Understanding XJ Timing

Am I pleased to find you guys! I thought me and my XJ were all alone in the world!
This is my problem: Replaced Head Gasket. Appeared to put everything back correctly but now it wont run properly (plus rattle from midway / front of engine). Timing is clearly out.
Here is my confession: I really don't fully understand how the tensioner works and also, in a very stupid moment I turned the engine over (by hand), in the wrong direction. Could this be the root of my problems??
I am going to send off for the Technical CD on offer, meanwhile, any help would be much appreciated.

 

wish i could help more . My bike is an XJ 1100 ,there are marks that need to be lined up before adjusting cam chain tension. If not done properly or turning the engine in wrong direction can lead to problems (bent valve or valves) not saying this happened to you but you stated not running correctly? what symptems? poping coughing wheezing? skipped a tooth on sprocket can also be a problem. sorry i'm still learning also.

 

Welcome Virgo;
Your not alone, there are alot of us out here. just wanted to welcome you, can't help with your problem, but I'm sure you'll have an answer shortly.
I've heard they are coming out with a new 3 disk version of the XJCD so you might want to wait on the new one to come out. Someone might know more about when it's coming out.

 

If you are questioning the timing then remove the cylinder head cover and the left point cover. Set to TDC and check the indicator on the cam journal to the arrow on camshaft cap #2. If this checks out then check the camshaft caps to make sure they are in the right position. They are numbered from I-1 to I-3 & E-1 to E-3. I stands for intake, E for exhaust and 1,2,3 is the position relative to the head. If these are misplaced it can cause vibration. It is also a good time to check the torque settings again on the camshaft caps. Then check the cam chain for taughtness. Since you didn't mention which bike you have I don't know if you have an automatic or manuel tensioner. The automatic is just that. You will only have to adjust the manuel. That is fairly easy. Just remove it and loosen the lock nut and push the bolt in. Then refit to the head. Let us know what you find. The timing marks are the biggest consideration and if they don't line up then most likely your assembly went wrong while replacing the cam chain and sprocket.
The front of the chain must be kept tight. After getting it and the sprocket on secure the sprocket with 2 bolts and rotate the engine through 2 revolutions with a wrench on the timing index at the left point cover. Bring it back to TDC and see if the timing marks align. This has to be done!!! Not rotating the engine may leave a kinked chain in position that upon rotation relaxes into a miss timed positioned. If you feel major resistance while rotating the engine stop. Rotate back and check the timing marks. If they are good then wiggle the chain and proceed to rotate. You are trying to keep from bending a valve. Make sure all spark plugs are removed so you are only feeling the valve train and not compression. Let us know what happens so we can help more!

 

Theres a fair amount to consider here.

What all did you take apart? Did you remove the pucks from the valves? The whole caps? Did you alter the TDC mark?

This is in addition to what is already been posted. Give us a step by step of what all was removed.

 

Many thanks for all the replies. There is some real practical help here which I think will be of real assistance.
The bike is an XJ550 I think the tensioner is automatic. (It contains 2 spring assemblies and a locking bolt. It all fits into a "cup" which slides into the cyliner block and, I assume, up against the chain. This could be pushed back and forth, but was very stiff.
I will not have chance to look at this until the weekend. So I will wait and report back to you guys then.

 

Well if it's a 550 then I have a correction to make. There will be an aditional cam shaft cap on each cam. An E-4 & I-4. ALso the 550's had manual cam chain tensioners. Let us know which year and model also.

 

I think it's 1983 / 84. Did my commentsb on the 2cup" make sense? What's the sequence for adjusting the manual tensioner?

 

To adjust, remove the left point cover and with a 19 mm wrench rotate the engine anti-clockwise until the "C" (not TDC), mark aligns with the fixed pointer. Then loosen the lock nut on the tensioner and the internal spring will set itself. Tighten the lock nut and replace the left point cover.

 

i recently bought an '83 seca 750. i havent had a chance to order the xjcd yet. is the tensioner in the 750 automatic? it sounds loud to me but the power is good.. a little flat around 3ooo rpm but i think the carbs are dirty.

any help is always appreciated. thanks

 

Yep! The 750's for some unkown reason were equiped with automatic tensioners by Yamaha. Flatness around 3k RPM does sound like dirty carbs. This can be corrected by running some carb cleaner in the fuel tank. I would just get some carb cleaner off the shelf at an auto parts store and run a few tanks with it. If it doesn't clear up with that then I would do a carb sync and colortune set. If the bike has more than 20k miles on it I would also check the valve clearance. Loose valves make noise , which is better than quiet ones which are worn and may be leaving valves open.

