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Honda ST1100 Section => Honda ST1100 General Questions => Topic started by: VirtualT on September 14, 2014, 09:32:59 AM

Title: Carb Sync
Post by: VirtualT on September 14, 2014, 09:32:59 AM
Hi

I have just bought a 2000 ST1100, pretty happy with it so far although it seems to be making a knocking noise from the motor at idle and when pulling away in the lower gears. The noise goes away when you pull in the clutch or if you rev it.

A car mechanic neighbor said that it might be the carbs need syncing, I hope so because this is my everyday vehicle and I can't afford to have it off the road, just been made redundant.

Can anyone tell me the best (read cheapest) place to get this done in Perth and approximate cost?

Thanks a lot.
Title: Re: Carb Sync
Post by: StinkyPete on September 14, 2014, 01:00:41 PM
Hi VitrualT and welcome to OzSTOC from SA.   :hatwave   I'm sure that one our WA people will be able to answer your question.
Title: Re: Carb Sync
Post by: alans1100 on September 14, 2014, 02:16:46 PM
Hi

I have just bought a 2000 ST1100, pretty happy with it so far although it seems to be making a knocking noise from the motor at idle and when pulling away in the lower gears. The noise goes away when you pull in the clutch or if you rev it.

A car mechanic neighbor said that it might be the carbs need syncing, I hope so because this is my everyday vehicle and I can't afford to have it off the road, just been made redundant.

Can anyone tell me the best (read cheapest) place to get this done in Perth and approximate cost?

Thanks a lot.


Welcome aboard from SA.

More here http://ozstoc.com/index.php?topic=7557.msg86789#msg86789 (http://ozstoc.com/index.php?topic=7557.msg86789#msg86789)

The 1100 seems to do this but it's a minor issue. It normally only happens at idle and the sound can vary when pulling the clutch lever in but once under way it's all quiet.
Title: Re: Carb Sync
Post by: saaz on September 14, 2014, 05:12:33 PM
Mine has always had a clutch and other rattle (cog on the left hand cam is a bit loose) regardless of synching the carbs time and again.  Only notice it at idle if in a shed to reflect the sound. At 215,000kms does not seem to have affected the reliability.
Title: Re: Carb Sync
Post by: Pezzz on September 15, 2014, 12:04:45 AM
Have you checked timing as well? How mechanically minded are you?

Sent from my GT-I9507 using Tapatalk

Title: Re: Carb Sync
Post by: VirtualT on September 15, 2014, 10:03:26 AM
Have you checked timing as well? How mechanically minded are you?

Sent from my GT-I9507 using Tapatalk

No, I presumed these bikes were electronic ignition?

I am reasonably handy with tools but usually stay away from timing and carbs if there are more than 1 :)
Title: Re: Carb Sync
Post by: Oddjob on September 15, 2014, 01:10:12 PM
VirtualT,

Where in Perth are you, I live in Bassendean and have a SK airflow meter to balance the carbs. Takes 15 mins tops to check including stripping some plastic. My 1100 does similar, I thinks it's very common, I just keep the maintenance up and ride it as often as I can.

Let me know.

Geoff.
Title: Re: Carb Sync
Post by: Pezzz on September 15, 2014, 01:42:38 PM
Hey Geoff,
Is your balancer the trumpet type or the one that goes on the little vacuum hoses? I actually need to check my mixture as I think it is rich.

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Title: Re: Carb Sync
Post by: Pezzz on September 15, 2014, 01:43:57 PM
I am in Beechboro but used Yorkies trumpet style balancer last but I think he may have lent it out right now.

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Title: Re: Carb Sync
Post by: Pezzz on September 15, 2014, 01:45:45 PM
Someone had similar knocking noise issues and it was suggested they check timing marks on belt to make sure not slipped and therefore firing too early which can lead to knock.

Sent from my GT-I9507 using Tapatalk

Title: Re: Carb Sync
Post by: VirtualT on September 15, 2014, 02:26:19 PM
VirtualT,

Where in Perth are you, I live in Bassendean and have a SK airflow meter to balance the carbs. Takes 15 mins tops to check including stripping some plastic. My 1100 does similar, I thinks it's very common, I just keep the maintenance up and ride it as often as I can.

Let me know.

Geoff.

Awesome, I am in Spearwood, maybe I could shoot out one evening that would be great!

Someone had similar knocking noise issues and it was suggested they check timing marks on belt to make sure not slipped and therefore firing too early which can lead to knock.

Sent from my GT-I9507 using Tapatalk

Ahh I see, hoping this would not be the case bike has only done ~75K Km I wouldn't know how to do this anyway
Title: Re: Carb Sync
Post by: saaz on September 15, 2014, 04:08:00 PM
I have the flowmeter type and carbtune vacuum tube style balancers. Both get you to the same point, although some have reported over the years that one or the other does a better job on their particular ST, so worth giving one or more of them a go.
Title: Re: Carb Sync
Post by: alans1100 on September 15, 2014, 04:18:13 PM
Someone had similar knocking noise issues and it was suggested they check timing marks on belt to make sure not slipped and therefore firing too early which can lead to knock.

Sent from my GT-I9507 using Tapatalk


The belt isn't smooth like a fan belt. It has teeth so it can drive the cam gears and is driven from the crank shaft so slipping would seem a remote possibility. Even with the tension adjuster slackened off the belt will still drive as when replacing the belt we need to make sure the belt tracks correctly by turning the motor by hand a few turns.

