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Indirectly relating to this subject, while upgrading to wide pulsers I'm changing out all early oil pump drive gears to late model. The late gears have a numerically lower ratio resulting in the pump turning faster and more oil flow.

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Installed a thick pulser in my L. It definitely starts easier. Carb is gummed up with crap modern gas so I have to rebuild it before I draw more conclusions.

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how late is late? and what model? xr650l  or xr600r or the same anyhow.

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88 and later 650L and 600R oil pump drive gears are the same but the thick pulser is 88 up 600R only.

Edited by valvesrule

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On 2/15/2017 at 9:26 PM, brianhare said:

 

 

And yes get an XR600R bosser,the XRR timing was 6 degrees base timing and 31 total degrees....the XR650L timing is 8 degrees base timing and 28 degrees total timing..

 

the base and total timing is the product of the pulse bosser.......so if you put a XRR bosser in your stock bike you immediately have a lower intial timing and more total advance with changing anything..

 

B

just got myself an xr600r boss for my nx650 , thinking the few extra degrees of advance should work well with the 103mm 10:1 piston and fcrmx that i'm running, still got stock cdi but will no doubt switch to an ignitech sooner or later ,

so what does 2 degrees less advance on base timing do for bottom end ? i would have thought it would make less power at low revs , but i dont know 

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Im confused... what is going on here? Whats the deal with swapping the thick pulsers? and what is a bosser?? Im just trying to understand this haha :ride:

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On 12/1/2017 at 1:42 PM, paint it black said:

...so what does 2 degrees less advance on base timing do for bottom end...

It's an RPM based curve so you'll notice it be a little more "lazy" (should be easier with your bumped ccompression) on the start but you won't notice an effect power at all because you probably never actually be moving at that low an RPM.  It probably idles above that point on the advance curve.

Edited by Hollerhead
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13 hours ago, brraaapperdoodle said:

Im confused... what is going on here? Whats the deal with swapping the thick pulsers? and what is a bosser?? Im just trying to understand this haha :ride:

This is a picture of a pulser (a modified 600R version).  The boss is the "block" sticking up. 

This pulser rides round and round under the right side cover and tells the ignition when to do it's thing by interacting with the pulse generator.

Moving the leading edge of the boss in relation to crank rotation will retard idle, or initial, timing and make for easier starts.  Moving the trailing edge of the boss (like I did on this one by adding metal and re-machining) will allow more max timing advance.  

A modified pulser can be good for a stock CDI but really shines with an adjustable ignition module like the Ignitech quite a few of us use. 

20160724_183357.jpg

Edited by Hollerhead
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Thanks for the replies guys, 

sounds like its worth a go fitting the xr600 part with the stock cdi then , 

i'll be getting an ignitech cdi pretty soon anyhow, just because 

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On 2/27/2017 at 0:55 AM, valvesrule said:

40 is a lot of lead for air coolers unless they are built low compression turbo motors by my old world schooling.

 

How about adding a knock sensor to the aftermarket CDIs. Do either have a provision in the software?

Under throttle, 40° is a truckload of advance for just about any engine, period. My turbo Pinto has 40° in a few cells, but only up to about 65kPa of manifold pressure. By the time manifold pressure reaches atmospheric (~100kPa), timing is down to 31° and it drops rapidly from there. It's an old 2v '70s design, so it wants more timing than newer "fast-burn" and pent-roof architecture. RFVCs have a big, hot, open chamber with little quench and unknown swirl, so less timing is probably safer than more.

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Ignitech is killer.  Even stock curve seems great to me.  Order one instead of stock CDI!!  I think it's like 200 bux. Worth it!!! 

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still using megajolt after all these yrs... very reliable, made in lynnwood, wa, excellent customer service, and even in english, surprise.

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I've got one that I haven't gotten around to putting in yet , but I've got my pulse generator advanced 6* along with an Ignitech.

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