December 2, 2019
I have overhauled engine recently and noticed an intermittent rattle on accelerating noticing more in top gear. Idle perfect and slowing down ok also.
I removed chain cover today and saw the chain has worn the upper part of cover where bolt goes through.i assume this could be issue. If I lift chain with screwdriver it comes close to upper case.this is a new ISIS chain.any ideas please?
November 6, 2016
Hi Neily,
Not sure what you mean by removing the chain cover but I assume you mean the inner cover that holds the clutch actuating mechanism worm ??
I have to ask if the new chain is compatible with the existing sprockets – if it is lifting so high you either have a bad adjustment or the chain is the wrong size………. might be worth checking this out first.
Why it is rattling on acceleration in top gear is a bit of a head scratcher and unlikely to be chain related, unless your sprockets are extremely worn, but I would advise get the drive chain sorted first and if the rattle persists then you can delve deeper into probable causes.
Sponge
April 10, 2020
Neily
I think you must mean the primary chain? If so then, under acceleration, the top run of the chain is pulled tight and the slack would be on the bottom run so, whilst the chain may be slack when checked static, it should not be contacting the top of the cover under acceleration.
The issue of slack primary chains has been covered many times in the past and it may help to have a look at what others have recommended. Some say that even with a new chain there is still a fair amount of slack. Try this link to a Google search ** Please log in to view **
However, before you look at altering the primary chain setup I think it may well be worth checking how much free play you have in your throttle slide/carb body. Take off the air cleaner pipe / filter and with the slide raised a little get a finger in the slide and try and move it backwards and forwards. If it rattles about this may well be the noise you are hearing. What happens is that under acceleration the induction pulses pull and push on the slide and ifs its worn it rattles about and this is quite audible and can be mistaken for something else. If you can hear the rattling noise when you rev it up on the stand then you can stick your finger against the slide and see if that stops it.
Cheers
alan
1939 Ariel VH, 1942 Ariel WNG, 1951 Triumph 6T Thunderbird, 1970 BSA Bantam B175, 1980 Honda CB250N, 1986 Yamaha SRX600
Most Users Ever Online: 223
Currently Online:
20 Guest(s)
Currently Browsing this Page:
1 Guest(s)
Top Posters:
cocorico: 4722
Cornish Rooster: 2892
Blue Heeler: 2393
bart: 2364
sunny: 2332
Sprung Chicken: 2085
David Dale: 2001
Stoo63: 1762
Piquet: 1749
mike p5xbx: 1743
Newest Members:
MartW
Forum Stats:
Groups: 9
Forums: 50
Topics: 11657
Posts: 101392
Member Stats:
Guest Posters: 1393
Members: 4250
Moderators: 4
Admins: 2
Administrators: Bantam-Super, Jimi
Moderators: pete (Secretary and Essex and London Rep), DrT, Johnny D, Gina Hinde