like 6 or so months ago i posted about rejetting (i started to take it apart, gave up and took it to my local shop) since i have put the WB pipe on instead of the mbrp race pipe its running HORRIBLY....wont start, and when i finally get it "warmed up" it bogs like crazy (the grab bar and the discs all have a ton of black soot) and im assuming my plugs are nearly solid black again....


so i bought 4 more main jets 155-160-165-170-175 and i want to get it running pref. without having to pay another 50 bucks....

the last time i posted someone had a picture of hte bottom of the carb and it showed where each jet was...i. have decided to try this without taking the carb off and that pic would help a lot seeing as i can hardly see anything up in there.

any help is appreicated!

 

This should help.. you need Adobe to view it. After you click on the link, click on "PDF".

Dyno Jet

RoughRider01

 

I already told you what set up you should use. If you want walk through help just PM me.....

 

If you haven't replaced the screws on the carb don't bother trying to take the bowl off the bottom while it is on the quad.

Unfortunately, this task really requires you to take care of the bowl screws first! Get some cap head allen screws as replacements. Then you can re-jet with ease.

Don't bother changing anything but the main jet. That's all you need to change.

As for why it is tough to start. . . your pilot jet could be clogged (mine has had that before. . . seems to gum up. Take it out and clean it with carb cleaner and re-instal.

Also, how many hours do you have on your quad? Have you checked your valve clearances? This may be why it is tougher to start!

 

are the bowl screws that everything says you need vice grips to get off- the 4 goldish colored phillips head screws on the very bottom of the carb? (3 of them are like 2/3 of an inch, and one of them is like 3/4 of an inch long?)

if so, i was able to get 3 of them off quite easy (this may be becasue when they rejetted it they had to loosen them up)

the only one i cant get off is the one that faces the right rear tire (this woudl be if you were sitting on the quad, it points toward the R-R tire)

i tried various screw drivers (hard to get pressure on it so it dosnt strip) and pliers, and the smallest vice grips i have wont fit there....

so ill probably have to go buy a tiny tiny pair if i can find some....

o and Pushin, i have you on my list (i saw you on the other day for only a few minutes) my name is r00st650 on the yahoo msgr.

Thanks again pushin and everyone for responding, im hoping this will save me the cash and ill can the knowledge needed to do it in the future for riding trips and weather changes)


**** ( also, i tried that Dynojet PDF file, but everytim i click it the only options (in a new window that open) are "download adobe" and "close this window" and i already have adobe.... (i can open those other files, but the "PDF" wont open...) ****

 

Your options for removing the screws are:

Needle nose vise grips
Impact Driver (if you haven't stripped the head yet) - These are available from your local autoparts store and cost about fifteen bucks.
Lastly, you may need to get a Dremmel and cut a flat head into the screw. You will then probably want the impact driver above to get it out.

I think some people have cut the heads of them off then drilled them out but, I haven't done that.

Whatever you do go get some allens. Don't put those things back in there.

Oh, and you will need the carb off the bike and against a hard surface (block of wood on the ground) for the impact driver to work.

 

ok. I think for now ill try a new pair of vice grips.... (i would rather not take the carb off right now if its not a MUST)

the head is SLIGHTLY stripped....but i think ill probably try the dremel on it if the vice grips wont fit....

ya my main other hobby is rc cars, so i have a ton of 3mm screws but none in the 4mm (i beleive these are 4mm?) so ill have to go pick some up tomorrow....


i also forgot to answer you Duneme.... the quad probably has about 40 hours on it now.... (i have about 4 oil changes...i did one after one hour just becuase i was paranoid about metal shavings...then one at 7, one at 15, and the other at around 25)

I have not checked the valve clearance....what do i need to do to check this? is it a really time consuming process? (lots of parts have to come off?) or just the top of the head?

ill unscrew my pilot jet after i get my main jet changed and make sure its not clogged....

Thanks again guys for the responses

 

how long should u go before u have to check or adjust your valves?

 

I got the bottom screws off with channellocks, just squeeze really tight!

My other main hobby is RC's too. I got two nitro trucks (tmaxx and losi). I love the sound of those little engines and chasing cars that go up and down my road..haha.

RoughRider01

 

The DS 650 uses the Rotax 650 engine that BMW has used in their F650 for years.

This site has good info on engine maint. etc.

I think the manual calls for checking the clearances after the first 10 hours.

It is pretty easy really. You will need to get the engine to TDC (Top Dead Center).

Take the front plastic off then remove the gas tank (easy!)

Make sure you are in neutral.

Remove the valve cover on the engine and you can use a socket on the cam chain sprockets to turn the engine. The lobes of the cams should point out - away from eachother - when it is at TDC. You should remove a plug and use a plastic straw or something like it as a feeler to tell when the piston reaches the top. There are marks on te cam sprockets that should be horizontal and align with eachother.

You can lock the engine at TDC with a TDC bolt (you can make one yourself) TDC Bolt

You will need a set of feeler gauges (Sears or Autoparts stores have them.) Check the manual for the correct tollerance. Make sure the engine is cold (has been sitting over night at least!)

Make sure you take out the TDC bolt before you start up the quad!