I have picked up a number of parts bikes with head and piston in that kind of condition.
It is just  N A S T Y   ! ! !

Yuky even.

Hi Fellars..am on the tail end of a motor build after some modifications to a 2014 S40 & noticed the DR cam discussion, I used the DR cam as it seemed like a reasonable option given the shipping/time & our exchange rates in Australia. When I set up a degree wheel & dial indicator to check the cam timing it was pretty much spot on as it says on the spec sheet (new cam chain) but its a tricky process & I can see how easy it would be to be slightly out. I could with some fiddling alter the timing about 9 degs eg..instead of the inlet opening at 6 BTDC it could be 15 BTDC & all the other relevant openings & closings follow suit..which may be something to experiment with at some point but I have set them as the DR specs state. What I did do however is drill the oil holes in the cam as the 95 DR cam has only one hole looking horizontally through the centre of the cam, this hole is 1.5mm where as in my LS40 cam it was 2mm, so I enlarged it accordingly & also drilled the 2mm oiling holes in each lobe...it wasn't that difficult..the cams are just cast metal..not hardened..maybe make up a couple of wooden dollies to sit the cam in..sharp bits & take care.. I didn't have any problems & the factory must have found it worthwhile.  Another point of interest to me is Ive fitted a 96mm DR piston & have read in other posts in this forum of 10.5:1 9.5:1 compression  ratios with the DR piston but when I cc'd the head & did the sums for the cylinder & gasket using the bore x bore x stroke x .7854 formula all I could get was 9.1:1...are the higher comp DR pistons available?... There is so much gap between the top of the edge of the piston & the base of the head (I measured approx 5.9mm with the gasket) that there is no squish effect (the piston is much closer in a DR).. I have also opened up the ports & had the valve seats angled..am going with a 38mm mikuni round slide & a slightly larger diam header pipe with a modified muffler so am interested to find out what its like! Love riding this little bike so hopefully this will give it a bit more spirit!

sparktfxr wrote on 10/03/18 at 04:28:37:


We do not use the stock Suzuki DR pistons - but use the Wiseco pistons made for the DR.  The Wiseco pistons are not made for the LS but are close enough that they can work - the squish is better than the stock LS piston but I still don't believe it is ideal.

The plot thickens.  Just when you think you got things figured out the page turns.

Greetings SPARKTFXR.  I'm very interested in your experience with the DR cam.  Great info on the drilling.  Sounds like I should be able to pull that off with the carbide bits that I originally ordered.  I just didn't have the nerve.  Now that I know it can be done I think I should plan on doing it to mine.


I'm very curious about the timing numbers.  I installed a stock DR650 cam (1995 model year).  The part number should be shown on a picture earlier in this post.  The cam came in a plastic bag (shown in the aforementioned photo).  The bag was factory sealed.  There were no timing specifications included.  I have some questions:

Is your DR cam a stock, genuine Suzuki, 1995 DR650 cam, or is it some sort of aftermarket cam intended for a DR650?  

Did it come with a spec sheet with timing data and instructions packaged with the cam, or did you get the timing specs somewhere else?


At what lift points are you taking your readings (.020", ,040", .050", etc.)?


When I checked the timing at .040" & .050" I got intake opening at 14 and 10 degrees BTDC, respectively.  That's why I'm so curious about your cam.


Regarding your comment about altering timing, I also have given that some thought.  What method are you considering (Elongating holes in the sprocket, drilling new holes, etc.).  Seems to me if you advanced the timing 9 degees to get your intake opening sooner, you might end up with some detonation and starting issues since the intake would then close 9 degrees sooner.  My data shows the DR cam closing the intake sooner than the stock cam.  Advancing 9 degrees would aggravate that.  I was considering going the other direction (retarding) by about 4 degrees.  I might do that if/when I increase displacement and compression.  What are your thoughts.  I would really appreciate any info you can provide on your timing checks (specs, procedure, etc.).


Best regards, Mike

"One of our members (was it Armen or Gary_in_NJ) found out the number of splines on the cam drive sprocket on the camshaft can be rotated in conjunction with moving the teeth on the sprocket - and you can advance or retard the cam timing incrementally."

Yup, that was me. You can make some small cam timing changes by moving the cam sprockets on the crank.

Well, I'm really bamboozled now.  I went to the ProCycle website and the only DR650 cam they sell is for a 96 thru current.  They provide a spec sheet that shows the stock 96 thru current DR cam with intake opening at 6 degrees BTDC, same as SPARKTFXR quoted.  

SPARKTFXR, are you sure you got your timing data correct?  It seems to me your are using the wrong specs for the 95 cam.  The #190 cam they use for comparison is their cam for the 96 thru current.  The numbers look nice to me but unfortunately that cam won't fit our bikes.  Please double check and let us know.  

DBM, have you removed the cam yet?  You mentioned you were going to check for wear on the undrilled cam and followers?

How much thinner head gasket can this engine use without problems?

might be tricky to take care of the extra slack in the chain.

Verslavy