E: Engine Comet Mongrel

Martyn Goodwin

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Simply bearings have them at nearly £2 for two -5/16" id good luck with your search prices seem to have gone up a tad...
the 5/16" is the one on TOP of the banjo - I'm asking about the one underneath the banjo
Not sure what to say about the YP250. I assume it is a beer fetcher strapped to the back of a motorhome and you didn't want oil dripping on your nice chrome bumper.
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Actually the YP250 was an inner city daily ride - saw over 50,000 miles before I sold it on.
 

Cyborg

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That's a lot of miles.... I never came close to putting that much on any one bike, but then I grew up in the land of ice and snow where you needed ice racing studs to ride past October. Now I've moved to place that seldom sees snow, but riding during the monsoon season isn't all that inviting.
Hoping my chart for the DRO is accurate. Working on the inner primary.
Inner primary.jpg
 

vibrac

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It would seem that my back plate using a pillar drill the original back plate casting and a sheet of 8mm alloy plus some deft work with a hand drill, file and hole saw has been lucky to last 10 years of racing:oops: thank heavens nowadays all I need is cardboard sissors hole punch and a clever man with a water cutter just up the road
 

Cyborg

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Those water cutters are wondrous things and there is apparently one up the road, but I think you have to know someone who knows someone to get a small job done. The upside to doing on the mill is that I finally learned how to map things out and use the boring head that has been sitting idle since it unceremoniously landed in my lap. Don't anyone be thinking I know what I'm doing, because I don't. I'm just so thrilled that the holes appear to be in the correct place and the whole thing didn't turn into a pile of chutney.
 
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stumpy lord

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the 5/16" is the one on TOP of the banjo - I'm asking about the one underneath the banjo


Actually the YP250 was an inner city daily ride - saw over 50,000 miles before I sold it on.
!/4 " dowty seals are available for the oil feed banjo holding down bolts that are 1/4 B.S.F. bolts number188 in the spares list.
For far superior seals, see the V3 advert in the rear of M.P.H. number 824. I have no connection with V3, apart from being a very satisfied customer.
stumpy lord
 

Chris Launders

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One problem I have found with these modern gizmo's is that if you give someone a drawing and they copy it unless they're careful it gets smaller and if that person copies it, it gets smaller again. Someone once sent me a drawing for an engine plate (about 8" long) which I copied and gave to a friend (who's friend could get laser cutting done) who copied it and gave it to the laser cutter. Result, 6 pairs of engine plates 3/8" too short.
That's when I learnt about this problem.
By the way my local patternmakers will only work off hard copies of drawings and will insist the customer verifies the drawing is correct.
I've had it happen even where I've given them a drawing and told them "it needs to be this size, bring me one before doing a run" and the prototype was still too small, when I laid it on the drawing and it didn't match the only reply was I don't know how that happened, I do, not knowing what they're doing !!!
 

vibrac

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Perhaps I am lucky with my water cutters for the 2020 I am not going to carry the weight of the front stands as I have a lightened Dave Hills stand but I want to keep the mag shield so I just took on support plate over and asked for two in 8mm alloy they take the profile from the item to the cutting jet directly
 

Bill Thomas

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Perhaps I am lucky with my water cutters for the 2020 I am not going to carry the weight of the front stands as I have a lightened Dave Hills stand but I want to keep the mag shield so I just took on support plate over and asked for two in 8mm alloy they take the profile from the item to the cutting jet directly
I am making plates like you for the 560, Hope our bikes won't look the same !!, 2 great / Oldish ! minds !.
Might make them for the L/ning also, Now I have got rid of the E/Trunk breather, May fit a Mag' cowl to change the look of the bike.
If anybody see's a photo of my L/ning on the Forum, Can they P.M, it to me, My Computer Died with all my photos !! Bugger !!.
Cheers Bill.
 

vibrac

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No Bill they wont look the same I have a secret alteration(details held) and for extended two up I also will swap the standard seat for the extended seat with the front half reduced height which I shall share with the twin.
 

Cyborg

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I'm likely going to use this piston, because I have it and it will fit. The bore is STD and shows some light scoring, but would rather bore it to .010 over and have everything straight and round. The long term plan is for something larger, but figure it is best to get the engine together and start figuring out things like what frame I am going to use. It is a Specialloid H92, so 7.3 to 1 CR. +.010 and no "N" stamped on the crown. According to Richardson, Shadows used them fitted with .006" to .0065" clearance and I know some folks suggest more. I guess the question is how much more. Road use only and riding fast is not recommend in my neighbourhood....

Specialloid +.010 H92.jpg
 

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