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Post by sidney81 on Mar 19, 2024 8:04:57 GMT 1
Hi ,you should enjoy it when it's up and running,I have the 370 and it goes fantastic,it's 57 bhp on the Dyno and has good mid range,it's great fun ,Chris .
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Post by abar121 on Mar 19, 2024 9:03:40 GMT 1
Hi Chris, Hope you are well mate.
Your feedback has made me even more eager to get mine finished.
Cheers.
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Post by sidney81 on Mar 19, 2024 9:16:04 GMT 1
Hi Chris, Hope you are well mate. Your feedback has made me even more eager to get mine finished. Cheers. hi,im well thank you ,hope you are also,yes get it finished im really pleased with mine đź‘Ť
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Post by archloafer on Mar 20, 2024 21:35:33 GMT 1
Hi ,you should enjoy it when it's up and running,I have the 370 and it goes fantastic,it's 57 bhp on the Dyno and has good mid range,it's great fun ,Chris . Hey Chris. Just had a look at your hybrid build thread. Awesome bike, and the work and skill that went into it - another level. 57hp with PWKs, pod filters and expansion chambers - nice. That amount of power in a hybrid probably feels pretty good, but on my (mostly) standard bike it would be a bit hairy I think. If I get between 45 and 50 I would be very happy. We'll see how it goes...
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Post by archloafer on Mar 20, 2024 21:42:38 GMT 1
Got a pair of pistons back with the top end. 250 small ends too narrow, I understand. Will 350LC ones fit, or should I get Blaster or DT200 ones? Ron also chucked in a gasket set. NE good? I would only need the head gasket, thinking it might be worth getting an Athena one instead.
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Post by chippy348 on Mar 20, 2024 22:10:04 GMT 1
Use RD350LC small end bearings, Head gasket is going to be a issue @ 66.00 mm you will find it hard to get a off the shelf head gasket to work. You may end up going Genuine Yam multilayer steel type and opening that out to 66.50
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Post by sidney81 on Mar 20, 2024 22:54:01 GMT 1
Hi thank you , yours will be great fun , the head gasket ron supplies is the correct size , Athena is to small ,I tried to open out a genuine gasket and it didn't work it leaked ,by the time it's opened out enough your eating into the raised ring , you might be lucky but it didn't work for me ,the gasket ron supplies works fine i did use sealant with it , mine was a bugger to seal up ,, Chris
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Post by archloafer on Mar 20, 2024 23:48:05 GMT 1
Hi thank you , yours will be great fun , the head gasket ron supplies is the correct size , Athena is to small ,I tried to open out a genuine gasket and it didn't work it leaked ,by the time it's opened out enough your eating into the raised ring , you might be lucky but it didn't work for me ,the gasket ron supplies works fine i did use sealant with it , mine was a bugger to seal up ,, Chris Thanks Chris - that is very helpful. I had it in mind already to use sealant. I have some permatex copper spray, wellseal and loctite 3020 - what did you end up using? I was actually looking through your build thread, and a few others, to see how people have solved this problem before. Prepping the surfaces well seems to be a good shout. The head had a few light machining marks when I got it back from Ron, and the powder coaters added a couple of scratches, but after simply cleaning it with some scotchbrite it's looking pretty good. The top of the barrels on the other hand have deeper machining marks on them. I'm very wary about 'lapping' them individually. I'll have a think. So, you used the gasket Ron gave you, and standard 0.5mm base gaskets? Can you remember what you measured the squish at? Was the leaking just from the water jacket?
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Post by sidney81 on Mar 21, 2024 11:15:21 GMT 1
Hi , I used genuine base gaskets I can't remember the squish I'd have to check my notes on that one! , I did tourque the head to 20 lbs and it did seal up I kept getting a weep at the front , I was going to get them o ringed over winter but it's all sealed up nice so I thought if it ain't broken don't fix it ,but I think in the future that will be the way I go đź‘Ť
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Post by lcmarky on Mar 21, 2024 12:08:15 GMT 1
I made some new fitments for my Nikkon pipe attachments.. Will post pics in case it helps.
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Post by lcmarky on Mar 21, 2024 12:11:16 GMT 1
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Post by foxyjohn on Mar 21, 2024 13:07:00 GMT 1
I used A Athena head gasket with no problems for 6 years on my Fahron 370 Then It developed a little weep on the front of the left barrel So I got it O ringed by Mutsnutts So I would say get the head O ringed and save yourself the messing with head gaskets Enjoy your 370 they are a total hoot to ride
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Post by archloafer on Mar 21, 2024 13:47:46 GMT 1
Very nice indeed So, it slots into where the crush ring gasket would go, and you just use a flat gasket under the black flange bit?
