Running rich?

[bigchris]

Hi, all.

I'm in the process of re jetting my carbs and had a few questions.

Rode the bike today and here's what I found.

1. Bike seems to have lost torque and power .

2. Engine coughs when blipping throttle down gears. Backfires through exhaust also, but not every time.

3. Power loss seems worse after engine braking for any period

4. When cracking throttle open from idle, engine seems to hesitate. Not a lot but enough for me to notice.

5. The bike generally feels restricted.

Are these symptoms of running rich?

I'm thinking that after adding larger main jetts I may need to lift the tank and get a performance air filter to get more air in?

Any help apriciated. Cheers,

Sent from my iPhone using Tapatalk

[hardhat_harry]

Take spark plug out, does the anode look wet and sooty (too rich) or white (too lean)s a beige colour its ok.

Also check you have put all the pipes on the airbox including the blanking ones

[hardhat_harry]

Btw what mods have you made to make you think you need bigger jets?

[bigchris]

Btw what mods have you made to make you think you need bigger jets?

Fitted a Beowulf open can, the bike ran like crap after that.it was very lean. Was trying to cut out at low revs and would cough and die when blipping down gears. I could pull the choke on when the engine was warm and it would just rev out rather than cut out as expected, so I put 140 mains in and new 17.5 pilots, needle set at 2cd notch from blunt end & running standard air filter. Balanced the carbs and now it seems to have lost torque and power???


Sent from my iPhone using Tapatalk

[rictus01]

sounds like you've mucked it up, fitting a can won't cause the symptoms you describe, so I'd guess you had another problem, and now all you've done is cover it with a further one.

lifting the tank will only increase the noise, and changine jets/ mucking about with neddles only makes sense with a free flow filter (something like a BMC RS) and a full exhaust system, anything short of that, leave the jets alone.

I'd suggest you return the carbs to standard, find the original problem, and take it from there.

Cheers Mark.

[bigchris]

sounds like you've mucked it up, fitting a can won't cause the symptoms you describe, so I'd guess you had another problem, and now all you've done is cover it with a further one.

lifting the tank will only increase the noise, and changine jets/ mucking about with neddles only makes sense with a free flow filter (something like a BMC RS) and a full exhaust system, anything short of that, leave the jets alone.

I'd suggest you return the carbs to standard, find the original problem, and take it from there.

Cheers Mark.

I may just do that, what could cause the probloms if it's not the jetting?


Sent from my iPhone using Tapatalk

[rictus01]

I'd guess an air leak, but it's worth checking everything systematically rather than going for one thing to "hopefully" fix it, do a proper job and you don't have to guess.

Cheers Mark.

[hardhat_harry]

I think you need to go through a series of elimination.

Check plugs is it rich or lean?

Put standard jets in and the can you had before the Beowulf, is it still doing it?

Then you should know where to go from there but I suspect either airbox not fitted correctly, fuel line trapped, spark plugs or HT Leads not on properly

[bigchris]

I think you need to go through a series of elimination.

Check plugs is it rich or lean?

Put standard jets in and the can you had before the Beowulf, is it still doing it?

Then you should know where to go from there but I suspect either airbox not fitted correctly, fuel line trapped, spark plugs or HT Leads not on properly

Will check the plugs. I did put the original can back on and the probloms stopped? This what made me think the jetting was the problom. All the fuel lines were checked and the tap and pump. All fine. Thinking of just getting it to a dyno. I'm getting ready for scrapping it!!!


Sent from my iPhone using Tapatalk

[bigchris]

Will check the plugs. I did put the original can back on before i changed the jetts from standard and the probloms stopped? This what made me think the jetting was the problom. All the fuel lines were checked and the tap and pump. All fine. Thinking of just getting it to a dyno. I'm getting ready for scrapping it!!!


Sent from my iPhone using Tapatalk




Sent from my iPhone using Tapatalk

[yorkie_chris]

If it is going "bleh" on the blip when you downshift then it is likely the needle position. Leave that in stock position, only change one thing at once.

They #should# run fine with just a slip on can and no rejet. Makes me think you have another problem somewhere.

If chasing rich or lean, a rich problem will be worse when hot.

[bigchris]

If it is going "bleh" on the blip when you downshift then it is likely the needle position. Leave that in stock position, only change one thing at once.

They #should# run fine with just a slip on can and no rejet. Makes me think you have another problem somewhere.

If chasing rich or lean, a rich problem will be worse when hot.

hi yc

the stock position being the 3rd clip with no shimming? i did have the needles set at this but the bike seemed to bog down from a standstill to around 30mph? ( enough to notice anyway ). will put them back as the bike didnt "bleh" at this setting.

Also because i have upped the mains to 140 from 137.5 will i need to get more air in via some snorkle butchery? im still using the stock filter you see?

could i still be running rich even with the ideal needle setting because of the standard filter?

hope this makes sense?? :confused:

[Stig]

Best way of finding out if it's running rich is use your nose. Smell the exhaust when it's running. If you have a strong smell of petrol, you have your answer. Are you sure the choke isn't stuck on?

[bigchris]

Best way of finding out if it's running rich is use your nose. Smell the exhaust when it's running. If you have a strong smell of petrol, you have your answer. Are you sure the choke isn't stuck on?

im sure the choke isnt stuck on, ive had the plungers out 3 times now and they look clean as a whistle, even replaced the o rings.
i opened and closed the lever with the plungers out and they moved freely?
greased em up and put em back in.
when i put them back in they seemed to fit properly.
unless im missing something regarding the choke? :confused:

[Stig]

unless im missing something regarding the choke? :confused:

Nope.

I'd do what others have said. Set it all back to standard and start again. As Chris said, change one thing at a time and go test. At least if you have symptoms after only changing one thing, you'll know exactly where the problem is.