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Roger Miller

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  1. Roger Miller

    '05 ignition on an '04

    The difference between the 02/03 CDI and the o4 and CDI is that the older CDI has one modular connector and the newer CDI has two modular connectors on the end of the CDI itself. So to swap the new CDIs onto older engines, you need the wire harness from the newer model. Then for connecting to the stator/ignition trigger, you need to make up two short connector wires with all male push on connectors. This adapts the old stator cable to the newer harness. The old connection was all females on the stator and all males on the harness. The newer harness has two females in place of males. The color code still works, so, you can either make a permanent change on the connectors on one side or the other, or do what I suggest, which is the short jumpers with males on both ends.
  2. Roger Miller

    CR250 crankshafts

    Are the later model crankshafts, like a 2005/6 compatible to replace a 2002-2004 crankshaft? I heard that the 2005/6 crankshaft is a better part. Thanks
  3. Roger Miller

    Cam chain gear question on new top end??

    Having been through this a lot this past season as a result of a shop screwing this up big time last spring, and costing me two top ends plus many other parts - you are on the right track. What you should see is something real close to aligned, and maybe just a touch above and below on each side of the cam gear/cam tower alignment marks. If you take it apart and shift it one tooth one way, put it back, shift it one tooth other way, you will see the difference. Also, when you install the cam chain tensioner, you want it retracted when installed, then let it go to tension the chain. Don't install it extended, it doesn't pull back real well, it just puts too much tension on the chain. One other thing, once you have everything aligned, and you install the cam chain tensioner, roll the engine over all the way to everything lining about again, and the cam lobes point back towards the carb, and see how things line up.
  4. Roger Miller

    Just rebuilt, won't start

    Well, the winner is Firedude. My engine builder and I got together this afternoon, and with all of the other troubleshooting - - which to finish Sunday, swapped the flywheel, no change. Swapped back in the Hot Cam, just to see if the '02 cam I picked up was messed up, no change. Stuck the running engine back into the kart and it fired right up, as usual. So, at the end of yesterday, and this AM, I was back to just the core engine, and so the engine builder and I agreed that I should bring it in for a leakdown test and we found an exhaust valve leaking, rather badly. This head was on the engine that tossed a rod, and although both the piston and the head/valves have no witness marks of things colliding, it would seem that there was enough collision when the rod let go to tweak at least one of the exhaust valves. So, shame on us for not checking that closer prior to reassembly. We stuck on the spare, stock, 04 head we had removed from this motor and the leakdown was perfect. So, the engine is now all setup with that head, the '02 cam, and reshimmed and all that. We had planned to rebuild that head before using it, but we have a race this weekend, and no more time. So, we will have to hope that there is not a pending valve failure or anything, but it is properly adjusted. I will be sticking it on the kart in the AM and testing it, and breaking it in, and the doing all of the final setup and packing for the weekend. Thanks for all the suggestions and comments. And yes, I am very careful with the wiring - always - and, I have 2 really short jumpers with male/male connectors that adapt the 02 stator assy to the 04 ignition. Now that all of this is sorted, I will be moving to all '04 electrics as I can to eliminate this little thing.
  5. Roger Miller

    Just rebuilt, won't start

    I have swapped out the plug a couple of times. I put a new plug in the running engine last time it was in, and it was fine, and then have used that plug since. So today, I changed the flywheel, no change to the problem. I swapped out the '02 cam, and put back in the Hot Cam that was with this head, no change, although I didn't reshim and the exhaust was about .0015 tighter than before. The intakes were unchanged at a very loose .005 That's it, I have changed everything except the entire head, and I may do that tmw after I do some talking with Honda about the flywheels, and the engine builder that did the rebuild. He has been kept up to date by email, but he is just as stumped as I am. All of the "usual suspects" are what stays on the kart and are used by both engines. Done for tonight.
  6. Roger Miller

