Hitchcocks Forum

http://farm9.staticflickr.com/8329/8431 ... fde4_z.jpg
I took this shot of my bitsa motor with its new aluminium barrel (un tested) from Mr H. Not a bad bit of kit. (Excuse the Doris Day vasolined lens look but the iPhone gone a but oily) I made a 5/16" short stud with a stepped 10mm base to replace the heli coiled hole which I presume was 8mm and I had to grind out the hole for the small stud above the tappet cover as it was in the wrong place by a couple of mill but apart from that an excellent bit of kit and so much lighter that the iron barrel. I'll be really interested to see what difference it makes to the high speed performance on the bike. Before I could easily cruise at 65 mph but it would get way too hot if I did it for too long. I wonder if this will make a substantial difference. Well worth an £80 gamble I thought. I'll give it a gentle run in with the new set of rings then give it a real test. Watch this space. S;)

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Oooh, precious, wants the shiny thing... Sorry, carried away there! Nice looking motor, they are very good looking lumps in my opinion. However, I don't think you'll notice a real performance improvement from an alloy barrel alone, although some cooling benefits will be evident. What I'm saying is, don't be disappointed if it doesn't go noticeably faster and take care to run it in properly! I have an all alloy Redditch 350 motor in my Works Replica and it's noticeably noisier than a cast iron barrel so be prepared for that too! REgards, Mark

THAT MAN THERE !! -------------- YES, YOU, SIMON chappy -----------HALT!!---Please---please---please read this posting before you go any further..What I'm about to relate here is the God's honest truth,and is in no way intended to slur our good hosts name, OK ?? }---- I also bought a "Not checked" alloy barrel from them at £85...The first problem was the lip on top of the barrel was too tall and there was little or no clamping force onto the head gasket between the cyl.head face and the barrel top face..As my main lathe was out of action it was clamped onto the vert. miller and some steady cutting over an hour saw the job done.....The OEM piston at std. bore with rings went in with no problems and, after the re-build I started it up..All went well for the first 1/2 hour of run-time---then the leaks started !! At first it had all the symptoms of the head gasket not sealing properly around the inlet pushrod tube area as oil was seeping from that joint-----OR SO IT LOOKED!!! -- I removed the head, cleaned, checked etc--- re-built and started it up again...OK for the first 1/2 of run-time---- then the leaks started !! from the SAME PLACE !!... This time a closer inspection showed the oil to be slowly seeping from between the two bottom fins in that same area---in other words we had POROSITY !!!--------------- SO, off with the head and barrel-- a good wash in the parts washer, an air-blast dry and I gave both the push-rod tubes a thorough torch-light inspection.... Guess what ??...there it was---a blow-hole in the casting that must have connected with the outside world....Remember, the pushrod tunnels have a slight pressure in them as well which will magnify the problem as will the heat-induced expantion...SO, what to do ??? Well, you could buy a tin of Crankcase Paint at £26 for 500ml and hope that works OR}-- I chose to liner the tunnel in the same way as you re-liner a cylinder..I used a thick-walled aluminium tube --found on E-Bay--- and used a 2 thou interference fit with the top end peened over into a slight countersink.... All ok now..It won't go any faster but certainly IS lighter... It'll warm up quicker ( and thus cool down quicker ) ---- hope that helps you somewhat ???

------------PS, forgot to say }-- I think that photo is how most of us see our beloved engines/bikes in our mind's eye ??? The reality is somewhat different--- eh ??

Mmm interesting Alan, I'll keep an eye out for leaks. The previous incarnation was totally leak free so it will be pretty obvious however I have split the crankcase and used homemade gaskets so we will have to see. There is a similarity with the one ring that binds them all Mark in that for my wife the minute I get involved in the shed and the mechanical features within I mysteriously become invisible!