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Post by buster on Jun 13, 2021 15:55:00 GMT
not quite yet, I'm running on last minute a bit, decided to change the front tyre today and gambled on the inner tube being good. as soon as I took the valve out green goo started coming out so into the bin with it and new tube ordered. Derby will be a hell of a test run on a largely untried bike, better get some breakdown cover
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Post by buster on Jun 14, 2021 19:55:23 GMT
had an unfashionable idea, instead of buying things off ebay I went to a bike shop instead, predictably they didnt have an inner tube in the size I wanted but they did have a 400/450 19 so I bought it. then had the usual fight to fit it, went to pump it up (with my old foot pump) and its not getting any pressure, bugger thinks I, I'v nipped it. so one tyre bead back off, inner tube out and tried to pump it up again. virtually nothing. so used the car battery pump, tube flies up and a good dunking showed no leaks. ARGH! so it seems I'd got it on ok first time, oh well I'll leave it till tomorrow now just to make sure it holds wind before I bolt it back in
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cb400a
Jun 16, 2021 16:10:43 GMT
Post by buster on Jun 16, 2021 16:10:43 GMT
so the tyre is still up (hooray, I didnt nip the tube) and last night I went for a bit of a run round on it, the intention being to get the mileage up to around 50 (ready to check through the cylinder head, torque/tappets) problem is I'm now starting to think that honda 'strangled' the engine with the 250 head. its ok up to about 45mph and even using it gently I can feel its not going to go any higher without serious (and unnecessary) abuse. so my thoughts now are try a 400 head, this brings about its own problems as I'll need to check valve to piston clearance but I may be able to overcome that with a low power german cam shaft (which should still have decent duration and hopefully suit the 'bottom end' nature of the pistons) I'v also got a set of old vb31's somewhere so they will go on too. the joys of modifying things...
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cb400a
Jun 16, 2021 16:27:12 GMT
Post by BritPete on Jun 16, 2021 16:27:12 GMT
so the tyre is still up (hooray, I didnt nip the tube) and last night I went for a bit of a run round on it, the intention being to get the mileage up to around 50 (ready to check through the cylinder head, torque/tappets) problem is I'm now starting to think that honda 'strangled' the engine with the 250 head. its ok up to about 45mph and even using it gently I can feel its not going to go any higher without serious (and unnecessary) abuse. so my thoughts now are try a 400 head, this brings about its own problems as I'll need to check valve to piston clearance but I may be able to overcome that with a low power german cam shaft (which should still have decent duration and hopefully suit the 'bottom end' nature of the pistons) I'v also got a set of old vb31's somewhere so they will go on too. the joys of modifying things... I bet you used to make everything that was on Blue Peter Buster
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cb400a
Jun 16, 2021 18:47:45 GMT
Post by buster on Jun 16, 2021 18:47:45 GMT
so the tyre is still up (hooray, I didnt nip the tube) and last night I went for a bit of a run round on it, the intention being to get the mileage up to around 50 (ready to check through the cylinder head, torque/tappets) problem is I'm now starting to think that honda 'strangled' the engine with the 250 head. its ok up to about 45mph and even using it gently I can feel its not going to go any higher without serious (and unnecessary) abuse. so my thoughts now are try a 400 head, this brings about its own problems as I'll need to check valve to piston clearance but I may be able to overcome that with a low power german cam shaft (which should still have decent duration and hopefully suit the 'bottom end' nature of the pistons) I'v also got a set of old vb31's somewhere so they will go on too. the joys of modifying things... I bet you used to make everything that was on Blue Peter Buster nah, never had any double sided sticky tape
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cb400a
Jun 17, 2021 5:52:24 GMT
Post by buster on Jun 17, 2021 5:52:24 GMT
so dug out an old 400 head that I'd previously written off as parts only, someone had drilled one of the exhaust studs out and wedged an m10 bolt in the hole. had a go with the aluminium brazing rod at filling it in then looked at the other studs, not a single thread in tact and the one opposite the one I filled appears to have been filled with plaster (not sure if its board finish or multi ) so more work needed...
