XJ750 Seca Cam Chain Adjustment - New Method ?

Hello
I'm (still) thinking of buying a Seca 750 I rode the other day, a non advertised friend's. I read here that auto cam chain adjusters can be coaxed into adjusting themselves by hand cranking the engine backwards.

I have another idea...why not put it in 5th (the easiets gear to rotate engine) and push the bike backwards, forwards, and then repeat this a few times until the chances are you did the same as the more 'exact' method?

M

 

i can't say that the jerk backwards thing ever did anything for me, so try it. there's no way of knowing if it did tighten up, you can't see anything happen.
probably have to take the plugs out. i never tried to push it like that but i bet it isn't easy

 

Turning the engine backwards might unstick it if it's stuck, but they generally don't get stuck to begin with. The nature of how they work precludes them from sticking in place. The ratcheting pawl is a one-way affair (preventing the adjuster rod from being pushed back into the adjuster case), with the spring providing constant pressure on the adjuster rod.
The issue with turning the engine backwards is that it can cause the chain to jump a tooth on one (or both) cam sprocket(s).

Besides, "fixing" something without diagnosing that a problem actually exists with a particular system is just another way of wasting time.

A better way is to pull the valve cover off and have a look. If the seller won't let you do that, then walk away.

 

i think, way back when this started it was to get that pawl that was just about to move itself to move now. the only way it might help is if you thought the spring was weak.
like clutch and fork springs that sat compressed 30 years it might need some help. like maybe some washers?

 

But the pawl doesn't keep the adjuster from moving outward. It only works the other way; to prevent it from moving back inward as the chain moves. The only way I can see one sticking is from an inordinate buildup of sludge, or a PO "repair". In any case, we really aren't sure that the nose he was hearing is from the cam chain, or even if it's a nose that wouldn't normally be heard from an XJ.

OP, can you shoot a video of the engine running the next time you look at it? A slow walkaround from one side to the other, going around the front.

 

Well I haven't bought the 750 yet, I'm just researching what I'm getting into.

Yes, I'm sure it's the chain. I've been around engines all my life, Dad used to race cars, and me MCs; MX. The chain isn't the big issue for me, it's the starter clutch. Still researching though...do I buy another XS650 or try the Seca ? 650's have a nice powerband IMHO, lots of low end, unlike the Seca.

 

I enjoy how smooth my 4cyl is. Very little shaking/vibration that my buddies with xs's have. Not to mention that like you said, they may have a touch more on the low end but once I get wound up, which doesn't take long, they can't dream of catching me. Just saying.

 

could be your cam chain guards are worn to the point of making the adjuster useless.

i have read here that the old adjustable style can be replaced with the auto adjusters. makes me think if you wanted you could replace the auto ones with the old style adjusters

 

Both types do interchange.