My ST1100 - overview

[ST_SVK]

I posted some information about my bike at another thread, but I am creating this one because of all repairs and information about my bike (kinda archive for me).

So:
Honda ST1100 Pan European (Switzerland model - lower power)
Year: 1999
Color: Midi Blue Metalic
Power: 53kW (72HP)
Mileage: 47400km

Main issue of PO (10/2021) - timing belt damage - it was "happy" accident - no engine damage (everyone knows, that this can be very dangerous)



04/2022 - water pump leak



This is her now after my first 40kms (25/03/2023)



What have I done (03/2023):
Oil change (3,5l Motul 10W40)
New spark plug caps
New spark plugs (NGK 3797)
Refurbished clutch slave cylinder
New brake pads - front + rear
Cleaned brake calipers + changed weared parts
New brake fluid (front brake, rear brake, clutch)
New thermostat housing + thermostat
New coolant (Motul Motocool Expert)
Refurbished turn signal switch
Cleaned rear drive + fresh lubrication of gears + new diff oil (75W90)



New oil seal (clutch cover) - no problem, but I was there, so I changed it



I will add more photos to some of this points.

What next?
During 04/2023
Check valve clearances - DONE
According to valve clearance check - new shims - DONE
After that carb sync - in progress

 

[Erdoc48]

Interesting…with the ST1100, a torn belt, especially at that low mileage isn’t very common. Was your water pump seized as a cause of the belt tear?

 

[Smudgemo]

If you're asking, I'd make sure the cooling lines are all recent or consider replacing them. Check the ignition wire at the starter relay for any sign of melting or damage, check the fuel pump output (they can stop working when they heat up on a hot day with low fuel - had it happen to me), check the sub-air filter in front of the air filter housing isn't crumbling. Other things like fork seals is more obvious when attention is needed.

 

[ST_SVK]

@Erdoc48: hard to tell, it was previous owner issue. Only thing was, that there was original belt (from 1999), so it has 22 years when that happened. And my thoughts are, that also water pump was slowly leaking somehow and that damaged timing belt. But who knows.

Smudgemo:
1. Water lines - I drained coolant, cleaned water cooler, changed 2 short hoses from it, I cleaned all parts of thermostat housing (2 small holes were totally clogged for example) and I installed new thermostat and coolant after. Only thing, which I want to do in terms of cooling are parts under carbs, but that part will be done when carb removal time comes. Also considering pair remove, when I´ll be in that area. I will see how will bike ride during summer, but I´m planning this as a maintenance for next winter.

2. PO made red wire bypass and socket on starter relay together with wires are brand new.

3. I only checked fuel pump the way manual describes - I pumped amount of fuel to a canister, that I measured it and count, that volume of fuel is according Honda specs. Is there any other way how to check fuel pump? (resistance measure or something similar?)

4. That small filter looks like cotton candy or how to decribe it. I can´t tell the condition, but I will make a picture of it, if you think it has to be replaced.

Thank you very much for inputs.

 

[ST_SVK]

So, today I found a while, so I measured valve clearances:

Honda spec:
Intake 0,13 - 0,19
Exhaust 0,22 - 0,28
Camshaft holder torque: 12Nm

Results:
Cylinder nr.1:
Intake1 - 0,17 (OK)
Intake2 - 0,16 (OK)
Exhaust1 - 0,26 (OK, current shim 2,08)
Exhaust2 - 0,27 (OK - current shim 2,05)

Cylinder nr.2:
Intake1 - 0,14 (OK)
Intake2 - 0,13 (OK, but lower tolerance)
Exhaust1 - 0,22 (OK, but lower tolerance)
Exhaust2 - 0,25 (OK)

Cylinder nr.3:
Intake1 - 0,16 (OK)
Intake2 - 0,16 (OK)
Exhaust1 - 0,3 (NOK - current shim 2,08 - new shim needed - 2,125)
Exhaust2 - 0,3 (NOK - current shim 2,05 - new shim needed - 2,1)

Cylinder nr.4:
Intake1 - 0,16 (OK)
Intake2 - 0,16 (OK)
Exhaust1 - 0,26 (OK)
Exhaust2 - 0,26 (OK)

So, not bad at all, I am planning to change 2 shims on cylinder nr. 3.
Or do you think, that 2 on cylinder nr.1 should be replace too?

 

[Smudgemo]

My fuel pump stopped working on a hot day in the mountains where I stopped frequently to take pictures and was fairly low on fuel. It ran fine all through the desert in very hot weather when I made the effort to stop for fuel more often and kept moving. Other than trying to test it when warmed up, I have no suggestions.
The sub-air filter might crumble so be ready with the vacuum to keep the bits out of the carbs. If it's still spongy and in one piece, it might be fine. Some guys cut up lawn mower air filter material as a sub, but I just buy the Honda part.
As for the red wire bypass, the bypass doesn't solve the issue the bike might have, it just gets you going again. I can only speak for myself that if the bypass was done, I'd probably be concerned as to why and would consider the ignition relay bypass mod.
Good idea to replace all the hoses when you pull the carbs next winter.
That's all I can think of.

