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Post by 90GTVert on Jun 17, 2024 6:09:26 GMT -5
Anyone have a reasonably priced source for AF18 seals for large (20mm) cranks? Looks like it should be 20x25.5. I found a site listing conversion seals for $35, prob plus shipping. He’s not gonna pay that. I’m thinking if all else fails, maybe a 20x25 seal with sealant on the outer edges or a 20x26 if it will go in without deforming. I’d prob just buy the conversion seals, but I’ve also seen plenty of leaks from new seals that fit as intended when leak testing. You sure of those dimensions? that's like an O ring Somewhat sure. I measured the shoulder on the crank at just under 20mm (and the bearing is 20mm ID). I measured the ID of the case at ~25 (tough with the crank in there). Then we found his old seal and it's a 25.5mm OD. Stock seal is 15.6x25.5. So, 20x25.5 is what should be required. I think he ordered 20x25 last night. I told him that it should be tested regardless, but with a 25 or 26mm seal vs the known OD of 25.5 stock, it's an absolute must to me. I'm hoping he really does make a tester and check both of the engines he's got once assembled. I'm curious now if these AF18 swap seal kits for too much money are even 25.5 or if they just found that a 25 or 26 works and made a seal kit for big profit. The places that I saw them didn't specify size. That said, I'm not spending the money to find out. |
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Post by 90GTVert on Jun 18, 2024 17:22:10 GMT -5
The Dio guy came over today because it won’t start. He put an AliExpress stator on and said he didn’t see the reviews that it wasn’t working for others till now. He doesn’t have a flywheel puller so I gave him an amazon link for one cheap and removed the flywheel for him. He said it kicked back hard and was hard to kick. Lots of resistance on the kick lever, so I said it probably has high compression. He did say it popped and spit fire when kicked over, so it had some sort of spark. I checked squish clearance at a little over 0.7mm. It was around 1.35% of stroke. With that clearance, the ports flush at BDC, and the port timings, it may not be far off of a strong setup with a good pipe. The problem is, the combustion chamber is tiny.  I measured it at less than 8cc. This is a 125. I told him I can’t cut it in the lathe because of the angled plug. Suggested a ball end mill if he wanted to go to a machinist or buy a large spherical stone to make it easier at home.  He told me later that it fired right up with the old stator. I told him to be careful because it’s high compression and is probably going to overheat. He said he cut the head a little bit. I’d like to think he’s finally got something that will run, but he hadn’t checked squish before this as I had advised and shown him, hasn’t leak tested, and I told him I’d want to look for at least 11-12cc in the head and offered to give him plexiglass if he just picked up a syringe at Walgreens or something but he didn’t want the plexiglass. He seems to just want everything running ASAP. |
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Post by oldgeek on Jun 18, 2024 17:27:25 GMT -5
And somehow, sometimes they get a real runner. Just slap it together and go!  |
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Post by aeroxbud on Jun 19, 2024 3:13:53 GMT -5
And somehow, sometimes they get a real runner. Just slap it together and go! But for how long? 🤔 |
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Post by 90GTVert on Jun 24, 2024 20:43:19 GMT -5
I cut and assembled ANOTHER Honda bottom end today. He said the AF18 that I did last wasn’t going to work because the crank is too long. He couldn’t get it to work with the CVT cover and kick start and there was some issue with the variator. When I look up info about the AF18 I only see the issue we found on assembly with the crank seal.
Even stranger; he said this is an AF18 too. It’s just like the other big crank Honda cases AFAICT.