    Just rebuilt, won't start

    Understand that is a common problem. We blew the base engine (which is the currently "running" engine) twice last season due to a shop screwing up the timing before I knew much about the engine. I have since become pretty much expert at cam timing. Using a piston indicator, the left side timing marks, and the cam gear marks. Like I said in the first post, the running engine (which has not been touched, and has been raced) and the non-running engine, which was just rebuilt, side-by-side, have identical timing for the cam, versus the timing marks, and the piston position. I just tore down the left side again, as that is the only "active component" area, to look at the flywheel. I was holding the flywheel from the engine that threw the rod in my hand, and noticed they were different. I found the part numbers on the flywheels, and the one in my hand, from a '02 motor is part number - MEBA 0032000-9812 followed by 8CX The one on the non-running engine ('04) is - MENA 132000-0052 followed by 9EZ So this is a Honda part, Service Honda shows the same part is used for 02-04, 31100-MEN-000 - so I guess tmw I will be calling Honda to see if I can track this down. Overall, they look the same as to where the timing magnet is and the timing marks and all. The non-running engine I purchased used, as a 2004 engine, and I sent it off for rebuild without any testing. It had all of its parts and looked fine. The rebuild was to put in an aftermarket rod and of course new piston, rings, etc. We swapped onto the engine an '02 head that was on the engine that tossed the rod. It had a Hot Cam Stage 1, and kibblewhite valves. The head was not touched by the rod issue. And we took out the Hot Cam and put in a stock '02 cam. The stator tests with a DVM the same as the one on the running engine. So I am at a loss at this point, unless it is the flywheel. To review the information: Running Engine: '02 with '04 piston, stock cam Non running engine: '04 with '04 piston, '02 cam, KW valve kit Common between the two, what is on the kart: Carb, Coil, CDI ('04), Wiring harness ('04, with adapters plugs for '02 stator when needed, like on running engine) and Fuel pump/ fuel supply, and water system. What is not common: Stator (which we swapped an "04 and replaced it with an '02 on hand from a previously running engine), Flywheel and hard parts. Spark plug replaced, swapped several times, etc. The third engine I mention from time-to-time is an '02 that I bought from the Classifieds here, it had the worked head, with the Hot Cam and KW Valve kit. We ran it for about 3 races, and then it threw the rod. Looks like bottom bearing failure, or, the rod itself just let go, the bottom end of the rod that wraps around the bearing broke into three pieces, and the cage was severely mangled. The rod buried itself in the case where the counterbalance shaft runs from side to side. The piston was cocked in the bottom of the cylinder and damaged the cylinder a bit. It might even be below where the piston even goes normally. But like I said, the head wasn't touched. The valves were perfect. And that is the head on the non-running engine. The head from this engine is being worked for a valve kit. I am trying to decide between KW and RHC. But that isn't the point right now. Thanks for all your time.
  7. Roger Miller

    Just rebuilt, won't start

    OK, tried that took off the cam gear, turned the engine one revolution and remounted the cam gear. No joy. I wasn't sure why that would work anyway as there have been numerous threads about the ignition not knowing compression stroke from exhaust stroke to know which TDC to fire, that there is a spark every revolution. Anyway, I have checked things over several times, and still, swapping back to the base engine and it runs, and the rebuilt one doesn't. The only thing I can think of that is active now that hasn't been changed is the flywheel. Or, I have two bad stator/ignition sensor assys here, one bad on the engine I bought and rebuilt, and one bad on the engine I was just running last season that tossed a rod. What a mystery.
  8. Roger Miller

    Just rebuilt, won't start

    Freshly rebuilt - from the crank up. Won't start - just a nasty back fire every few seconds on the electric starter. (Yes, this is an R, but with an outboard starter) Swapped in the unrebuilt engine and it starts right up. This says the carb, CDI, coil and wiring harness, and the fuel supply is all good. That leaves the Stator, Flywheel, and then the hard parts only. Swapped the stator and no change. Swapped back in the unrebuilt engine and it still starts right up. The valve timing is correct - visually matched to the engine that runs. Valve adjustment is right. What am I missing on the rebuilt engine that would cause this???
  9. Roger Miller

    Ignition Identification

    Looking back on the ebay transaction, it was listed for a "450R" I wonder if maybe it is a TRX ignition????
  10. Roger Miller

    Ignition Identification

    Hi - need some help folks. I am piecing together ignition systems for our machine, and I recently obtained a 2004 CRF450 engine with the ignition included. We have been using 2002 engines and I am aware of the basic difference of the connectors, that the 02/03 has one connector, and the stator connectors, and I can see how to adapt the 04 ignition with two connectors, and the 04 harness to the 02 stator. All that is straight forward. But at some earlier time, I bought a late model ignition module off of ebay, ane now see that it has a different configuration of the pins in the two connectors on top of the module. The two modules are like this: The one that came with the '04 engine is marked: 071000-2430 and MENA the two connectors are: 4 pins and 6 pins and the module is the same physical size as the 02/03 module The other one (suspect) is marked: 071000-2510 and HP1A the two connectors are: 6 pins and 8 pins and have none of the "keying" tabs inside, and, obviously do not fit the '04 harness I received with the '04 above. And, the module itself is larger than the other ones, the known 04 and the older 02/03 Any help? Did I get a YZF module disguised as a CRF Module? Thanks,
  11. Roger Miller

    The Forum is now split!

