OzSTOC
Honda ST1300 Section => Honda ST1300 General Questions => Topic started by: CallMeSteve on October 02, 2019, 07:34:39 PM
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STrudel went in to Brisbane Honda this week for his 42k service. I asked them to look into why he was running very lumpy and rough, and I demonstrated my knowledge by suggesting that maybe the throttle bodies needed syncing. 8)
A few hours after leaving the bike I got a call. Yeah the throttle bodies were way out, but there was also a thingamebob missing from the doo-Hickey attached to one of the widgets. They fitted a replacement thingamebob and showed me a photo. See the attached photo. Looks like a previous mechanic was sloppy to say the least.
Can anyone explain in plain English what the missing thingamebob does?
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Looks like the starter valve screw🤓
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Well thank you, kind sir. :-++
Any guesses as to the effect of the missing bush and nut?
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I haven’t delved that deep into my ST but that is the adjustment screw and if missing would definitely cause an imbalance between the four cylinders.
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Would be interesting to know the difference after the bits were replaced?
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Any guesses as to the effect of the missing bush and nut?
A nut like that would normally be a lock nut, but being halfway up the thread doesn't make sense unless it's working against what appears to be a black sleeve. Might the original have vibrated out if there was no lock nut?
Still waiting for a better explanation. Alan might be along soon with an exploded parts diagram...
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Would be interesting to know the difference after the bits were replaced?
The difference is astonishing. I'd gone to a bit of trouble shortly after I got the bike to smooth out the rough low-throttle response which seems to be characteristic of STs. I had a Bazzaz ZFI installed, and got myself a silky smooth throttle response on low throttle and all the way down to idling revs. That silky smoothness that I paid so much for is now back :runyay
It now also idles nicely whether hot or cold. Plus, I think the fuel consumption is back to 'normal' as in 5-ish l/100k rather than 6-ish, although probably a bit early to tell for sure. It had been chewing extra gas for some time, so this might save me some dollars on our upcoming Melbourne trip.
Mind you there were two issues coz they also balanced the bodies and said they were way out. The last time they were balanced was at 12k, and now i'm at 42k.
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Still waiting for a better explanation. Alan might be along soon with an exploded parts diagram...
The only item that looks anything like what is in the image is item 8 from here. https://www.partzilla.com/catalog/honda/motorcycle/2005/st1300a-a-st1300a/throttle-body-comp (https://www.partzilla.com/catalog/honda/motorcycle/2005/st1300a-a-st1300a/throttle-body-comp)
It says starter valve of which there are four.
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Doesn’t show the adjusting nut and bush, tightening or loosening the nut must adjust the spring loaded plunger thingy (no8) in the starter valve effecting the volume of air . Might have a look next I have the air box off👍🤓
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This looks more like Steves photo:-
http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352 (http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352)
but from it you would go back to Alans suggest that it is part of item 8.
A similar view:-
http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352 (http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352)
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Doesn’t show the adjusting nut and bush, tightening or loosening the nut must adjust the spring loaded plunger thingy (no8) in the starter valve effecting the volume of air . Might have a look next I have the air box off👍🤓
I had a look in the workshop manual and the parts that were missing are related to adjusting the starter valve which is set at the factory and according to the manual should not be touched or it can cause throttle and idle valve synchronisation failure.
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This looks more like Steves photo:-
[url]http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352[/url] ([url]http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352[/url])
but from it you would go back to Alans suggest that it is part of item 8.
A similar view:-
[url]http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352[/url] ([url]http://partsfinder.onlinemicrofiche.com/wingstuff/showmodel.asp?type=13&make=hondamc&a=1352[/url])
The throttle body assembly does show the complete starter valve assembly but the parts list for the components (page I linked to earlier) doesn't show the lock nut and bush (??) items; I'm guessing that it comes as a set and is not something that one would usually need to replace.
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Fuel consumption is looking good. I went for a 150k round trip today - pure highway - and returned 5.0l/100k, which is what I used to get in the 'old days'. For the last year it's never gone below 6l/100k even on the highway. Happy camper :-)