Post by: AshimotoK0 on April 14, 2020, 07:37:07 AM
Wondering what everyone does when rebuilding a bomber engine in terms of replacing the front idler assembly?(14610-283-000). These are virtually unobtainable NOS and I reckon all used ones will have hardenened rubber idlers after being inside an engine for around 50 years. I know Cappellini does a replacement sprocket for this part but how about the rubber rollers? My buddy Graham Curtis does a fix on a CB72/77 camchain tensioner roller by re-machining the outside of the rubber surface to reveal a non-hardenened rubber surface underneath. I thought about doing this on the 450 but would like to maintain the geometery of the chain path and keep the same roller diameters. I removed one of the rollers from a scrap CB450K0 assembly and one from a scrap CB750 camchain tensioner (the roller part is also the same on a CB250/350K twin as the 750). My theory is that you could take a 750/250/350 idler wheel and machine it to the same size as the Bomber ones. Only difference is that the Bomber one has a plain bearing and the 750 etc ones have a needle roller bearing but the centre pins are exactly the same diameter on both types. Plus some shims would be necessary to prevent the side wall of the idler contacting the metal holder. I tried to annotate this on the attatched photo.
Also I found that the Kawasaki KZ650 has sprocket type idlers with the same number of teeth as the Bomber and wondered if this could also be adapted to fit the Bomber....however at least there are parts available from Franco Cappellini to deal with a badly worn sprocket. David Silver also sells the single sprocket idler for this engine, which again may be able to be modified. The Kawasaki design is very neat as it has built in rubber cushioning and there are quite a few decent used ones out there (there are two in the Z650.... I got mine from DK). My old spoked wheel Z650B1 was a beautifully designed engine and I am surprised those bikes don't sell for decent money ...perhaps if they had fitteda 4 into 4 exhaust like the Z1 it would be more desirable.
Franco Cappellini also does a repair for the camshaft sprockets (if cam has the pressed on type sprocket)
http://www.cappellinimoto.it/catalog/motorbike/CB450K/product/37
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Cappellini's sprocket fix link : http://www.cappellinimoto.it/.../motorbike/CB450K/product/13
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Post by: AshimotoK0 on April 14, 2020, 07:39:20 AM
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Post by: UK Pete on April 14, 2020, 07:50:19 AM
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Post by: AshimotoK0 on April 15, 2020, 07:11:14 PM
"Description
Honda CB450 Cappellini Moto rebuilt original good used FRONT chain tensioner has new chain guide sprocket, #205. Franco's sprockets are sold separately, but rubber OEM Honda rollers are available only from Honda."
https://www.ebay.com/itm/Honda-CB450-Cappellini-Moto-rebuilt-FRONT-chain-tensioner-w-guide-sprocket-205/172265886841?hash=item281bd8d479:g:FWEAAOSwOVpXfaQg
Post by: UK Pete on April 16, 2020, 08:07:39 AM
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Post by: royhall on April 16, 2020, 05:09:45 PM
Post by: AshimotoK0 on April 18, 2020, 11:27:44 AM
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Post by: SeanFD on February 10, 2021, 12:33:32 PM
When talking about hard and soft rubber, what do you mean by "soft"? Squishy soft? With just a little give?
I'v always found it difficult to make a decision without a new item to compare with.
Post by: AshimotoK0 on February 10, 2021, 04:13:51 PM
I just came across this post today.
When talking about hard and soft rubber, what do you mean by "soft"? Squishy soft? With just a little give?
I'v always found it difficult to make a decision without a new item to compare with.
Just a little give without a hard 'skin' on the top