Mikes XS Big Fin cam chain tensioner ????

TheFatGuido

TheFatGuido

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Hey guys!
We are going to put this setup on my XS and have the head off, noticed that the new cylinder has different cam chain design than mine. I looked around and some people said to screw the tensioner into the cylinder but that would mean there would be no guide for the chain to ride on. There is no way the chain is supposed to ride on the end of the metal tensioner is there?
I am ready to return this kit, could anyone point me in the right direction??

Thanks for your help guys!
 
the rear cam chain guide itself is inside the motor... I don'tt get what you are asking? all the plunger does it push against it. it is held in with 4 screws I think, you can get to it once you have the jugs off.
 
Sorry about the confusing description, here are some pictures of the two cylinders and the tensioner. I have the common 6 bolt setup on my original cylinders, and the new one has this weird one hole. Its very odd and I don't get what to do because there has to be some kind of guide for the tensioner to push against.
 

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So it sounds like a 447 head....447 rods.....but i think those type of tensioners only work with 256 cam chains as they are a different pitch. So you have a 256 crank and cam more than likely. And 256 jugs obviosly.

Posted via Mobile
 
There's a couple of threads here with similar scenario, someone wanting to use 256/306 sprocketed tensioner on 447 camchain. Search 'tensioner' to find those.

First thing is to confirm you've got 447 crank sprocket, matching camchain and 447 cam sprocket. Do this by counting teeth on crank sprocket and cam sprocket, and links on camchain.

256 will be 17 crank, 34 cam, 102 link chain.
447 will be 18 crank, 36 cam, 106 link chain.

If you confirm 447 setup, good thing you caught this. That tensioner sprocket is for the 256 8mm pitch chain.

If you confirm 447 setup, just use tensioner in ggggGary's parts picture, you're good to go...
 
You also need the 447 block to use the slipper style adjuster the slipper bolts to the top crank half. And yes I do have a complete set of 447 tensioner parts on hand.

Getting to the bottom of this should interesting, keep posting what you find.
"franken-engine" There's a bunch of those out there.
 
Or you could just send that kit back and try and bore yours to 700. I think you can go that big without re-sleeving....i think. Since you have 447 pistons they arent to badly priced...if it turns out you have a 256 cam chain and cases that dont accept the 447 cam chain guide....my head hurts.

Posted via Mobile
 
Not necessarily. You say your engine is '79. Serial number will confirm this.
256 stuff is less common. It's quite likely that you have a genuine 447 setup, just need to be sure.
That early cylinder and tensioner is throwing you. Probably Installed previously by unknowns. If so, it doesn't really belong on your 447 engine, and the MikesXS cylinder is actually correct for your bike.

So, it boils down to confirming what you have...
 
That's the scary part. This tensioner stuff can be easily intermixed by unwary rebuilders.
The only real impediment was a narrowness in one range of cylinders, but creativity overcomes that.

There's an ever-increasing number of franken-engines out there, so individual component identification becomes important. Plus smartphone pics...
 
Ok so update time, the engine is a 447 and gggGarys tensioner looks like it would work, the thing is I would still need the corresponding guides and sprockets. With this new cylinder there is nowhere for them to mount up! I may have to just shelf this kit for now and find a used cylinder and just rebore. What a weird issue I thought this was the easy option. Lesson learned, never buy a rebuilt engine from someone you don't really know, too many surprises.

This was purchased by me last summer with a 750kit and Boyer installed, and in one season I started having starting and running issues and it turns out this bozo did not get the perfect match on pistons and rings for the cylinder, which essentially got oil up where it shouldn't be and messed me up bad. Even the valve seats were all pitted and some serious craters in the chamber. Also a pain in the ass to kickstart with all that compression.

Anyway that was the reason for going back down to stock and that's why I bought this cylinder kit and a clean head on ebay, it ending up being a real thorn in my side but I'm not gonna toss this perfectly good bottom end with the Sparx setup and all that Boyer stuff just because of these issues. Anyway I am ranting, any more ideas would be great but I am gonna hunt for a good cylinder starting tomorrow.:doh:
 

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