In the middle of a timing belt change RIGHT NOW!

[MaxPete]

Hi Dirt Road:

I have followed this thread with great interest because I'm an engineer and engine design is my thing. Having said that, I'm an ST1300 guy so we don't have to content with timing belts. I totally understand your concern about the slight misalignment of teeth count, timing marks etc. and will assure you that there is always a bit of variation from engine to engine and belt to belt. Not as much as one whole tooth, but a bit.

One suggestion I might offer based on my OHC automotive experience (and 1100 folks PLEASE feel free to criticize) would be:

- once you have it all back together and buttoned up as best you can - with spark plugs OUT - turn the engine over in the normal direction of rotation, VERY SLOWLY WITH A RATCHET on the crank (drive) pulley - BEFORE cranking it with the starter.

If the engine rolls over OK, all the way around with nothing stopping it (like a valve clipping a piston), then you should be OK to start it up. If a valve collides, you will be going slowly AND GENTLY and you'll feel it before any harm is done and then you can remove the belt, reset everything and try again.

Be be patient and methodical - you'll get there.

Pete

 

[Dirt Road]

Hi Dirt Road:

I have followed this thread with great interest because I'm an engineer and engine design is my thing. Having said that, I'm an ST1300 guy so we don't have to content with timing belts. I totally understand your concern about the slight misalignment of teeth count, timing marks etc. and will assure you that there is always a bit of variation from engine to engine and belt to belt. Not as much as one whole tooth, but a bit.

One suggestion I might offer based on my OHC automotive experience (and 1100 folks PLEASE feel free to criticize) would be:

- once you have it all back together and buttoned up as best you can - with spark plugs OUT - turn the engine over in the normal direction of rotation, VERY SLOWLY WITH A RATCHET on the crank (drive) pulley - BEFORE cranking it with the starter.

If the engine rolls over OK, all the way around with nothing stopping it (like a valve clipping a piston), then you should be OK to start it up. If a valve collides, you will be going slowly AND GENTLY and you'll feel it before any harm is done and then you can remove the belt, reset everything and try again.

Be be patient and methodical - you'll get there.

Pete

This is exciting, I have so many questions!

1). Why is it important to take the spark plugs out? What difference does it make? I've heard that it makes the engine easier to rotate. Why? Is this all, or will something not work/get damaged if I you don't?

2). When you say "all the way around" do you mean 1 rotation of the crankshaft or 4 like the manual says. Though I'm a relatively new engine enthusiast, I understand the basics of a 4-stroke, and I'm guessing that they say to do 4 because that's a full run through the cycle, correct?

3). What you say about feeling for a valve colliding has finally made my mental image click regarding how the valves function. What will it feel like if a valve hits while I'm slowly cranking the engine over? Will it just be a resistance? Is it subtle or obvious? Does it make a noise? If this does happen (knocks on wood), I don't want to push through and bend the valve, so would it be okay to crank it back the other way?

4) Suddenly I'm realizing that I did fully rotate the left pulley (from rider position) a few times because it kept snapping out of proper position. Have I destroyed a couple of my valves? I know one of the cylinders is in TDC. I never felt anything that I would have interpreted as a valve bending.

5) You guys with 1300s don't have to deal with timing belts? You lucky *******s! Do you have timing chains instead?

 

[mcthorogood]

Yes, put the cover on the left driven pulley. Make a mark on the cover that lines up with the index mark on the left pulley.

Then follow the procedure (pages 8-13 and 8-14) in the service manual for setting the tension on a new belt. You do have a Honda Service Manual?

 

[Jim Van]

Nice pics, but it looks like you are one tooth off on both camshaft gears or you are one tooth off on the crank pulley.