 

[ST_SVK]

Valve clearances succesfully set.

New data for cylinder nr.3
Exhaust1 - 0,26 (OK - current shim 2,1)
Exhaust2 - 0,25 (OK - current shim 2,08)



@Smudgemo: now I understand what you mean. We have "hot days", when there is around 30°C (86°F I think) around, also that is why I always try to have fuel tank full on every vehicle I own. So, I will see, when I heat it up

I also ordered new OEM sub-air filter (5€). Thanks for recommendation.

 

[ST_SVK]

Transmission lever cleaned, lubed and reinstalled.



I have 2 questions to carb sync:

1. Cylinders nr 2 and 4 have common adjusting screw?

What to do with 3rd vacuum tube (middle one on the picture) during carbs sync? Or just plug it with screw?

 

[Smudgemo]

Someone can correct me if I'm wrong as my last sync was done a couple of years ago, but I think the answer is one of them is the baseline and you adjust the other three to match.
I believe the third line in the photo runs down to the PAIR system, but I don't recall that you need to plug it. You can see it on this '97 I once had.

 

[ST_SVK]

Yes, 4th cylinder is baseline, and other 3 are corrected to its value. So 1 screw on left side is just for cylinder 2. Sound logical. Nr4 can´t be adjusted (or I saw 1 screw on the bottom of carb nr4, but there is no way to get to it when carbs are mounted on bike.

Oh, so one extra tube for pairing system, thanks for info.

 

[John OoSTerhuis]

Adjust the #4 carb during a sync session to maintain the correct idle speed using the knob located in the fuel tank fill splash surround. The center hose ‘T’d’ to the intake manifold hoses for #2 and #4 provides vacuum to the Air Suction Valves (aka PAIRs). You do not need to plug it during a carb sync (think about it…).

John

 

[huntingdog]

Do you know how the Swiss model has its power reduced? I am guessing airflow restrictors to the carbs and different jetting?

 

[ST_SVK]

Adjust the #4 carb during a sync session to maintain the correct idle speed using the knob located in the fuel tank fill splash surround. The center hose ‘T’d’ to the intake manifold hoses for #2 and #4 provides vacuum to the Air Suction Valves (aka PAIRs). You do not need to plug it during a carb sync (think about it…).

John

When I set up idle with that knob it´s nearly fully closed (fully to right possition). So I was thinking, that I will slighly adjust also carb and then move idle knob somewhere in the middle. But maybe I am overthinking. Thank for advice.

@huntingdog : honestly I don´t know how they achieved it, but logically it´s exactly how you wrote - something with jets and air restriction. I want to investigate it when carbs will be out one day, maybe it will be something to adjust and "open" full power.

 

[Upt' North]

When I set up idle with that knob it´s nearly fully closed (fully to right possition). So I was thinking, that I will slighly adjust also carb and then move idle knob somewhere in the middle. But maybe I am overthinking. Thank for advice.

@huntingdog : honestly I don´t know how they achieved it, but logically it´s exactly how you wrote - something with jets and air restriction. I want to investigate it when carbs will be out one day, maybe it will be something to adjust and "open" full power.

I think someone asked about this before, and through a whisky single malt induced fog I think the Swiss bikes had different carbs. I can't imagine the bodies were different but their insides had been messed with. It would seem the easiest solution for Honda in restricting the power for those Swiss banker types.
After all why would you need all that power climbing those small mountain passes in Switzerland .
Good luck.
Upt'North.

 

[ST_SVK]

Bike have enough power as it is now, I can tell. But if that means that is all about carbs "inside", so why not to try figure out, what is different.

 

[huntingdog]

In the service manual the carb identification numbers are different VD B1A is the normal type and there is the VD BFA for the Swiss model. The differences are different pilots screws initial opening 1 and 7/8 vs 2 and 1/2, and a special pilot screw tool is needed for adjustment on the Swiss model vs a plain old cross screw for the normal version also the idle speed 1000rpm vs 1200rpm. There arent other differences shown.

 

[ST_SVK]

So just remove pilot screws and put new ones in and bike will have full power?

 

[huntingdog]

No. Pilots screws regulate the air fuel mixture at idle mainly. There is not enough info given in the manual to answer how the power reduction is done. Even the main jets are the same. Maybe a throttle limiter?

 

[ST_SVK]

So, today I synchronized carbs (kinda, I can make check at shop with better measuring device).

I made test ride and it rides nice and smooth.
Can someone who knows its sound write his opinion, if it sounds OK for him? I know its hard from video, but maybe.

 

[Roger]

Seems OK to me.