Is your DRZ S or SM with steel tank and vacuum petcock leaking?
Looking for a non vacuum petcock option that will fit well?
The Yamaha Raptor OEM petcock is an inexpensive reliable swap... Except it does not fit
....With the steel tank that is...
It became popular with the DRZ cult ....when we found it was a direct fit to our DRZ...with OEM or aftermarket plastic tanks ..My personal DRZ last had a steel tank in 2003.....and all that came in to my work place were having the steel tank swapped for an aftermarket larger plastic tank...I just never noticed the fitment issue with steel tanks until it was pointed out to me but other forum members.
Then about a year ago, I had a guy wanting to keep his steel tank on his SM build........and I had 4 brand new Raptor petcocks sitting on the shelf ..
The OEM vacuum operated petcock found on the DRZ400S and SM is a part that will fail.. Not the parts fault, just that rubber and today's gas don't do well together. (that's actually not really true, its just the type of rubber being used is not holding up)
Sometimes the OEM vacuum petcock fails on the gas side, other times the vacuum diaphragm side.
The Yamaha Raptor non vacuum OEM petcock was found to fit well so it was a common go to swap.....
The problem was, those ,making that recommendation had a DRZ400E plastic tank, or one of the many aftermarket plastic tanks and we did not know the part did not fit well with the OEM steel S/Sm tank and either the stock BSR36 carb or the commonly swapped in FCR. The issue is the fuel line path..
With the steel tank and BSR or FCR, you have a close fit, large misalignment, and interference with the FCR choke
Though same have figured out a way to make it work....
I call this one "The long way home"
About a year ago, I had several new OEM Raptor fuel petcocks on the shelf and a DRZ customer with a built SM but using a stock tank..I needed to make it work...
Over the years I have seen more then a few pressed in steel barb fittings come out of a aluminum petcock ...so i figured, way not remove that steel one on the raptor part and put a barb on the other side.
I tried it, and it works, so have a few of them on bikes for years now..both FCR and BSR bikes.
Parts required:
- Raptor petcock Yamaha FUEL COCK ASSY 1 (5LP-24500-01-00)
- 1/8" NPT hex socket plug (you can use brass, steel, aluminum, and it can be hex socket, or an external drive type..I prefer the socket hex so it will be recessed , but anything will work. If i were to use an external square drive plug, after installing it, id cut off the plug flush to the petcock body for more finger clearance on that side and a cleaner look)
- 90deg 1/8" NPT x 5/16" barb (again there are lost of options, you can use fancy Aeroquip, Earls, , Jegs branded aluminum fittings here or brass stuff from the local hardware store.. BUT, most of those I have found have been 1/4" barb, which is slightly underside to stock..in action, they have worked just fine though. You could also use a 90deg 1/8" NPT male x 1/8" NPT female fitting and then a 1/8"NPT x 5/16" barb if the barb/NPT fitting is not available.)
- Teflon tape or other fuel resistant sealer
- LTR Q drill bit (21/64 is the closest fractional bit to the LTR Q, it is slightly undersized, but I have found most are not using an ultra precision mil to drill the hole, so some wiggle in the drill bit happens in your drill press or hand drill , that makes the hole slightly oversized...and it works out just fine.)
- 1/8" - 27 TPI NPT tap (not super common at big box hardware stores, so you may have to order it)
New Raptor petcock stripped down read to go, the steel tube that was in the right side comes out easily with a pair of pliers, crush and twist/pull .
A way..... I have used a drill press, mil, and hand drill.... all work.
When I use a drill press or the mil, I put a piece of drill rod (you can use a twist drill 5/16") inserted in the hole left from removing the tube... ..insert the drill as far as it will go into the petcock, then chuck up the drill.... now adjust your vice or other hold down to hold the part... Your drill press is now centered and aligned to drill straight through the port at the same axis as the old hole....
Once the part is set up..
Drill a hole all the way though..
Go slow and sneak up on the thread depth...test fit the plug / fitting after every few turns of the tap... there are lots of variables in thread size I have found in off the shelf NPT products.. if you cut too deep, the plug or fitting may go in to far and block the transfer port...not deep enough and the fitting/ plug will not go in far enough to be stable and be retained. As you can see below, the threads are of different depth on this one..I had to cut a bit deeper to get the 90deg fitting in 4 full turns. The particular hex plug I used this time must have been at the smaller range of allowable diameter for the thread size as it went in flush with much less thread cutting..Test fit, often........
Once your done cutting threads on both sides, blow out the holes, flush with some break clean to remove cutting fluid and swarf...
Plug installed on the right (forward facing) side of the petcock where the steel tube used to be..it is flush with outside, and not interfering at all with the fuel transfer port
Screw in the 90deg fitting and reassemble the petcock. I cleaned up all the exsposed teflon tape for a cleaner look
In no way is this anything more than A WAY to MOD the Raptor petcock to work with the DRZ Steel tank....