RVF rattle slowly getting worse and now very loud

[Cammo]

Anyone know a good bike mechanic in Sydney???

RB Racing is the shiznit when it comes to honda v4's.

http://www.rbimports.com.au/RB_Racing/a ... /index.asp

[Neosophist]

Uh oh!

That doesn't soud too good.

Rattles can be quite decieving tho.. comming from somewhere completely different.

As Mr Monkey said check / set the valve clearances as a matter of course of investigation.. if this remedies the problem it will also save a mechanics bill.

I had a rattle once on an old 2 smoker.. bit of the plug cermaic had broken off and fell into the bore.. left a lovely set of imprints all over the place..

Engine still ran for quite a bit too!

[XXXV4]

guys i think i found the issue.. I had all the fairings and tank off and decided while i was there to check the plugs. i pulled out the two rear plugs and found them both to be very carboned. i then put the plugs back in and ran the bike. as i took the leads off the rear plugs one by one it made almost no difference to engine speed. i also can disconect the coil primary wires and no change... as soon as i touch one of the front ones it stalls.

after this little discovery, i took the plugs back out (ie no compression in rear cylinders), disconected the coil and started the bike... and hey presto, no knock! runs just as it was and it seems the rear cylinders were not pulling thier weight and causing chatter in the timing gears or elsewhere.. i have ordered a new set of plugs and a new coil and i have my fingers crossed!

Its strange cause it would seem that it hasnt been running on those cylinders, but how on earth would I not be able to tell??

[skinnydog0_0]

It could be that your valve timing is out. If someone has put the cams back in, and got the cam timing out by one tooth, you could get what you are describing. I am sure someone will correct me if i am wrong, but if your exhaust valves are opening late, the exhaust gasses will remain in the cylinder to long possibly causing the rear plugs to carbonise. aslo really affecting the performance as the fue mix will be late arriving in the cylinder and mixing with the exhaust gasses to much.
Have you checked the valve clearences?

[XXXV4]

not as yet, i might pull the inspection cover off and check the timing and also the valve clearances soon as i get a chance.

I saw a video the other day and it was of a bike that had had its carbys rebuilt, and was making a very similar noise. he said he balanced the carbs and the knock dissapeared.

he said once the bike was back in balance the noise went away seemingly due to chatter and backlash through the driveline due to poor engine balance..

im sure two innoperative spark plugs would lead to quite an unbalanced motor! just hope it hasnt done damage

[XXXV4]

Anyone know a good bike mechanic in Sydney???

RB Racing is the shiznit when it comes to honda v4's.

http://www.rbimports.com.au/RB_Racing/a ... /index.asp

was referred to them actually.. they were closed on sat arvo ill g check them out!

[XXXV4]

hey all sorry i took so long but i found the problem.. 3 out of the 4 inlet valve shims on the rear bank had decided that they didnt like staying in position and fell out.. found all 3 in the top of the head.

on the front bank i found 2 out of the 4 missing and one was in the head at the top the other was in the sump stuck in the pickup.. needless to say my heart was in my mouth during the whole process. put them back in and all runs ok, going to have the clearances done soon.

im not riding at the moment cause i have no licence.

thanks for all the suggestions appreciate them!

[CMSMJ1]

lol - one last suggestion...why not do the clearances when you were putting the shims back in?

I reckon that poor motor will be buggered.

Shame, but at least you found it out..good skills for getting round to it.

no licence...

[GCD]

You sure its not the exhaust?


Kris

i can vouch on personal experiance,

do you have small/young children?

Mmmm.....small young children. About a year ago my CBR929 developed a sudden clanging noise from the bottom end. It turned to be two socket heads down my exhaust system, care of my 2yr old son.

[XXXV4]

lol - one last suggestion...why not do the clearances when you were putting the shims back in?

I reckon that poor motor will be buggered.

Shame, but at least you found it out..good skills for getting round to it.

no licence...

main reason i didnt do clearances was really due to just wanting to put it all back together to see if it solved all the strange noises, its not too hard to pull it apart again to do the clearances. and to my delight it runs smooth as a bird no noises at all. i figure i may have punished it a little to hard without warming it up for long enough, but ive never revved it past 12k since ive owned it and def wouldnt go anywhere near that when its cold.. guess it will remain one of lifes little mysteries!!!


Thanks for all the input guys really appreciate it!!