CCt should be easy, right?
08-22-2007, 03:39 PM
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CCt should be easy, right?
I think it's time to replace the CCT's on my '01 hawk at 20,000 mi. after reading all the horror stories of failed OEM units. Anyway, I've searched the forum for install tips and it doesn't seem that bad. The only thing I noticed is everybody stressing how important TDC is, like if you're a vaginal hair off either way the partially opened valve will cause the chain to jump a tooth. Theoretically, it seems to me if both spak plugs are removed the motor will turn pretty easy with a raised rear wheel. Placing a thumb over the spark plug hole (theoretically if it fits) will tell you when the cylinder has reached the compression stroke. Wouldn't Anywhere between this point and TDC of the compression stroke be safe to remove the tensioners? I mean both valves are closed on the compression stroke eliminating any pressure from the valve springs on the chain, right? I know it's not that hard to find TDC on compression and I will set it there when installing but , I was just thinking for some piece of mind since alot of the threads make it seem like you must be at true TDC if you don't want your chain jumping teeth.
08-22-2007, 06:01 PM
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I think your reasoning is sound. There is one other empirical test. Like you say, with the rear wheel raised and the plugs out the engine will spin freely. The r/r doesn't know that so it's going to do its kilowatt thing regardless. Attach a digital multimeter to the cylinder that is your target. Spin the tire freely for a turn or three. Once the capacitors are charged you can slowly creep up on TDC. You must approach TDC with 30 seconds or so to blib the gauge. I would think the charge might bleed off if more than 30 seconds expired. But if you can observe it - you'll be within 10-12 degress of TDC. Make sure you set your meter up high enough to measure this!
I even found a gadget on one of the sites that is a flasher that you can put in line with the plug. I bought it with the idea of just grounding it to the block but still able to read the "flash" of the plug firing.
It wasn't expensive so I didn't feel that I was out anything but I did think later that a hand-spun engine may not make enough voltage to fire it. Haven't tried it yet but I will. However, within reason, a hand-spun engine will blib a meter if it's set up properly.
In this case, don't send pictures. Please confirm methodology.
I even found a gadget on one of the sites that is a flasher that you can put in line with the plug. I bought it with the idea of just grounding it to the block but still able to read the "flash" of the plug firing.
It wasn't expensive so I didn't feel that I was out anything but I did think later that a hand-spun engine may not make enough voltage to fire it. Haven't tried it yet but I will. However, within reason, a hand-spun engine will blib a meter if it's set up properly.
In this case, don't send pictures. Please confirm methodology.
08-22-2007, 07:56 PM
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Theory is correct... but I'd just like to say, if you can take the extra 2-3 hours to remove the vavle covers and make sure your at TDC with the cams in the right spot... you should be A-OK on getting the CCT replacement right, plus you can check the valve at the same time and then you know not only you cam CCT's are good, but your valve are OK as well, and your good for another 10-15K..... basicaly kill 2 birds with 1 stone...
J.
J.
08-24-2007, 02:08 PM
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Yeah I know. I was trying to avoid that but slowhawk has a good point with the whole kill two birds with one stone idea. I guess it's time to check the valves anyway. Thanks alot guys!
08-24-2007, 03:02 PM
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I respect what SlowHAWK is saying but it's the 2-3 hours that bothers me. I have done extensive reading in the archives about valve adjustment and bikes with twice my miles are fine. I'm at 16K. Right now the bike doesn't move until the MCCT's are installed. It's not quite riding weather here in Texas yet and the shop is just as hot. Another month and I will want this project into the history books. I think Honda valve trains are amongst the best in the world so I don't think checking them every 15K is required. Knowing some of the Honda engines like I do I would put their valve train frequency at about 60K - to be safe - 45K. If the bike races every weekend or twice a month - maybe every 15K under those conditions. I don't look at as two birds. I look at as two factory seals that I really don't have to break until necessary. If you do your CCT's make damn sure you torque properly and locktite the bolts. I can't believe the number of posts lately about leaking installations. Just my .02
08-24-2007, 03:49 PM
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The spark/multimeter/flasher idea is novel...but horribly inaccurate on any modern engine. Modern spark ignition engines fire off well BTDC(Before Top Dead Center)...not @ TDC, sometimes by as much as 45 or 50 degrees BTDC...the timing of the spark is varied by the ECU based off throttle/rpm/load maps stored in the ECU. It should NOT be used to find TDC.
There's a really easy way to do this. (figure out TDC). Simply put a wooden dowel (or a long straw) down the spark plug hole. now rotate the engine (or rear wheel). When the stick/straw stops rising, you've found TDC...if it starts descending..you've gone too far. This should get you within 5-10 degres of TDC.
The spark trick would allow you to figure out the difference between between strokes (near TDC on the Compression/ignition stroke and near TDC on the exhaust/intake stroke), but not truely determine where TDC is.
There's a really easy way to do this. (figure out TDC). Simply put a wooden dowel (or a long straw) down the spark plug hole. now rotate the engine (or rear wheel). When the stick/straw stops rising, you've found TDC...if it starts descending..you've gone too far. This should get you within 5-10 degres of TDC.
The spark trick would allow you to figure out the difference between between strokes (near TDC on the Compression/ignition stroke and near TDC on the exhaust/intake stroke), but not truely determine where TDC is.
08-25-2007, 09:58 AM
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I find top dead center on my '70 Ironhead with a pencil like RPV said and I agree with nuhawk, I'd hate to break the factory seal, in fact I hate to loosen any bolts I don't have to in fear of them snapping or me loosing them, not that it happens much but you never know. Anyway on my sporty I'll pull both plugs, put my thumb over the hole and have someone slowly rotate the kicker pedal until my thumb is blown off the plug hole from the compreeion. I've found the begining of the compression stroke. I place a pencil, eraser end first into the hole and rotate until it stops rising and a mark on the crank lines up in a view hole. Primitive, but it works every time. I know how to find TDC and I will when I install my ccts, I just can't see (for conversation sake) how it's that important when both valves are closed on the whole compression stroke eliminating any force from valve springs to cause the chain to jump teeth. Is there anything else that I don't see putting force on the chain that requires TDC? Thanks for the input!
08-25-2007, 07:30 PM
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I doubt that the ignition advance will be 45 to 50 degrees with the engine off. The straw method only tells you that you are at TDC but on what stroke? It gets there four times but only once on the ignition stroke. At least with the empirical method of manually feeling the compression stroke by plugging the spark plug hole can you be sure. The multimeter and the spark plug dealy will get you within 12 to 15 degrees max. The cylinder probe will get you the rest of the way home.
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