ENGINE RATTLE

[blob748]

I bought this bike with the front cam chain failure. I have replaced the front head and the cam chain adjusters, there was no damage to the top of the piston, just a few light scratches. When I fired up the bike it ran for about 2 mins then started to rattle. Its not the clutch because as I pulled the lever in the sound did not change. I have rechecked the timing and valves, also balanced the carbs. The sound seems to be coming from the front of the clutch area between the clutch and the anti rattle gear but I can not pin point it for definite. The bike runs perfectly through all the gears. I was just wondering if anyone has any ideas or perhaps someone would listen to it for me. Im in the Gravesend area and happy to take the bike locally to someone.
Thanks

[MacV2]

Hey up Blob, long time no hear !

Tonys ya man for that one mate, drop him a PM.

Mac

[blob748]

Hi Mac,
yeh im always watching on here but tend not to comment much. This problem has really stumped me and thought I could do with some help.
Cheers for the reply.
Med

[macdee]

hi blob
do you know if a ignition advancer has been fitted to your bike

[Wicky]

What kind of CCTs did you fit? OEM Honda or aftermarket manuals? If manual CCTs did you adjust them correctly...

[sirch345]

Hard to say without listening to the bike. Has it done loads of miles if so it could be worn carb slides if you hear it on tick over

Chris.

[blob748]

Hi, thanks for the replys. It has no ignition advancer, I fitted manual ccts which I have screwed in and out all the way to see if the rattle would stop , and the bike has done 21,000 miles.
Thanks

[darkember]

I know you say that there has been no visual damage to the top end but if there are marks on the pistons your valves will have come into contact & they may not be seating correctly. Did you do an overhaul before the rebuild? Before doing this check the carb sliders first as Sirch suggested.

[sirch345]

It shouldn't be a carb problem at 21,000 miles, so long as they are the original carbs.

Following along the train of thought of Darkember's, may be a compression test would be a good idea. That would rule out any bent valves, but of course the noise from that would be in the cylinder head which you don't think it is,

Chris.

[blob748]

Hi Chris, I re-seated all the values, changed the front head as the old one was damaged, Honda new head gasket. The bike has had 2 owners, full service history from a Honda dealers, so I think the carbs are original, I have also been all around the carb area with a mechanics stethoscope and can not find the rattle there. The rattle sounds like a chain being dragged over metal slowly, the sound does not change when you rev it which makes a real head puzzler.
Thanks

[tony.mon]

I'm in Kemsing and would be happy to have a listen to see if we can identify the culprit.

There are lots of possibilities, depending on what you took off.
But if it doesn't increase tempo when you raise the revs, it can't be engine related, only gearbox back, or something loose rattling.

Check the cam box breathers- the front one's a bugger to connect properly under the airbox, and can make some odd noises if loose or disconnected.

I'll pm you my address and a contact tel number.

[chris freckle]

Have you checked that the crankshaft primary/antirattle gear has been preloaded ?

[sirch345]

Hi Chris, I re-seated all the values, changed the front head as the old one was damaged, Honda new head gasket. The bike has had 2 owners, full service history from a Honda dealers, so I think the carbs are original, I have also been all around the carb area with a mechanics stethoscope and can not find the rattle there. The rattle sounds like a chain being dragged over metal slowly, the sound does not change when you rev it which makes a real head puzzler.
Thanks

Hearing that I would also think the carbs are most likely the originals. Going by the work you have done on the front head that should be fine, even more so as the sound doesn't change when you rev the bike. If it was a cylinderhead related problem it would change as you revved the bike as you probably know. Taking up Tony Mon's offer to have a look and listen could be your best option. Worth checking that air-box front hose Tony mentions first though,

Chris.

[blob748]

I removed the air box and put it back at least 5 times, dam that front pipe! I spoke to tony, he going to listen to the rattle on Saturday. I will let you know what he finds.
Thanks lads.

[sirch345]

That's good, fingers crossed you'll get it sorted. it will be interesting to hear what it is, no pressure Tony

Chris.