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Post by fletche36 on Jan 13, 2021 17:30:58 GMT 1
just asking, does anyone else other than Fahron do the machining on the 250 barrels to make them 370 s. its just an idea that is hatching in my head thanks.
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Post by rigga on Jan 14, 2021 4:38:26 GMT 1
Not heard of anyone else.
Would have thought someone would of offered the conversion.
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Post by lcmarky on Jan 14, 2021 10:51:39 GMT 1
I've had my 350 barrels/head modified by Fahron up to 400cc, ported and re-profiled head with TZ O ring.
Yet to get the motor assembled and running, but the engineering looks OK to me.
I don't know the first thing about Fahron as the work was through Norbo, so if anyone has some info' I'd be interested.
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Post by veg on Jan 14, 2021 11:12:18 GMT 1
If anyone’s going to know it’ll be Dave (Muttsnutts) however I suspect as rigga says it’s only fahron I think he wants to retire but work keeps him busy I’m sure I’ve also read that he tried to train someone but no one was interested. Did rob (4lo4ever) mention something as well? I’d pm them both.
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Post by Tobyjugs on Jan 14, 2021 12:09:49 GMT 1
I know people that can do this type of work, but most can ony do parts of the work, i would have to visit two different people to get the work done.
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Post by 4l04ever on Jan 14, 2021 13:41:09 GMT 1
I know people that can do this type of work, but most can ony do parts of the work, i would have to visit two different people to get the work done. Same here. Got a great engineering company who could put liners in but they don't do porting
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Post by rigga on Jan 14, 2021 14:31:09 GMT 1
Mick Abbey might be worth asking.
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Post by chippy348 on Jan 14, 2021 19:37:44 GMT 1
There is a lot of work in this conversion, and to be honest it is Fahrons conversion so trying to copy it is not as simple as it looks, its not just a case of punching out the cylinder and fitting a new sleeve. The cylinder needs to be bored out, port work carried out before making and fitting the new sleeve, then more port matching once the sleeve is in, the cylinders will also need to be decked to suite the piston height, and then there is the cylinder head which again to go from 54-66mm is a lot of machine work.
To be fair to Fahron what he charges i dont think he would be making much on the job, also from my point of view lots of work for not much gain over a 350 set up if any.
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Post by 4l04ever on Jan 14, 2021 21:41:30 GMT 1
I think people choose this option due to price and availability of 350 cylinders. They are a great alternative for a great price. To get the most out of any cylinders will need a few more items and a good setting up session.
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Post by muttsnuts on Jan 14, 2021 21:53:59 GMT 1
I have been asked many times about this, I could do the work, but I don't have the equipment and as Paul (Chippy348) has said, Ron can't really be making anything out of this as its very labour intensive. I've spoke to Ron about this and other mods he does a good few times and he would be happy to take me through it, but I'd have to invest heavily in equipment and the return on that investment just isn't there, especially when you consider how much labour is involved.
I am afraid at the cots Ron charges, he is really the only option , I reckon to get a pair of barrels done elsewhere the cost would be significantly more, when you consider the piston kits alone are the neck end of £100 fior the pair !
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Post by fletche36 on Jan 14, 2021 22:58:39 GMT 1
Thanks everyone for the replies. i dont question his work or the price , its just the long wait i dont fancy. im happy with my bike as a 250 but as 250 barrel sets are for next to nothing ( relatively) i was going to pick a set up and have them done just so i can have a mess in the future. saying that , as im in no rush , it wouldnt matter if it took 6 months. 350 barrels are just silly money for what they are .
