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Discussion Starter · #1 ·
Hi guys :)

I'm having a go at syncing my bike but a bit of a novice and was wondering if someone could give me a basic rundown please of what's going on with the throttle stop screw under the main tank, the one that's a pain to reach.

I don't think I can quite "imagine" what it's supposed to do to the mechanism it's affecting, such as what happens when turning it in and what happens when turning it out.

Any help would be appreciated.

Thanks.
 

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There is a SST (special service tool) you can purchase to assist in synching the crabs however if you remove the gas tank and open the throttle you will find that the adjusting screw will be pointing straight up and accessible from above. Kind of a PITA because you have to take your reading, shut the bike off, make your adjustment and restart the bike to see the new reading and repeat as needed.
 

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Not sure on your bike, but on my 1100 it can be reached from the left side with a long shank screw driver, not the best solution and not really easy but it was better than taking the tank off again!
 

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Discussion Starter · #4 ·
There is a SST (special service tool) you can purchase to assist in synching the crabs however if you remove the gas tank and open the throttle you will find that the adjusting screw will be pointing straight up and accessible from above. Kind of a PITA because you have to take your reading, shut the bike off, make your adjustment and restart the bike to see the new reading and repeat as needed.
Hi thanks for the reply.

Yeah I have something for the screw head but it is hard to reach still. I took the main tank off yesterday and made some adjustments but really not sure I've made any difference to the sync. I was turning out with the screw very very slowly and couldn't tell what difference it was making.

In theory if you were to turn it nearly all the way in, what would this do?
 

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If you've never done this before start here
Honda Shadow Forum - Search Results for sync
and read and read and read. I searched here and watched youtube vids for probably 2 or 3 weeks before I made a manometer and synced my carbs. You don't really want to be twisting on the adjustment screw with out the manometer attached, you won't know what you've done to the sync of the carbs but it probably won't be a good thing.

Keith
 

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Hi thanks for the reply.

Yeah I have something for the screw head but it is hard to reach still. I took the main tank off yesterday and made some adjustments but really not sure I've made any difference to the sync. I was turning out with the screw very very slowly and couldn't tell what difference it was making.

In theory if you were to turn it nearly all the way in, what would this do?
If you turn it all the way in or out it should run like crap (if it runs at all). What are you using to get your readings? Carbs are near impossible to synch if you don't have some type of meter. We are talking carb synch and not idle fuel mixture screws correct?
 

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Discussion Starter · #7 · (Edited)
Yeah throttle stop (not sure of other names for it but that's the one I got from the VT750 PDF manual) under centre of main tank.

This is the kit I'm pretty much using:




It did feel a little "loose" actually as though it might be very turned out.

The pointers on those dials were all over the place buzzing around, hope that's normal. They were kinda close but you could tell they weren't settling on the same figures on the dials so yeh, can't be synced already.

A/F's are currently 2 1/2 turns out each, generous to factory/750 manual recomendations for now.

Just wondering really what this screw's doing. Is it turning a valve, opening/closing something, tension on a spring or affecting length of throttle cable? Not sure what it's function is really and what sound to listen for if I turn it any particular direction.
 

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Yeah throttle stop (not sure of other names for it but that's the one I got from the VT750 PDF manual) under centre of main tank.

This is the kit I'm pretty much using:




It did feel a little "loose" actually as though it might be very turned out.

The pointers on those dials were all over the place buzzing around, hope that's normal. They were kinda close but you could tell they weren't settling on the same figures on the dials so yeh, can't be synced already.

A/F's are currently 2 1/2 turns out each, generous to factory/750 manual recomendations for now.

Just wondering really what this screw's doing. Is it turning a valve, opening/closing something, tension on a spring or affecting length of throttle cable? Not sure what it's function is really and what sound to listen for if I turn it any particular direction.
Yes, the pointers will jump like crazy until you install the those plastic air flow reducers. You should be able to close the reducers until the pointers move less than one degree on the gauges and then make your adjustments to get the pointers equal.
 

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Discussion Starter · #9 ·
Yes, the pointers will jump like crazy until you install the those plastic air flow reducers. You should be able to close the reducers until the pointers move less than one degree on the gauges and then make your adjustments to get the pointers equal.
Woooh thank you thank you!!!

I feel such a fool now lol I had no idea what they were for, really didn't (still learning ;) ). There wasn't a guide with the kit, nothing in the PDF and somehow I haven't read anything about reducers, so I realllllly appreciate your reply there.