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Post by archloafer on Mar 21, 2024 14:07:07 GMT 1
I used A Athena head gasket with no problems for 6 years on my Fahron 370 Then It developed a little weep on the front of the left barrel So I got it O ringed by Mutsnutts So I would say get the head O ringed and save yourself the messing with head gaskets Enjoy your 370 they are a total hoot to ride Cheers John. O-rings are one of the options I am mulling over. With that you just use some sealant around the water jacket, direct on the metal? Also, the o-rings I imagine give minimal squish clearance between the head and barrels, so you would have to compensate with a thicker base gasket?
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Post by midlifecrisisrd on Mar 21, 2024 20:36:09 GMT 1
When the head is o ringed they squish band and dome are cut deeper to compensate
Steve
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Post by popeye69 on Mar 22, 2024 0:33:39 GMT 1
I cant see them on safari on my iPad can see on safari, Mac book.
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Post by archloafer on Mar 22, 2024 21:31:30 GMT 1
I cant see them on safari on my iPad can see on safari, Mac book. I changed the image hosting from Dropbox to freeimage.host. I have the free Dropbox account and I think there might be a download limit for linked images.
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Post by lcmarky on Mar 23, 2024 13:06:13 GMT 1
Very nice indeed So, it slots into where the crush ring gasket would go, and you just use a flat gasket under the black flange bit? Gasket sits between the round boss & cylinder.
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Post by foxyjohn on Mar 23, 2024 17:46:27 GMT 1
I used A Athena head gasket with no problems for 6 years on my Fahron 370 Then It developed a little weep on the front of the left barrel So I got it O ringed by Mutsnutts So I would say get the head O ringed and save yourself the messing with head gaskets Enjoy your 370 they are a total hoot to ride Cheers John. O-rings are one of the options I am mulling over. With that you just use some sealant around the water jacket, direct on the metal? Also, the o-rings I imagine give minimal squish clearance between the head and barrels, so you would have to compensate with a thicker base gasket? Have a chat with Dave aka MuttsNuts He will reprofile your head For the O ring on your head Then use some sealant for the water jacket
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Post by lcmarky on Mar 25, 2024 10:01:56 GMT 1
Cheers John. O-rings are one of the options I am mulling over. With that you just use some sealant around the water jacket, direct on the metal? Also, the o-rings I imagine give minimal squish clearance between the head and barrels, so you would have to compensate with a thicker base gasket? Have a chat with Dave aka MuttsNuts He will reprofile your head For the O ring on your head Then use some sealant for the water jacket My Fahron head uses TZ750 O Rings and I have it torqued down more than a standard head gasket.. Just FYI.
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Post by abar121 on Mar 25, 2024 11:05:54 GMT 1
I got my kit from Fahron yesterday, what a lovely man.
Looking forward to fitting it soon!
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Post by archloafer on Mar 26, 2024 19:11:10 GMT 1
Did some work on the exhaust stubs over the weekend. Bit of a squeeze in the vice with some heat, wet and dry on a flat thing to find out where the low spots were, some attention with a big hammer, careful filing and more sanding. They are now pretty good and mate nicely with the outlets. Found this flat gasket in my collection. Useless. I have some gasket paper so will make up a couple. Copper crush rings in many sizes and thicknesses are readily available, so I'll try and find something that fits better than the ceramic ones.
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Post by archloafer on Mar 26, 2024 19:14:26 GMT 1
I got my kit from Fahron yesterday, what a lovely man. Looking forward to fitting it soon! Good news He is a very nice man indeed. What will we do when he finally decides to hang up his tools and retire? Will you be putting a thread up when you fit yours? Interested to see how you get on...
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Post by archloafer on Mar 26, 2024 19:21:49 GMT 1
Have a chat with Dave aka MuttsNuts He will reprofile your head For the O ring on your head Then use some sealant for the water jacket My Fahron head uses TZ750 O Rings and I have it torqued down more than a standard head gasket.. Just FYI. Thanks Mark. Who did the o-ring work on yours? Also, the tops of your barrels look good and flat - did you get them skimmed? I've noticed on mine that as well as the machining marks there is a slight step between the liner and the casting, which I think it would be good to get rid of.
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Post by abar121 on Mar 26, 2024 19:55:19 GMT 1
I got my kit from Fahron yesterday, what a lovely man. Looking forward to fitting it soon! Good news He is a very nice man indeed. What will we do when he finally decides to hang up his tools and retire? Will you be putting a thread up when you fit yours? Interested to see how you get on... I will, hopefully in the summer.
