Knocking noise

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MacV2
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Location: Grain

Re: Knocking noise

Post by MacV2 »

Honeybadgerted wrote: Tue Aug 08, 2017 1:45 pm
alanfjones1411 wrote: Tue Aug 08, 2017 6:43 am What revs are you idling at.I have mine idling at 1100/1200 rpm.As for the" backfiring a little bit" may be just the normal carb farts which most vtr's seem to suffer with.
Not sure, my tach doesn't work. Not sure what's wrong with it. There are no breaks in the wire between the cdi and the cluster
OK, so you say it has the pairs system, is it a late model with the digi petrol gauge ? or an import early from the states or parts of europe ?

I ask as it's easy to find early clocks, late ones harder to find & more expensive... However the easy way to find if the clocks are faulty is to swap with a known working set, if thw swap set work theres your fault, if the swap set dont work you have a fault somewhere else in the system...Trouble is that that fault may be killing the tacho which then means you have two faulty sets... :crazy:

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Early pre facelift clocks.

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Later version with digi clocks.

Is this knocking noise like a thump that you feel in the air box ? If so that will be carb fart as mentioned above.

Carb sync helps a bit on that...

Also you dont need the tach to raise the tickover...just play with the adjuster & you'll hear the revs rise & or fall.

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Look through the right hand side of the frame in front of the coolant res, at rear of the front cylinder. The knurled knob with the spring is the tickover adjuster. The red circle is the front vac take off. If you have a tube there as in the pic thats the pipe you need to balance/sync the carbs...If it just a small allen head bolt in there then to do the carb balance you'd have to fit the take off...Without the tube is as it is std btw...
Making up since 2007, sometimes it's true...Honest...
Honeybadgerted
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Joined: Fri Jul 14, 2017 6:32 am

Re: Knocking noise

Post by Honeybadgerted »

Awesome thanks for the pics! I have the earlier gauges. I'd really like to fit digital gauges from something, but that's a project for later.
Honeybadgerted
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Joined: Fri Jul 14, 2017 6:32 am

Re: Knocking noise

Post by Honeybadgerted »

I haven't had the tank off/up when it happens, so I don't know if you can feel it in the air box, but it feels like the tank vibrates
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MacV2
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Re: Knocking noise

Post by MacV2 »

Honeybadgerted wrote: Tue Aug 08, 2017 2:45 pm I haven't had the tank off/up when it happens, so I don't know if you can feel it in the air box, but it feels like the tank vibrates
Yep carb fart...This will not be the most technical answer but basicaly the carbs are backfirering into the air box, you sort of hear it but more feel it through the tank.

Carb sync will lessen it a bit, raising the tick over will help it a lot at low revs...not unusal for the bike to stall at a junction if this happens...turn up thr tick over a bit at a time, do it by ear as you have no working tacho...you'll hear it racing if its too high...you can just about do it with gloves on when stationary but still sitting on the bike.

Go for a ride get it warmed up, choke off, reach down & have a twiddle of your knob... 8O ...then set the tick over...

BTW the clocks in the pic, the early ones are up for sale... :thumbup:
Making up since 2007, sometimes it's true...Honest...
Honeybadgerted
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Joined: Fri Jul 14, 2017 6:32 am

Re: Knocking noise

Post by Honeybadgerted »

Sounds good. I'll have a go at it some time this week. My days a packed right now doing work around the house!

Can you sync with just a vacuum gauge? If so, what is the reading supposed to be?
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MacV2
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Re: Knocking noise

Post by MacV2 »

Honeybadgerted wrote: Tue Aug 08, 2017 3:03 pm Sounds good. I'll have a go at it some time this week. My days a packed right now doing work around the house!

Can you sync with just a vacuum gauge? If so, what is the reading supposed to be?
Use a pair of gauges & just get them to read even...The adjuster is on the left hand side of the carbs...There is a how to in the workshop section but the pics are no longer veiwable...

viewtopic.php?f=31&t=18430

There is also the TPS to set...but I was trying to do this for a fellow Stormer here in the UK whos bike it turns out is an import & the bolts you have to loosen off to adjust the TPS were not the normal security TORX bits but the blind snap off type, like the ones that hold on the ignition barrell...It's doable but you'd have to have the carbs off & drill the bolts out to do it...

viewtopic.php?f=31&t=29429

Have fun let us know how you get on.
Making up since 2007, sometimes it's true...Honest...
Honeybadgerted
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Joined: Fri Jul 14, 2017 6:32 am

Re: Knocking noise

Post by Honeybadgerted »

ill definitely give it a go. I'll have to pick up another vacuum gauge and I'll set that before I do the tps. Thanks for the info!
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Cadbury64
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Re: Knocking noise

Post by Cadbury64 »

If you join your two gauges using a "T" to a single vacuum source, you can check they read the same before you start adjusting the cylinders. The key to a successful synch is to get the cylinders drawing the exact same vacuum.
2017 MT-10SP, 2019 Vespa Primavera 150
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