Loss of power

eoinkildare

Hi lads,
Brand new to biking. Have a suzuki gs500e (2003 25000km). I ride it on the motorways and big roads and I've found that on my way into work i can get it up to 140,150 and 160 km/h fairly quickly whereas sometimes on the way home from work it seems sluggish and struggles to get to and past 140km/h. Any ideas what might be causing the problem.
Obviously I know that my bike doesn't know whether i'm on my way to work or home but the reason i mention it is because i tend to be on my way in during the day and way home at night so i was thinking that maybe the cold or something was affecting it???

or is the bike just not firing properly sometimes?

Oh the bike is restricted learner legal,

Cheers,
Eoin

Hotblack Desiato

Going up a slight hill one way and down the other way?
Going into a prevailing wind one way and with it the other way?

Richard tea

My restricted cb400 struggles to maintain 140km/h on the motorway. I would imagine this is due to my fat arse though:o

I experienced a loss of power on the motorway before & to my embarrassment it turned out that she was running out of petrol. I wonder if its a fuel issue your bike has?

eoinkildare

There's definitely fuel in it so unless its not getting into the engine properly. weird that it only happens sometimes.

i travel in the n4 onto the m50 northbound. then the reverse on the way home. would have thought it was all reasonably level...

Richard tea

eoinkildare wrote: »

There's definitely fuel in it so unless its not getting into the engine properly. weird that it only happens sometimes.

i travel in the n4 onto the m50 northbound. then the reverse on the way home. would have thought it was all reasonably level...

Travel the N4 myself. How far does the rev needle move when you experience the loss of power?

Fuel Deprivation

• Power loss associated with fuel deprivation typically displays itself as an inability to rev completely though the engine's rpm range. Instead of revving cleanly, the engine will bog near the half-to-full throttle range. In most cases, fuel deprivation is caused by an obstruction anywhere in the fuel tank valve, the fuel hose and the carburetor, reducing the maximum fuel flow required at higher engine speeds. A pinched vent tube will severely limit the fuel flow. Fuel deprivation can also occur if the carburetor's high-speed fuel jet is clogged. In either case, cleaning the carburetor jet, fuel valve or fuel hose can restore the flow of fuel to its maximum volume.
  
  

Hotblack Desiato

You're going into the prevailing wind on the way home so.

Steve.N

eoinkildare wrote: »

Hi lads,
Brand new to biking. Have a suzuki gs500e (2003 25000km). I ride it on the motorways and big roads and I've found that on my way into work i can get it up to 140,150 and 160 km/h fairly quickly whereas sometimes on the way home from work it seems sluggish and struggles to get to and past 140km/h. Any ideas what might be causing the problem.
Obviously I know that my bike doesn't know whether i'm on my way to work or home but the reason i mention it is because i tend to be on my way in during the day and way home at night so i was thinking that maybe the cold or something was affecting it???

or is the bike just not firing properly sometimes?

Oh the bike is restricted learner legal,

Cheers,
Eoin

My wife has a Gs500, I rode it up from Trim to Hillsborough to get it restriced and I was impressed by its ability to hold 80mph on the motorway. Even up the long climb to Newry it held a constant speed even with my 13stone weight. On way home after being restriced it took a tiny bit longer to get to 80mph, but once there held it with ease.

Start at the beginning - tyre pressures, chain condition.
Have u changed the plugs? You'd definately feel if it wasn't firing correctly.

What year is it? Mileage etc?

eurofoxy

or maybe its the bikes subtle way of telling you to get off the motorway and enjoy some lovely twisties instead of just going in a straight line at a constant speed...

eoinkildare

Richard tea wrote: »

Travel the N4 myself. How far does the rev needle move when you experience the loss of power?

I'll have to look and see but I think it is moving through the full rev range fairly smoothly. Like it will still accelerate quickly at the slower speeds

ninja900 wrote: »

You're going into the prevailing wind on the way home so.

maybe so. wouldn't have thought it would make such a difference but with a fairly low powered bike...

Steve.N wrote: »

My wife has a Gs500, I rode it up from Trim to Hillsborough to get it restriced and I was impressed by its ability to hold 80mph on the motorway. Even up the long climb to Newry it held a constant speed even with my 13stone weight. On way home after being restriced it took a tiny bit longer to get to 80mph, but once there held it with ease.

Start at the beginning - tyre pressures, chain condition.
Have u changed the plugs? You'd definately feel if it wasn't firing correctly.

What year is it? Mileage etc?

its a 2003 with 25k (km).
tyre pressures were okay the other day. chain could maybe be tighter but not particularly slack either i dont think. there is a bit of up/down travel on the chain but not anything mad.

I haven't done anything with the plugs. the bike always feels fairly smooth. what is the sign of misfiring?

eurofoxy wrote: »

or maybe its the bikes subtle way of telling you to get off the motorway and enjoy some lovely twisties instead of just going in a straight line at a constant speed...

thats for the weekend, this is just commuting!

Mr Sheen!

Air would be colder in the morning so that would be my first thought. . . . Otherwise dont be having such a big lunch in work !!

Hotblack Desiato

eoinkildare wrote: »

chain could maybe be tighter but not particularly slack either i dont think. there is a bit of up/down travel on the chain but not anything mad.

Don't know if you know this already, but a lot of people overtighten the chain.
There has to be slack to allow for the suspension movement, if the chain ever gets fully taut when you're riding then it can damage the chain (and eventually your wheel or gearbox bearings) so there has to be enough slack to allow for a fully loaded bike going over a bump.

Usually the recommended slack is 25-35mm in the middle of the bottom chain run, between all the way up and all the way down, with no weight on the back wheel (bike on centre stand.) This does vary from bike to bike though so check in the manual.

skapegoat

ninja900 wrote: »

You're going into the prevailing wind on the way home so.

This is the true reason!
I cycle it every so often and the wind in the evening is a killer!
Takes 10mins longer!