Jerks when accelerating

[mrToby]

Hi all,i bought my first bike 2 weeks back.A honda jade cb250 92.Great fun :).
Anyways when i go to accelerate it jerks.But only when i accelerate from having no throttle on at all.So when i'm engine braking or just letting off cause my speeds picking up when i go to apply throttle again it jerks a bit.Not bad enough to effect my riding ability though.However if i throttle on very slowly it doesnt do this.But regardless of it being normal throttling or "spirited :)" throttling it does this.

I dont know alot of people with bikes to try and compare or ask for opinions on the matter.Everything else on the bike runs fine and all other aspects of the acceleration/deceleration process seem to work flawlessly.i just worry that eventually over time it might cause damage,or is already a problem : /

My best thought was perhaps the carbs are dirty and dumping just a little too much fuel in when i first open the throttle.
Sadly my knowledge with bikes is very limited.

Does anyone have any ideas or is this normal for a bike?

Cheers :)

[Akzle]

chain tension

[mrToby]

chain tension

Loose or too tight?

[Akzle]

Loose or too tight?

yep .

[caseye]

Most likely too loose!
Don"t worry about young Akz there he means well, just can't always get it out proper like.

[Akzle]

Most likely too loose!
Don"t worry about young Akz there he means well, just can't always get it out proper like.

shaddup old boy, stick to your latés and smog.

It makes no difference, our new esteemed colleague has to check his chain tension to ensure its CORRECT.

And i dont always mean well :devil2:

[unstuck]

How much water is in your fuel?

[Erelyes]

There are plenty of jerks out there, I just ignore them regardless of whether I'm accelerating, cornering or whatever. HTH

[mrToby]

Thanks for the info guys i looked up how to check my tension and at a fiddle it appears to be a little loose but auckland strikes again and rains just as im getting ready to get stuck into and make certain its too loose.

So when auckland lets me i'll get into it and let you all know :)

[mrToby]

Ok so i've tightened the chain but sadly it hasn't effected it.There is however a tiny amount of play in the sprocket itself that i discovered.Not side to side but in the direction that the chain flows.just 2-3 mm total backwards an forwards and i have to grab the sprocket and hold the wheel.doesnt move that easy lol.I did a quick google search before posting it here an bothering you all and some people said that its a indicator of a worn cush drive and others say that a small amount of movement is normal.I hate the internet sometimes.so indecisive lol

thoughts?


Edit-been doin alot of reading and it seems a little movement is normal and too much means broken lol

[haydes55]

Can't you get done for indecent exposure for jerking on a motorbike?

Also, if your revs drop down quite low then most bikes would jerk a bit getting going again. So a bit of jerking is normal.... All boys do it.

[mrToby]

Can't you get done for indecent exposure for jerking on a motorbike?

Also, if your revs drop down quite low then most bikes would jerk a bit getting going again. So a bit of jerking is normal.... All boys do it.

If only the jerking im getting was that much fun.Doesn't matter where the revs are at.Just that theres no throttle open at all.When i reapply some gas is give a tiny jerk.My friends bike doesnt jerk but his bike is very different to mine.fuel injected,vtwin 2011 model bike.Its a bad comparison.

[Akzle]

Ok so i've tightened the chain but sadly it hasn't effected it.There is however a tiny amount of play in the sprocket itself that i discovered.Not side to side but in the direction that the chain flows.just 2-3 mm total backwards an forwards and i have to grab the sprocket and hold the wheel.doesnt move that easy lol.I did a quick google search before posting it here an bothering you all and some people said that its a indicator of a worn cush drive and others say that a small amount of movement is normal.I hate the internet sometimes.so indecisive lol

thoughts?


Edit-been doin alot of reading and it seems a little movement is normal and too much means broken lol

i would think 2-3mm IS excessive for cush wear.

just wanted to rule out the obvious first.

however, it's starting to sound like backlash in the box, which there is SFA you can afford do do shit about. get used to it.

take the chain off, with it in gear, turn sprocket by hand widdershins, until you pick up the crank, then turn it deiseal until it picks up something else. that's your backlash.

[Akzle]

oh yeah. and auckland sucks balls all the time.

[mrToby]

Thanks for the advice.Just did some reading on backlash and it sounds like its hit the nail on the head.I think i'll still replace the cush drive first chance i get and try what you said too.

But yes i dare say i'll get used to it lol

[Rhys]

Lift the back wheel of the ground and spin the wheel look at the chain and see if there is a "tight spot". It won't go around the sprocked as well as the rest of the chain

[Katman]

I think i'll still replace the cush drive first chance i get and try what you said too.


Read post #16 first.

[mrToby]

Lift the back wheel of the ground and spin the wheel look at the chain and see if there is a "tight spot". It won't go around the sprocked as well as the rest of the chain

Done.Its just fine.But thanks for the idea

[local]

When were the chain & sprockets last changed?

If you've already checked and/or adjusted the chain tension, next step is to get into the cush drive rubbers and pack them out with some inner tube or something (cheap option), or replace them. From there a new chain (and sprockets) will probably reduce a little of the slack, especially if the chain is of unknown vintage.