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Post by lcmarky on Mar 27, 2024 10:26:34 GMT 1
My Fahron head uses TZ750 O Rings and I have it torqued down more than a standard head gasket.. Just FYI. Thanks Mark. Who did the o-ring work on yours? Also, the tops of your barrels look good and flat - did you get them skimmed? I've noticed on mine that as well as the machining marks there is a slight step between the liner and the casting, which I think it would be good to get rid of. Fahron did the O Ring grooves. I just lapped the barrels & head. Personally I would lap the top of your barrels, not machine them. Happy to offer guidance how to lap properly if you need it? The turning marks in the barrel & liner look different, so I think the liner has been finished & then pressed in afterwards.
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Post by muttsnuts on Mar 27, 2024 22:52:13 GMT 1
make some thin ally spacers up that go into the exhaust spigot so that the exhaust gasket is sitting proud of the barrels flange so that the exhaust flange has something to seat against
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Post by archloafer on Apr 17, 2024 18:05:02 GMT 1
Right. After reading threads about other people's experiences, looks like sealing these up is a common problem, so I've decided to get it o-ringed. Thanks in particular to Chris (sidney81) who called me and described what he went through to get his working properly. That conversation alone might well have saved me several headaches. Got hold of Andy at 2T, had a good chat to him on the phone, then took the engine (all of it) up to him last week. Some interesting findings. The barrels came back from Fahron not honed, so I asked him to take care of that as well as the o-ring work. When I got up there he got a bore micrometer in them and saw that the clearance at the top was OK, 0.05mm, but tighter at the bottom (forget what the actual measurement was, 'pretty tight' in his estimation). Also slightly oval at the bottom. Both barrels. He suggested this might be due to the boring machine distorting the liner where it sticks out of the casting. He agreed that the top surface of the barrels needs to be skimmed to remove the machining marks and the step between the lining and the alloy. Originally I was just going to take the top end up to him, so he asked me to put it all together to measure the squish beforehand. Initially I tried it without the head gasket with the bolts done up finger tight to see if there was any clearance - nope. Then I put the gasket on and went through the spark plug hole with the solder. Got some mixed results: RHS Front: 1.0 Back: 0.94 Left: 1.02 Right: 1.06 LHS Front: 0.95 Back: 1.10 Left: 0.96 Right: 1.14 I can understand the front - back variation because of the piston being able to rock slightly on the gudgeon pin. Left - right is slightly more puzzling. I measured the gaskets. Head was all over the place - between approx 1.25 and 1.45mm depending on where the measurement was taken. I guess it would 'even out' when torqued down but still, doesn't scream quality. Also, the OEM base gaskets I used were bang on 0.6mm. I always thought they were 0.5 I did it again using this method and got similar measurements. As noted by Rob earlier in the thread the head moves around by a surprising amount. I didn't measure it but I would estimate at least 5mm back and forth, with all of the bolts in finger tight. Is this normal?? So I figure that a combination of the uneven surfaces on the tops of the barrels and the crap gasket might account for the variation in squish? Anyway, all of this is what changed my mind to taking the whole engine out and up to him. What I am having done then, in total: Hone the bores and remove the taper and oval-ness. He seemed fairly confident he can sort it out. Piston / bore clearance might end up being a bit bigger than normal, which he didn't seem to think was an issue. Will be a bit rattly when the engine is cold. O-rings. Into the barrels and not the head, purely because it will make it easier to put together and there doesn't seem to be any particular penalty for doing it that way. CNC re-shape of the head chambers. Skim the tops of the barrels. Put locating dowels into the head. Take off the sharp edges of the ports. Looks like I'm down a rabbit hole already
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Post by wallcraft on Apr 17, 2024 21:02:25 GMT 1
That’s worrying, quite few people including myself have one of these top ends. Mines in the loft, I do remember thinking the bores on mine looked like they hadn’t been honed , also the port’s sharp edges look like they need to be smooth etc..
Dam, nothing’s straight forward. Looks like a fair bit of finessing then🙄
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Post by tony2stroke on Apr 18, 2024 17:51:37 GMT 1
That's shocking
You're doing the right thing sorting these issuesout, it is so disappointing to go through all this, seems like half a job was done.
You are only as good as your last job, and that doesn't inspire confidence.
I think maybe you should consider contacting him with your findings, maybe a mistake was made sending them back unfinished, because they certainly seem unfinished.
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