This warrants a retry on Friday. Once tomorrow is out of the way, it's tank off time baby! :D

Happy New Year too by the way to everyone! :)
 

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Woooh thank you thank you!!!

I feel such a fool now lol I had no idea what they were for, really didn't (still learning ;) ). There wasn't a guide with the kit, nothing in the PDF and somehow I haven't read anything about reducers, so I realllllly appreciate your reply there.

This warrants a retry on Friday. Once tomorrow is out of the way, it's tank off time baby! :D

Happy New Year too by the way to everyone! :)
By your last post I had a feeling the reducers were not installed. Glad I could help! That's what there forums are all about, right? ;-)

Happy New Year to you and yours!!
 

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Discussion Starter · #11 · (Edited)
By your last post I had a feeling the reducers were not installed. Glad I could help! That's what there forums are all about, right? ;-)

Happy New Year to you and yours!!
Hi back sooner than I thought ;)

Been thinking about what you said regarding the plastic reducers and I just can't imagine where they'd go.

I found this video on Youtube with a guy using pretty much the same gear as me (although mine only has two dials, it is essentially same company and equipment).

https://www.youtube.com/watch?v=t0qf11BOx6o

Thing is, he rigs everything up just about same as me and doesn't use the plastic reducers. His dials are pretty stable compared to mine, mine're flapping wildly.

Just wondering where they go.

...do I have to pierce them with a pin or anything?
 

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He was probably synching a crotch rocket or similar? They don't have the vacuum fluctuation of a cruiser. Just cut the hoses a few inches from the gauges (to keep them from the heat of the engine) and put the reducers inline.
 

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Discussion Starter · #13 ·
He was probably synching a crotch rocket or similar? They don't have the vacuum fluctuation of a cruiser. Just cut the hoses a few inches from the gauges (to keep them from the heat of the engine) and put the reducers inline.
Cool thanks.

Just wondering too, I seem to have lost the "screw" in the air reducers, probably rolled off into oblivion at some point.

I saw in another carb thread something about aquarium air taps, kinda like this I found on ebay:

3x 4/6mm inline Aquarium Airline Connector Control Valve T-style air line regula | eBay

Will this work?

Also, Is it a case of very gently unscrewing the tap until air passes into the gauge and control the flow for a steady reading?
 

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Yes, those will work just fine. Your local pet store should have them in stock.
 

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Discussion Starter · #16 ·
Hi jack I saw this link. Good luck Mike

https://www.youtube.com/watch?v=3c317i64358
Thank you!!!

Same bike, same gauges, very good! I remember seeing it a long long time ago before the idea of syncing carbs and totally forgot about it so thanks for posting it!

He doesn't move his camera around when he adjusts stuff but I get the idea of things AND you can see his air reducer taps on his air tubes also which gives me hope of stablising my gauge dials. They went really smooth once he rev'd the bike and were good ticking over too.

I've ordered those air taps from eBay so they should be here this time next week. I'll sync the carbs next weekend and report back :)
 

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Discussion Starter · #17 ·
Ok so the air taps arrived and work really great! I managed to get the pointers on the gauges really super steady and smooth, much much better now so thanks for all advice!

But...a question I have is, I noticed the pointers on both gauges are not at the same place when the gauges are unplugged. The pointers are noticabley at different places on the dial face.

Should the be at the same spot when at rest if the guages have been caliberated correctly?

Is this nothing and will they become "accurate" once they have air to move them?

I gave things a short tryout and plugged everything in with the new air reducers/restrictors installed also and the pointers are definitley not synced. How much does them being different at rest affect the accuracy when in use?
 

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Discussion Starter · #19 ·
Hi Jack, they do need to be the same (in sync) before you use the gauges. There should be an adjustment screw on the gauges. On some you remove the top glass and there is an adjustment screw.
Ah ok cool thanks for the reply I wouldn't have known nor dared to mess about with it.

I was kinda thinking it was just their "rest positions" if you know what I mean, kinda stopping in different places due to friction, but it seems to me they really should be in sync since syncing is their job.

Thanks! :)
 

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Discussion Starter · #20 ·
Just a bit of advice please...

I've setup the sync gauges and checked out the readings after a good run on the bike, returning home for the readout after it's nice and warmed up. The readouts are kinda within one click/point of each other on the dials, they're pretty close but not perfect.

Is it worth messing about anymore until I clean the carbs, then at that time re-do the whole sync thing after that now that I know what I'm doing?

I'm thinking so since things have noticablly improved (I think I fluked things to be honest before buying and using the air taps).
 
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