Finally the search is 450f acquired!

Stan, thanks for the heads up, no go get some hours on that bike!

Gray, thanks for the information. He must have done some stopping, starting at the crest because even the breather tube had sand in it all the way up to the port on the valve cover. Im making up a new breather tube this week at work, and ill get it installed this weekend when I go home.

The main bearings are my biggest concern as well, along with the cylinder walls. I hope he never changed a plug the way it was, cuz who knows how much sand would have gotten into the cylinder upon removal...But im hoping the main/rod bearings will be ok.

I was already planning on taking a close look at the oil filter when I changed the oil. I was looking to do it this past weekend to get that sand out, if there's much in that motor, and thats when I noticed the leak out of the tensioner.

With that tensioner, is it just a simple pull it out, and put it back in? I see the manual states something about winding it back up, so I assume its just an automatic spring inside of that tensioner? I have only worked with the tensioner on old honda 350's, and I assume that this one is pretty different. I just wanted to make sure I can get it back in and bolted up ok with no binding on the tensioner or worry that the cam chain isn't loose with no tension placed on it.

When you take the bolt off the end of the tensioner you'll see a slotted turn screw. Use a flat head to wind it up and hold it while re-installing it. It just makes it easier to re-install, so you're not fighting the tension when trying to bolt it up. Don't forget to re-install the screw and copper washer at the end of the tensioner.

The tensioner is so simple that it's brilliant, IMO. The plunger is keyed to the housing so that it can't turn, and inside it is a worm gear ("screw gear") that is rotated by a coiled spring. At he least bit of slack, the spring unwinds, extending the plunger. The plunger cannot be pushed back by the chain any more than you can back a bolt part way out of a hole and push it straight back in.

Winding the spring back doesn't make it easier to install, it makes it possible. If you try to bolt it in place without doing this, you'll break something. Remove the center bolt as shown, and insert a small straight slot screwdriver. Push the plunger inward as you turn the blade so as to keep it from popping back out. You may find that you can get it to "stick" all the way back in if you release pressure on the screw then gently let off of the screwdriver. You can also use a wider screwdriver, a pen knife blade, or a random piece of metal to hold it in place by engaging both the center screw and one of the 4 slots in the housing. Either way, hold the screw with the plunger retracted, put the tensioner in place, bolt it down and release the screw to allow the tensioner to extend. Rock the crank forward a bit then back ad forth a time or two check the timing, and spin it two turns forward by hand to be certain in all sets in as it should.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now