Bws Bogging problem all restrictors removed and rejeted from 70 all the way to 86

[bashyy21]

Hi this is my first post hopefully someone can help here,

i have a yamaha bws 2006 model its done 12500km

it have pm tuning raceing pipe and 3.1g rollers all other engine parts are stock,

fo some reson the bike bogs all the way to 30mph then seems to pull ok to 50mph, accept when u de-throttle to say 20mph then if u throttle again it just bogs again and takes along ages to pick up speed, i can only get 50mph when i pull off from a stop start

i have tryed rejetting it from 70 all the way to 86 and its done nothing i have evern just put in new piston and rings today still nothing,

could it be the stock 12mm carb or i have been told it could be cdi but i dont no if my cdi is restricted or could it be clutch springs maybe ??

i have no idea could anyone help please been trying to sort this for a few months now.

 

[Lodewijk]

• Topic moved to English section of this forum

On what clip/position is your throttle-needle? And what do you mean exactly by "bogging"

 

[bashyy21]

• Topic moved to English section of this forum

On what clip/position is your throttle-needle? And what do you mean exactly by "bogging"

hi the neddle is now on the top it was in the middle but hasnt seemed to make much diffrence, well it just seems like the revs drop and it takes ages to pick up speed, like theres no power only seems like theres power after it gets to 30mph but thats only from a stop start.

 

[Lodewijk]

Its not just a matter of too heavy rollers or the wrong spring? Also put the needle back in the middle. You dont have "false air"? Im not sure how you call this in English, its for example when your engine is getting air from a small gap between the carb and the airfilter (when mounted incorrectly).

Have you tried a smaller main jet? Going down to 68 66 even 62 is worth a try. Some enginges just dont need thata big main jet. Try before you .. give up

 

[bashyy21]

Its not just a matter of too heavy rollers or the wrong spring? Also put the needle back in the middle. You dont have "false air"? Im not sure how you call this in English, its for example when your engine is getting air from a small gap between the carb and the airfilter (when mounted incorrectly).

Have you tried a smaller main jet? Going down to 68 66 even 62 is worth a try. Some enginges just dont need thata big main jet. Try before you .. give up

i havent tryed smaller jets it come with 70 jet standard with de-restricted standard exhaust i havnt tryed changing spring yet and rollers are really light 3.1g and theres no false air getting into the carb

 

[Lodewijk]

It just sounds like the whole scooter needs to be jetted/adjusted/tuned.. sorry, my English fails me here.. but I mean that the carburator and variomatic system have to be setup with the right jet, rollers, springs, and belt. Is the belt in OK condition btw?

Can you describe the RPM course from 0 to topspeed when you drive away fullthrotthle?

 

[bashyy21]

It just sounds like the whole scooter needs to be jetted/adjusted/tuned.. sorry, my English fails me here.. but I mean that the carburator and variomatic system have to be setup with the right jet, rollers, springs, and belt. Is the belt in OK condition btw?

Can you describe the RPM course from 0 to topspeed when you drive away fullthrotthle?

yea it seems to pull ok to 10mph then the rpm seems to drop and it takes ages to pick up the revs and speed again, and the belt is in good condition the rollers come with the exhuast so they should be ok, but i havnt touched the clutch it seems the pull off at about half throttle revs dont seem to be high on pull off

 

[Lodewijk]

Put in that 70 jet and put the needle back in the middle.

Drive fullspeed for a minute or so (the scooter must already be warmed up at this point). When you are driving +- top speed full throttle, turn of your ignition switch and hit the breaks. Now screw out your sparkplug and look at its color.

It should be caramel / coffee-with-a-little-cream, something like this:

http://i42.tinypic.com/i1jwnt.jpg

If that is the case, then you can leave your carburator alone and you'll know that the problem is in the transmission (variomatic system). Just to be safe, try a little lighter rollers if you have them. What contraspring do you have? And are the rollers new or are they old and square?

"the pull off at about half throttle revs dont seem to be high".... wel that seems kind of obvious ?

 

[bashyy21]

Put in that 70 jet and put the needle back in the middle.

Drive fullspeed for a minute or so (the scooter must already be warmed up at this point). When you are driving +- top speed full throttle, turn of your ignition switch and hit the breaks. Now screw out your sparkplug and look at its color.