 

[Jim Van]

Alright, I corrected it. The tic marks are each about half a tooth off (too far clockwise) as you can see in these pictures. Dwalby said above that it's okay if the pulleys are a fraction of a tooth off. Is this okay? I considered whether it's possible that there's a problem with the distance between the crankshaft and the left side pulley but wrote that off, mostly because 1) the crank is in the correct position and the pulleys are equally off by less than a tooth (about 1/3 of a tooth), and 2) I counted and marked that distance on the old belt before taking it off and it is perfectly matched on this one. SO: the problem seems to be with the tension. From what I'm hearing from a number of you, this tends to happen, it's usually slightly imperfect, and there isn't a whole lot to be done about it. Should I just tighten all the bolts down to the specified torque settings, put the pulley cover plate back on, and turn the engine over a few times at this point? Or, is there anything else I can do to possibly bring it into line? Over all I'm feeling pretty good about it so far!

Nice pics, but you are either one tooth off on both camshaft gears or one tooth off on the crank gear. Give us a pic of the crank gear. You still aren't there ..... If you slightly rotate the crank gear CCW both the camshafts will be dead-nuts. Maybe you crank gear is just slightly off.

 

[Dirt Road]

Nice pics, but it looks like you are one tooth off on both camshaft gears or you are one tooth off on the crank pulley.

Can anyone else verify this? It's definitely less than a tooth off on both pulleys. If it's one tooth off on the crank pulley would that cause it to be less than a tooth off on the cam pulleys?

 

[mcthorogood]

Nice pics, but it looks like you are one tooth off on both camshaft gears or you are one tooth off on the crank pulley.

Is the misalignment because the belt doesn't have any tension on it?

 

[Jim Van]

If you slightly rotate the crank gear CCW both the camshafts will be dead-nuts. Maybe you crank gear is just slightly off. Give us a pic of your crank gear after you slightly rotate the crank CCW.

 

[Jim Van]

I thought the tensioner was installed ?? But if it's not fully tensioned now and then was fully tensioned, that would cause one camshaft to rotate CW and the other CCW, right ? That would cause the misalignment to be even more, right ?

 

[MaxPete]

This is exciting, I have so many questions!

1). Why is it important to take the spark plugs out? What difference does it make? I've heard that it makes the engine easier to rotate. Why? Is this all, or will something not work/get damaged if I you don't?

2). When you say "all the way around" do you mean 1 rotation of the crankshaft or 4 like the manual says. Though I'm a relatively new engine enthusiast, I understand the basics of a 4-stroke, and I'm guessing that they say to do 4 because that's a full run through the cycle, correct?

3). What you say about feeling for a valve colliding has finally made my mental image click regarding how the valves function. What will it feel like if a valve hits while I'm slowly cranking the engine over? Will it just be a resistance? Is it subtle or obvious? Does it make a noise? If this does happen (knocks on wood), I don't want to push through and bend the valve, so would it be okay to crank it back the other way?

4) Suddenly I'm realizing that I did fully rotate the left pulley (from rider position) a few times because it kept snapping out of proper position. Have I destroyed a couple of my valves? I know one of the cylinders is in TDC. I never felt anything that I would have interpreted as a valve bending.

5) You guys with 1300s don't have to deal with timing belts? You lucky *******s! Do you have timing chains instead?

Hi again:

Good questions! OK - here are my responses and again, I would be very pleased to have a sanity check from an experienced 1100 person - because I've never worked on one of those big girls.

1) SPARK PLUGS OUT - because there will be no compression which means that it will be easier to turn the engine over with a wrench but more importantly, you will feel any resistance to rotation VERY DISTINCTLY. Also, when there is engine compression, the engine will tend to "lurch" as each piston goes over top dead centre and that makes it difficult to go slowly.

NOTE - only use the wrench on the crank (drive) pulley - NOT on the camshaft or driven pulleys.

2) ALL THE WAY AROUND - yup, just to be sure I would rotate it several times (3 or 4 complete revolutions) - although one complete engine cycle is only two revolutions. The term 4-stroke (more correctly, 4-stroke cycle) refers to the fact that the piston in each cylinder must go up and down TWICE to complete the full intake - compression - combustion/power - exhaust cycle. That means that the crankshaft rotates TWICE for each complete engine cycle.

