Help! Cam Chain Tensioner

MBT · Mar 3, 2007

Anyone from Chiang Mai (prefferably) that knows something about fitting a cam chain tensioner?

My old Honda GL 400 Custom or otherwise known in Europe as a CX 400 (they did a 500 as well)needs some repair work.

Ok heres the story. The engine gave up barking and coughing losing all compression. It starts and ticks over but akes a horrible noise when revved but no smoke! I did a check and found that the model was recalled long ago needing a new cam chain tensioner. If the modification was done there would be 3 punch marks on the engine number. Mine hasn't! I have been told by a reliable source the cam chain tensioner is the problem!

Now...My problem is finding someone capable and with the time to sort it out.

If anyone is interested in helping me out on this one please let me know.

The next problem would be sourcing a tensioner for a 1984 Honda but I am confident I can get this part at least sorted I;ve been told the part is just 1000 baht or so.

Just for the record...1984 model, shaft driven beast and currently in a horrible state needing a complete overhaul and paint job but when working its actually a lovely bike to ride.

Any physical help out there?

jonadda · Mar 3, 2007

You still pissing around with that thing

MBT · Mar 4, 2007

John, I never even started the project but got the bit between my teeth now and am gonna get it done!

mikerust · Mar 4, 2007

Nice Bike. Keep going. What about a turbo from the CX 500/650?

Klaus · Mar 4, 2007

As far as I remember the GL has a 90 degree V engine kinda like an air cooled a Moto Guzzi; and it doesn't have a cam chain or tensioner, it has pushrods driven by the crank . . . or am I wrong?

MBT · Mar 4, 2007

Its a V-twin and it does have a cam chain tensioner. The bikes were re-called by Honda years ago to have fitted a modified tensioner but my bike missed the re-call so it was never replaced.

I have had 2 Thai mechanics look at the bike but but without even trying to start it they just say fit a new engine. 2 western Mechanic (one bangkok, one Chiang Mai (Joe)) when I told them the symptoms they both immediately said cam chain tensioner the common fault on the cx 400/500. This confirmed everything I have read on the internet about this. The Bangkok mechanic is too far away from me and Joe is as always rushed off his feet with work and unable to undertake the work.

I did try to buy a new engine in Bangkok but the only one I saw also did not have the 3 stamps on the engine number so the cam chain tensioner was also not fitted so no point in buying an engine that will eventually have the same problem.

If anyone can contact me that are mechanically able to do the work I will of course be happy to pay what is needed. I have been told the job is about 1-2 days work but as yet no-one able to do it.

It's a great bike (when working) and they are lovely to ride, smooth and bullet proof, I want to try to get it working before the rainy season so I have a project during the wet months doing re-sprays and gettting it looking good again for the dry days!

Klaus · Mar 5, 2007

Seems like some engines do have cam chain tensioners, even though the engines don't look like they would have OHC's. Most Guzzi's and all BMW boxers have pushrods, which keeps the engine more compact and there are way less moving parts.
Other websites I checked mention rocker arms, which are activated by pushrods. Check out these sites (if you haven't already):
http://www.turbomotorcycles.org/TMIOA/T ... ckCam.html
http://en.wikipedia.org/wiki/Honda_CX_series#Engine
The latter website mentions pushrods on the CX 500.
One never stops learning - I would have made a bet that the GL/CX series didn't have OHC's . . .

Klaus · Mar 10, 2007

Well, they obviously don't have OHC. Talk about learning - just learned that the cam chain runs a cam somewhere close to the crank. I was thinking of old Harley engines, which push their valves with rods which are being run by gears. Now I know that "cam chain" doesn't automatically mean OHC, even though 98% of japanese bikes today have OHC, most have DOHC. The old GL/CX series had both - pushrods AND cam chains.