Tillotson throttle travel

Classic short-frame models

Tillotson throttle travel

Postby ThumpStreet » Fri Jun 30, 2017 9:49 am

Good Morning All,My XLCH project is approaching the first fire up mile stone so focus has been intent on correct operation of all systems and their controls.I noticed yesterday while setting up throttle coil that a full twist of the grip doesn't get the throttle plate to WFO.Looks to be at approx.7/8 open.I have been trying coil positions by pushing or pulling on the inner wire and setting it which will achieve a good position for idle or a true wide open throttle plate.I have not found the sweet spot that will give a full throttle travel.It has crossed my mind to mill the handle bar slot a little more to get the spiral to push the plunger that silly extra mm more to get the WFO position.Any tips as to what could be a miss,observations members have noticed on throttles they have worked on would be appreciated.I am not a big fan of taking chunks of metal off of stock parts when it's very likely I could be overlooking a detail that others are aware of.Thanks all for your time in advance.Come on Boys! Chime on in here I'm sure some one else has seen this condition before me.Peter
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Re: Tillotson throttle travel

Postby ambike » Fri Jul 07, 2017 3:21 am

What carb ?

Hard wire lubed and secured in the plunger ?

Do you have the correct bracket to hold the outer coil ?
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Re: Tillotson throttle travel

Postby thefrenchowl » Fri Jul 07, 2017 7:43 am

TILLOTSON
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Re: Tillotson throttle travel

Postby ThumpStreet » Fri Jul 07, 2017 10:23 am

Hope all had a Great Independence Day! Thanks for the replies.I see the Tillotson vs.any other carburetor ever built will continue until the complete demise of the internal combustion engine.To the French Owl,thank you for the morning laugh!The simple response "Tillotson" spoke volumes to the passion and peferences that different members have.To get down to Ambikes questions and the findings: Carb HD1C,bracket original,inner coil well lubed.While I was still scratching my head over the condition,I called a friend back east and asked him to go look at his CH throttle cable.Before he even left to go out to his shop he asked me if the throttle coil was an aftermarket offering.Answer yes.Point noted, some aftermarket inner coils much thinner than HD factory coils..013" to be exact.Stock inner coil measures .055"vs.042 for replica.The wimpy inner coil flex is what made it feel like it needed more slot in the handle bar.With that located and careful routing and clamping I get full travel and smooth action no crazy mod required.Devil is in the details bringing me to ask another tip from those that know.Routing being what it is,the outer coil is touching the rear cylinder head which I don't think the outer vinyl cover of the outer coil will hold up very well to.Is additional insulating wrap in this area standard procedure? Thanks again for replies and humorous comments.All points of views welcome.Peter
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Re: Tillotson throttle travel

Postby jOe » Fri Jul 07, 2017 3:45 pm

Don't overthink. Twist the grip to wide open throttle, then set the disk to wide open throttle. Close the throttle and see where you're at for an idle position. Start it up and if you have to adjust it towards closed- do it.
You're much more likely to be concerned with the disk being in the right position for idle rather than for wide open throttle- unless you're on the track and not the street.
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Re: Tillotson throttle travel

Postby ambike » Fri Jul 07, 2017 11:56 pm

My asking if the inner wire was well-lubed covers the gamut of what can happen.

If the inner wire and outer coil bind or flex in undesirable ways - and inner corrosion & dryness can make the outer casing bend & lengthen - the inner wire's net travel will be less.

Also, if the outer casing is badly kinked, or routed improperly, the inner wire's travel is slightly reduced. It won't be very much, but remember, the net travel required is multiplied by the throttle arm's length.
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Re: Tillotson throttle travel

Postby jOe » Sat Jul 08, 2017 2:13 pm

Measure the full travel of the control wire and then the full travel of the are lever. There's a difference. Always has been.
I don't think the plunger travel was increased for the Tillotson over the D.C. Linkers .
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Re: Tillotson throttle travel

Postby thefrenchowl » Sat Jul 08, 2017 7:24 pm

Yes, I do love the Tillies, but I also hate the ""push cable to go fast"" throttle idea...

In all My sportsters years, I've always reversed the action by using ""pull cable to go fast"" throttle and fitted a return spring, be it Tillies or DCs, cuts out for ever the slack and imprecision...

Patrick
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Re: Tillotson throttle travel

Postby jOe » Sun Jul 09, 2017 7:15 pm

If I just had to have the absolute maximum WOT on the disk, I'd probably pull the throttle arm and shaft, weld up the hole for the control wire block and re drill it about 3/32 closer to the shaft. That distance is just a guess. That would give the arm and shaft more throw with the existing wire travel. The penalty would be more force is required, but it would probably not be noticeable. There could possibly be some clearance issues, but that seems unlikely.
I don't think it's a good idea to tamper with the spiral and plunger.
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Re: Tillotson throttle travel

Postby Lisa » Sun Jul 09, 2017 9:21 pm

If you have a problem getting full travel don't hack something up to get it just figure it out and fix it - simple really easy fix with thought.
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