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Post by aeroxbud on Jun 25, 2024 3:39:44 GMT -5
I think he has a side line selling bored out Honda cases on Facebook.  |
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Post by 90GTVert on Jun 25, 2024 8:18:29 GMT -5
I think he has a side line selling bored out Honda cases on Facebook. Yesterday, he said we could get engines and cut them and then sell them as strokers. Yeah, he'd buy them and I'd do all of the work and we'd split the profit. lol I'd have to do that on my own because they would need to be quality all the way through and by then the 90cc BWSP engine for $1100 that includes new everything would make more sense to most people since he's not finding cheap cases. $400 for a whole Dio is great, but not if you just want engine cases. Next cheapest he was looking at was someone wanting $300 for cases. None of these are nice clean stuff. One has an exhaust tab broken off to be welded back on. I tried to tell him last night that at this point he should have just bought one of the ones he's been looking at. He thinks he's saving money this way, but I've personally cut and assembled 3 bottom ends now and did a quick finishing pass on another that was ruined when he sanded the sealing halves after a weld job for a crack. One is in his scoot running, with the case halves welded together. The one from last night is going to be a spare. Then the AF18 that didn't work out is supposed to get a crank that someone says will fit it. One will be liquid cooled, but I don't know which... and don't think he does. I don't think any of these have been leak tested. They really should be for many reasons. Hoping he doesn't keep having failures like he's talked about in the past from overheating... but if you won't leak test and reuse old seals and weld parts of a case together and don't cc the head you modified and... I think he'd be better off leaving all parts with me and giving me the time to assemble it how I would for my own stuff rather than pushing to get one engine apart, another cut and together, swapping out seals and bushing and bearings while he waits. He wants to do it himself though as much as he can. Says he knows the consequences of things, but doesn't stress over them. To me, you kind of have to "stress" over the details if you ever want it to be a good engine. I'm even bothered by the fact that I have to go from cutting and chips and stuff all over the place to assembly. I do a very quick cleanup of the immediate area (board that I do some stuff on so I don't tear up the bench). For my own or anyone that gave me the window to do it my way, the entire bench gets cleaned up and all tools are cleaned before I do any assembly because I don't like dust and grease and chips around when an engine goes together. On the bright side, he was trying to clean up a little while I was switching from cutting to assembly and said he's been around me too much. He also cleans them up before he brings them now because he said "he's gonna kill me if I bring this thing all nasty". lol Not why I'm doing this, but I mentioned wanting to do something with painting a scooter but said I'd probably just sticker bomb it and clear it because I'm no good at paint work. He said he could paint it... that's what he does for a living. I said yeah, but painting is expensive. He said yeah and how much does cutting a case cost? I said, isn't automotive paint expensive? He said if I have something leftover from a car and you like the color, you can have it. I've seen his scoots and others that he painted and they look nice. Might have to give one of the scoots sitting in the corner a makeover. |
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kosmos
Scoot Enthusiast
Posts: 108
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Post by kosmos on Jul 1, 2024 23:57:56 GMT -5
Anyone have a reasonably priced source for AF18 seals for large (20mm) cranks? Looks like it should be 20x25.5. I found a site listing conversion seals for $35, prob plus shipping. He’s not gonna pay that. I’m thinking if all else fails, maybe a 20x25 seal with sealant on the outer edges or a 20x26 if it will go in without deforming. I’d prob just buy the conversion seals, but I’ve also seen plenty of leaks from new seals that fit as intended when leak testing. this says it is bearings for the stroker crank, thinner bearings, and seals for the stroker.
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kosmos
Scoot Enthusiast
Posts: 108
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Post by kosmos on Jul 2, 2024 0:06:31 GMT -5
I cut and assembled ANOTHER Honda bottom end today. He said the AF18 that I did last wasn’t going to work because the crank is too long. He couldn’t get it to work with the CVT cover and kick start and there was some issue with the variator. When I look up info about the AF18 I only see the issue we found on assembly with the crank seal. Even stranger; he said this is an AF18 too. It’s just like the other big crank Honda cases AFAICT. there is an issue if you switch to the dio type transmission into an af16.. I've never heard about af18's whether they use the elite type cvt or the dio one. the difference is a smaller driven pulley and shorter thinner belt. the thicker belt sticks out more, have to have a longer drive boss, etc. the cvt cover needs spaced out to accomodate that, and its about 3mm. if thats what he has done, af18 i think can have the elite version of the cvt stock, you need to.. grind out the cvt case to fit the larger belt, and use a spacer. gaskets cut them out yourself 3mm thick stack them up or, CVT spacer linkOR, he can just put the honda elite type cvt, drive boss, front face drive pulley, and driven pulley and belt. each of those are different than the dio version.
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Post by mopedmofun on Jul 11, 2024 8:48:14 GMT -5
Brent, I have ALWAYS wondered why you build up Chinese bikes, is there any specific reason? I am a total noon compared to you, but only search out Japanese or Taiwan. Kymco, Honda, Yamaha. Italy intimidates me.
Is it cost or ownership? Just what you found?
Just curious?
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