At 90,000 miles the valves are all in spec but I found this ..... perhaps the the cam timing is off by a tooth.................

[PhotoDoctor]

The timing mark and cam marks did not line up per the Honda Book so I rotated the cam lobes away from the valves and checked each valve clearance and they are all within specs. But It appears to me that the cam timing must be retarded a bit from where it's supposed to be.

I bought this bike with 47k from a friend who did the timing belt just before I bought it due to age of the belt not the miles. He builds several bikes a year and is top notch but maybe he got distracted and let it jump a tooth. The bike has run great for the 43K that I've rode it in the last 2 years. It runs so good that I may not even pull the radiator and check for the marks hidden down there at this time, as if I wait another 50K miles or about 2 more years it will be time to do the belt again anyway. (I've done plenty of timing belts and chains so am not afraid of it - I just have other projects I'd be glad to move onto)

Bike runs strong, gets the normal fuel mileage of 42 ish on the interstate and more on back Hwys.

Anyone see this before, or am I missing something?

 

[John OoSTerhuis]

Dang. Puzzling for sure. Amazing though... It may be running OK, but personally, I’d take it apart and set it right. JMO

I expect others will weigh in and I welcome their opinion.

John

 

[sirbike]

I don’t know if that ST1100 belt can stretch like my ST1300 chains
I was going nuts last week setting timing with the marks not lining up perfectly. After some surfing all the way to Australia I found out cam chain stretch comes into play.
Setting the cam shaft gear marks lined up and having the timing mark approximate, in view was correct. When I moved one tooth over the engine mark went way off.


It was hard for me to accept initially but made sense. Stretch wear on the chain means engine timing mark won’t be perfectly lined up with cam gear marks.
When I’ve done ST1100 shims I have simply marked the belt and “gears” and put back together lined up on my marks.
Only time the I set the timing from scratch was when installing a new belt. Of course all factory markings lined up.
In short it theoretically could be belt stretch throw you off
Most likely given how properly the bike runs.

 

[dwalby]

In short it theoretically could be belt stretch throw you off
Most likely given how properly the bike runs.

that's not it, the belt doesn't really stretch at all, and certainly not anywhere near that amount if it did stretch. We have a large number of belt replacements performed on this forum, if the belt stretched anywhere near that much it would have been reported before. When I replaced mine at 90k miles and 16-17 years the timing marks were still dead on.

I'm surprised the bike runs normally being that far off. Also, in one of the pictures it appears that the head material around the spark plug is cracked, is that real or an illusion?

 

[John OoSTerhuis]

In over 22 years on the ST1100 forums I’ve never heard of a timing belt stretching. My person opinion is that they don’t. My firST two belts certainly hadn’t (90K each), not a millimeter.

John

 

[STRider]

... Also, in one of the pictures it appears that the head material around the spark plug is cracked, is that real or an illusion?

Are you referring to something along the top edge of the spark plug hole, or down inside it? If the top, it's the protrusion from from the cam holder on the left side of the photo. If down in the hole, where there's a subtle color change then I think it's a casting artifact where different fronts of the molten metal met inside the mold.

 

[sirbike]

Given no stretch that takes us back to did it jump or was it set wrong?
What could cause a jump? Weak tensioner, bad pulley?
Then what are the odds of a jumped tooth?
If conditions caused it to jump once, I’d suspect it would jump again fairly soon. And again.

Me thinks more likely set wrong at install.
42mpg sounds low. My 1100s ran about 47-48 at 65-70 mph freeway. Higher cruising secondary roads.
Using mileage for comparison, what speeds are you at?
I suggest taking it apart and setting the belt timing correctly.

 

[PhotoDoctor]

Well check this out. I may have an accidental performance Mod here : )

I've found a little info regarding advancing / retarding cam timing. Apparently a little retard gives more high rpm power and advance gives low rpm power.

This may be giving the bike more kick on the higher revs.

The head is not cracked - I think you are seeing a thin scrap of silicon that PO used for sealer.

 

[dwalby]

here's what I was asking about that has the appearance of a crack.

 

[PhotoDoctor]

Not a crack, it's just a piece of dry silicone that I had not cleaned off - look around the valve cover surface and you will see more. The one you are looking at is just a finer, smaller piece.

 

[PhotoDoctor]

Thanks for the input, it is a curiosity and I'm still pondering on which way I'll go with it. (Knowing either way will be fine leave as is or set to Honda specs)

I've had Four ST1100's looking for the one that gets 50 mpg...........so far all of them get about the same gas mileage for me which is the low 40's. I did get a solid 50 mpg while riding the back roads with a friend who didn't like to go over 50 mph due to a valve guide replacement on a BMW and break-in period. I'm not a really fast rider but generally 80 mph indicated on the interstate. I do ride around 24K a year and check my gas mileage has a habit.

Here is a link to the fuelly website that shows what many have listed for ST1100 fuel mileage: https://www.fuelly.com/motorcycle/honda/st1100


I have pulled the top timing belt covers and the belt is clean, dry, and tight.

