CB250 Cafe #2, headstem, brakes, speedo...

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Prof
Founder, Choppers Australia
Posts: 5936
Joined: Sat Oct 22, 2005 3:54 pm
Location: Willunga, South Australia
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CB250 Cafe #2, headstem, brakes, speedo...

Post by Prof » Wed Feb 05, 2014 4:47 pm

Cameron asked if I could replace the headstem loose ball bearings with tapered rollers bearings. His bearings and races weren't worn, but the tapered rollers are much more convenient and very long wearing. I like to put them on raked front ends on heavier bikes, because they carry a lot more load than ball bearings. They are easily available for the CB750's, XS 650's and of course HD.

In fact as it turns out, most of the CB's; 250 through to 750 use the same bearings...
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Here's the contents of the packet.. top and bottom inner and outer bearing races, dust seals, and spacers because steering heads may be a few mm different in height... Instructions with bearings explain how to determine if you need one of the spacers. We needed the thinner one.
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Paint needs to be cleaned out of the area and the old ball outer races knocked out.
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Make sure the steering head is very clean and free of paint. Put the outer races in the freezer for a couple of hours. Grease the headstem and pull the cold and slightly shrunken out races into place with a large bolt, nut and appropriate size washers that clear the steering head, but hold on the outer edge of the races. Make sure you put the outer races in the correct way around. Sounds like a silly comment but I have done it!!!
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Slightly heat the bottom inner race and bearings or put them out in the sun for an hour or so if the day is hot and again using grease on a totally clean headstem drop in the seal and then force the bearing into place using a suitable piece of clean tube. The tube must bear on the inner lip of the race not the roller cage...

You can see Jake in the back ground greasing the bearings. You can buy a bearing packer, but I've never used mine... quicker and just as effective to spin the bearing while forcing in grease... bit messy but...
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Next step is to slide in the head stem and drop in the top inner bearing followed by the seal and the original dust cap, then screw on the C nut. Tighten it til there is no slop but the head stem moves freely and then put on the top triple tree.
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You can make your own C spanners out of some 3mm sheet steel using an angle grinder.

Forks can now be installed. Make sure triple trees are lined up and twist the fork tubes as you push them through. Line up fork tubes with a couple of metre rules (see another post) and tighten the bottom clamps. Lightly tighten the top clamps and double check for movement in the bearings by pulling and pushing on the fork tubes. Forks should have no play, but swing freely side to side. Then do a final tighten of top clamps and its done.

Front Brake...

With the front wheel on we now need a brake anchor and a cable. Jake sets up the brake at an angle that will provide a suitable angle for the brake and speedo cable... and makes sure the twin leader linkage clears the lower leg. A piece of 30 x 5 stainless is measured up centre to centre and drilled and shaped so that the brake end is slightly thinner that the rear end.
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Now for the cable. More pieces missing. I found an adjuster for the hand lever end so we just need a retaining block at the brake plate. This is turned up out of aluminium... Drill bit here supports the piece while it is being parted off... it doesn't have to be retrieved form the bottom of the tray!
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A slot for the inner cable is cut with an angle grinder...
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Cable is held by the retaining block and measured with the brake lever pulled almost full on.
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Cable is cut and nipple here seen ready for soldering. Before you cut an inner cable slide on the nipple... much easier than trying to put on after cutting when a strand or two can come adrift. I have a run down of soldering nipples on inner cables else where, but two important factors to success are spreading the cable so solder can permiate and form a solid black that cannot pull through and make sure when soldering that everything is hot enough and that the solder sticks well.
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Here's the finished job.
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Twin leader adjustment... Adjust up the main lever at handlebars til drum is just off touching. Then adjust up second lever at the linkage until you hear it scrape and then back off the same amount as you did with the main lever.

Rear Brake...

Rear brake anchor was also missing, but one from a CB750 and a nice chrome one it is too.

Foot lever had been partially cut with an angle grinder and was badly grooved, presumably from cutting off an exhaust at some stage...
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Welded up and a drain hole drilled to release any moisture. Super Chrome spray paint covers it all nicely and seems to last fairly well.
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Speedo...

I spent a bit of time looking at possibilities of mounting. Because the rider sits well towards the handlebars it can sit failry low unlike a chopper where the rider is well back and the speedo needs to be up higher or behind the bars.

Solution turned out to be really simple... a straight piece of flat bar bolted to the bottom of the handle bar risers, here being measured with verniers.
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Bracket made and painted...
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Speedo is easily viewed but nice and tidy and not obtrusive...
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Cameron purchased the speedo from Mike's XS in the USA so it is highly likely that speedo ratio will not be the same as Hondas.

Cable wise, I have found that all the 70's-80's jap bikes have the same speedo connections, but there are half a dozen variations at the speedo drive end... so it will be a case of Cameron taking the bike into a bike wreckers and picking up the right length Honda cable.
Chopit'nrideit... Prof

gsand
Posts: 268
Joined: Fri Feb 19, 2010 2:55 pm
Location: South Australia
Interests: Riding bikes.

Re: CB250 Cafe #2, headstem, brakes, speedo...

Post by gsand » Fri Feb 07, 2014 4:46 pm

Coming along really nicely!

Perhaps the owner wants to have a speedo fitted, it's worth noting that regulations have changed in SA for older motorcycles (to our benefit) and speedometers are not required pre '88. Also the 45° guard coverage does not apply pre '88 :D

http://www.sa.gov.au/subject/Transport, ... quirements

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