some times when i go trail rideing and when i start to kick into it i hear and feal a thumbing sound under my seat . it only does it one time when it happens . whats that all about? [img]i/expressions/face-icon-small-confused.gif[/img] all stock DS 03''

 

I hear the gears clunking at the lower RPM range when starting out sometimes. Usually when turning.

I think that is a normal sound?

 

That is probably the chain jumping under high load at low rpm. Might try tighten a little.

 

common problem with the ds is the upper chain roller, check that.

 

no,no, its nothing like that , its the air box i can feal the air box lid like move up when it happens ,i saw it happen one time when i had the seat off ,the air box lid moved up like the air box was expanding !! and it makes a thumbing sound and then stalls out !! thats what its like. [img]i/expressions/face-icon-small-sad.gif[/img] i took it to the dealership and there like, OHH its probley the jetting , but it was not the jetting! hmmm anyone know ??[img]i/expressions/face-icon-small-confused.gif[/img]

 

Sounds like backfire through the carb. The most common response on the forum is jetting or valve clearances. have you checked your valves? If they are too tight they won't seat and the combustion gases come back out the carb.

Justin

 

ok, no clue what youre talking about,ive herd about jetting and stuff but never done it my self . if i take it to the dealer ship what shod i tell them to do to it ?

 

when i first got my baja it would backfire through the carb when i landed on it a little hard.

 

1st of all, buy a service manual. Everything is easy to do on the DS with the proper help. Here is a link on how to check the valves.Valve Check. You can also do a search on the forum for valve, valves, clearances, etc and find lots of posts on the suject. Also, is the jetting on your carb stock, and have you done anything to the bike that would require jetting changes, ie. pipe, filter.

Justin

 

all stock ds650 2003 , thanks for the help .