Hey guys new here, I'm going to be buying a 92 F2 hopefully from my flight instructor tomorrow and had a tech question. He is a mechanic and has kept it up very nicely but he said the carbs need to be re-synced? Just curious how you would go about doing this. He said they make kits for this?

I was also curious on what the minimum octane these bikes should be running with. I ride dirt bikes so im always throwing in the highest I can find, is it the same case with these older F2s?

 

Higher octane can actually hurt the horsepower in most motors that aren't designed for higher octane (higher compression and whatnot)

You'll be fine running ~87 octane in the bike, unless you live on top of pike's peak or something.

The carb sync is described in a few threads around here - a decent set of meters can cost you $40-80 bucks. My local shop quoted me $140 to have them do it - so if you don't want to mess with it, then find a shop that's reputable.

Or - have your mechanic buddy you're buying it from do it before he sells it and throw him another $100 for the effort.

 

Actually I disagree with this to a certain extent. It can cause issues as he said on some motors and deliver worse performance, as octane largely relates to volatility, and more expensive fuels are less volatile. Therefore, they withstand compression better and don't blow up early in high compression motors (knocking).

The CBR600F2 is a high compression motor, believe it or not, and will do best on premium. Extra power? Nope! Less engine wear, probably.

Can you survive on 87. Undoubtedly. Is it the place to go trying to save a few dollars? Probably not.

A carb synchronization is a bit big of a task for a first time bike owner, especially on an line four. I would pay some one the first time, and get your hands dirty on other basic things before getting into the bike that far.

 

agreed on the newb sync.

I honestly didn't realize our engines were 12:1 motors - for some reason I thought it was a bit lower than that.

It almost sounds like the seller meant that the carbs need to be re-jetted if he mentioned getting a kit for it. Depending on what mods are done to the bike, it may or may not really be necessary.

 

Probably because they only push 85+- hp, heh.

Definitely rejet and pay for a carb synch. Rejetting is EASY. Carb synch, not so much. Do the rejet yourself, take the carbs to a professional to synch once you get it almost all the way buttoned together. Stop with the airbox together and then hit up the mechanic.

 

I cannot recommend anything on the synchronization of carbs. but I can tell you something about high octane fuel. As of right now I only have my '07 Sportster for a street bike (I have a '91 CBR 600 in the works though) and it has a 9.7:1 compression ratio. Now as far as bikes go, that's not high but as far as gas powered engines in general go, that's high enough that premium fuel is required. It IS required by HD for this bike. I accidentally put some 87 in mine once, old single grade pumps at an unfamiliar gas stop, and my bike hated it! It would CLANK if you didn't give it plenty of gas on starts and it had a really weird "dragging alum. foil across glass" sound if you got on it on the highway. I went to my nearest auto parts store and dumped some octane boost in it and it went away immediately. Please don't hate on me for having the Sportster, I truly am a motorcycle enthusiast. If it has two wheels I'll ride it or with it, it don't matter.

 

I only run 91 or higher oct with NO ethanal <--------- its bad in these motors

 

I run premium all the time which is 98 ron, seems to go further.

 

Thanks for the help guys. Obama is here in california so I can't fly today or pick up the bike but hopefully I can get itsometime this week and get the carbs fixed up.

 

So what's the rub with ethanol? Just curious. I'm guessing it has something to do with aluminum. Just a guess mind you.