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Post by grahamb on Jun 17, 2021 7:50:41 GMT
so dug out an old 400 head that I'd previously written off as parts only, someone had drilled one of the exhaust studs out and wedged an m10 bolt in the hole. had a go with the aluminium brazing rod at filling it in then looked at the other studs, not a single thread in tact and the one opposite the one I filled appears to have been filled with plaster (not sure if its board finish or multi ) so more work needed... Every one knows they should use Carlite Bonding on that sort of job.
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Post by buster on Jun 23, 2021 19:33:48 GMT
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cb400a
Jun 27, 2021 15:18:49 GMT
Post by buster on Jun 27, 2021 15:18:49 GMT
cylinder head time, I had problems getting the alloy filler rods to tin, cant really get the cast alloy head hot enough, mapp gas helps but the gas axe would really be the way to go. my (bodge) solution was to fill the stud holes then turn the collar slightly and drill part casting and part filler. will it hold? time will tell long and pedantic job cleaning and fettling. I'm not a fan of the casting flash in the exhaust ports (inlets in my opinion you wont get them any better than honda did, but thats only my opinion) then lap the valves in and a final major degrease before assembly including my patented (not really) engine fin cleaning tool, just wrap a strip of scotchbrite over it then onto final assembly, it was so nice of honda to include the two little trays for keeping your collets in
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cb400a
Jun 27, 2021 15:27:26 GMT
via mobile
Post by andy1kenobe on Jun 27, 2021 15:27:26 GMT
cylinder head time, I had problems getting the alloy filler rods to tin, cant really get the cast alloy head hot enough, mapp gas helps but the gas axe would really be the way to go. my (bodge) solution was to fill the stud holes then turn the collar slightly and drill part casting and part filler. will it hold? time will tell I've used a product called Lumiweld on an aluminium windscreen frame on a kit car I built. It works with an ordinary butane blowlamp. I have seen Frost sell it. www.frost.co.uk
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cb400a
Jun 27, 2021 15:36:08 GMT
Post by buster on Jun 27, 2021 15:36:08 GMT
cylinder head time, I had problems getting the alloy filler rods to tin, cant really get the cast alloy head hot enough, mapp gas helps but the gas axe would really be the way to go. my (bodge) solution was to fill the stud holes then turn the collar slightly and drill part casting and part filler. will it hold? time will tell I've used a product called Lumiweld on an aluminium windscreen frame on a kit car I built. It works with an ordinary butane blowlamp. I have seen Frost sell it. www.frost.co.ukI'll have a look at that andy, problem is though I got a lesson in how efficient cast alloy is at dispersing and getting rid of heat. If it was a hole in a coke can I could do it dead easy as its easy to get the metal up to temperature. I'll keep dreaming of that tig welder...
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Post by buster on Jun 27, 2021 17:29:16 GMT
I had thought that I was short of one intake rubber, this is one of the 400n's
so I bought some cheapo jobbies off ebay, utter crap, I dont rate them at all
so I scraped the goo off the dodgy looking one to see what was going on. underneath I found a perfectly good usable inlet rubber? (the gooed one is on its edge)
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Post by BritPete on Jun 27, 2021 17:31:54 GMT
I had thought that I was short of one intake rubber, this is one of the 400n's I have the ones taken off SME if any good fit you
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cb400a
Jun 27, 2021 18:17:35 GMT
Post by buster on Jun 27, 2021 18:17:35 GMT
I had thought that I was short of one intake rubber, this is one of the 400n's I have the ones taken off SME if any good fit you thats a really kind offer pete but I think I'm sorted
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Post by andy1kenobe on Jun 27, 2021 20:59:28 GMT
I've used a product called Lumiweld on an aluminium windscreen frame on a kit car I built. It works with an ordinary butane blowlamp. I have seen Frost sell it. www.frost.co.ukI'll have a look at that andy, problem is though I got a lesson in how efficient cast alloy is at dispersing and getting rid of heat. If it was a hole in a coke can I could do it dead easy as its easy to get the metal up to temperature. I'll keep dreaming of that tig welder... I've still got some here if you want to try a stick.
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