Author Topic: CB250RS Rebuild Progress  (Read 5757 times)

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #15 on: September 23, 2017, 02:44:00 PM »
Newman Cams reprofiled the rockers, £37.50 each. Not cheap but you get what you pay for and they were really helpful.  Their phone number is 01689 857109.
They told me they have a new cam for a 400/4!

Offline Jamesh_sussex

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Re: CB250RS Rebuild Progress
« Reply #16 on: September 23, 2017, 02:45:13 PM »
Sorry, I meant who did the chrome plating. Looks lovely..!

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #17 on: September 23, 2017, 02:54:47 PM »
Sorry James, I read your post too quickly. Chrome and zinc plate was done by Gary at Hayes Electrofinishing in Middlesex.  He's great, does a fantastic job, loves old Jag bikes and V Dub campers. He only does work for people he knows well, I've known him nearly 30 years. If you need anything doing let me know and I'll ask him. You'll need to drop it off and collect it though, he doesn't like doing all that as he's really geared up for industrial work but likes doing some bike stuff for a bit of variety. Every time I go there its touch and go if he'll be staying due to the environmental issues of his work.

Offline Jamesh_sussex

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Re: CB250RS Rebuild Progress
« Reply #18 on: September 23, 2017, 04:01:12 PM »
Top man. I'll drop you a pm..James

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #19 on: November 12, 2017, 05:59:48 PM »
Some good progress to report this weekend on the rebuild. Although I seem to have spent the previous two days over the parts washer! I stripped the gear clusters and gear change mechanism down to their component parts and gave everything a good clean. The gearbox bearings, dogs, shafts and gears are all in perfect condition having used a strong magnifying glass to check all the teeth. The clusters are now all back together oiled, bagged and put to one side ready for engine assembly.
I've also given the paintwork a good scrub prior to packing and sending to Menno tomorrow in a huge box (it weighs 11.5kg fully packed!!!). I'm going to change the colour to red as it was the optional colour at the time.
Cylinder head assembly tomorrow  :)

Offline HWG27

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Re: CB250RS Rebuild Progress
« Reply #20 on: November 29, 2017, 03:21:34 PM »
Hi,
I'm new on here and stumbled accross this thread by googling 'removing cb250rs cylinder head cover pins'  ;D
I wonder how you eventually got those out ?
I'm at the stage where I have dremmelled a groove in them but still nothing is budging. Was going to attempt to Tig something on them this coming weekend, just a bit wary of melting the bloody thing.
Really interesting thread (for me at least) as I'm in the process of renovating an RS myself and have bits all over the place right now.
The chroming you've had done looks great. I got several quotes for some of the same parts (without gear change, brake pedal and kickstart) and prices were just too much, double what you've paid. Going to try a bit of DIY nickel and see how that turns out.
Anyway, will be following with interest.

Regards,
Huw



Offline AshimotoK0

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Re: CB250RS Rebuild Progress
« Reply #21 on: November 29, 2017, 03:48:37 PM »
Have a NOS rocker for one of these on eBay at the mo' ..if anyone is interested in it make me a reasonable offer.

https://www.ebay.co.uk/itm/142600335322?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline hairygit

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Re: CB250RS Rebuild Progress
« Reply #22 on: November 29, 2017, 03:49:13 PM »
Hi, and welcome to the forum. 250 RS was a great little bike, and for whatever reason never sold as well as the Superdream 250. Much nicer bike than the Superdream though, and would leave a Superdream for dead on acceleration and handling, much lighter and more "flickable" too.

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If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #23 on: November 30, 2017, 07:27:53 AM »
Welcome to the forum Huw. There's great people on here with lots of advice.
The pins, yes the dreaded never to be removed pins  >:(! In the end nothing worked to get them out, I cut a groove in one of them as you have, it set up a weak point and it snapped! I got them both spark eroded out in the end, £50 but that was in the form of a 'drink' for the guy who did the work in his lunch breaks. The company I took it to work on aero engines and when they saw it quoted silly money, they didn't want to do it. In the end a guy who is into bikes said he'd give it a go in his lunch breaks. Spark eroding is the only way to get them out, they really are hard and brittle.
I'll be starting engine assembly over the weekend and will post some photos of progress.
Good luck with your rebuild.

Offline AshimotoK0

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Re: CB250RS Rebuild Progress
« Reply #24 on: November 30, 2017, 08:36:22 AM »
Following this post with interest. I am pretty sure one of the magazines did a CB250RS rebuild a few years back (possibly CMM in Rod Gibson's time).

Interested in the cam/rocker refurb , as I have a couple of Bomber cams that have perfect journals but one lobe is pitted. Any prices to share on camshaft work by Newman Cams?

Looking at my NOS rocker the pad profile looks to have more curvature on the edges than the reworked ones. Probably of no significance as Newman always come up as being the 'go-to' place for camshaft work. Do they Stellite (or similar) weld and then grind the profile? Will be a lovely example when finished.

“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #25 on: November 30, 2017, 07:49:31 PM »
More photos to follow over the weekend Ash. I'd be interested in seeing that rebuild article and see if they had the fun I had (and now Huw) getting those pins out  >:(!
Newman Cams did a great job with the rocker arms but unfortunately....... they did grind the sides of the pads down to the correct shape. It was only after I put them back in the cover with the hard to fit (and extract) and tried the cam I realised the exhaust cam lobe also opened the inlet rocker at the same time  :o. To be fair to Newman's there was no quibble at all. They asked me to send it back, paid the postage and sorted it out and sent them back within 24 Hours, great service and I wouldn't hesitate to use them again. I haven't looked at your listing on ebay but how much do you want for your rocker arm, it's good to have a spare?

Offline AshimotoK0

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Re: CB250RS Rebuild Progress
« Reply #26 on: November 30, 2017, 09:34:01 PM »
Deal done with Dave on the NOS  rocker  :)
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline AshimotoK0

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Re: CB250RS Rebuild Progress
« Reply #27 on: December 01, 2017, 09:37:42 AM »
I think the rebuild was in CMM and possibly the last resto that Rod Gibson did before he sadly passed away .... I may have a couple of copies with part of the rebuild in Dave. I will look over the w/end.
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #28 on: December 01, 2017, 06:46:50 PM »
Thanks Ash. PM me your details for the rocker arm.
I'm just back from dropping the rebuilt wheels off at the tyre shop, collect tomorrow after visiting Kempton Park to collect the TEC shocks.

Offline Laverda120

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Re: CB250RS Rebuild Progress
« Reply #29 on: December 02, 2017, 02:59:58 PM »
Just back from Kempton Park autojumble with a new pair of TEC shocks. Stopped off at the tyre fitter on the way back to collect the wheels with new Roadriders fitted. Wheels are now all complete with stainless spokes, repainted hubs, new bearings and vapour blasted rims.
Engine rebuild to begin tomorrow.