Hey guys i'm new to the forum, and actually new to the streetbike world after owning a few fast cars and a dirtbike and quad. A few months ago I bought a 2002 f4i to commute around town for college and work. I hadn't drove it much after I bought it because I didn't get my license yet, so I didn't realize it had a gear problem until about a month after I bought it.

The deal is, past 6 or 7 k it will pop back into first gear from second under hard acceleration. From the research i've done it seems like it may be a bent shift fork? The only gear problems i've found similar though are when 2nd pops back into neutral.

Can anyone give me some insight on this? Any help would be much appreciated. Thanks

 

How are you accelerating if you're calling it "hard acceleration" at 6k-7k RPMs in second? As in, when are you shifting to second? Because if I'm accelerating hard there's no way I'm in second gear at 6k-7k RPMs, so I'm wondering if you shift up to second at the end of first gear, what happens? Do you have problems in any other gears?

 

the stereotypical pop back to neutral from 2nd occurs immediately after shifting -- it never fully engages; usually from a quick shift during rapid acceleration but never really anything to do with rpm range. are you saying yours goes straight from 2nd to 1st even after things have been fully engaged?

 

Hard acceleration as in whenever I start to get up in rpm's in second gear it pops out, after it has fully engaged. If I go all out in first and shift into second it will pop back down almost immediately. Under normal easy driving I don't have any problems, and have no problems at all in any of the other gears.

I was just stating the rpm range because thats when the gear starts to jump down when i'm trying to open it up.

Hope that clarifies it a little better

 

symptom sounds like worn gear dogs or shift forks

 

Do I have to completely split the case to replace the gears? Or can I go about it some other way?

I've heard that the case needs to be split, and i've also heard that the forks can be replaced through the clutch cover. Im new to these engines so don't really know the peticulars.

 

Yeah, it happens to me sometimes if I do things wrong. They will wear down after time - the spring will lose some tension, the gear dogs will wear down a bit, kind of like a sprocket wearing down, etc.

They make shift kits to replace those parts, which would likely help a lot.

In the meantime, something you can do when you're riding harder and want to prevent that: when you shift into second, keep your foot held up for an extra 1/2 - 1 second during the shift. It'll help make sure the gear stays put. I need to do that when I'm drag racing my Kawasaki because it's starting to get unreliable in that way.