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you could also cut the top of the tube to the length you want, then thread it to accept the fork cap. After that you put in a racetech spring which is already short and use a spacer to get the proper height and pre-load.
You could also leave the forks stock length and rebuild them properly and maintain the appropriate amount of ground clearance.
 
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lol i didn't pull everything off just to slide the forks up and cut the tail. I am actually rebuilding everything. The forks' internals were shortened by 2", or rather shifted. Engine will get pulled out soon enough as well, taken apart, cleaned and re-assembled with new-ish components. The frame/electronics are all stripped because they will all be relocated. I am well aware that the 3 bikes i posted are more works of art than road legal motorcycles. My project will focus on the form first as well, but keep the function in mind in order to make it pass safety and get plated later on.

I do find it interesting however that there is so much hostility towards new projects on the forum. Given that cafe racers are at the end of the day custom motorcycles, that are primarily built to the liking of the builders themselves. So what looks "good" is very subjective. Either way not going to take this off topic.

Thank you for your input everybody, I appreciate any technical expertise and suggestions.
Your picture shows a non functioning bike, tubes slid through the triple, an angle grinder on the ground and the framing chopped off. All signs indicate another artsy piece of shit. You could have sorted the entire bike, before you took anything off, so you know what you have. The up swept exhaust, that's where you want it, out of the road. If it was an actual cafe racer you were trying to emulate then suspension behaviour and exhaust dragging would be two areas to be addressed. You want to degrade the handling and drop the exhaust, which is more likely to drag with your shitty suspension. The circle of strife.

Most "custom builders" and especially those calling themselves "cafe racer builders" are producing garbage that isn't worth riding. Virtually none of it would pass a proper inspection in Ontario. The bike in your sketch will not certify, I know my insurance company wouldn't touch it and moreover it would be a real pileocrap to ride. All flash and fluff, no real stuff. The problem with cafe racers is "that are primarily built to the liking of the builders themselves" and the vast majority like what doesn't work.
 

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Discussion Starter #24 (Edited)
Thanks for the replies. My purpose for posting on here was indeed to get technical expertise advice as I go through the process. Hence why i didn't just finish the bike and post a picture of the done product in the Pictures thread.

as a curiosity, because i have an interest in suspension without any great knowledge, how did you do it?
As for how i did it the video shows what was done to the internals. Right around 12:22 minute.

To summarize, the forks were already slid up into the triple tree about 2" from stock. I took them apart, cut a 3" piece off the main spring, used it to replace the rebound spring (a.k.a. shifting the resting depth of the fork), and cut a PVC spacer to make up the difference on top and add a little bit of extra preload. The forks do need new fork seals which i'll do further down the road, i want to sort out the engine first.

Here is a picture of one fork shortened and the other in its stock state and slid up to.
IMG_20181013_145618.jpg
 

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You could also leave the forks stock length and rebuild them properly and maintain the appropriate amount of ground clearance.
The only way the method I described would be appropriate is if you were shortening higher performance (but longer) forks in order to maintain geometry
 

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Post a picture of the crankcase damage. Do you have any idea how the damage occurred? Usually occurs because something really bad happened (like a brick wall). Begs the question... what else is damaged. Unrepaired frame damage? Remaining mounts cracked/damaged. To me, it makes no sense to spend money until you know exactly what you are dealing with.
 

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Discussion Starter #28
It is indeed a curious case of how the hell did that happen.
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I was planning on buying one of these and completely replacing the bottom crank case of the engine:
bottom_crankcase.jpg

There does seem to be a slight dent on the frame on that corner. Based on everything else i saw on the bike I would not be surprised if the engine had been taken out and dropped on that mount point, and snapped off. Alternatively it could have been some sort of other high speed impact like Cyorg said. The remaining mounts are in good condition. When I bought the bike it did run and I did ride it home for about 2.5 hours (which in retrospective was probably one of the more stupid things i've ever done, given the condition of the bike). So it would appear that the damage is only external. Disassembly will show the full condition. I mean for $400 CAD one can't really expect much.
 

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It is indeed a curious case of how the hell did that happen.
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I was planning on buying one of these and completely replacing the bottom crank case of the engine:
View attachment 95519

There does seem to be a slight dent on the frame on that corner. Based on everything else i saw on the bike I would not be surprised if the engine had been taken out and dropped on that mount point, and snapped off. Alternatively it could have been some sort of other high speed impact like Cyorg said. The remaining mounts are in good condition. When I bought the bike it did run and I did ride it home for about 2.5 hours (which in retrospective was probably one of the more stupid things i've ever done, given the condition of the bike). So it would appear that the damage is only external. Disassembly will show the full condition. I mean for $400 CAD one can't really expect much.
The cases are machined as a set, so you have to replace them as a set. You would be better off finding a known good engine. Way way cheaper in the long run. Keep in mind this bike will not be worth anywhere near what you put into it if you rebuild that engine. Plus you need to learn about a lot of things before you even take that engine apart. You need to know what to look for and how to measure things.
Read up on crank bearing selection just for starters.
 

