hey all -

so after my whole snafu with the stator/R-R/starter plus the stupid molding in the engine case breaking and having to be weld-repaired (search my old posts) i'm now noticing the motor has a weird sound from the bottom end. it doesn't seem to do it as much or at all when cold, but once it's warmed up, there's a definite knock-type sound coming from way down low in the motor - almost sounds like it could be in the tranny too. it doesn't change if the clutch is in or out. i was thinking the chewed up aluminum bits that went through the crankshaft bearing area when the motor case molding broke apart might have screwed the bottom end up? is this possible or probable?

I've already changed the oil once after the repair, I'm gonna do it again with honda oil this time.

.....or am i just being a hypochondriac. the bike runs fine, no noticeable differences. except from time to time when coming to a stop, the RPMs will reach idle, then dip to about 1k, then come back up to idle. i don't know......

anyway, thanks for reading!

-T

 

The noise you are hearingsounds like it could beyour CCT. Is it coming from the right side of theengine and down low? Listen the next time you start it up.Doesthe noise go awaywhen you rev it up? If you answer yes to both of these questions, that is where Iwouldstart. I think mostF2 owners eventually replace there stock CCTwith a manual one andnever have a problem again. Good luck!

 

the bike has an aftermarket manual CCT, but i've never thought to check the tension on it.....

interesting idea.

i'll let you know tomorrow after i change the oil and get it started again with fresh oil.

-T

 

Then you are good to go. Just give it a little (use very small adjustments!!) tweek tighter and see ifthe noisegoes away or lessens a bit and fine tune it from there. Hope that is all it is for you.

 

yeah that makes two of us. but then again i've always wanted to try my hand at a motor swap. good excuse to shove a 900 in the frame, maybe....[8D]

-T

 

well, completed the oil change, haven't had a chance to start her up yet....but here's a strange new discovery. idk if it could be related to the knocking soundbut hey, what the heck.

so i went to replace the spark plugs and check the air filter while i had the bike apart, and the filter was fine, plugs looked a little dirty but not too black or white, maybe a little rich but not anything huge. got the new plugs in (apparently you need the hands of a 5-year-old to do it the way Honda wants you to in the owners manual) and just thought, having never worked on carbsangled this way before, that i'd take a look down the intake and see if i could get a look.

interesting thing i found when i opened the throttle and slid the #3 carb slide up....i could see down into the area where the valves were, there was actually gas pooled on top of the valves. now i've been noticing a gas odor when parked if i don't turn off the petcock, but the bike's not leaking it anywhere, and the #3 plug was no different than the others....

when this kind of thing happened to my EX500, the thing ran like crap and belched smoke and it ended up being a little piece of dirt on the float valve, preventing the float from closingit all the way. but the CBR doesn't have any problems running or idling - except sometimes the idle will dip when i stop.

now am i just unlucky? or could this SOMEHOW maybe have to do with the strange knocking noise i'm hearing? since the noise has an uneven pattern to it - maybe the #3 cylinder is just being cranky? and for that matter, how much of a PITA is it to get the carbs off this beast and clean them? i had it down to a science on my EX, but that was only 2 carbs to deal with.....[8D]

if you read this far, you rock. thank you.

-T

 

Ah, good ol' EX. I had a 95, fun little bike. If you've got experience pulling carbs then its not really any different, only there's 4 of them. I'm guessing that that number 3 carb is having an issue with the needle or seat that keeps allowing gas past and into the engine. Once the engine is running for a while it should clean up the plug some and not really appear to be different I'd think. I'd still expect the plug to look a little blacker. If you only run it for a little bit I'm guessing the #3 carb will be darker than the rest.
There's some good carb cleaning posts on this site, here and in the general tech forum where you can also pick up the service manual if you don't already have one. Definitely check it out.