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Post by Fox on Sept 29, 2015 0:25:15 GMT -5
There's been some "discussion" about how long a top end install takes. I said I can do one in about a half hour and I got flack for it from one member but the truth is that's really about all it takes but until tonight I didn't elaborate as to why I can do one so fast. I'm talking about installing a BBK or new stock top end on an engine that has already had the old top end removed. The number one reason would be repetition. You do things enough you get faster at it. Simple yes, but not the whole story. My second reason for a fast top end swap is a magnet on a stick for when I slide the jug onto the studs. I stick the magnet through the cam pass-through and grab the chain at the end as it's hanging down and pull it through the pass-through and just let go of the magnet. It holds the chain so it doesn't want to slide back toward the motor. Then I do the piston ring compress with my fingers and once the piston starts sliding into the jug, with one hand I use the magnet pull the chain taught so it can't hang up on the cylinder and with the other hand the cylinder slides on easy peasy. Once the jug is seated on the engine, then install the lower chain guide and position the chain so it's resting on the lower guide and hanging down. Then install the two dowels and stick the magnet through the head gasket and slide the head gasket onto the studs and immediately I do the same thing with the magnet through the cylinder head pass-through and slide the head on. Once the head is seated, install the last two dowels, grab the cam, recheck the T mark , install the cam, recheck the T mark and cam holes, two dowels, rocker assy., tighten the 4 head nuts and the two long bolts that were loosely installed with the jug, Once they are all tight, cam chain tensioner, rotate the engine a couple times, set valve lash, install valve cover blah blah blah. That simple little magnet on a stick reaching through the pass-throughs and grabbing that chain and pulling it through the holes real fast makes a huge difference for me. It's not a "specialized tool" but it sure does make the whole thing so much faster and easier. Everyone should try it once.  |
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Post by spaz12 on Sept 29, 2015 0:44:28 GMT -5
When I built 4t's (hopefully that'll never happen again) I made a T handle with a small hook on the end out of a metal coat hanger to grab and hold the timing chain. It worked great and was an free, easy to make specialty tool. I didn't NEED it though. Just something that I made up to make things easier.
I'm sure that as many people seen that thread and not one called you on your time, it's safe to assume that many of them can, or have, done top ends in the time that you mentioned. Just because a new guy can't do it, doesn't mean that it can't be done. I think the first time I did one it took me about two hours and that's because I was trying to remember where everything went, and because the motor was still attached to the bike.
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Post by Fox on Sept 29, 2015 1:00:02 GMT -5
Yes a coat hanger with a little hook bent on one end is good. I like the magnet cause there's no need to hook it onto the chain and it has some mass to it so you can let go of it and the chain doesn't wanna slide back down the chute while you are inserting the piston into the jug.
Either way it's about that old saying:
"work smart, not hard"
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Post by spaz12 on Sept 29, 2015 1:08:22 GMT -5
True, sometimes the weight of the chain wanted to pull my tool back through if I was just letting it hang.
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Post by katastroff on Sept 29, 2015 4:11:28 GMT -5
-A good working environment: Lighting, workbench, organized toolbox, music, no cell phone, no wife around...
-Being prepared: "oups! forgot to buy oil."
-Getting info: read how-to. watch videos. read on other peoples BBK installation and see where they struggled so you can avoid th same mistake. Listen to advises...
I'm probably forgetting stuff but i'm sure others will fill in.
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Post by 90GTVert on Sept 29, 2015 8:14:36 GMT -5
Good tip. Thanks.
For people new to this work... or even those experienced... planning a BBK in 1-2 hours is just a bad idea IMO. I'm not saying you can't do it. I'm saying if a new rider plans that 2 hours before they have to leave for work on the scoot that they'll start installing a kit, it's a terrible idea. It takes me the better part of a day to do. Stuff like checking ring end gaps and cleaning mating surfaces adds up, but a lot of it is that a good install is complete only after the carb and CVT are tuned IMO and it's not a big secret that I don't believe in any plug and play jet size or roller weight that works on all scoots so tuning passes take up a lot of time.
