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| | | | | Gas Bicycle Engine Kits Most motorized bicycle engine kits are either a 2 stroke or 4 stroke. Both need careful installation and setup, find out from our professionals here! | Wristpin Bearing Upgrade? Discussion at Motorized Bicycle Engine Kit Forum in the Gas Bicycle Engine Kits forum. I've gave it some thought and I plan on using a bushing. Mine was loose from the get go ...  | | 
02-26-2008, 11:15 AM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 1,354
| | Re: Wristpin Bearing Upgrade? I've gave it some thought and I plan on using a bushing. Mine was loose from the get go I think, but it runs good still. needle bearings are good but why do the wrist pin and not the crank? I'm thinking maybe split the crank and have a look at that's in there as well and maybe re bush all with a quality bushing. Then again I maybe blowing smoke out of you know where. I'm going to start today as I might be back to work by tomorrow. My original plans were ride it until it drops then buy a new engine. But I got to liking this engine so I hope to breath more life into it but I might kill it on the sacrificial table to the God of speed. Well a quick look at the rest of the posts then off to the alter.  
Norman
aka Lord Vader( very heavy breathing and the theme song music as I walk to the shop)( and heavy meowing from the walking grease rag Rufus as we waltz off to the shop)
I need to get back to work.
Last edited by Norman : 02-26-2008 at 11:19 AM.
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02-26-2008, 01:22 PM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 1,354
| | Re: Wristpin Bearing Upgrade? The engine is off the bike and in the stand took 30 minutes to get it off the bike and on the stand now the fun will begin. Pictures will also start. I'll try to show how much slop was in the wrist pin bushing. I'm supprised it didn't come apart. Back to the shop.
Norman | 
02-26-2008, 01:29 PM
|  | ADMINISTRATOR | | Join Date: Dec 2007 Location: St. Croix, US Virgin Islands
Posts: 1,820
| | Re: Wristpin Bearing Upgrade? awesome! looking forward to it | 
02-26-2008, 05:35 PM
| | Master Motorized Bicycle Builder | | Join Date: Feb 2008
Posts: 224
| | Re: Wristpin Bearing Upgrade? yes. I have replacement bushings.. A few left. They are hardened ones. Thanks... | 
02-27-2008, 10:45 AM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 1,354
| | Re: Wristpin Bearing Upgrade? Dax
Have you found that the wrist pin hole is off set in the rod?! Mine is by a few thousands I made a jig so if I replace it I can get it back in almost the same spot. Notice I said almost. The wrist pin has no up and down play. Its still has no slop in the hole but if you take the pin, and push it to one side and wiggle it it will rock about 0.015. This is loose to me but I can't see any wear marks so this must of been that way from the factory as I don't have that many miles on it( mileage unknown) The piston and cylinder still look very good tiny bit of wear on the skirt at the bottom in one little spot. No blow by visible on the piston.
What type of bearing material is your wrist pin bushing made out of. I looked at your site and it says brass. Is it an alloy?
I have taken this booger all apart except for the crank as I would destroy the roller bearing getting them off to split the crank. I can see there is needle bearing on the big end so I don't think I'll mess with it and this crank has no bolt on weights its a 3 piece not counting the main shafts 2 flywheels and a main pin all pressed together best I can tell.
One thing I did find and I don't recommend anyone doing this and that is don't take the clutch pads housing off of the inner drive part its pressed together. When I pressed it apart 10,000 little renegade balls took off to the four corners of the earth and a few even acted like Curly from the three stooges. I had a long Easter egg hunt to find all of them something like 56 or so. What a time I had with that .
I'm really thinking about just putting it back together and running it cause as sure as I change that bushing my edge on Bob's bike will go away. So what do all you guys think I could show how to do the bushing but not actually do it. But what fun would that be, then again if I do I might mess it up and have a ho humm engine. I'm going to look and see what kind of bushings I can find here or stock that I can roll my own out of. that to me is the fun part.
Norman
Last edited by Norman : 02-27-2008 at 10:51 AM.
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02-27-2008, 12:42 PM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 1,354
| | Re: Wristpin Bearing Upgrade? I called Dax a while ago and learned some interesting things from Duane. I'm going to leave the wrist pin bearing alone as they are not as precision made as I would have liked( what is in my engine and not what he sells) and they are ran a lot looser than I like but what is the way it is. I still want to change it. I'm going on a gasket run and if I find the right bronze bushing stock I'll mess with it. I need to learn to leave things alone, sometimes I can but this is buggen me. I need to get over it. I made most of the tools to take it apart and put it back together again.
Ever have one of these days when you can't decide?! Its killing me. I took it all apart to do this now I'm not or at least I don't think I will.
I do have pictures to show you so I 'll do them soon. If I do need or decide to do the bushing later all you have to pull is the top off and not take it apart like I did. Well day is turning into night so I better get it in gear.
Norman | 
02-27-2008, 01:47 PM
|  | Moderator | | Join Date: Jan 2008 Location: Pampa, Texas
Posts: 1,368
| | Re: Wristpin Bearing Upgrade? You know you want to Norm. Go for it. You didn't go back to work today. I've heard no wailing and gnashing of teeth...... ......................
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02-27-2008, 08:40 PM
|  | LORD VADER Moderator | | Join Date: Jan 2008 Location: pampa texas
Posts: 1,354
| | Re: Wristpin Bearing Upgrade? Well I got a bushing and then decided not to change it as Duane talked like it was normal for the slop. Any way with the 36 tooth sprocket I will not need to wind it out like I have been doing. I'll wait and maybe do the bushing swap later I now have all the tools and jigs made to change it and the bushing I bought I'm taking back. I do have ideas on some cheap easy performace things now as well after seeing all the insides of this engine. By the way its all back together and running. I ran out of scrap gasket material and I bought some to do the crank case and it was $10.00. I was suppried at the price I almost was going to go to the gasket shop for more scrap but the round trip of 60 miles would cost that in gas.
The gasket for the crankcase is a booger to make and get right I made 4 patterns before I was happy with the results. It got the gasket right on the first try so the extra time was worth the trouble.
Norman | 
02-27-2008, 09:02 PM
|  | Master Motorized Bicycle Builder | | Join Date: Jan 2008 Location: north carolina
Posts: 3,758
| | Re: Wristpin Bearing Upgrade? I never could get a crankcase gasket made. I used some gasket seal and let it go at that. I wanted to keep the dust out not enter it in a bike show lol. I sure hope it works for that. | 
02-28-2008, 07:22 AM
|  | MODERATOR | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 4,073
| | Re: Wristpin Bearing Upgrade? Norman-
You probably know this, but next time if you want to make a troublesome gasket, spary some contact cement on the gasket material, then lay the old one on it. If you only spray it on one side, it's easy to peel the old one off and it doesn't move when drawing the pattern.
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