[tz250-geo]

Is that an oil filter at the bottom left of engine? Do 4 strokes absolutely need oil filters? I would think with a dry clutch the oil should stay fairly clean. Anybody have some insight into this.



Regards,



Geo

 

[tz250-geo]

Re: Dirty Oil

Yes, but your car has to go 5000 miles between oil changes. I think aerobatic aircraft run without oil filters. I think the engine will run fine for an hour or two without an oil filter. I might be wrong, but I don't think it was that stupid a question.

Geo

 

[tz250-geo]

Solve this probelm by pre-running engine, then drain initial dirty oil. Then change oil after every race.

 

[tz250-geo]

Two strokes use air. No oil filters there - Oil screen. I agree if you run in an extremely dirty surroundings (off-road) it would make sense to put oil filter in - hence the KTM comment. But for prototype production machine...



Obviously the reason is good enough because Honda did put one in. I just wanted to hear some comments on the issue.



Geo

 

[tz250-geo]

Fair enough. There are so many bearing surfaces in a 4 stroke that a little bit of dirt can probably do a whole lot more damage that on a 2 stroke.

 

[tz250-geo]

You are referring to production machines, GP is one off machines with services every few hundred kilometers.



Some reasons to return to the dark ages: less oil required, smaller pump for given pressure.



As I noted before, Honda decided to go with the oil filter and I am sure they have very good reasons. I just made an observation to try an get a reasonbly intelligent reply. Perhaps somebody out there knows about a previous 4 stroke race bike that ran without an oil filter.



Geo