Timing belt inspection tips?

SpoogyWoogy

Joined
Apr 8, 2026
Messages
52
Age
25
Location
Japan
Bike
ST1100
Hi again all,

I recently purchased a 1991 st1100 with 58k miles on it.
I don’t know of it’s service history so I’m going to be changing the timing belt.
(It should arrive in the next week or so but I’m not sure).

Google tells me it’s a ticking time bomb but a lot of forum users seem to ride on original belts for well over 100k miles.

I’d like to be able to ride the bike until the timing belt arrives but I’m not sure if that’s a good idea.

Is there a way to easily inspect the timing belt for any wear (without pulling off the radiator) to see if it’s good for maybe 100 miles or so of chill riding until my timing belt arrives?

Just don’t wanna blow up my engine and I wasn’t able to find a thread on this topic specifically.

Thank you!
 
Ticking time bomb - that's a joke.
I don't change mine until 100,000 miles regardless of age (BTDT 3 times).
The ST1100 timing belt is thankfully well over-engineered. ;)
 
Uncle Phil said:
Ticking time bomb - that's a joke.
I don't change mine until 100,000 miles regardless of age (BTDT 3 times).
The ST1100 timing belt is thankfully well over-engineered. ;)
Click to expand...
Phew!
Good to know. I’ll be changing it in the coming weeks for peace of mind but until then I’ll keep enjoying the bike as is!
 
SpoogyWoogy said:
I don’t know of it’s service history so I’m going to be changing the timing belt.
Click to expand...
For peace of mind, I'd agree wholeheartedly...
plus:
- idler pulley
- spanner pulley
- w/pump
at least check them... (those on my '00 ST with ~150,000km turned out already quite worn and noisy...)

 
ST1100Y said:
For peace of mind, I'd agree wholeheartedly...
plus:
- idler pulley
- spanner pulley
- w/pump
at least check them... (those on my '00 ST with ~150,000km turned out already quite worn and noisy...)

Click to expand...
I haven’t ordered the pulleys or pump.
Do those give out before the belt? If so I might order them now.

Edit: just to check how many of each would I need to order? Sorry, my service manual hasn’t arrived yet so I don’t have any access to diagrams or parts lists on hand.
 
Last edited:
pulleys are a good idea to change, but they are expensive.

tensioner pulley part number is 14510-MT3-003
idler pulley part number is 14560-MT3-003

water pump is crazy expensive, but I'm not sure if its even available from Honda any longer, part number 19200-MAJ-G20
 
ST1100Y said:
For peace of mind, I'd agree wholeheartedly...
plus:
- idler pulley
- spanner pulley
- w/pump
at least check them... (those on my '00 ST with ~150,000km turned out already quite worn and noisy...)

Click to expand...
Just had a look. Yeah… a bit pricey.
I guess I’ll just get the idler and tensioner 😓.
If they aren’t prone to failing and eating up my new (also expensive) timing belt I’d rather not buy them but for peace of mind I suppose…
 
Expensive but possibly a wise investment. Most ST1100 engine damage related to timing belt failures that I have ever read about were due to the water pump or pulleys failing. This caused the timing belt to fail, jump, or break, resulting in engine damage but the initial failure was never the timing belt. I have never read of an ST1100 timing belt failure that was due specifically to the timing belt. Most ST1100 timing belts still look new at 100,000 miles.
 
Andrew Shadow said:
Expensive but possibly a wise investment. Most ST1100 engine damage related to timing belt failures that I have ever read about were due to the water pump or pulleys failing. This caused the timing belt to fail, jump, or break, resulting in engine damage but the initial failure was never the timing belt. I have never read of an ST1100 timing belt failure that was due specifically to the timing belt. Most ST1100 timing belts still look new at 100,000 miles.
Click to expand...
Good to know!
I’ll be replacing the pulleys then but the water pump is like 45k yen (a lot for someone on a Japanese salary) so I’ll stick with an inspection for the time being.

Are there any warning signs for a bad pump? Noises or the like I should be looking (or listening) out for?

Thanks!
 