It should be caramel / coffee-with-a-little-cream, something like this:

http://i42.tinypic.com/i1jwnt.jpg

If that is the case, then you can leave your carburator alone and you'll know that the problem is in the transmission (variomatic system). Just to be safe, try a little lighter rollers if you have them. What contraspring do you have? And are the rollers new or are they old and square?

"the pull off at about half throttle revs dont seem to be high".... wel that seems kind of obvious ?

haha yea the spark plug is caramel colour and i will try rollers the rolers i have now are new i dnt think i can go much lighter and im not sure what spring i have thats still all original that come standard with the original exhaust

 

[Lodewijk]

I read on the internet that there is a restriction on the CDI of old type BWss. If there is a cable with a plug/connector at the and of it coming out of your CDI, that is not the main connection to/from the CDI.. then try to disconnect it. It should be a green thingy. If you dont have this, it might be possible to cut "a red wire" coming from the CDI.

I must warn you that I only read this on the internet, so I cannot confirm if this is true or works. Well.. if it doesnt you will know soon enough, so might be worth a try since it does stroke with your problem description

Oh and a fresh sparkplug can never hurt if you haven't installed one already

 

[bashyy21]

I read on the internet that there is a restriction on the CDI of old type BWss. If there is a cable with a plug/connector at the and of it coming out of your CDI, that is not the main connection to/from the CDI.. then try to disconnect it. It should be a green thingy. If you dont have this, it might be possible to cut "a red wire" coming from the CDI.

I must warn you that I only read this on the internet, so I cannot confirm if this is true or works. Well.. if it doesnt you will know soon enough, so might be worth a try since it does stroke with your problem description

Oh and a fresh sparkplug can never hurt if you haven't installed one already

on my cdi i just have 1 box connection with all the wires coming from it, and yea i have installed a fresh plug

 

[bashyy21]

I read on the internet that there is a restriction on the CDI of old type BWss. If there is a cable with a plug/connector at the and of it coming out of your CDI, that is not the main connection to/from the CDI.. then try to disconnect it. It should be a green thingy. If you dont have this, it might be possible to cut "a red wire" coming from the CDI.

I must warn you that I only read this on the internet, so I cannot confirm if this is true or works. Well.. if it doesnt you will know soon enough, so might be worth a try since it does stroke with your problem description

Oh and a fresh sparkplug can never hurt if you haven't installed one already

yoo i have now tryed yellow clutch springs from polini still no diffrent the bike sounds fine on the stand it doesnt sound like theres any rpm drop has any1 else got any ideas ?

 

[oerski]

sounds to me like rollers are too light. if you are all stock in the trans sans rollers, and all stock in the motor sans the pipe, try about 30gr total weight or 5gr rollers. your vario is prob opening too soon because of the light rollers, also might consider a different pipe. not sure how pm tuning racing pipe compares to any other pipe, but it doest sound well suited for a stock cylinder at all.

 

[ipx]

its not carb , so put original jet back in

what happened is %100 normal

you guys put a chamber with stock pullies expect it not to bog in the middle ?

5 gram is stock , so you say is heavy ?

go to lighter rollers ( remove 1 or 2 or 3 ) .. and use stiffest clutch spring and it get better but it STILL lose RPM in the middle of range

because stock rear pully has bend in its tracks so rpm suddenly drops = slow down .. then it go out of range so rpm go back up again

must use streight track rear pully and stock variator is a joke .. both must be changed ..

other option is put STOCK PIPE BACK ON and all be fine

 

[janet986w]

Hi this is my first post hopefully someone can help here,

i have a yamaha bws 2006 model its done 12500km

it have pm tuning raceing pipe and 3.1g rollers all other engine parts are stock,

fo some reson the bike bogs all the way to 30mph then seems to pull ok to 50mph, accept when u de-throttle to say 20mph then if u throttle again it just bogs again and takes along ages to pick up speed, i can only get 50mph when i pull off from a stop start

i have tryed rejetting it from 70 all the way to 86 and its done nothing i have evern just put in new piston and rings today still nothing,

could it be the stock 12mm carb or i have been told it could be cdi but i dont no if my cdi is restricted or could it be clutch springs maybe ??

i have no idea could anyone help please been trying to sort this for a few months now.

Thanks you for the post. :love::love::love::love:

http://moviesonlineworld.com