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Discussion Starter #30
Good point, i've entertained the idea of grabbing a working engine or even a parts bike. I'm willing to learn and I'm certainly not doing this for the profit of building a custom motorcycle and selling it. Profit is not at all why I got into this. I have a passion for motorcycles, for the countless hours spent in the garage covered in oil, for the overwhelming gasoline smell of carbureted motorcycles. So all in all I have the time (not in a hurry), I have the drive, and i am willing to learn.

I never thought about the fact that the cases are machined as a set. I did notice that all the ones for sale are sold as a set, and it didn't click in until now. Thanks for the insight.

I managed to finally pull the carbs apart with the exception of 1 of them.
IMG_20181020_170710.jpg

I got one of the screws that holds the air box bowl to the carbs mostly stripped. I soaked it with all sorts of things and it would still not budge. Any suggestions on how to remove it?
IMG_20181020_171258.jpg
 

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you are not really supposed to take those off the airbox bottom(rack)...getting that screw out is literally going to be 50 times easier than re-assembling and having everything work right

...drill the head off, spin the the remains out with your fingers, needle nose pliers, vice grips, etc.
 

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Discussion Starter #33
you are not really supposed to take those off the airbox bottom(rack)
Do you say that just because there is a lot of parts and its complicated to re-assemble or there is an actual technical reason? I am taking everything apart to give a thorough cleaning. The only way to achieve that is to dismantle down to single pieces.

Lol woodsman that bike doesn't work and is like 4 hours away from Toronto. I am not about to go that distance to get another non working bike.
 

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I wasn't suggesting you were doing it for profit. That can be a very difficult thing to do. Just trying to keep you from getting buried too deep. As for stripped screws, get a good quality impact driver. I'm not suggesting you let lose with one on the carbs. Maybe with a bit of practice and knowing how to hold it and what you can get away with... it can be done on the larger fasteners, but you are better off drilling it (as previously mentioned) now that its knackered.
Make sure whatever tip you are using is a proper fit in the screw. Most modern good quality phillips bits will work with JIS screws (look that up). Not necessary, but nice if you can find some old T handled screw drivers. The best ones I came across were made by Kowa and sold through Honda.

ps. if you are going to buy an engine, before laying down the cash, pop the valve covers off and check the cams and followers for wear..... and when you go to adjust your valves in the future (assuming you don't come to your senses before then) you need a special tool to hold the cam while you adjust the valves.

Impact.jpg
 

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:I never seen anybody dismantle forks like that before, that was slightly painful to watch, did you finally figure out how to remove the stanchion tubes from the lower fork legs?

Will give you a hint; you do not need to pry it apart with sharp screwdrivers, wood chisels and gouges,
once you removed that allen bolt in the bottom of the lower fork leg you are ready to knock it apart.
 

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Buy an impact screwdriver like the one Cyborg posted above and save your JIS screws from damage, (I bought mine when I was 11 years old & it still works great) if the dome head screws get completely rounded :/ use a hack saw blade to turn it into a straight slot screw, drive it out with the straight slot bit on your impact driver and then replace it with the appropriate sized allen head machine screw that you can buy from somewhere like Brafasco.
 

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Discussion Starter #39
Haha ye, it was comedic. Eventually it clicked in that there was a snap ring in there, which i took out later on that day. I bought a hand impact screw driver, will attempt it later on today, but i fear its drill time already. I disassembled and cleaned one of the carbs, the idle jet as expected was completely clogged. A bunch of the screws on the carbs themselves have been stripped or all out swapped. So i'll have to replace most of them.

I did some research, and i don't have the means to do soda blasting or sonic bath to remove the harder residue from the carbs. So what would the experts on here suggest to use for a 24h-48h soaking bath? I've heard of all sorts of wierd things like gasoline, lemon juice, Sea Foam, Acetone, etc.
 

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It's a very strange and rare substance that you need, I once was told by very old and wizened japanese mechanic that this substance can be found at an auto parts store but that doesn't really make any sense and he was very hard to understand due to his strong accent...I think he called it CARB-R-8-OR CLEANER but I really cant be sure
 
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