Same inspections that apply to any shaft driven appliance that runs through bushings or bearings. Excessive play both vertically and laterally. Smoothness- there should be no rough spots, notchiness, no points at which it is harder to rotate, no excessive noise that sounds like gravel rolling around. No coolant leak. If your inspection determines that everything is in good shape you have determined that they are in good shape at that moment. Will they still be in that condition in another 30,000 miles? Impossible to know, which is why some people opt to change everything when they change the timing belt.
 
Fair enough. If I could afford to I would swap all the parts out but I simply can’t do so at the moment.

I suppose I can simply reinspect next time I do a coolant flush.

I was wondering if there were any noises specific to a failing water pump (squealing, clunking, etc).

Thanks!
 
Totally fair.
I’ll have think about whether I can spare the cash at the moment.
I’m already quite over budget with the bike but I’ll see if I can handle it.
Thanks.
 
SpoogyWoogy said:
I was wondering if there were any noises specific to a failing water pump (squealing, clunking, etc).
Click to expand...
In my case, yes, the bearing started to squeak so I replaced it. I wouldn't assume that all failures give warning though.

curious if Uncle Phil heard anything from his before they failed, he didn't say in his reply.
 
Good to know! I’ll keep an ear out for that. I’ll also be careful about the water pump as well.
 
SpoogyWoogy said:
Edit: just to check how many of each would I need to order? Sorry, my service manual hasn’t arrived yet so I don’t have any access to diagrams or parts lists on hand.
Click to expand...
Fortunately are there sites like Classic Motorcycle Spares featuring a library of full fiche to locate P/N:

www.cmsnl.com

Honda ST1100 PANEUROPEAN 1991 (M) EUROPEAN DIRECT SALES / KPH parts lists and schematics

✓ Honda ST1100 PANEUROPEAN 1991 (M) EUROPEAN DIRECT SALES / KPH parts lists and schematics ✓ Easy repairs with Honda diagrams ✓ Free access!
www.cmsnl.com www.cmsnl.com

As for ordering, in your neck of the woods this site might be interesting:

Motorrad-Teile aus Japan - Webike

Webike Japan! Das größte Lager von Motorradteile & Motorradzubehör online. Wir bieten internationalen Versand.
www.webike.co.at
 
dwalby said:
In my case, yes, the bearing started to squeak so I replaced it. I wouldn't assume that all failures give warning though.

curious if Uncle Phil heard anything from his before they failed, he didn't say in his reply.
Click to expand...
On the first one that grenaded the engine I heard what I thought was gravel in the fendaextenda but turns out it was not.
The water pump and pulleys were 'supposedly' inspected by the Honda shop that did the timing belt change and other service work at 100,000 miles. Though the valves were bent, the timing belt did not break.
The second one, I just notice a line of antifreeze down the left side of the engine.
 
If you decide to replace the timing belt, you might post where you found it. There have been a number of posts recently saying these are hard to find and have been discontinued by some mfrs.

For what it's worth, I replaced the timing belt on my Honda Accord maybe 6 months ago. It was 22 years old and had around 70k miles on it. I took the old one and bent it backwards and forwards, looking carefully. I could not see any cracks or damage to the old belt. It was indistinguishable from the new one. Maybe the wear was internal? Lacking an xray machine I don't know. Honda specs doggone good belts.
 
SMSW said:
Honda specs doggone good belts.
Click to expand...
I suspect the entire industry has really upped the quality of rubber products compared to decades ago. Timing belts, hoses, serpentine belts all last much longer than the ones from the '80s. But we've kept the mindset of the '80s where they would fail within a much shorter interval than they do now.
 
ST1100Y said:
Fortunately are there sites like Classic Motorcycle Spares featuring a library of full fiche to locate P/N:

[/URL]

As for ordering, in your neck of the woods this site might be interesting:

[/URL]
Click to expand...
Thank you!
Yep my parts are from webike.
Although for the water pump (which I may need to replace…) will have to be ordered from the states and shipped here (cheaper than buying from webike).
 
You must log in or register to reply here.
Back
Top Bottom