That is down-up-down-up - which is 4 strokes per cycle. You may someday hear the expression suck-squeeze-bang-blow - it isn't porn, that is how 4-stroke cycle engines actually work. Incidentally, that is also why the crank (drive) pulley is exactly HALF the diameter of the driven (camshaft) pulleys. The camshafts turn EXACTLY once for every two revolutions of the crankshaft - and that is true for all 4-stroke cycle engines.

3) If a valve touches a piston crown - it will be very distinct and the crankshaft will NOT want to continue to rotate. You may or may not actually hear anything - but you WILL feel it. That's why you go VERY slowly, gently, no spark plugs and pay close attention.

If you do feel a strong resistance to continued rotation - STOP - go back the other way and TAKE THE BELT OFF AND START OVER. Reset the crank and camshaft timing marks and re-install the belt.

4) If the timing is way off and a valve touches a piston, it is NOT TOO likely that you have bent a valve unless you used the electric starter. If a valve is bent, the engine will lock up as the valve will not close - and you would feel that in your wrench as you try to turn it over.

5) Yup - the 1300s have a timing chain driving the cams rather than a belt. Apparently, the 1300 engine is somewhat shorter front-to-back than the 1100 and one of the ways Honda accomplished that is by switching to a chain which is a bit more compact than the belt. The downside is that chains are more expensive than belts, they can be noisier and they need to be lubricated.

Pete

 

[Dirt Road]

Okay, I'm going to follow the manual at this point: I've loosened the tensioner bolt (it's been loose this whole time), and I'm going to put on the left driven pulley guide plate, turn the engine over a few times with the spark plugs out, and see how it feels. I'll check back in a couple minutes. If it's still messed up I'll put up a picture of the crank pulley as well. From what I'm hearing, 1 tooth on the crank equals 1/2 a tooth on the driven pulleys, so it is possible that the crank is a tooth off.

EDIT: Turns out I don't have a plug socket that fits down those little tubes, so I'm gonna be doing this with the plugs in.

 

[MaxPete]

Okay, I'm going to follow the manual at this point: I've loosened the tensioner bolt (it's been loose this whole time), and I'm going to put on the left driven pulley guide plate, turn the engine over a few times with the spark plugs out, and see how it feels. I'll check back in a couple minutes. If it's still messed up I'll put up a picture of the crank pulley as well. From what I'm hearing, 1 tooth on the crank equals 1/2 a tooth on the driven pulleys, so it is possible that the crank is a tooth off.

OK - now this is getting too specific for me to comment further because I don't have an 110 manual and have never work on one of those bikes.

....over to you 1100 people.....

 

[Jim Van]

BTW, I would rather have a ST1100 with a belt than a ST1300 with the chain. Mainly because changing the belt every 85K miles is no big deal ( and the belts are cheap ) , but more importantly because it's a breeze to remove the camshafts if the valve clearance shims need to be changed.

I also have a ST1300 manual and it sounds like a real PITA removing the camshafts since the timing chain has the be slipped off the camshaft gears to accomplish that.

 

[mcthorogood]

I would put the cover on the left pulley, apply tension to the belt by loosening the tensioner bolt and rotate the crank gently for 2 - 4 turns. The worse that could happen is that the engine locks up and you need to start over. Then line up the punch mark on the crank with the projection and check the alignment of the index marks on the driven pulleys.

 

[mcthorogood]

If everything lines up then follow the procedure for setting the tension for a new belt. Turn the crankshaft CW 3 teeth further and tighten the tensioner bolt.

 

[mcthorogood]

Turns out I don't have a plug socket that fits down those little tubes, so I'm gonna be doing this with the plugs in.

The plug socket is part of the Honda toolkit.

