Yoshimura RS4 baffle retaining bolt.

[yoyo]

I have a Yoshi RS4 (as pictured), I've lost the bolt that holds the end cap and baffle in, I've tried a couple of metric bolts and either the thread is stripped or it's an imperial thread, does anyone know for sure what bolt size is used?

If it's stripped if got no chance or tapping a new thread due to a lack of space.

I wasn't too concerned as the end cap was a real tight fit but it shot out of the can on my last right, luckily I managed to go back and find it.

The bike sounds great without it in but its a little too loud for anyone following!

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[EricV]

Ask Yoshi?

 

[yoyo]

I've asked the UK importer but still waiting on a reply, will have to try Yoshi directly I think.

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[bimota]

hi yoyo,

i have same can on mine, didn,t think the baffle could come out of these newer ones, how do you even get at it

rob

 

[EricV]

I wouldn't expect the importer to know. It's a manufacturing item. I'd be surprised if it was imperial thread, considering it's made in Japan. There are standard fine and coarse pitch metric threads. Any chance you can accurately measure the inside diameter of the threaded hole? A local machine shop should be able to help measure it if you don't have anything to use. Knowing the ID will identify the size of the bolt better, then it's just finding the correct pitch. Sometimes the local hardware stores don't carry fine pitch bolts.

Edit - Forgot to mention that the older units had a bolt, but reports have been that the newer ones are just spot welded.

Another option would be to use a self tapping bolt or screw.

 

[yoyo]

The US importer came back with 6mmx12mm with a 1mm pitch, it looks like the thread in the end can has stripped, I'll have to come up with some other way to secure it, I might drill right through from the outside and use a nut and bolt.

Rob, if your's is the race version there is an allen bolt inside, I have to say it's bloody loud without the baffle in, sounds good though!

 

[bimota]

hi yoyo,

mines the same as picture with that plastic small end peice, i think early ones did not have that but don,t know why they are different

rob

 

[EricV]

A 1/4" x 1/2" long imperial self tapping bolt might do the trick. 1/4 is 6.35mm, so just a tad larger and might be just right to cut enough threads to hold nicely. Pop on down to Wilco or Swansea Timber and Plywood and see if you get lucky. Or perhaps the "Repair" section at the auto parts store?

 

[yoyo]

hi yoyo,

mines the same as picture with that plastic small end peice, i think early ones did not have that but don,t know why they are different

rob

The tail piece on mine is steel, the baffle with a 45deg bend fits inside it and both are held in by the bolt.

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[yoyo]

A 1/4" x 1/2" long imperial self tapping bolt might do the trick. 1/4 is 6.35mm, so just a tad larger and might be just right to cut enough threads to hold nicely. Pop on down to Wilco or Swansea Timber and Plywood and see if you get lucky. Or perhaps the "Repair" section at the auto parts store?

Thanks for the reply Eric, I'm guessing you are an ex Swansea resident! Due to the hole for the bolt being inside the end can I can't get anything in there other than a hex head bolt I can tighten with an Allen key. I've tried 6mm x12mm but it looks like there is an issue with the thread as I can't get the bolt to start threading in. Will try again tomorrow.

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[EricV]

A trick I have used in the past when I had nothing else to lose. Using a Dremel tool disk, cut a slot in the threads about 3-4mm long, starting at the tip of the bolt, at a right angle to the threads. This is for relief and to allow space for deformation or cuttings from the mating threads. If you have a thin disk, cut two slots, opposite each other. Then file or grind a short taper in the tip of the threaded end of the bolt. These features will combine to hopefully allow it to start threading into what threads exist, and help clean them up a bit if there is some damage.

 

[Don in Lodi]

Drill the rivets and pull the whole end cap. With the thing in your hands you can make sure things are all lined up.