ST 1100 Timing Belt Replacement

[Stan ST]

Hi everyone. I would like to share my experience and information related to timing belt replacement.
During my preparation for this maintenance activity I have read on some forum on timing belt replacement, that only the kilometres or milage is relevant because the service manual is not mentioning the time interval. True. However, I have been looking that information on timing belt manifactures websites or pdf files and I have found on couple of different places that change interval for this belt particularly is 150 000 or 160 000 km depend on manifacture and 5 years.
My Honda ST1100 is 1996, and I don't have service buck as well as an information on timing belt. The bike km is 088000 but 24 years. I have took it off, and I would say that it is in very good condition. I is UNITTA Japan HONDA 147RU24 and beside 14401 MT3 004 (belt model/type) numbers there are some 6-05 which I haven't found what are they but I assume that could be a month and year of production. However, since it is HONDA genuine it might be actually a 24 years old. I bought a GOOD YEAR G1274 (for opel ascona, combo, cadet / vauxsal astra, astravan etc) for 7 €. 147 teath and 24mm wide. I have compare them by putting them one against another and tention them slightly. The old good looking one was visibly stretched. Some 3-4 cm longer than new one.

Another interesting fact related to belt changing is that is not actually a complicated job to do. Also during my preparation I have found a video on YouTube on this and among other parts they took off the exhaust pipes, drained oil, clutch housing and part of a frame in front of the engine.
That is complicated and not necessary.
I have took off the bottom plastik cover, left and right plastic panels, radiator, horn and belt covers on engine. It seems that plastic cover on the front could not be pooled out because crankshaft pooly lock bolt.
I just followed the manual, unscrew that bolt and pool out the plastic cover. Pretty simple and fast to do. To block the engine "put i 5th gear and press the rear break... Manual says.
Of course, while doing on timing belt it is necessary to be careful and to check everything, to be sure that everything is in place and tighten correctly.
Follow the manual...
The manual say that belt should be inspected on 100 000 and changed on 150 000.
My advice would be, if you reach the belt, change it.

 

[cjames431]

You can pull the plastic left, right, and center timing belt covers without removing the driven gear bolt. Link below. It is not overly complicated though as you have said.

Article [11] - ST1100 - Timing Belt Replacement | ST1100 Articles

Timing Belt Replacement (2/1/2003) The top fairing doesn't have to be removed for the job. Draining the radiator so it can be removed. Radiator removed. The timing belt cover needs to come off next. As Jeff Bertrand said, the cover can be removed with a 'little' cursing and prying...

www.st-owners.com

 

[John OoSTerhuis]

Hi STan. Congratulations on a successful timing belt replacement. Thank you for the poST.

The old good looking one was visibly stretched. Some 3-4 cm longer than new one.

My guess on that is that the aftermarket belt is that much longer than a Honda belt. I’ve done two belt replacements and there was no discernible difference in belt length between old and new. I bought Honda belts. Four centimeters is a lot! I’d be concerned about that. They don’t stretch in my opinion, certainly not that much (~1.5 inches)!

edit: did you mean millimeters?

It seems that plastic cover on the front could not be pooled out because crankshaft pooly lock bolt.

It will come up and out, you just didn’t pull hard enough. Many of us that have done a belt replacement trim the cover for the next time.

Regards, John

 

[Stan ST]

For JohnOoSTerhouis:My apologies, typing mistake! I wanted to say/write 3-4 mm not cm. But after more precise measuring it is closer to 5mm.
I have tried to pool it out (you ar right, I haven't use any tool like lever or/and strong force to rip it out) . And my first idea was to cut off the small peace of plastic at the bottom in order to get it out. But after a couple of minutes of thinking I've decided to remove the problem as easily as I can, so the unscrewing the lock bolt was very easy and after that pooling the plastic cover was simply... I could say that ti come out almost it self... After that I have screwed back the bolt just to fix the plate with marks to check the positions... After that relace the tensioner, fix it in lowest position and unscrew the lock bolt again and removed the plate with marks... The benefit of removing that plate is that the belt removing and installing is much easier, just like with removing the guide plate on the camshaft.

 

[Roger]

Trim here - picture borrowed from somewhere or other.....

 

[John OoSTerhuis]

Here’s one picture showing the main area to grind off material (link below for others/more in my timing belt album):

Area marked in white grease pencil.

Error - ST-Riders Media Gallery

www.st-riders.net

Trimming will greatly help remounting the cover.

Regards, John

 

[Smoother]

I changed my belt recently (75,000mi, possibly 19 years old). I too, had the YouTube video playing, slides only (with weird conversation in the background). It was a great help but as pointed out, has unnecessary steps in it. I also avoided draining the oil, removing the clutch slave, removing the clutch cover, disconnecting the frame, and removing 2 exhaust header, by using the “wriggle it out past the big crankshaft bolt” method. On a bike this old the less systems and bolts you disturb, the better. There’s nothing like opening up a can of worms, to find more cans of worms inside.

get yourself an idler pulley and tensioner pulley before you start, and a new tensioner spring (all cheap insurance). A water pump would be ideal but they are expensive now (£245). There are bearing replacement kits for the water pump, around £20, but you need access to a hydraulic press, and we are in lockdown #3 so that’s not practical, and it’s my daily rider right now, so I had to finish by Sunday night.

I used a Vauxhall/Opal belt, £11 delivered, and about £70 in pulleys and spring.

both belts I have replaced in my life, looked almost perfect. There is always a thought to just put it back in. DONT DO IT. Once you’ve got that far just keep going. Rubber parts can look great but be minutes away from catastrophic failure, ESPECIALLY if they are very old. The mechanics industry seems to think a belt is old around 5 years, so 19 is definitely past its prime. I would love to know how much longer my belt would have lasted, but not at the price asked (handgrenaded engine and possibly stranded miles from home/ accident). If you’re worried about your belt just change it. It’s a PITA, sure, But mostly because of all the Tupperware removal/replacement. The belt itself is pretty straightforward. I did it in my living room (warm, comfortable, bright) with minimal mess (mostly dust/road crumbs falling off the Tupperware).

One final thought:
people get all paranoid about keeping the pulleys 100% stationary for the duration, and any movement will result in catastroph. Poppycock!
if a pulley moves, MOVE IT BACK. It’s that simple. That’s what the timing marks are for. One of my pulleys moved over 70 degrees, more than once. I simply rotated it back to the mark and continued. I actually deliberately rotated the second cam pulley (right cylinder bank) backwards about half a tooth, to allow the belt to engage, without having to yank really hard on the belt. Once the tensioner does its thing, that 1/2 a tooth got sucked back to the right place (checked three times, before and after rotating the crank pulley 2 full turns). I’ve ridden the bike all week since then and it’s running fine, so proof that cog movement is no big deal, as long as you move them back. So don’t fear the process, just correct if necessary.

 

[ST1100Y]

That’s what the timing marks are for.

Indeed, see that everything is aligned afterwards and be done with it...

 

[Oldbikefixr]

When I replaced my belt, I highlighted the timing marks with white paint marker before I moved anything. There are matching features on the pulleys and the castings...just makes alignment easier.