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PostPosted: Sun Dec 13, 2009 7:18 pm 
proff. patpending
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Joined: Wed May 06, 2009 8:20 pm
Posts: 14745
Current ride: Victoria Sponge
Location: Bristol - Gateway to all things good
Or rather the things you are not told you have to do when fitting your Mikuni HSR42.

New How To coming up...

Is it just me, or when people fit Mikunis to S1s and M2s, do they end up with a choke cable and a throttle cable about an inch too long?

Well, when putting the S1 back together, I found the choke cable too long to put the knob back into it's slot (fnarr fnarr) without forcing the cable against the cylinder head and bending it to fit in places it really didn't want to go. Can't really see it in the picture below, but the outer is being forced in every direction possible.


As can be seen here, the cable is about an inch too long.


I spoke to Maz and a few others and the options appear to be:

1. Leave the choke cable off
2. Make a new bracket and space it out
3. Shorten the cable

I preferred number 3, so I started measuring. 22mm from the top of the nipple to the shoulder of the cable guide (I measured to here cos I was not sure if I could get a suitable nipple to fit through it).


So I pulled the guide off, and got my Shimano cable cutters out and snipped the outer back 20mm. I also cut the nipple off the inner. And most importantly, I get myself a ferrule out of my bicycle box (your bicycle shop will have one) to terminate the outer.


Next thing was to find a nipple. Venhill stock them and I selected a BN6. Then it was a case of putting the nipple onto the inner, fraying the end (very important to stop the cable pulling though when soldered in place) and pulling the nipple back to 22mm.


Then it is a case of heating the nipple up with a blow torch (I don't have a very powerful soldering iron) and dipping it into the Bakers soldering fluid (to prepare the surface). Then heating up again and applying solder.

When soldered in place, I used a bench grinder to tidy up the protruding outer. When finished, it looked like this.


I then did a bit more grinding to allow it to fit through the "nut" on the carb. Careful when you do this cos the nipple can heat up enough to melt the solder...

Here is my comparison between old and new cables.


Then when fitted, it goes in nice and tidy.


The next job was to take up the slack in the throttle cable... Off to the Blue Peter box to find a bit of bar to machine something up... Maz keeps these in stock...

Image Image Image

Adam wrote:
I've never had a pair of dedicated cable cutters but to stop the cable fraying when cut, I've always tinned it with solder and then cut it with a very sharp cold chisel. When you push it into the nipple and heat it up, the wire spreads out as the solder melts (you can help it with a screwdriver, or spike etc) Then you can fill it with solder.

Small brass climbing micro nuts are made like this but use Silver Solder instead. The brass nut deforms before the solder lets go :lol:

08 Specialized Langster

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