b40rt Posted January 17, 2009 Report Share Posted January 17, 2009 Interesting topic. Regarding rear end rising or falling under power, must affect grip. There is a lot of talk elsewhere of fitting longer shocks to tighten up the steering, this must upset the relationship you have mentioned for the rear end. The chain touches the top of the swinging arm on my B40, wore two groves, then bedded in. Its probably a little over engineered anyway. Quote Link to comment Share on other sites More sharing options...
jon v8 Posted January 18, 2009 Report Share Posted January 18, 2009 I've added a couple more pics,to show how wrong it is.The white cross is where I am thinking of raising the pivot to - 25mm higher.Not totally decided,but it sorts out the chain run and there isnt much more I can do.It will mean cutting and raising the subframe mounts and adding extra metal around the new pivot hole.By leaving the top shock points in the same place I should end up with pretty much the same height/ground clearance,the only worry is the rise/fall under power. All good fun,if it does not work I'll build a frame from scratch,using a jig that keeps the original dimensions and angles from the TY frame - lets hope its not needed. Quote Link to comment Share on other sites More sharing options...
b40rt Posted January 18, 2009 Report Share Posted January 18, 2009 How many hours into the project so far ? Quote Link to comment Share on other sites More sharing options...
moleman Posted January 18, 2009 Report Share Posted January 18, 2009 It is a step in the right direction. "if" you can get it closer to the gearbox sprocket all the better i used to trial a complete Serow (kick only, with valve lifter) and used from memory a 420 chain with a very small front sprocket (held with circlip) it may be worth your while to compare diameters of sprocket between 520 and 420 the smaller you go on the front the more it may help your compromise on picture 3 it looks like the rear wheel spindle is slightly higher than the line through the first two points, you should try and get the rear spindle to drop below the line when at rest, weight off but your proposed new swing arm pivot point will certainly help. good chain guide, and a very good spring on you chain tensioner! The CV carb will require a decent size air box to work correctly, but we will discuss that no doubt further down the road... Quote Link to comment Share on other sites More sharing options...
jon v8 Posted January 18, 2009 Report Share Posted January 18, 2009 B40RT, I'm not counting the hours - I'm savouring them as time enjoyed doing something for myself that I really like,(As I locked the workshop door this afternoon I agreed with my father that earning a living is a pain in the bum as it gets in the way of living ! ) had lots of ideas over the years but often they never get done. Moleman, I still need to sit down and actually work out the best way forward,but I think the compromise,(as you rightly say) will be to raise the pivot by approx 25mm. With the CV carb I'll have a fair bit of room for the airbox,but my memories of Strombergs on Rover V8's was that they like a bit of depression upstream to make them pull properly,but thats a bit further on.I spent a couple of hours fitting points/condensor and cleaning the carb on my TY250 - not ridden it at all since September,it was in a bit of a state - water in the float bowl etc,very poor waveform when I scoped the plug lead.So having a nice 4t twinshock hybrid to ride will be a waste of time if I'm so rusty and fat its not true ! First Bath trial is 14th Feb,better start practicing..... Quote Link to comment Share on other sites More sharing options...
copemech Posted January 19, 2009 Author Report Share Posted January 19, 2009 I know I started this stupid thread jokingly! But Jon, I seen this friggin honda something 220, 215, 225, last weekend(trail bike) and fact is the motor seemed much more accomodating and smaller! Still had no kicker! Maybe time to start over? To be honest, the XT (Serow) seems to do well on the roads, but in the rough, it seems to be a real pig! I wish you could buy a old Yamaha 2T enduro in 175 or 250!, somewhere around "75 vintage! Quote Link to comment Share on other sites More sharing options...
jon v8 Posted January 19, 2009 Report Share Posted January 19, 2009 No,I'm going to keep going - moving the swinging arm pivots is no real drama and there is no hurry.If I can build a reasonable bike form the TY and the Serrow I'll be happy - 4 reasons; 1 Its not a Honda. 2 Its electric foot. 3 Its a well proven and reliable 4 stroke. 4 It wont cost more than about Quote Link to comment Share on other sites More sharing options...
jon v8 Posted June 28, 2009 Report Share Posted June 28, 2009 There is some progress after almost 2 solid days of fiddling.(Not that it looks much.)Got my camera back and sort of sussed out how to post piccys direct. Quote Link to comment Share on other sites More sharing options...
