Ducati Monster Forum

Moto Board => Tech => Topic started by: junior varsity on October 14, 2010, 12:11:29 PM

Title: Fork into very tight triples - suggestions
Post by: junior varsity on October 14, 2010, 12:11:29 PM
Got some 53/53 bored triples to put some SBK forks in.

I have all the nuts, bolts, and whatnot, but here's the issue:

In a test fitting, the triples were very tight, nearly impossible to get the forks into the lower triple, even just a small amount. I whipped out trusty calipers to inspect hole diameter, sure enough: 53. Right at 53.

I thought, "nbd, I'll use a wedge in the pinch bolt gap to relieve some pressure." - Tried it, not enough to make a difference.

What other methods are there to fit forks into triples without scratching the F@{% out of the forks?

Are there issues with heating the triple clamp?

I can't help but think that any lube would be a poor idea.
Title: Re: Fork into very tight triples - suggestions
Post by: corey on October 14, 2010, 01:13:30 PM
my thought was wedge-it as well... not sure what else you could try... ???
Title: Re: Fork into very tight triples - suggestions
Post by: junior varsity on October 14, 2010, 01:20:22 PM
Thinking about brake cylinder hone to remove a fractional amount of material.

This is the second triple clamp setup I was going to do today. I got up early and put the DucShop 30mm triples on the 748/900 project bike with 1098 forks. It was a breeze (and they were not purpose built for this application).

The 53mm triples are purpose built for the Monster, and may have been bored just ever so slightly to closely / looks like nearly an interference fit.
Title: Re: Fork into very tight triples - suggestions
Post by: battlecry on October 14, 2010, 01:27:16 PM

I like the hone idea.

Title: Re: Fork into very tight triples - suggestions
Post by: corey on October 14, 2010, 02:27:57 PM
yea, i say give it a whirl. just do a little bit at a time.
it IS a clamp, so if you go a little too far, you should still be fine.
Title: Re: Fork into very tight triples - suggestions
Post by: junior varsity on October 14, 2010, 02:30:59 PM
That's definitely the plan. I first considered there may have been simply a rough spot or something similar, so I grabbed the simichrome, and polished the inner diameter of the lower triples. They look like mirrors after very little work. Still no dice.
Title: Re: Fork into very tight triples - suggestions
Post by: Speeddog on October 14, 2010, 02:44:08 PM
Talk to the triples vendor.
Title: Re: Fork into very tight triples - suggestions
Post by: WTSDS on October 14, 2010, 02:55:03 PM
>>>Talk to the triples vendor.

+ 1

Don't do anything further to those holes yourself.
Title: Re: Fork into very tight triples - suggestions
Post by: junior varsity on October 14, 2010, 02:58:35 PM
Noted.

Left message, will revisit later.


In other news, those Ducshop 30mm triples for the SBK project look great. They have adjustable eccentric steering stops for use with 848 and 1098.

I also enjoy how much easier it is to work with the new style steering head assemblies, the stem nut, etc. Much simpler than the eccentric wrench assembly for the pre-02 frames.
Title: Re: Fork into very tight triples - suggestions
Post by: junior varsity on October 14, 2010, 07:32:21 PM
in case i was blaming triples for something unrelated, i tried a different set of SBK forks.

I am going to use 748 showa with ohlins internals. 53/53

I grabbed another set of forks in the garage from an 848 (also showa, also 53/53) - but still no dice.
Title: Re: Fork into very tight triples - suggestions
Post by: Howie on October 14, 2010, 09:27:26 PM
Since you work at a dealer find a stock superbike triple and measure it on both axis.  Is the bore really 53mm or 53mm plus a smidgen?  Is the bore a little oval?
Title: Re: Fork into very tight triples - suggestions
Post by: Speeddog on October 14, 2010, 10:03:13 PM
I would imagine the OEM stuff is slightly undersize on the fork diameter, and slightly oversize on the triple.
That's the metric way of doing shaft fits.

Like 52.9mm and 53.1mm.
Or 52.95 and 53.05...

I've had forks in the past that needed the triples wedged to get things assembled/disassembled.

I haven't had to wedge any (undamaged) Duc fork stuff.
It all fits together just the way it's supposed to.
Title: Re: Fork into very tight triples - suggestions
Post by: suzyj on October 14, 2010, 11:13:18 PM
I think the hone is the right idea.  When I measured my forks, they were 52.9, so I bored the triple to 53.0.

It's a good idea to carefully de-burr them, too, to ensure you don't scratch your forks.
Title: Re: Fork into very tight triples - suggestions
Post by: junior varsity on October 15, 2010, 09:08:51 AM
Talked with the Costas, they shoot for 53,003, and I figure it might be a smidge under.

I need better calipers.