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Post by steve63 on Jan 15, 2021 9:34:44 GMT 1
Thanks everyone for the replies. i dont question his work or the price , its just the long wait i dont fancy. im happy with my bike as a 250 but as 250 barrel sets are for next to nothing ( relatively) i was going to pick a set up and have them done just so i can have a mess in the future. saying that , as im in no rush , it wouldnt matter if it took 6 months. 350 barrels are just silly money for what they are . Most of the 350 barrels must be reaching the end of their life in terms of oversize. I have a set of std porting 350 barrels on 1mm and a set of tuned ones on probably 0.5 or maybe even 1mm as well. The YPVS ones are on 0.5 I think. I sold a set of Stephens production tuned cylinders for £30 many years ago because they had some damage (con rod snapped)and were on 0.5mm. Still regret that to this day. I think about it whenever I'm tempted to sell anything
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Post by liffy16 on Jan 15, 2021 11:50:51 GMT 1
Doubt fahron is making much on this and that's only because he has lathe /mill and all the fixtures which is the main setup cost,as mutts points out.any one off has very little profit ,run three sliding head cnc lathes myself and you can only make money on high volume work, as they take 2-3 hours to program/set and m/cs are about £150k each ,sometimes we don't appreciate how much time and effort goes into making stuff
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Post by lcmarky on Jan 15, 2021 12:36:46 GMT 1
Pressing the old liners out and new liners in also takes some kit and a heap of experience to not end up with expensive scrap.
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Post by Tobyjugs on Jan 15, 2021 15:59:18 GMT 1
Pressing the old liners out and new liners in also takes some kit and a heap of experience to not end up with expensive scrap. I don't think you can press the old liners out.
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Post by lcmarky on Jan 15, 2021 17:52:41 GMT 1
Other than machining, how else can a liner be removed I wonder?
Maybe some clever trickery with heat, but I don't see how else to get a liner in/out.
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Post by Tobyjugs on Jan 15, 2021 18:17:28 GMT 1
Other than machining, how else can a liner be removed I wonder? Maybe some clever trickery with heat, but I don't see how else to get a liner in/out. Totally agree with you if it's a straight liner but i think the original liners are not straight on the outside so have to be machined out. Then you can put your liner in using a temperature difference between the two parts. I've got two sets to do. When i do make this job i will know for sure. Unless Chippy wants to tell us now.
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Post by midlifecrisisrd on Jan 15, 2021 19:05:17 GMT 1
Unlike some other liners
Remember I painted an xl500 barrel and sat it propped up in front of a fan heater while I did another job
I heard a thud and thought the barrel had fell over
Nope, the liner had fell out 😂
Steve
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Post by 123 on Jan 15, 2021 22:11:17 GMT 1
alan millyard used his barbeque to heat the cylinders and liners would fall out
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Post by reedpete on Jan 15, 2021 22:37:40 GMT 1
You have to go as far back as 1972 to find a press fit yamaha liner on a two stroke. All Aircooled RDs and the LCs thereafter had over-cast liners. With the exception of the later of the TZRs which are plated . So only way to remove an LC liner is to machine it out, then you got to fit n peg a new liner ( which you have to machine from a blank) and have it and the casting ported to suit. Lots of hours.... Think the only reason to do it now would be to get a ‘sleeper’ 250.
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Post by pedheadfred on Jan 15, 2021 23:18:48 GMT 1
I know Ron extremely well his Engineering knowledge is vast as it's all he has been around since being a small boy. Ron's no spring Chicken at 70 odd yrs old, he was taught his trade by his Dad. The name Fahron was created by his dad three people was were it came from. Father Harry & Ron FAHRON this is fact as it came from Ron's own lips while we were supping tea n eating Cakes 😜. As people say the conversion is very time consuming and you have not only got to have special kit. Lathes milling machines boring machine press carbide cutters for the long throat die grinder. But Ron has made many special mandrels to mount the cylinder heads and barrels in his machines aswell to ensure accurate precice machining. The original Yamaha cylinder have to be cut out on the lathe as people have said they are over cast. So any attempt to press one out will destroy the cylinder, BANG! Like a Grenade. The time it takes Ron to do things is forever he will not give time on jobs, it's done when it's done is his attitude. And if somebody who is a racer needs something sorting to get back on track he will usually put that job in front of anything else. Being a racer himself his first TT was in 1962 he knows that racers always are fixing there bikes to try and win races. My personal opinion is as Ron seems to be the only person doing this work, given his age I would personally get mine in before he eventually stops working.