Given the bike's vintage, some slack in the gearbox is unavoidable. Only remedy for that is to re-tune your wrist to roll on the throttle more gently, or just never let off the gas?

[FJRider]

My friends bike doesnt jerk but his bike is very different to mine.fuel injected,vtwin 2011 model bike.Its a bad comparison.

Buy one like HIS then ...

It's all in the RPM YOU are using ... keep the rev's up and give it heaps. Don't just pour on the gas and expect GO ... drop it down a cog and go ...

You're welcome ...

[mrToby]

When were the chain & sprockets last changed?

If you've already checked and/or adjusted the chain tension, next step is to get into the cush drive rubbers and pack them out with some inner tube or something (cheap option), or replace them. From there a new chain (and sprockets) will probably reduce a little of the slack, especially if the chain is of unknown vintage.

Given the bike's vintage, some slack in the gearbox is unavoidable. Only remedy for that is to re-tune your wrist to roll on the throttle more gently, or just never let off the gas?

The previous owner says they were changed recently but who knows really.They seemed in good enough condition when i bought the bike so i wasnt too worried.Yea aparently i have to get use to a little gearbox slack lol
I'll get into the cush drive an have a look first chance i get :).

[mrToby]

Buy one like HIS then ...

It's all in the RPM YOU are using ... keep the rev's up and give it heaps. Don't just pour on the gas and expect GO ... drop it down a cog and go ...

You're welcome ...


To be honest i didnt have the cash to buy just any bike i wanted and i've been doin my best to learn how to reduce whats happening be it different gears,rev range etc.

I'll get it in the end :)

Thanks

[mossy1200]

Are we talking a sudden harsh jerk or a surging power delivery?

My bike jerks when you add a heap of throttle. Feels like your arms might pull out and often the front wheel comes up off the ground.

[mrToby]

Are we talking a sudden harsh jerk or a surging power delivery?

My bike jerks when you add a heap of throttle. Feels like your arms might pull out and often the front wheel comes up off the ground.

It is sudden but i wouldnt call it harse at all.At worst its annoying.
Was more worried it might cause damage over time or be the beginning of something bad.

I'd have to be trying to get my front wheel up :)

[mossy1200]

It is sudden but i wouldnt call it harse at all.At worst its annoying.
Was more worried it might cause damage over time or be the beginning of something bad.

I'd have to be trying to get my front wheel up :)

I wonder if you have a carby issue. Slide sticking, bellows split or blocked primary jet.

Does it jerk when you throttle off also?

[mrToby]

I wonder if you have a carby issue. Slide sticking, bellows split or blocked primary jet.

Does it jerk when you throttle off also?

No i dont think so.

[mossy1200]

No i dont think so.

You would expect a chain or sprocket or final drive bearing to be harsh when coming off the throttle suddenly also.
Easiest thing to do is find someone that has been riding a while to have a ride.

[Akzle]

Easiest thing to do is find someone that has been riding a while to have a ride.

where in dorkland, newguy?

[mrToby]

where in dorkland, newguy?

Lol.Im located in west auckland.Te Atatu sth to be exact.

[haydes55]

Lol.Im located in west auckland.Te Atatu sth to be exact.


Come to rosebank road speedway for a look today (practice day, if the track isn't too wet) free entry and loads of bike mechanics around to have a look in exchange for a beer (cans only, no bottles).

[mossy1200]

Come to rosebank road speedway for a look today (practice day, if the track isn't too wet) free entry and loads of bike mechanics around to have a look in exchange for a beer (cans only, no bottles).

Get in early before mechanics are drunk.

If you turn up later you will get a jerky turbo installed.

[mrToby]

Thats a awesome idea and i wish i could go.Might have to be next weekend.My wifes out and im looking after the kids today.

[Rhys]

Just give the kids a bottle of coke and a bag of chips sit them in front of the TV should be good for a couple of hours

Kiwi biker the place to get good parenting advise

[mrToby]

Just give the kids a bottle of coke and a bag of chips sit them in front of the TV should be good for a couple of hours

Kiwi biker the place to get good parenting advise

That might just work a treat.Now i need tips for dealing with the homicidal axe weilding wife said tip will create :) lol

[mrToby]

So today i pulled my back wheel off and got the cush rubbers out and yea they were worn.So i did what so many forums suggest to do and chopped up an old bike inner tube and stuck them to the rubbers.Worked a treat has taken care of 2/3s of the prob.The rubbers where quite stiff so im guessing brand new ones will be perfect.

Cheers for the help guys :)

[*Boot's*]

Swap for a yamaha 250cc FZR no wof no reg (de-reg) left front fork leaks, chains far too loose and clutch slips when power band hits? also all fairings been removed and color of bike is completely different than that specified on original color chart…. no rear lights work and if your really unlucky the bloody thing talks to you. last i heard it was going to F me up! if i ever stuff it around again!!!! sheesh…. two wheels with a vengeance and its not me!