This project started due to a blown hose under the carbs so I've replace all the hoses, vacuum hoses, and removed the pair system. I have cleaned the carbs and replaced the float needles and bowl gaskets. It did appear that two of the old bowl gaskets had seeped a bit. .........and while the plastic was already off I check the valves.

 

[wjbertrand]

In over 22 years on the ST1100 forums I’ve never heard of a timing belt stretching. My person opinion is that they don’t. My firST two belts certainly hadn’t (90K each), not a millimeter.

John

Nor have I heard of an ST1300 cam chain stretching. The timing marks on my ST1300 could all still be aligned perfectly at 150,000+ miles.

 

[John OoSTerhuis]

I’d take it apart and set it right. JMO

I suggest taking it apart and setting the belt timing correctly.

I've replace all the hoses, vacuum hoses, and removed the pair system. I have cleaned the carbs and replaced the float needles and bowl gaskets.... I check[ed] the valves.

As long as you’ve gone this far, why not go a little further? But I’m anal retentive and juST couldn’t leave something like this alone. JMHO

John

 

[Erdoc48]

Wow, that’s very interesting. When I did the timing belt on the 94, I had a similar event occur. The cam timing marks matched but the crank mark was off (before any disassembly or removal of the belt). The bike ran fine (strong actually). What I did for the new belt is to line up the cam marks and make a new mark on the crank pulley (used one of those gold pens from the local CVS). I didn’t have an impact wrench to take the crank bolt off and align the pulley to the proper mark. I very carefully checked TDC on cylinder #1 by using a dowel in the spark plug hole and watching with engine rotation when it was at the top of its movement in the cylinder. Made the mark on the crank pulley (the new TDC mark) and with the new belt, cam marks were in synch with the new mark I made. Bike was as strong as ever. Not at all sure why this occurred with my bike and I’m fairly certain the prior owner didn’t mess with the crank bolt in the past (although possible). Runs great to this day years later. The proper thing to do would be to reset everything (make all marks in synch by loosening the crank pulley) but like I said, I lacked the tool to loosen the pulley.

On the 2000, all lined up properly before tearing it down. Both STs easily get in the low 50s mpg wise. Lastly, I put new belt on top of old when I swapped them (and used the Gates belt) same size, no stretching, and the OEM Honda belt looked as new despite its age.

 

[Erdoc48]

Thanks for the input, it is a curiosity and I'm still pondering on which way I'll go with it. (Knowing either way will be fine leave as is or set to Honda specs)

I've had Four ST1100's looking for the one that gets 50 mpg...........so far all of them get about the same gas mileage for me which is the low 40's. I did get a solid 50 mpg while riding the back roads with a friend who didn't like to go over 50 mph due to a valve guide replacement on a BMW and break-in period. I'm not a really fast rider but generally 80 mph indicated on the interstate. I do ride around 24K a year and check my gas mileage has a habit.

Here is a link to the fuelly website that shows what many have listed for ST1100 fuel mileage: https://www.fuelly.com/motorcycle/honda/st1100


I have pulled the top timing belt covers and the belt is clean, dry, and tight.

This project started due to a blown hose under the carbs so I've replace all the hoses, vacuum hoses, and removed the pair system. I have cleaned the carbs and replaced the float needles and bowl gaskets. It did appear that two of the old bowl gaskets had seeped a bit. .........and while the plastic was already off I check the valves.

I did my hoses on both bikes but at what mileage did the hose fail, and which hose was it?

 

[Larry Fine]

I've found a little info regarding advancing / retarding cam timing. Apparently a little retard gives more high rpm power and advance gives low rpm power.

Can the 1100 valve timing be intentionally adjusted just one or two degrees, or only in greater increments?

 

[GGely]

Elsewhere is my post about the same issue CYYJ and I found on my 2001.

Runs strong, no I’ll effects that I can find so I am not going to change a thing.

 

[TerryS]

Nor have I heard of an ST1300 cam chain stretching. The timing marks on my ST1300 could all still be aligned perfectly at 150,000+ miles.

Thats good to hear. I do know that my VTR1000F chains have stretched noticeably after 80,000km, effectively each head is a single cylinder so gets quite a lot of pulsing/uneven cam loads, compared to the ST which is effectively a parallel twin with even firing every 360 degrees.

This was the front head cam timing (exhaust to left) with the crank aligned; runs great:

 

[sirbike]

Nor have I heard of an ST1300 cam chain stretching. The timing marks on my ST1300 could all still be aligned perfectly at 150,000+ miles.

That is interesting. My bike has 58,000 miles.
Here is the link that, in the third reply, resembles my situation

http://ozstoc.com/index.php?topic=7711.0

 

[PhotoDoctor]

Thanks for the info that others have had this issue. I'll have to check to see if the crankshaft mark is off by physically checking TDC on #1 piston as ErDoc48 did.

The large hose on right side under the carbs failed by the elbow that goes into the crankcase. The hose was ballooned and split open about 2" long. It appeared they were the original hoses from 1997 so were about 23 years old.