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 Post subject: 74 MX360
PostPosted: Thu May 29, 2014 11:30 pm 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
Ok, long story short, my AHRMA club does NO post vintage events and I'm forced to get an older machine. I'm picking up an 74 MX360 this saturday and no fricking idea on what decent MODS to do. I grew up riding in the late 70's so this 4" suspension has me at a disadvantage. I realize the MX is porkish heavy has anyone ran other rims, or different forks or shocks from other machines and still keep the GOLDEN 4". I've heard of people running YZ400 ignition, removing the counter balancer (it's a MX360A) etc. I do have access to a SC500 and was wondering what everone thinks of that bike. Any help is greatly appreciated.


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File comment: There she is. I think I'm gonna leave the tool kit on the fender and put a Coors Light equipped sticker on it.
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 Post subject: Re: 74 MX360
PostPosted: Sun Jun 01, 2014 7:53 pm 
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Joined: Fri Jun 02, 2006 11:12 pm
Posts: 159
Location: Salinas, CA
I had some very fun races on my 74 mx360, or as I affectionately called it "the bus". The forks were terrible, but I bolted up 75 yz250 forks with air caps and they worked very well. I did remove the balancer assembly while I had the cases split and it ran plenty smooth enough for motocrossing. The bike remained very rideable and the vibration was no problem at all. A 38mm carb from a 1982 yz250 or some other bike in that range squeezed right into the stock intake manifold and gave the bike an wide mid range that built into an unbeatable top end surge. I did have Boyessen reeds too, but I really think that big carb made the BIG difference. Run a good set of rear shocks too with proper spring rate for that big beast. As long as it is well suspended, the extra weight will be manageable on a normal vintage track. Try to run it with boingy suspenders and you will hate it. I also ran a 1976 yz125 fuel tank and that made the whole bike feel more slender while enabling as far to the front a seating position as you could want. The nard pad I made from a section of my weight bench's flooring allowed me to sit on the tank. That was way better than being on the tank. You can replace the front wheel with any more modern yz front wheel, and I've heard of guys slipping in a 77 or so yz250 rear wheel too. These are heavy wheels it comes with stock, so you might help with weight there.


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 Post subject: Re: 74 MX360
PostPosted: Sun Jun 22, 2014 5:59 pm 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
I'm looking for another left side forkleg and I'll weld a tab on it to hve the brake lever going forward and not down. But HOLY $HIT what a difference with braking. This will be the best mod by far. It also lost alot of weight running the newer wheel. I'm waiting for my odd ball bearings to show up to run the rear wheel. The MX bearing is 17x40x12mm and the YZ is 20x42x12mm and I don't want to alter the swing arm and use the MX axle. I'm trying to make these mod's all bolt on so it could be switched back if needed. So I have some 17x42x12mm bearing on order and that should work, If not I machined some 3mm sleaves to run the OEM YZ bearing.


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 Post subject: Re: 74 MX360
PostPosted: Wed Jul 02, 2014 10:45 pm 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
After extensive research I received my oddball bearings (17x42x12mm) to fit the YZ250 rear wheel while still using the MX axle. I have one more spacer to machine and she'll be track ready. But I'm seriously considering the bigger carb (38mm mikuni), but I want to see how it runs before I make another purchase.


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 Post subject: Re: 74 MX360
PostPosted: Sat Jul 12, 2014 12:08 am 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
Ready to get jetted tomorrow. I'm going to try out some Kenda Washougal's for the first time


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 Post subject: Re: 74 MX360
PostPosted: Sun Jul 20, 2014 10:53 pm 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
Found this chain guide on eBay for $67, and after looking around I decided to install a Mikuni VM38 (used was around $65 to $75) and found this new one on eBay for $98 delivered and the tool box decal still cracks me up. But when I went to solder a wire coming out of the stator/flywheel cover I came across this mess which amazed me it ran, and ran damn well too. Well I just glad I caught it before my race. :shock:
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 Post subject: Re: 74 MX360
PostPosted: Wed Jul 23, 2014 8:46 pm 
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Joined: Tue Oct 29, 2013 8:10 pm
Posts: 12
Location: Cotati, CA
Last two, until post race. Thanks for the carb advice mrmikkelsen. You're absolutely correct it really changes it into a different machine. I'm just going to deal with the suspension for now. I may end up with another machine, but I'm having some issues finding parts now for a mass produced Yamaha, let alone a Maico, Husqvarna or Bultaco, but hopefully they make a rule change to allow some newer bikes. :D


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