 

[Dirt Road]

alright, I rotated the crank four times and the punch marks on both the driven pulleys are still extremely close to where they were before. The marks on the pulleys are just a tiny bit past the marks on the case. Less than 1/2 a tooth, but not nothing. I felt nothing while rotating it, just the gentle resistance of the compression. I don't know...is it worth pulling it off and trying to adjust the crank by a tooth? It seems really close.

 

[Dirt Road]

You know what? I took the plugs out, gave it a few more turns (felt nothing) and got it back to where it's supposed to be but this time I used the tick marks on the driven pulleys to line it up and then checked on the crank to see how lined up it is. It looks great. I think I was at a bad angle previously when I was trying to line up the punch mark on the crank pulley. Here are some pictures. In the third one there is a fuzzy bronze sharpied line marking the punch mark. What do y'all think? Looks great to me!

 

[dwalby]

I thought the tensioner was installed ?? But if it's not fully tensioned now and then was fully tensioned, that would cause one camshaft to rotate CW and the other CCW, right ? That would cause the misalignment to be even more, right ?

Not necessarily. If the tensioner wasn't installed, when it is installed it could pull both cams CCW, as its on the left side of the belt path (looking from front), assuming the crank doesn't move under tensioning. Or it may do nothing, depends on the prevailing belt tension prior to tensioning. From the photos it looks like the relationship between the two cams is good, the question is where is the crank? If its a little bit CW from its TDC position, then everything looks good and would explain why both cams are a bit CW from their reference marks. If its TDC exactly, then I wouldn't worry about the 1/2 tooth offset on the two cams, its not enough to be a problem.

To answer the OP question about if this is what I was referring to, the answer is not exactly, but its a similar concept. What my problem was is with the crank at TDC and the left cam dead on its mark, the right cam was 1/2 tooth off, and I couldn't stretch the belt enough to remove the 1/2 tooth discrepancy. If what the OP has in the pictures is a perfectly aligned TDC crank, then he is seeing a 1/2 tooth discrepancy between crank and left cam, but perfectly aligned left/right cams. In that case I'd button it up and move on because you can't fix 1/2 tooth adjustments anyway. Also, you're not going to bend a valve with a half tooth, or probably even a full tooth misalignment, you'd need to be off by more than that to do damage. One full tooth off might be noticeable in terms of performance, but I'm not even sure about that, it might take a couple teeth to notice it at all. And, once you find out how much fun it is to put the radiator, etc. back on, you won't want to go back in to re-adjust it again anyway.

edit: I saw your latest pics and it looks good. Not perfect, the crank appears to be a little CCW of perfect, but as good as you're going to get. The previous pics of the two cams 1/2 tooth CW past their marks would seem to be consistent with a dead on crank (double check that yourself). If that checks out then you're good, and you can't make it any better, so you're done with that task. Now you can look forward to the Honda hoses that are 0.00000001" larger in diameter than the metal pipes they fit over.

 

[John OoSTerhuis]

I'm coming back to the discussion late tonight. Coupla points - I did say to tension the belt after putting it on and then check the marks.

What manual are you using? If the Honda manual, follow the last, final step in the whole procedure, the part about initial tensioning and final torque for A NEW TIMING BELT. If you don't have the Honda Manual I can transcribe that part here in a post for you.

Are you installing a Honda new stock timing belt or an aftermarket, e.g. Gates? A new belt's teeth fully seated in their slots in the crank should arrive at the left driven pulley and seat in those slots/valleys so the marks align perfectly. Yours problem there as described would be the first I've ever heard of... hence the mention of double-checking the crank alignment marks. The only other explanation would be a non-standard (length/tooth spacing) belt.

Just a personal observation/comment, but turning the engine over with the spark plugs still installed should have been very difficult. You need a plug wrench. Seriously.

Yes, I'd pull the belt and reinstall as I mentioned above.

John