a glass bowl w/ water. You can put the carb in up to the body, and observe when the float closes.
I just align it so it seats the needle when the float is parallel to the body. Blowing in thru the fuel inlet simply verifies it is closed, and sealing.
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Hey again. Sorry for the silence. I've just had no time to work on my venox. I tried starting again today. Zombie. Perhaps you can do me a favor? This is a link to a picture I took of one of the floats. Could you perhaps use paint or some type of program to draw the line you were speaking of and re-upload it? http://img.photobucket.com/albums/v96/GreyOmini/20140813_142816.jpg (http://img.photobucket.com/albums/v96/GreyOmini/20140813_142816.jpg)
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did the air filter come in?
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Yes sir.
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One other question as well. What does it mean when you're idling in neutral, and when you blip the throttle, The revs go up, then WAY down ( almost stalling ) then slowly climb back up? I get the feeling this may be connected to the poor off the line acceleration im having
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rich idle running, but sometimes its normal when the engine is not hot enough.
The reason is easy, too much fuel gone in on the bleep and when you shut the air going in to the carb you still have a bit of unburnt fuel in the manifold, causing it to idle low and climb back again after the fuel air mixture normalizes. best way to tune is to ride around until the engine is at operating temp then park the bike with the engine running, then bleep the throttle and play with the idle mixture screws, be aware that the rear carb might cook your hands.
do 1/8 turns a time on both of them and 1/2 maximum in or out will be the adjustment from stock setting, after you are happy with the setting let the bike idle for 2 min then kill the engine and cool down to examine the plugs to see if the mixture is ok for idle.
NOTE! this will only be helpful if you have two carbs balanced. it has happend that the carbs were not balanced and one cylinder was dragging the other cylinder. as a plus it will be better if you had a vacuum gauge hooked up during the tuning of the idle mixture screw because it does have a play on the balance also.
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So I noticed that as I turned the screws out. It got worse. When I turn them in it gets better. Are these screws reverse from normal where in = more air? However, it doesn't seem to matter how I adjust them, the bike still has crap acceleration from a stop
I'm starting to wonder if my CDI unit is faulty >.< however I'm not really sure how to test that
Ok quick little update. I tried doing some testing on the coils and wires and what not to make sure the ohms were in spec. Which they all were. Tested the spark. Spark looked good. So I went for one more ride and I noticed when I ride in 1st gear from 0 to about 15 mph, It runs like absolute crap. Sounds/feels like it's missing/stumbling and will continue to do so until the revs kick up, then it runs great and strong from there on.
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they are not idle air screws!! these are fuel screws, turn in closes idle circulation of fuel and out gives more idle fuel.
try closing them completely, if your bike still turns over and has a unstable idle then your choke is not working 100% or your air filter is so clogged up that its enough to keep the engine running even having so little amount of fuel when you closed the idle mixture screws.
when your bike is doing this sluggish pull on 1st gear... and pulls better when your rev increase you are most probably running on one cylinder. when the rev increase the running cylinder gives out more torque and horse power making you feel this symptom.
check the plugs one should be fouled or bone dry you can even feel the difference in temperature by touching the cylinder one will be cooler then the other until the water pump heats up the cold one. one cylinder might be on boarder line richness miss fire on low reves or clogged idle jets depending on the plug read you get.