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Post by Fox on Sept 29, 2015 10:24:21 GMT -5
-A good working environment: Lighting, workbench, organized toolbox, music, no cell phone, no wife around... I'm probably forgetting stuff but i'm sure others will fill in. I have to agree. For me, having NO distractions is also key to completing any mechanical work quickly and correctly. I have told so many customers that want to stand there and talk to me while I'm working on their scooter that if they continue do that it's going to take longer and I may lose my place and forget to tighten something. I do my best work when left alone. A radio in the background or a TV with the game on is okay but other people talking to or around me can be a major annoyance. Good tip. Thanks. For people new to this work... or even those experienced... planning a BBK in 1-2 hours is just a bad idea IMO. I'm not saying you can't do it. I'm saying if a new rider plans that 2 hours before they have to leave for work on the scoot that they'll start installing a kit, it's a terrible idea. It takes me the better part of a day to do. Stuff like checking ring end gaps and cleaning mating surfaces adds up, but a lot of it is that a good install is complete only after the carb and CVT are tuned IMO and it's not a big secret that I don't believe in any plug and play jet size or roller weight that works on all scoots so tuning passes take up a lot of time. Right but I was just talking about the time it takes to install the new parts. If you wanna add the time it takes to go from a running 50cc scooter to a running 80cc scooter, then yes, you can be talking a whole day or more. I think too that some people are just better suited for this kind of stuff than others so they are faster for no other reason than their brains work faster. People who have never done a BBK before or are just not mechanically inclined shouldn't go in with any time frame expectations, especially if they are prone to fits of anger or they have been drinking or smoking something. |
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Post by 90GTVert on Sept 29, 2015 12:14:52 GMT -5
I knew what you meant, but just had to throw that in anyway. I'm definitely one of those slow-brained people. It's never paid for me to rush mechanical jobs.
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Post by Fox on Sept 29, 2015 13:09:44 GMT -5
Here's some other things I have learned along the way to help speed things along. When you pull off the carb and intake to get the old jug off the engine, you don't have to separate them. You just remove the intake and carb as a unit and move it aside toward the back wheel leaving all hoses and the throttle cable attached to it. You don't even have to drain the carb. You don't need to remove the air box either. Just loosen the clamp and it will separate from the carb when you lift it off. Then the whole unit goes back on in no time and it's full of gas and all tubes and cables are already done. Two nuts. Boom! done. You don't have to drain the oil to replace a top end so those of you who might be doing so, you can skip that step unless you over-filled it. A can or two of carb cleaner and some rags sitting on the bench are a good thing for cleaning off oily residue etc... On most scooters you don't have to completely remove the exhaust pipe. If the muffler has clamps then I just loosen the front clamp and remove the rear one and the pipe will move out of the way and go back on in a jiffy. On pipes with two long bolts holding the rear part, many times you can get away with removing the lower bolt only and loosening the upper bolt and it will swing out of the way enough to accomplish the task. One of these not-so specialized tools is helpful in removing the old gasket from the engine if it's stuck on there followed by a light sanding to make it smooth and your in business.   |
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Post by derbiman on Sept 29, 2015 16:47:46 GMT -5
Hell, I usually just tie a piece of mason's string to the timing chain. Lol But everyone does their own thing. Whatever works. Like Fox said,you get quicker with every one that you do.
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Post by blaq on Sept 29, 2015 18:45:55 GMT -5
I use a zip tie to hold the chain lol I use to use a coat hanger type wire but it got in the way sometimes and wasn't flexible
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Post by ams417 on Sept 29, 2015 20:07:21 GMT -5
I'll say this, I learned a lot the first time. I have a pretty good aptitude for the mechanical. The second time was way faster because I knew what I would need in the way of tools and parts. On a 2T it's very, very simple. I've worked on a lot of different types of engines, but scooter are still kind of new to me. Now that I've completely rebuilt a couple there is no fear of the unknown.
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Post by Deleted on Sept 29, 2015 21:27:23 GMT -5
The Wood Brothers could do it in less than 20 minutes. That would also include an oil change, new tires, and a carb rebuild. Well, back when they were young...
Bill
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Post by ams417 on Sept 29, 2015 21:29:56 GMT -5
The Wood Brothers could do it in less than 20 minutes. That would also include an oil change, new tires, and a carb rebuild. Well, back when they were young... Bill I bet these guys could do it in about 37 seconds... youtu.be/gKF6dcKjLJo |
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Post by spaz12 on Sept 29, 2015 21:38:15 GMT -5
Wow lol!
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