Air filter confusion.

[oobyscoot]

OK, I am confused by GS,

I have had one for a few years, The first time I came to service it, I broke the air box, so for the next 2 years, it had no air box, its been running fine, I had no problems that  i was told I would have, (overheating, backfiring etc) other than being a little louder, there was no difference in the bike at all.

Recently I aquired a VERY tatty 1998 GS500E. It was rattly and very tatty, but it cost me 2 land-rover wheels that had been in my garden for many years, so I considered it a bargain, and It made the journey hlme with no breakdowns. I decided the first thing I would do was to "borrow" the air box for the origional one. Now both bikes are running like bags of scrap. My origional GS which ran fine with the air box on before I broke it, now seems reluctant to accelarate and very sluggish at low revs. The newly aquired GS now seems to cough and splutter at high revs (anything over 6k ish).

I guess the newly aquired bike is acting normally, But why is the origional not liking having an air box?  I put a new filter in, as I purchased it 2 years ago before I broke the air box and its been on my shelf ever since. If I get 2 of the cone type filters for each bike, will they both be happy again? or am I missing something more fundamental? Could I have done some damage to "Ruby" by riding her for 2 years without an air box, explaining why it wont run with one now?

[ohgood]

ouch. 2 years with no filter at all ? wonder what the rejetting matrix says about that..

and the 'new' bike, it likely wants it's carbs pulled apart and cleaned too.

then decide how you're going to run them (filtered or not) and start the rejetting fun, or just get used to them running like crap, and everntually they'll suicide underneath you.

[pjm204]

yea, no matter how you look at it, running with no filters is never a good idea. I agree with the above, clean the carbs, rejet them, and run both with filters.

[The Buddha]

Floats wear and when that happens they get high. That makes it richer. Your filterless bike has them wore and sitting high.
The new one OTOH, may have them correct, or not as high. Either way, get them all fitted with air filters and get the carbs settled out right, it should get better.
Yea valves and other BS should be checked on the new one as well as old one.
Cool.
Srinath.

[oobyscoot]

Cheers guys,

What is this rejetting matrix? Is it something I need to consider, or is it just too late now? (its been a little over 2 years and about 21k miles since she had an air box fitted) Could I have killed it already? I think I changed the oil some time last year (ish) so its not been totally neglected. What damage will result  from running without a filter?

I think I will put the air box back on the old one for now and wait until I have made up my mind on what to do with them. My origional plan was to attack the new one with the matt black and just run it until it dies, but I may do an engine swap as the new one is real scruffy, but only has 17k on the clock, the origional is pushing 70k, Trouble is, the new one has quite a harsh rattle comming from the top end, Could this be a result of standing in the guy's shed for a few years? Anyone know what sort of mileage is average for these little engines?

Trouble is, the GS has always been transport, whereas the other bike is for fun, so the GS was never as well cared for as it could have been. Sorry for going on, but the reactions so far have got me a little concerned that I have done some serious damage over the last couple of years.

[oobyscoot]

Sorted it, got some cone filters for  the first GS and put the air box back on the second. They both run fine again now.