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  • destroyed DCR head inserts

    (mainly a q for rgvlee and druu)

    is there any place in perth where i could pick up standard inserts for DCR heads? i screwed up my inserts (guessing through detonation) had no compression on my horizontal cylinder. photos below

    at this rate, i'll probably revert back to standard heads if i can't get an insert any time soon, but i'd like to use the DCR heads rather than have them sitting in a box in the shed

    any advice or pointers are greatly appreciated
    Attached Files
    Originally posted by Pkunk
    It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

  • #2
    not in perth dude just get them from the tuning works, they only take like a week to ship.

    Comment


    • #3
      already got an e-mail from [email protected] he's a top bloke, always willing to lend a hand. going to have to run on standard heads next round, but that probably isn't a bad thing
      Originally posted by Pkunk
      It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

      Comment


      • #4
        That isn't deto.

        To crack outside of the combustion chamber is intereting, is the top of the barrel square? It is thin there, that is probably the reason the new inserts went from a 3mm oring to a 2mm oring.

        i have a spare set with 0.85 cut into them, but I don't know if they'll fit. Sean said the new CR inserts won't fit your heads, but they do fit mine. There were 3 versions of the heads, you've got v1 and I have the v2 heads.

        It took Sean 4-6 weeks last time to get a set of inserts made, they are made to order.

        Comment


        • #5
          yeah, sean's already said that the CR inserts wont fit the original DCR heads, but i'll check with the sizing on my heads. at this rate, i'll probably wind up standard heads for next round. i need to dumb things down until i get fast enough to justify getting the bike faster

          the crack is at the top (intake side) of the barrel square. the insert is quite clean at the intake end, the exhaust side being browned quite a bit

          at the track, the bike was revving reasonably well, but it wasnt pulling at all. it was not revving past 10k5 out of the basin. i had thought that i had leaned out the fuel/oil ratio too much (up to 36:1) and this was why it was losing top-end power. spark plug is chocolate brown tho, and i was told that that is what to aim for (i've been told that honey brown is ideal, but at that point, you freak out that you're running too close to the edge and enrich the mixture)
          Attached Files
          Originally posted by Pkunk
          It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

          Comment


          • #6
            the colour of the insulator is not a good indicator. the smoke ring at the bottom of the insulator is what you want to look at. You also want to pay close attention to the electrode to make sure you are running the correct heat range for the track. you'll be needing 10s minimum.

            that brown/tan colouring is caused by the oil.

            if you a running a good full synth, you'd probably be able to go right out to 40:1. It depends on the oil though.

            can't say much more on tune without knowing the full picture of mods.

            Comment


            • #7
              *nods*

              just read the article linked to by RGV250 forums. running Redline race synthetic atm with pump RON98 (Caltex, tho i doubt that makes any real difference). i have the DCR valves and heads, NGK BR9ECM plugs, Tyga stainless exhausts. i havent got the carbies in front of me atm, but i'm guessing 260/270 mains with 27.5 pilots and stock needle. std 22d30 SAPC box, std airbox and filter, no other mods to mention
              Originally posted by Pkunk
              It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

              Comment


              • #8
                Why do you want to run such a high fuel / oil ratio at the race track???

                I ran 125 GPs along with heaps of others (Tom Hatton, Bryan Staring, Bob Huphries etc...) and never ran less than 30:1 - We all used high end exotic oils - elf / rock oil / Motul etc. Running a ratio as high as you suggest is fine for a boat motor or dirt bike where you spend very littel time a WOT or with throttel closed at high revs..
                IMHO with ratios as high as you suggest you are just asking for trouble. You are just asking for bearing failures (esp little end) and poor ring / bore life. It is a myth that running less oil produces more power esp at club racing level and the potential point of tune of an RGV .

                Comment


                • #9
                  that's what i heard (and read) too. the comp kit suggests running 30:1 as standard
                  Originally posted by Pkunk
                  It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

                  Comment


                  • #10
                    Yes, but let the BS stories of some keyboard know fuck alls, other than what they did read on the interweb wanksites warriors, stop you blowing up all sorts of goodies.
                    how many actualy ever held a spanner or for that manner punted a bike around the track in anger?

