1988 bike
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@oldman they are not serviable as far as I am awake.
Thanks Calum, ordered one from Portugal (second hand) that looks good without rust for a reasonable price. Other 3bn barrel arrived today freshly rebored @1.25 over standard, and has been tuned. No id marks to say who did it , messaged seller to see if he knows. Mick Abbey marks his work as far as I am aware so doubt its him. Be good to know though and a bonus it's done. Will post a pic up later.
wrote on 29 May 2019, 18:56 last edited by@oldman What engine are you fitting this to?
3MB barrels and 3BN barrels are not interchangable!
The 3BN has a larger bore, therefore shorter stroke. If you fit this onto an engine designed to have a 3MB cylinder, you could risk the piston hitting the cylinder head.
It is very minimal, but they are different strokes.
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@oldman What engine are you fitting this to?
3MB barrels and 3BN barrels are not interchangable!
The 3BN has a larger bore, therefore shorter stroke. If you fit this onto an engine designed to have a 3MB cylinder, you could risk the piston hitting the cylinder head.
It is very minimal, but they are different strokes.
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wrote on 29 May 2019, 21:07 last edited by
By the way, I mean the 88 bike I am building (endurance blue), not the red one.
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@Calum it's the 88 bike engine, same as the barrel that came off, 89 bikes changed to accommodate new carb amongst other things, is that right? Matching frame and engine nos so original engine
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wrote on 30 May 2019, 09:01 last edited by
Will not need to though if it's an 88 engine? Just need to make sure crank is correct for stroke, will check part nos to be sure.
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Will not need to though if it's an 88 engine? Just need to make sure crank is correct for stroke, will check part nos to be sure.
wrote on 30 May 2019, 09:10 last edited by@oldman If it was running a 3MB and you put a 3BN barrel on it, the stroke will be too long. Is it the crank, is it the rod? I don't know. But the stroke is definitely different. So you will want to make sure you have clearance.
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wrote on 30 May 2019, 09:10 last edited by
Checked fowlers for part no, con rod for 88 listed as separate item, later years checked a(89 and 1990) and shows discontinued with no part nos? Have ordered a genuine 88 one to be sure but any info you have useful? Original barrel was already 1.75 over hence the replacement
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wrote on 30 May 2019, 09:14 last edited by
It's definitely an 88 bike and engine, the barrel was consistent with engine and I did have a spare 3mb barrel but sourced like for like. Cant be sure con rod in engine is correct hence ordering correct one from fowlers. Could be whole crank differs from later bikes but don't know (yet) will check clearances as built, lucky to find a matching barrel to be honest
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It's definitely an 88 bike and engine, the barrel was consistent with engine and I did have a spare 3mb barrel but sourced like for like. Cant be sure con rod in engine is correct hence ordering correct one from fowlers. Could be whole crank differs from later bikes but don't know (yet) will check clearances as built, lucky to find a matching barrel to be honest
wrote on 30 May 2019, 09:52 last edited by@oldman Yeah this.
The manual specifies both the bore and stroke for the 3BN, I'm sure. I don't have it to hand.
It is so minor I doubt it'll be too much of a problem. Powervalves are not interchangeable though.
As said, doubling up on base gasket will do the trick. My worry is that the con rod is designed to stretch and compress, how close will it be at 12k RPM is anyones guess!
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wrote on 30 May 2019, 12:35 last edited by
Have the original powervalve fortunately, the manual is. 4 or. 04 difference I think from memory, Will be checking when assembling .
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Have the original powervalve fortunately, the manual is. 4 or. 04 difference I think from memory, Will be checking when assembling .
wrote on 31 May 2019, 07:13 last edited byMy understanding is the 1988 has the BN barrel and slightly longer stroke 0.5mm or something. 88 on wards they had slightly bigger bore and shorter stroke. Think if you mix and match parts you can end up with a 135cc or similar.
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@oldman Yeah this.
The manual specifies both the bore and stroke for the 3BN, I'm sure. I don't have it to hand.
It is so minor I doubt it'll be too much of a problem. Powervalves are not interchangeable though.
As said, doubling up on base gasket will do the trick. My worry is that the con rod is designed to stretch and compress, how close will it be at 12k RPM is anyones guess!
wrote on 4 Jun 2019, 08:26 last edited by@oldman Yeah this.
The manual specifies both the bore and stroke for the 3BN, I'm sure. I don't have it to hand.
It is so minor I doubt it'll be too much of a problem. Powervalves are not interchangeable though.
As said, doubling up on base gasket will do the trick. My worry is that the con rod is designed to stretch and compress, how close will it be at 12k RPM is anyones guess!
Hello Calum,What's the difference with the powervalve? Have measured and dry assembled and seems no different than one that came with bike, bar original has no grooves for seals and diamond style pulley shaft on end? Frame back but waiting for rack, grab rail, footrest hangers, suspension spring, etc.
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@oldman Yeah this.
The manual specifies both the bore and stroke for the 3BN, I'm sure. I don't have it to hand.
It is so minor I doubt it'll be too much of a problem. Powervalves are not interchangeable though.
As said, doubling up on base gasket will do the trick. My worry is that the con rod is designed to stretch and compress, how close will it be at 12k RPM is anyones guess!
Hello Calum,What's the difference with the powervalve? Have measured and dry assembled and seems no different than one that came with bike, bar original has no grooves for seals and diamond style pulley shaft on end? Frame back but waiting for rack, grab rail, footrest hangers, suspension spring, etc.
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wrote on 7 Jun 2019, 21:56 last edited by
OK, thanks Calum. Replacement shock arrived and it's worse than the one I need to replace sadly. Lower ball joint corroded and worn and corrosion on plunger shaft has damaged the seal, very little damping going on. Will keep looking for a decent one.
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OK, thanks Calum. Replacement shock arrived and it's worse than the one I need to replace sadly. Lower ball joint corroded and worn and corrosion on plunger shaft has damaged the seal, very little damping going on. Will keep looking for a decent one.
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OK, thanks Calum. Replacement shock arrived and it's worse than the one I need to replace sadly. Lower ball joint corroded and worn and corrosion on plunger shaft has damaged the seal, very little damping going on. Will keep looking for a decent one.
wrote on 8 Jun 2019, 18:26 last edited byOK, thanks Calum. Replacement shock arrived and it's worse than the one I need to replace sadly. Lower ball joint corroded and worn and corrosion on plunger shaft has damaged the seal, very little damping going on. Will keep looking for a decent one.
look for a shock from a newer bike they have a white spring an fit on the 89 model
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wrote on 15 Jun 2019, 15:56 last edited by
Finally got a decent shock, waiting for powdercoating to return (have frame back though)so I can start rebuild. Seller of faulty shock not responded yet to return for refund, but covered via PayPal. Looked at getting a new indicator switch gear assembly and they are over £150. Put that on the wish list with everything else. Photos will be posted when there is something to show!
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wrote on 23 Jun 2019, 22:17 last edited by
Powdercoating back bar 2 items that should be here later this week, now where did I leave the assembly instructions????
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wrote on 25 Jun 2019, 15:45 last edited by
Haha that looks fantastic!
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wrote on 27 Jun 2019, 20:02 last edited by oldman
Thought I had most of it but still missing plenty of bolts and fixings. Returned some of the plating, looked bad to be honest. On top of that rats have chewed the brake pipes on my van so that's being recovered on a flatbed truck tomorrow, revenge for shooting one. Started off with the abs light coming on, took to garage and sensor wire cut. Went to take it for repair and no brakes at all, other rear sensor wire chewed and brake fluid squirting out of chewed hose. How lucky am I