Here's the belt in place http://ozstoc.com/index.php?topic=2977.msg34073#msg34073 (http://ozstoc.com/index.php?topic=2977.msg34073#msg34073)

Title: Re: Carb Sync
Post by: Oddjob on September 15, 2014, 04:44:51 PM
I have....
http://www.cbperformance.com/ProductDetails.asp?ProductCode=6537 (http://www.cbperformance.com/ProductDetails.asp?ProductCode=6537)
easy and accurate.

VirtualT, I will send you a PM with my mobile no.

Geoff
Title: Re: Carb Sync
Post by: Yorkie on September 15, 2014, 09:20:51 PM
My unit is on the way to Wagin, #4 is factory set, when the others are balanced the mixture is brought into line with #4, if you are to rich then it becomes a whole new game involving exhaust monitoring etc, to alter the mixture on #4 as a pre-requisite to then balancing the others.
Title: Re: Carb Sync
Post by: Pezzz on September 15, 2014, 09:32:42 PM
I think that is what I need to do as when I take off hard a trail black smoke. Better than blue.

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Title: Re: Carb Sync
Post by: VirtualT on September 17, 2014, 10:46:34 PM
Well went out to Oddjob's place today and we did the carb balance, thanks mate.

running better but the knocks still there

Title: Re: Carb Sync
Post by: Turtle on September 17, 2014, 11:00:15 PM
Try some fuel cleaner and change the oil see how that goes also have you changed the spark plugs ?

Turtle
Title: Re: Carb Sync
Post by: VirtualT on September 17, 2014, 11:02:37 PM
Try some fuel cleaner and change the oil see how that goes also have you changed the spark plugs ?

Turtle

Yep I have changed the oil already, pulled one plug out and it looked ok so didn't bother about the rest
Title: Re: Carb Sync
Post by: Turtle on September 17, 2014, 11:17:37 PM
The clutch can rattle a bit with no load ie idle
My old 1100 did could be what your hearing
Now my 1300 is way louder not like a Ducati tho
Maybe next do a clutch fluid flush also

Turtle
Title: Re: Carb Sync
Post by: VirtualT on September 17, 2014, 11:36:14 PM
Nah I don't think its clutch rattle, more like a knock, and It is quite noticeable with the clutch half out in first gear, for example if I load up the clutch in first gear with the brake on
Title: Re: Carb Sync
Post by: kappy5003 on September 20, 2014, 09:51:37 AM
Just thought I would jump in on the carby sync discussion.

Just recently Yorkie was kind enough to send Carby tool and since have been having a play.

My observations so far.
I have recently attended to all the valve shims and AnaSTasia has sat unfired for a little over 12 months,untill recently.

When starting for the 1st time i observed as mentioned above what quite metallic noise, quite scary really. also seems like engine vibration coming though hand grips, more than i seem to recall in the past.

Since then I have started her a few times seems as if getting  a little better. New fuel--carby cleaner.

Any way a couple of days ago I got to operating temp and noticed running better  when warm, so did carby sync some minor adjustment not really a lot, less than I would have thought.

Any way yesterday fired her up again, Wont fire without choke went cold and it not that cold really, anyway got temp up not as warm as the day before and checked carbs and discovered quite a bit of discrepancy. Thinks out loud, I look at that later.

Anyway this morning I start her with a little choke and notice a little backfire though carbs, even with choke off still a little backfire. Increase revs a little and can here a little popping, all with air cleaner cover off.

I also smell what I call a pepper type smell from around the intake area, I related this smell to a sort of coolant smell , takes me back to an old car I had with coolant leak car heater system.

So before I start ripping everything apart unnecessarily can I ask a few opinions factual would be appreciated.

Cheers
Kappy
Title: Re: Carb Sync
Post by: Greencan on September 22, 2014, 07:57:41 AM
Quote
Anyway this morning I start her with a little choke and notice a little backfire though carbs, even with choke off still a little backfire. Increase revs a little and can here a little popping, all with air cleaner cover off.

Understanding exactly how components work is handy when it comes to home maintenance.

...Crankhaft is flat plane with shared big-end jounals...Thererefore as 2 pistons on one side are at the top of their stroke, the opposite are at the bottom.

Ignition is banked (for want of a better word)...Therefore everytime a piston reaches its top, the spark plugs fires, irrespective of whether its top of its COMPRESSION  or EXHAUST strokes.

Any unburnt fuel is therefore ignited during the exhaust stroke...thus you here an occasional (common), or frequent (uncommon), backfire (for want of a better word).

Ciao, the can :-)
Title: Re: Carb Sync
Post by: Panman50 on September 22, 2014, 10:12:38 AM
Hi Virtual, if you say the noise is more noticeable when under load in first with the brake on the news may not be good.
That's normally a sign the big end is on the way out.
She will still run for a while but I wouldn't be doing long rides and definitely go easy on the poor girl.

Do we have any QUALIFIED bike mechanics on this site that can confirm my suspicions???

Regards,
Tom.
Title: Re: Carb Sync
Post by: Panman50 on September 22, 2014, 10:25:20 AM
Following my last post, the knocking noise would be a deep knock like 2 bits of heavy metal knocking together (1920's forging machinery), not a high metallic ping.
Regards,
Tom.
Title: Re: Carb Sync
Post by: duke888 on December 31, 2014, 07:55:36 PM
Sorry to hijack this thread, but as above, I am looking for a good bike mechanic to give my ST1100AY the once over before I put all the tupperware back on (and wow is there alot of that) - I live in the eastern side of Adelaide.
As it had done 100k I replaced all the standard things including timing belt and fitted new shock & fork springs.
Got rid of the vacuum fuel valve as it leaked.
Bought it in November from Melbourne as a repairable write off (mainly just tupperware damage)

Thanks in advance for any assistance,
Phil.