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Timing chain!


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Ok fellas, I have to say that this is my first post on Thumper Talk, so dont ride me too hard, but anyways, here it goes. I recently obtained a 2003 CRF450R. It has a bad crank, which I have already ordered with new gaskets, and I have to get a piston kit. But my biggest question is about the timing chain. I noticed that it seems to have a memory. Like it is sticky or something, does this mean its a newer chain or wore slap out. I know it was extremely tight even with the tensioner completely removed. I know they are suppose to be stiff, but all other motors I have rebuilt I have not seen this before. I mean its almost sticky. What exactly does this mean. And on the timing chain tensioner, are they suppose to be spring loaded? I know on the ol TRX300 they were. This one doesnt seem to be. I hate to put all this money in the top end, and then let it jump time and destroy all the $$$$ and time I am gonna have in it. Any help would be greatly appreciated. Thanks, George

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lots here will tell you make your own and save money, i just fail to see the time spent doing it is worth it but use the search feature and make up your own mind. I use APE on all my machines.. roadrace and dirt bike alike (about $45). Easy-peasy-nice-n-easy. provided you check tension once in a blue moon, you will never have to worry about teeth jumping on a hard decel or a stock cct spring failing. Happend to my super moto very expensive crf450 motor (Phil Wyat prepared head w/oversized valves, Tokyo mod carb/ecu).. not pretty, and very expensive.

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one more question, with these, manual chain tensioners, exactly how do they work, and when do you know when they are tight?? Thanks!๐Ÿ˜

they come with basic instructions, and there are numerous threads on the very topic of installing mcct. "search" and go in peace.. ๐Ÿ˜ I don't want to tell you something wrong, as i have done a bunch and it's by feel for me now.

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one more question, with these, manual chain tensioners, exactly how do they work, and when do you know when they are tight?? Thanks!๐Ÿ˜

You adjust them manually and check the tension of the chain to make sure its tight (just like checking the tension of the chain on your wheel, except a cam chain is tight like a guitar string practically lol)

only problem with a manual tensioner is your have to check it often, when the chain stretches, the tensioner doesn't automatically tighten up like a oem tensioner would

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If you don't supermoto or race your bike, then just put a new OEM tensioner in there and call it good. I've had an 04, 05, and now and 07 CRF and that's all Ive used. But I put a new tensioner in when I replace the cam chain.

to each his own, and i dont' race my 04, but i would never waste money on a stock cct. No way, no how. But that is just me.. and many others if you search. Stock tensioners have the potential to fail. REason enough to never buy anohter and put in a mcct.

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The 02-03 tensioners were known to give up, so they redesigned them, but even the newer ones give up now and then.

Id second the suggestion to replace the chain and the tensioner. TT offers a manual tensioner too.

Some guys get them close with the engine off, then fire it up, dial it back until it makes noise then dial it back in until its quiet. Snug it down and you're done. The thing about the manual is if it starts to get noisy, you can always mess with it a bit and know whats going on (whether its the chain or not).

Seems like you know it already has a bad crank. How's the top end? The 03 had a 11.25:1 piston, the 04 and up was 12.5:1. There's HP there by upgrading. Just a thought.

Also, the 03 crank was heavier, so if you go OEM and order an 03 crank, you may get the heavier 03 crank instead of the 04. And, no, they didn't just add weight to the flywheel.

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I actually am puttin in an 06 crank. Havent really decided what to do on the top end. Trying to get my finances together and decide what to do. I would like to stay as close to stock as possible for the reliability purposes. I love honda anything. I am goin thru the motor from the bottom up. The 06 crank is gonna be rebuilt by www.mrcrankshaft.com. I actually bought the crank on ebay, and I am gonna give him my old locked up crank as the core for the complete rebuild on the 06 crank. I am gonna put either a weisco or hot rod in it, havent really decided that either. After I complete the bottom end with newly rebuilt crank, new bearings, seals, and all gaskets replaced, I think I am gonna look into the heavier flywheel, seems a lot of people like them for trail riding. Then when I make it there, I need to decied what to do on the cylinder/piston. Then I will work my way up to the head and replace valves with stainless valves????, springs, seals, etc. So eventually I will have basically a brand new bike for way less than 1/4 of the price of a new one. Just takes a little time and elbow grease. I am still undecided on the whole chain tensioner, but there will be a new one thats for sure. This bike will never be raced or anything as long as I own it. Mainly trails and hill climbs. I rode a stock 08 and fell absolutely in love with the CRF. Plenty enough power. It actually has a Yoshimura RS2 full system on it. It was on it when I got it. Thats about the only thing aftermarker on it so far. I have a question, why does everyone change there oil so often on these things. I normally do mine twice a year on everything that I have ever owned. Whats the deal??

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