 

Hi Guys! After spending a few freezing nights in the garage, I am now able to give the following progress report:
When I stripped the bike down again I noted that all timing marks were still aligned at TDC but I followed Blue Maxim's instructions and re-set everything.
There were a couple of things I was concerened about:
1) There is quite a lot of slack in the chain / enough to almost be able to pass it over a sprocket 2) The rear (adjustable) tensioner did not move back and forth very freely but then later seemed to free itself. 3) The tensioner adjuster still does not make absolute sense to me / No predicted "clicks" when releasing. In the end I put it back unlocked and then nipped it up.
So how did the bike run after all this care and attention???
Started well, Ran quite crisp, Almost idled, Got hot, Slight rattle from front (nowhere near as bad as before), Ran rougher and rougher (but still picked up revs) and the stopped!
We are clearly making progress but I don't see what more I could have done. Remember this bike was running like a dream (except for a weeping head gasket) before I stripped it down.
Further advice gratefully received.

 

My first guess is that the tensioner is the problem. Glad to know timing is right according to the cam marks so I have heard of the springs in the tensioners being weak after so many years and I suspect dirt and grime could play a part in holding the tensioner's plunger back. I have not rebuilt one so I'm reluctant to say anything. However , if you know of someone else with an XJ then you could swap and see if your bike runs better with a known good tensioner. I have one I can send you but it is off an '83 Maxim 750 so it is automatic. I don't know if it would fit. I do know that if the tensioner is not keeping the chain tight ten the timing will be of and the engine will not run well.

 

Recently had to replace the ttensioner on my XJ550 as the housing cracked. Went thru all the 650/750/900 XJ engines in the wreckers yard but nothing was compatible with the 550. Eventually found one. Before installing it is very important to ensure everything is spotlessly clean otherwise they will stick. From memory there is a groove on the side of the main tensioner shaft. Make sure that is lined up with the locking bolt otherwise the shaft may get burred and not slide. Lube it all up with plenty of fresh oil.

You should hear it spring into place once the lock bolt is loosened.

This is a very important step. If you go past the C mark don't be tempted to go backwards as that will put slack in the front of the chain. Go around again.



Cheers
HG

 

Well this helps. I didn't know that tip/a.k.a. warning, about rotating "back" to the C mark. Maybe all he needs to do is clean the tensioner since he didn't hear it click into place. So sorry my extra tensioner couldn't help out. Amazing how Yamaha designed so mant engines that share similar cases yet the tensioner doesn't interchange.

 

If you have a hard time lining it up - take the spark plugs out...

 

Did some more checking and best info I got is that the 650 and 750 tensioners will interchange but neither will work with the 550. Seems the mounting plate is different. Good news for 650 owners who would like an automatic tensioner. You can take your 550 tensioner off and spray the inside with brake cleaner. This will really cut the grease and grime and get it out. Then oil liberally and reinstall. Then do the reset as mentioned before and let me know what happens.

 

Real progress. After following all your hints and tips, the bike is now running. The engine is as quiet as can be expected for a 55000 mile bike and it seems to be reasonably smooth. The only issue remaining is a slightly uneven tickover (engine "hunting"). Hopefully a carb balance will sort this out.
I thought a quick summary of keys points may be useful:
When fitting the chain, it is vital to first get good tension at the front between crank sproket and exhaust sprocket.
The rear tensioner was the root cause of most of my problems. As the team says; Make sure everything is spotlessly clean and the rear tensioner is moving freely then fit the adjuster using plenty of fresh oil.

Many thanks to Blue Maxim and everyone else for their help and guidance. When I first came on the forum I was in deep trouble with no solution in sight. Top team!!

 

55K is a good break-in on these motors. Keep the sucker clean and fit and you'll not have too many problems down the road. On the hunting idle, check the intake boots with WD-40 while the engine is running. If the liquid is sucked into a leak or crack, the idle will smooth out momentarily and the rpms drop (or is it rise? I forget, its been a while). Anyway the key is the idle smoothes out, unless of course you have more than one leak, but the idle will smooth out somewhat regardless. Get that sucker (the leak)and sync the carbs up, you should be golden! Cheers!