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Post by lcmarky on Jan 16, 2021 10:21:47 GMT 1
I know Ron extremely well his Engineering knowledge is vast as it's all he has been around since being a small boy. Ron's no spring Chicken at 70 odd yrs old, he was taught his trade by his Dad. The name Fahron was created by his dad three people were were it came from. Father Harry & Ron FAHRON this is fact as it came from Ron's own lips while we were supping tea n eating Cakes 😜. As people say the conversion is very time consuming and you have not only got to have special kit. Lathes milling machines boring machine press carbide cutters for the long throat die grinder. But Ron has made many special mandrels to mount the cylinder heads and barrels in his machines aswell to ensure accurate precice machining. The original Yamaha cylinder have to be cut out on the lathe as people have said they are over cast. So any attempt to press one out will destroy the cylinder, BANG! Like a Grenade. The time it takes Ron to do things is forever he will not give time on jobs, it's done when it's done is his attitude. And if somebody who is a racer needs something sorting to get back on track he will usually put that job in front of anything else. Being a racer himself his first TT was in 1962 he knows that racers always are fixing there bikes to try and win races. My personal opinion is as Ron seems to be the only person doing this work, given his age I would personally get mine in before he eventually stops working. Great post thank you.
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Post by lcmarky on Jan 16, 2021 10:24:40 GMT 1
You have to go as far back as 1972 to find a press fit yamaha liner on a two stroke. All Aircooled RDs and the LCs thereafter had over-cast liners. With the exception of the later of the TZRs which are plated . So only way to remove an LC liner is to machine it out, then you got to fit n peg a new liner ( which you have to machine from a blank) and have it and the casting ported to suit. Lots of hours.... Think the only reason to do it now would be to get a ‘sleeper’ 250. Makes sense. I wanted a standard looking 350 but pepped up a bit hence the 400 conversion. I’ve 28mm Keihins and Nikon pipes so it’ll look a little non standard I suppose but not too different.
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Post by Tobyjugs on Jan 16, 2021 11:39:00 GMT 1
I like this idea that's why I want to make another 400cc engine with all I've learnt since joining this forum.
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Post by headcoats on Jan 16, 2021 11:48:16 GMT 1
If these liners fall out with heat then how do they stay in under normal running conditions Sorry if it's a simple question !
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Post by beardy on Jan 16, 2021 12:31:00 GMT 1
I guess that once the barrel is sandwiched between the cases and head that’s what secures it?
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Post by midlifecrisisrd on Jan 16, 2021 12:46:43 GMT 1
As beard said
The liner has a step at the top so is only removed from the bottom up
The head bolted on holds it in
Steve
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Post by Tobyjugs on Jan 16, 2021 15:28:47 GMT 1
It's also an interference fit, so it stays in place unless its too hot. Ive seen barrels which have had no preparation before welding and when cooled down you can see where the body has started to lift away from the steel liner.
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Post by 29davyt on Jan 16, 2021 21:16:50 GMT 1
Thanks everyone for the replies. i dont question his work or the price , its just the long wait i dont fancy. im happy with my bike as a 250 but as 250 barrel sets are for next to nothing ( relatively) i was going to pick a set up and have them done just so i can have a mess in the future. saying that , as im in no rush , it wouldnt matter if it took 6 months. 350 barrels are just silly money for what they are . Make an offer on these buddy, you never know your luck ! www.ebay.co.uk/itm/233862037059
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Post by midlifecrisisrd on Jan 17, 2021 20:05:50 GMT 1
Thanks everyone for the replies. i dont question his work or the price , its just the long wait i dont fancy. im happy with my bike as a 250 but as 250 barrel sets are for next to nothing ( relatively) i was going to pick a set up and have them done just so i can have a mess in the future. saying that , as im in no rush , it wouldnt matter if it took 6 months. 350 barrels are just silly money for what they are . Make an offer on these buddy, you never know your luck ! www.ebay.co.uk/itm/233862037059Well??? They've ended, were you a lucky boy 😆 Strve
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