                    Ohh disclaimer after a PM; just to make it crisal clear.
                    This is NOT aimed at anybody specific, but if anybody feels that it could be him or her, then so be it.
                    Last edited by Jamathi; 09-09-2009, 02:32 PM. Reason: seems it needs a disclaimer.

                    Comment


                    • #11

                      Comment


                      • #12
                        And some like to visit HCMC race days and keep their bikes on a trailer:lol

                        Only kidding...

                        Regarding the head have you checked to see if you can get it repaired locally - someone like Les Dean might be able to do it.

                        Cheers
                        Last edited by PortedII; 14-09-2009, 08:45 PM.

                        Comment


                        • #13
                          The distance between the edge and the oring groove is too thin, hence the 2mm oring revised inserts. Getting it repaired won't help as it could happen again.

                          Norbit has a set of heads to get him through round 5 now and Sean from TTW is sorting out a new set of 2mm oring revised inserts (as he will for anyone else with these first version CR heads)

                          I will stand by what I said RE good full synth ratio, you can't really compare a GP125 to a proddy 250, the 125 will work much harder and it shows in the HP they make. Some marine oils go out to 100:1 for the good stuff, but if you want to talk oils, start another thread. Castor and some of the cheaper synths, TTS eg, need the higher ratio. The kit manual was written 20 years ago in the days when TTS ruled.

                          Comment


                          • #14
                            Just on oil... for what its worth...

                            When i rebuilt mine last, I ran 33:1 premix while waiting for the oil pump to prime (which was running at the same time) and it had no real impact on perceived performance for the first few tanks of fuel (filled up at about 1/2 through the first batch of premix, etc - weaning it back onto injection - so second tank would have been 66:1 + injection, etc - simply because i couldn't be fucked draining the premix - or rooting around bleeding the oil injection into a cup or whatever).

                            Obviously not measured on track or whatever... but that first tank must have been rich as fuck with oil and it seemed to run just fine.

                            I guess what I'm getting at is that I reckon the power difference between say 33:1 and even 25:1 is probably too small to even measure....
                            Last edited by thro; 15-09-2009, 09:02 PM.
                            “Crashing is shit for you, shit for the bike, shit for the mechanics and shit for the set-up,” Checa told me a while back. “It’s a signal that you are heading in the wrong direction. You want to win but crashing is the opposite. It’s like being in France when you want to go to England and when you crash you go to Spain. That way you’ll never get to England!” -- Carlos Checa

                            Comment


                            • #15
                              Originally posted by rgvlee View Post
                              The distance between the edge and the oring groove is too thin, hence the 2mm oring revised inserts. Getting it repaired won't help as it could happen again.

                              Norbit has a set of heads to get him through round 5 now and Sean from TTW is sorting out a new set of 2mm oring revised inserts (as he will for anyone else with these first version CR heads)

                              I will stand by what I said RE good full synth ratio, you can't really compare a GP125 to a proddy 250, the 125 will work much harder and it shows in the HP they make. Some marine oils go out to 100:1 for the good stuff, but if you want to talk oils, start another thread. Castor and some of the cheaper synths, TTS eg, need the higher ratio. The kit manual was written 20 years ago in the days when TTS ruled.
                              NORBERT!!!! everyone makes that mistake. bloody movie...

                              i've got a jet kit for my RGV on the way. have to start making a cheat sheet of jet settings. so the journey begins. apparently the biggest power gains can be gotten through matching up ignition, chambers, ports, deck height, squish and jetting. the best guy in all of WA for that was apparently Dean Harrison, but he passed away last year

                              i've got tips on a couple other guys, but any major plans will get postponed until next season. getting a reliable engine (ie. mechanically sound for more than a couple rounds) is more important than having a grenade that you can't handle properly yet and will have to rebuild every couple rounds
                              Originally posted by Pkunk
                              It is a SCIENTIFIC FACT that all blondes with good bodies look 80000000000000000000000x without blonde hair

                              Comment

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