Surging while riding

[Metalor]

Just wondering what you guys reckon. Just took my bike into Mt Eden Motorcycles cos it was surging slightly and the mechanic there told me it was most likely due to my chain being loose, so he jacked it up for me then and there, tightened the chain up and gave it a lube.

Then as soon as I get on the motorway to go home it's starts surging again but this time it's alot more noticeable as before it was only a slight surge.

Any ideas what this could be?

[ManDownUnder]

How fast is this surging? At open road speed - Lots of times a second, or 2 tmies a second, or every 5 seconds

Do you need to be going slow to notice it?

what about when you're riding and simply back off the power (no brakes)... does it stay there or go away?

[Metalor]

It does it does it about once per second, i think it's only when i get to the 80k mark and above (not quite sure though as I may have noticed it in 3rd at slower speeds but don't quote me on that).

When I did back the power off it surged a bit aswell, so I tried it a couple more times and found it only did it when easing the power of sometimes.
This was on the motorway by the way.


Would it be ok to keep riding it? Or best not to?

[ManDownUnder]

It does it does it about once per second, i think it's only when i get to the 80k mark and above (not quite sure though as I may have noticed it in 3rd at slower speeds but don't quote me on that).

When I did back the power off it surged a bit aswell, so I tried it a couple more times and found it only did it when easing the power of sometimes.
This was on the motorway by the way.


Would it be ok to keep riding it? Or best not to?

Hard to tell from the brief description on here but it will probaboly be ok. Bring it along to the Wed night ride/mentoring session (PM Disco Dan) and I'm sure someone there will be able to throw some experience at it.


If it is the chain you should be able to feel the surging with the motor off or in neutral and it'll slow down/speed up with the bike.

[Metalor]

Ok, kool. Thanks heaps. I've given Mt Eden Motorcycles a call and they're gonna have a look at it and take it for a ride to see what's going on, so hopefully they'll get it sorted for me.

[Metalor]

riding to uni this morning the bike seemed to be running fine with no surging.. weird :S

[vifferman]

It's not clear from your description whether the 'surging' is mechanical in origin (i.e, badly worn sprocket(s) and/or chain) or caused by the engine. Usually surging is caused by the engine running too lean, and is most noticeable riding on a constant smallish throttle opening. The mechanical kind will be there still if you pull the clutch in, and you will also be able to hear a regular noise associated with it.

[surfer]

How bad is this surging?

It might be that at low revs due to the carb set up this is how your bike behaves. Have you talked to other owners of similar bikes to yours?

My bike surges at very low revs. This can make slow manouvering especailly when turning very interesting, however it is a carb thing and a recognised problem of the make of bike.

[Metalor]

Oh ok. Well, I only noticed it slightly today, so you might be right about the surging at low revs, cos apart from that one instance it didn't do it again. It's only a very slight surge but still noticable, sort of as if the bike was running out of gas but a bit more subtle.

[wildpudding]

Just an idea, check the fuel line from the tank to the carb for kinks.

My bike did a similiar sort of thing(at open road speeds), which was found to be a fuel line slightly kinked, which was restricting fuel flow to the engine at higher power settings.

Stefan

[Metalor]

Ok, well I've been riding it round quite a bit now so I'm getting used to it, and it only happens when I'm doin around 100k's and it's only a very slight surge (I think the chain was a bit loose when it was surging before) but being a 250 and 100k's being near it's top speed I'm thinking this might just be normal behaviour for the bike... I can get it up to 115k at full throttle so i try to sit on 100 so not to push it too hard.

So does this sound normal? Or should I still get it checked out?

[Squiggles]

my bike "surges" by your description, usually in the low rpm but can feel it slightly the whole way through, hasnt gone bang yet though

[Metalor]

Ah k, cheers for the advice. Just went and checked my chain again this afternoon and it's loose again. Didn't know how loose it was before but it's only been a week and it seems loose again... do I need to get a new chain or what? What would be causing it to become loose so quickyl? that's if it is actually loose, I'm not sure as I don't have any idea really what I'm doin, but it doesn't seem to be on very tightly.

[surfer]

Are you loosening the wheel and then turning the wheel adjusters in to move the rear wheel back?

Make sure you turn them the same amount either side, usually half a turn on one side then half a turn on the other so your wheel stays in alignment. If you get your wheel out of alignment you will wear your chain.

[Squiggles]

if you were to push the chain up towards the swingarm from rest, at a point half way between the front and rear sprockets, the difference in its position should normally be between 2-3cm (dont have a tu manual but this seems to be the norm for bikes) turn the adjusters evenly on either side to tighten/loosen it and to keep it in alignment (you can check by looking on the markings on the side of the swingarm)

spin the wheel a turn, check again, spin then check

if its crazily out at one point (for my gsxr its time for a replacement as i adjusted and its 2-3cm then about 1.5cm then about 4.5) then its time for a new one, as it is if its rusty/kinked

lube your chain every 1000k's at least


lucky for you chains are cheap, i bought a brand new dido one from haldanes for $100, bought the one on the other gn from colemans for $65 (heavy duty chain, wont last quite as long as the dido brand one i got) and pretty easy to put them on as its a clip type