Kawasaki Motorcycle Forums banner

Jerking on accelaration -

3K views 18 replies 12 participants last post by  elr658 
#1 ·
First of all no I'm not that talented. :wink: My 2000 Vulcan 800 classic I just bought jerks on accelaration. Primarly when it's cold. Before I go and rip the carb out I tried changing the plugs. (the old ones are ok - spares now) Put in a K&N filter (Stock filter was nasty) and ran 3 tanks of gas through it with a little carb cleaner. The bike was sitting for about a year in a garage and had some old gas in it. A guy at work suggested something call seafoam. Haven't found it yet. Any suggestions? I saw a previous post, http://www.kawasakimotorcycle.org/forum/viewtopic.php?t=3048 that someone else had the same problem with his nomad. I really like the style of Kaws and was thinking about getting a new one next year. But is this a common problem?

Also on the fuel shutoff, how do you shut it off? I see RES, PRI, and ON. I assume RES is reserve, PRI is prime, ON is the main tank. What is PRI used for?

Thanks,
Randy
 
#4 ·
yeah, primarily when it's cold, warm the engine properly then see what happens, even for the first minute it'll seem jerky but since it was warmed properly it'll even out, that and replace with K&N
 
#5 ·
if its been sitting then you prob. have some gunk in the carb idle circuits/transition ports.
and the K&N is leaning you out even more than factory, so you really need to jet for that. call K&N tech support and ask then what settings you should set the carb at while your in there cleaning your jets etc..
good luck
 
#6 ·
TRY THIS

before you start the bike in the morning disconnect the gas line from the petcock, and run some of the gas into a jar or a paper filter and check for a small amount of sediment (rust). If you do then it would be advisable to order a rebuild kit for your petcock and get the sediment out. I have used SeaFoam in my bike to clean it out and it does work, but be patient, it doesn't work i just 2 or 3 applications. YOur can has enough for way more than you will need for the bike anyway, just give it time na dread the instructions about what gas to use! I'd too, say that it is running lean. maybe partially because of sediment, but try to go back to the Kawasaki stock air Filter for now, and wait to do the rejetting till this winter when you won't be riding so much...Winterizing a bike depends upon where you live and if you are going to be riding it or not...check the FAQ's page
 
#7 ·
The jerking was happening even before I changed out the filter with the K&N. It does get better when it warms up but that's after about 20 minutes. Even then it does it occasionally. So I'm going to check for rust first and try that seafoam stuff. A guy at work took his injectors out and soaked them in seafoam and in 20 min they were completely clean. If thsi doesn't work then I'll be ripping out the carb. Anything to look out for? I have a Clymer book and it looks like it gives good pics. What it a good cleaner to use. The book says not to use a caustic base.

Thanks
Randy
 
#8 ·
SOAK

You can use Diesel as long as you remove all the rubber and gaskets...it won't hurt the aluminum...just check the little holes and ports, make sure that they are clear. You might get by with just cleaning your petcock drain bowl...see if ther is crud in it and clean it out, reinstall it. THe SeaFoam will lube and Clean the system and it take s several tanks of gas depending upon how gummed up it is...but it will clean it up... Also put new plugs in it...You can't see carbon if it is up inside the cavity between the core and the enamal...
 
#9 ·
Don't mean to hi-jack your thread, but my 200 Vulcan 800 is having a similar problem. The jerking on accelleration does seem to lessen as the bike warms up, but I am still getting a slight stall at any speed while keeping the trottle steady. I even get a little missfire on deceleration. It definitely runs smoother with the choke pulled out about half way.
 
#11 ·
jerking

Kawasaki has this Japanese disease...it's caused when the rider gets all excited or nervous and starts shaking...and it is transfered to the throttle. the bike is just as nervous as a...well it's just very sensative...
then again perhaps with my spelling you may not understand, but Parkensons disease in its early stages...perhaps a Ninja 250R IS in your future after all! JK!!!
 
#12 ·
Just an update, I found that seafoam stuff at NAPA auto (they also had it at carquest) I put it in the gas tank but haven't had too much time to ride lately. I let you guy know if it works. But I didn't think about a air leak. I'm going to have to check out my hoses.
 
#13 ·
I have a similar problem with my 250r ninja. It is jerky when I first engage the throttle. Its not a huge deal.... but im wondering if it can be fixed. Would this be related to chain tension by any chance? I ask this because once the throttle is opened a bit the acceleration is very smooth, so its got something to do with the initial tensioning of the chain when power is applied (its too high). I can avoid the jerkyness by being VERY soft on the throttle initially, but thats hard to do. maybe thats just the way it is on a $3K bike...
 
#14 ·
Since it appears you may be running a bit on the lean side, and if it seems to run better with the choke knob pulled out some, have you tried adjusting the idle knob? This is explained in the MOM, and in the "Carburator Idle Speed Adjustment" section of the Clymers manual, chapter 3, somewhere around page 100, with a good associated picture (mine is figure #92). Tweak it a little- clockwise increases idle, but remember you are operating it upside down. This may be all you need to do. Good luck!
 
#15 ·
Also- if you increase the idle a little when the bike is cold, you can back off on the choke sooner. Be aware that as it warms up, the idle will need to be tweaked back a little. The idle knob is easily accessible while riding, so it's no big deal.
 
#16 ·
500R Jerking

Hey guys, I'm having the same jerking problems with my Ninja 500R. I really seem to notice it in the mornings I think... It's been about 30's in the mornings, about how long should it take for the bike to warm up? I usually let mine warm up while I'm puting my helmet and gloves on, so about a minute or so...

Could this jerking be hurting anything? Rather should I be worried or do I have time to figure out what the culprit is? I've also been using Seafoam but haven't noticed many results yet, I've only done about two applications so far though.

I also pulled my plugs this last weekend and took them into Autozone. I'm no pro at plugs but they looked pretty clean to me, the guy at Autozone thought so too. The bike only has a little more than 2,000 miles on it. I bought it from someone a couple weeks ago with about 1,700 miles on it. I can't imagine I'd need to worry about plugs yet right? Thanks!
 
#17 ·
mightybhwk said:
First of all no I'm not that talented. :wink: My 2000 Vulcan 800 classic I just bought jerks on accelaration. Primarly when it's cold. Before I go and rip the carb out I tried changing the plugs. (the old ones are ok - spares now) Put in a K&N filter (Stock filter was nasty) and ran 3 tanks of gas through it with a little carb cleaner. The bike was sitting for about a year in a garage and had some old gas in it. A guy at work suggested something call seafoam. Haven't found it yet. Any suggestions? I saw a previous post, http://www.kawasakimotorcycle.org/forum/viewtopic.php?t=3048 that someone else had the same problem with his nomad. I really like the style of Kaws and was thinking about getting a new one next year. But is this a common problem?

Also on the fuel shutoff, how do you shut it off? I see RES, PRI, and ON. I assume RES is reserve, PRI is prime, ON is the main tank. What is PRI used for?

Thanks,
Randy
http://www.seafoamsales.com/ You can get it from PepBoys, AutoZone & NAPA. Don't waste your money on Gumout. Sea Foam is a couple of bucks more but well worth it, it also has multiple uses, it can also clean your engine or transmission on your cage too. Oh & you acan also use it in place of Sti-Bil to store your bike to keep the fuel from turning stale.:cool:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top