    Well, great, this may save me then. I was going to ask what the pink wire mod was, as I can't find a pink wire anywhere in the wiring that we use for the Superkart. I guess this is an "X" only deal then.
  12. Roger Miller

    Opinions on a combo of parts

    Oh, and is the counterbalance shaft different between the older and newer crankshafts? I would think so if there is a weight difference
  13. Roger Miller

    Opinions on a combo of parts

    Hi everyone - thanks for more good information. I will ask a couple of more questions and answer a few as well. I am assuming the "air boot" is on the air intake side of the carb, not between the engine and the carb, is that correct? If so, then we are not using anything there, we have an air filter adapter attached to the carb and a universal Unifilter attached to that. The adapter provides a short "air horn" sorta thing but mainly provides a transistion from the carb intake diameter to the air filter diameter of 2.5" What is considered "High RPM?" We shift a 10K (or pretty close, 10.2 maybe max) and in 5th are so far geared to top out at about 9.2-9.5K We are still working on better gearing. Depending on the track and the length of the straights, we might be holding rpm for 30 seconds. See discussion of "2 strokes" below The best stock cam for power is the 05/06 - what kind of power? Low end? Or across the entire band? See discussions of 2 strokes below. Thanks for the tip on the cranks. I will discuss with my engine builder. See the rod discussion below. Now some answers 1/4 mile time? I don't know, but, I can give you some laptimes - Portland International - 1:12 - average speed of 98+ MPH Thunderhill Raceway - 1:55 - avg 93+ MPH (we have some work to do there) Road Atlanta - 1:33.6 - avg 97+ Top speeds of about 120 or so. For 2006 we are working on the aero package a bit and should be able to improve that a few MPH. Reliability? We have only had 2 engine related problems so far: 1. Broke a rod at our last race of the season in the 2nd engine I bought used from a fellow TT person off an ad here. I am not putting that on anyone. We didn't know how much time was on the engine, and both engines were planning to get heavy duty rods this winter anyway, just had to get a 3rd engine though, and that is the newer '04 that started this whole discussion. 2. Some jumping out of gear on our original engine. Will go through the tranny this winter. We had two other major catastrophies but they were clearly induced by the first shop that was working on the engines. Details left out to be polite. Against the 2 strokes - well at the end of our first season (2005) we seem to have measured up well. There were 2 competitors in the western series that seemed to have a little more than us, and if they had it all going right and hit the tune, would have us by a second or so, but the rest of the field we would have covered. Our on track reliability is much higher. These are fully wide open single cylinder 2 strokes as well. Only spec is bore and stroke for them. When we went to Road Atlanta for the Nationals, again, we had a couple of the 2 strokes to chase, the top guys, but otherwise we had the field covered, including several built 4 strokes as the USSC rules for 4 strokes is "under 500 cc" it is IKF that limits us to "stock/oem" The qualifying results at Road Atlanta went something like this: 1st - 1:31 and change - CR250 2nd - 1:32 and change - Gas Gas 250 (Euro engine) 3rd - 1:33 and change - us with the CRF450R, '04 piston and hot cam stage 1 '02 ignition 4th - 1:38 and change and the rest of the field following that. Also, several of the "built" 4 strokes (yamahas and hondas) had failures of various kinds, during the weekend. So - we are looking for just a few horsepower without compromising reliability to give us just that last little bit. We seem to have the kart sorted, and working well, our tires are looking great and lasting well. Some things we are working on is an improved cooling system, that is more aerodynamic, right now we are running too cool. So, by rearranging radiators, and having more control over the air flow, we can get the temp up. Also, we will be able to better route the exhaust, which may result in a little improvement. So, anymore thoughts are appreciated. I am appreciate the support. Sorry for the long post. Happy New Year
  14. Roger Miller

    Opinions on a combo of parts

    Thanks for the compliment. I posted new pics in the garage from Nov'05 at Road Atlanta. We changed to white bodywork. If you want to know more about Superkarts let me know by PM, I can point you to websites and more pictures. USSC is United States Superkart Championships. This is a pro organization, this isn't strapping something found in the backyard onto four wheels and seeing what happens. This is real, organized, sanctioned, racing on full size road courses. Now back to the topic: Best stock cam? What is the compression ratio of the 05 and 06 pistons? I understand that 04 is 12:1 versus the 02/03 11.5:1 Thanks
  15. Roger Miller

    Opinions on a combo of parts

    Burned, thanks for the info. Is there any info on the cam profiles of the different year cams? Are the O4 and O5 cams more aggresive and better performance, on the order of the mild aftermarket cams? In one sanction the engines rules are "Stock" but there isn't anything about mixing stock parts. So, if I can get a better cam using a stock part from another year, that would be great.