Distinguishing 110” bolt on vs standard 110” kit on used bike.

[838]

Is there a way to tell (visually) if the 110" cylinders are "bolt-on" or the original type that required case bore?

[kd]

Is there a way to tell (visually) if the 110" cylinders are "bolt-on" or the original type that required case bore?

It seems the bolt on spigot is thinner in the range of +.030.

[838]

What about if already fully installed?

[Geezer_Glider]

Doesn't the bolt on still use the o-ring and if the case has been bored you need to use a base gasket?
R Meyer

[FXDBI]

Doesn't the bolt on still use the o-ring and if the case has been bored you need to use a base gasket?
R Meyer

No o-ring used in the 110 drop on I did. Factory 110 has 110 heads on it.  Mine looks like it is still a 88.  Bob

[Geezer_Glider]

Interesting, HD 103 to 110 drop in kit shows cylinder base O-rings included.
R Meyer

[Don D]

The answer is no.

[Dodgy]

Remove the case bolt between the 2 cylinders. If it's 3 3/4" - 4" long there is a good chance the cases have been bored out for the standard 110" cylinders. Drilling the hole deeper is one of the modification for case boring. The drop on kit does not require the hole to be modified.

[Don D]

How can you get the bolt out if the barrel OD intrudes into the reduced diameter. of the bolt

[jsachs1]

Good way to crack the spigot on the cylinder, and/or lift the center section of the case top.
John

[Don D]

Yep, seen it done

[Dodgy]

The bolt dia is not necked down, The spigot bore dia has plenty of clearance on the spigot skirt. The only reason they deepen the hole and put in a longer bolt is the machining out of the case compromises the original thread.

[Hossamania]

The OP's question was if it can be determined visually.

The answer is no.

If it really needs to be determined, tear it down.
If it doesn't matter, ride it.

[Thermodyne]

I run drop in jugs, no difference in the appearance now from when it was a 103.  The drop in's use the standard 103 base oring. 

Some 4 inch bores on a 103 cases will have a nut on the right end of the case bolt that runs between the jugs.  And the case will be spot faced to accept it.  But its not mandatory. 

[Don D]

I run drop in jugs, no difference in the appearance now from when it was a 103.  The drop in's use the standard 103 base oring. 

Some 4 inch bores on a 103 cases will have a nut on the right end of the case bolt that runs between the jugs.  And the case will be spot faced to accept it.  But its not mandatory.

Not factory. If there is a nut on the opposite side the bolt is aftermarket and extra machine work was done to make that happen, likely during a case bore