marky g Posted March 4, 2010 Report Share Posted March 4, 2010 Just been trawling through the yam threads and came across this, what ever happened to it Jon? Quote Link to comment Share on other sites More sharing options...
jon v8 Posted March 4, 2010 Report Share Posted March 4, 2010 Still in a similar shape to the pics,I have made the airbox but its not finished.I need a bit of thinwall 1 1/2" alloy tube to get on with it.It will happen tho,I bought everything I could think of to finish it from BVM a while back,but there will be odd bits and pieces to add.Once the airbox is finished the main bit is the wiring - not too much of a problem apart from the W/S manual I downloaded off the net is for a US spec bike and I think mine was a Jap home market bike.Many of the wires are a different colour..... But as always there are distractions,I'm out in Oz for most of April,I also decided to look for a Pre65 rigid AJS/Matchbox trials,(No luck at all,if you know of anything PLEASE let me know) and just today I agreed to buy a Mike Hailwood replica Ducati. I wanted to ride the Serow engined bike at the Dartmoor 2 day last Sept,but the time just flies,the summer is blocked with dates that overlap,plus being talked into playing with vintage tractors.... I never said I was bored ! Quote Link to comment Share on other sites More sharing options...
marky g Posted March 5, 2010 Report Share Posted March 5, 2010 Do keep us posted on how it turns out mate, fair play to you for having a go. Just a thought, how will the twinshock brigade take to it I wonder?.....you'll probably get tarred and feathered if you dare enter it as a twinshock Quote Link to comment Share on other sites More sharing options...
jon v8 Posted March 5, 2010 Report Share Posted March 5, 2010 It'll get done,and no worries about entering as a twinshock - two reasons,first I'm a cr-p rider and second at least one twinshock Yam mono seems to turn up at every trial. Its not going to be ultra competative either,the starter and battery are quite heavy,and a TY175 frame is not exactly a Godden Majesty - its just an idea thats been hanging around in my mind for years,an all Yam 4stroke twinshock. Quote Link to comment Share on other sites More sharing options...
andy m Posted March 5, 2010 Report Share Posted March 5, 2010 There is a TY mono out there with a serow engine in I believe. Hailwood replicas..... Vintage tractors? same thing aren't they.. (joke) I had a Darmah years ago, the MHR is a cracking looking bike, not the sort of thing you see every day.. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 6, 2010 Report Share Posted March 6, 2010 Still in a similar shape to the pics,I have made the airbox but its not finished.I need a bit of thinwall 1 1/2" alloy tube to get on with it.It will happen tho,I bought everything I could think of to finish it from BVM a while back,but there will be odd bits and pieces to add.Once the airbox is finished the main bit is the wiring - not too much of a problem apart from the W/S manual I downloaded off the net is for a US spec bike and I think mine was a Jap home market bike.Many of the wires are a different colour.....But as always there are distractions,I'm out in Oz for most of April,I also decided to look for a Pre65 rigid AJS/Matchbox trials,(No luck at all,if you know of anything PLEASE let me know) and just today I agreed to buy a Mike Hailwood replica Ducati. I wanted to ride the Serow engined bike at the Dartmoor 2 day last Sept,but the time just flies,the summer is blocked with dates that overlap,plus being talked into playing with vintage tractors.... I never said I was bored ! When you said MH Replica and being stuck out in OZ I wondered if you were near here as I know of one of those for sale locally. Sorry no ideas for a rigid rear AJ trials bike for sale. I like what you are doing with the Serow TY175. It sounds like you are having great fun. David Lahey Gladstone, Queensland Quote Link to comment Share on other sites More sharing options...
marky g Posted March 6, 2010 Report Share Posted March 6, 2010 There is a TY mono out there with a serow engine in I believe.Hailwood replicas..... Vintage tractors? same thing aren't they.. (joke) I had a Darmah years ago, the MHR is a cracking looking bike, not the sort of thing you see every day.. Had a mk1 lemans in 84, great looking and sounding bike, I was after a Darmah at the time but got put off with all the horror stories about the engine's self destructing, I've got a VRF now and although it's great I'd love another old twin. Quote Link to comment Share on other sites More sharing options...
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