Sc500 fit into a MX 360/250 ?

[Freakshow]

Question i am thinking of borrowing the motor out of my Sc500A and putting it in my  mx250/360 FT champion frame and run it in the DT open class this year for a change ( currently has a MX 360A motor in it) before i go pulling every thing apart and finding nothing lines up, can any one tell me off the top of there head, actually better still can you confirm that the bolt holes line up so it will fit straight in and the width of the case mounts are the same spread width ?

AS it has a mx 250/360 set up one can assume if a sc550 would fit in a normal MX 250/360A mx frame it would be the way to tell for sure....anyone ?

for the part number freaks, will a 363 motor fit into a 354 or 365 frame 

[firko]

Bolts straight in Freaky. In the bleak old days I put an SC500 engine in my ROAD registered DT250 and rode it around for a few weeks until the novelty wore off. Later, I took the same engine out of my Champion frame and replaced it with a 250 while I rebuilt the 500. No probs at all.

[Freakshow]

Sweet.  Im assuming ill need to take the electrics with it.  The CDi should go with the motor cause of the curve in the stator etc, but the coil in there already should be ok from the 360 yes ?

this Sc i have has been too nice to ride, only started it etc, but i think its safe to say it should be used some more and i reackon some interesting things could happen if i run it this year, 4 speed box might even make it perfect for DT. 

I just hate seeing bikes i have with good bodywork sitting around cause im not ridding them for fear of gutting the paint ( after my TM tank experiance - dirt on my knee scratch the life out of the new tankin one moto...Doh)  so reusing the motors in USed Rollers and borrowed for short term projects on the way should keep the MX gods happy that they arent garage queens.

Have i missed anything ? same pitch front sprocket/chains. If the motor comes out as a complete unit im guessing i just need to clip on the Acecl cable, hook the chain up and hang on ?

[500Fool]

Why would yoo want to? Arms not long enough? 360 vibrations only put your arms to sleep, you want your whole body noddying off? Sick of not repairing cracked guards? Chains lasting too long?

The advantages are you won't have a stretched throttle cable, you won't use as much fuel (who's goana hold it flat out in THAT frame), if the tanks big enough to contact your dangley bits yool get heaps of jollies (sort of like a 240 volt vibrator). Even if your deaf you can tell the revs by the vibrations, it'll start with horendous at idle and get worse. If your eyesights getting crook (if your an old bastard) it won't matter cause you won't be able to focus anyway.

[jimg1au]

Kerry
in 1974 Neil appolonie from Griffith mcc had a hagon sc500 it was very fast and totally uncontrollable did i say fast.it was fun to watch as the japs and jawas round him up in the corners but then he would point it in a straight line and he would catch them again.
cheers
jimg

[Tim754]

Yep have to basically lump the Yammie SC500 (Owned one in a in a MX360 frame a Long time ago) with the Suzuki TM400  and my oath yes... I most certainly owned one of the Cyclone Horrors ) OK SC500 was  not as lethal but a pig shitty mongrel still in their own right!!!! Stick to the 250/360s and enjoy........... Tim
PS Freaky I have evil (wet???) dreams of hanging on to a Champion framed TZ700 / 750 Yamaha . Thank you Lord Kenny....

[Freakshow]

Carn fellas its just sitting there wasting away.

In my sweet champion Frame it should be nice,  even handle, cant hurt to bring it out on the long track surely and see whats possible, been a while since i shat  myself.

party poopers.

[yzhilly]

Come on Freaky dont scared off by the doomsayers ,Stick it in & wind it on . Just get someone teed up with the video  camera coz i want to see it.

[Freakshow]

Though you was going to say teed up with an ambulance. 

hehe..... i realy like the 360 motor its snappy and ok, so i cant say the 500 could be as bad as all you say it is, im vurious to say the least, beside im still not happy this bikes are just sitting around in my lounge room its a total waste, i ttake on board the 500 might be a shitter on the mx track, but surely that motor can be put to good wheel spin power ?  If not who out there wants to buy a perfect Sc500A to collect or ride ? or transform it into a YZ500 replica...cough

[mx250]

Though you was going to say teed up with an ambulance. 

hehe..... i realy like the 360 motor its snappy and ok, so i cant say the 500 could be as bad as all you say it is, im vurious to say the least, beside im still not happy this bikes are just sitting around in my lounge room its a total waste, i ttake on board the 500 might be a shitter on the mx track, but surely that motor can be put to good wheel spin power ?  If not who out there wants to buy a perfect Sc500A to collect or ride ? or transform it into a YZ500 replica...cough

Freaky, my understanding is that the SC had one very undesirable characteristic; the over abundance of power snapped on pretty much uncontrolablly. I believe there are a number of things you can do to control this 'hit' and once controlled the SC500 is a half way decent MX'er. Heavy, but half way decent but typical of ALL 500cc two strokes - you better have it pointed in the right direction when you 'pull the pin'.

I believe the uncontrolability of the beast was mainly due to an ignition issue. There is a simply mod such as changing a resistor or such (I don't know the exact answer but I'm sure someone will 'chirp in' at this point). I'm sure a modern ign would cure the prob if you went to the trouble.

A late model DT400 CDI ign could probably be fitted to advantage.

I beleiev the other issue is that a 5 speed mx 250/360 gear box does good things for the beast.

With a little thought, some mix and match, a little weight lost and modern suspension mods, I'm sure you could have a YZ500 and at least something of a 'sleeper' (use the 360 colour scheme ).

If you don't want to do it you could always sell it to me, I would love to have a go.

[cyclegod]

The best ignition is the outer rotor PVL, the extra flywheel weight and modern design transforms things considerably

[vandy010]

i've just fitted a DT400 cdi to my RT1 and the rotor weighs in at 1.8kg
my motor is bog stock, just rebuilt and it's smooooth as! i love it just the way it is and i reckon that big fat rotor is responsible.
sorry, did someone say flywheel weight?
 

[Freakshow]

MX 2fity, im Putting it in a champion frame. its for the Flat track series this year, it will only be point shoot lean, any flaw as a moto are irrelevant, its going speedway style so if i can streach the power band out i think this thing should be worth a laugh, i have outgrown the power on the 360 on some tracks and its not getting the same drift it used to , thats why im wondering a little bit more power might put me back on my toes and less of the circlulating feeling.

I have never rided the Sc its just sitting here.  IM happy to sell the whole bike on if someone wants a big bore open classer, its in original A colours and condition, hence why im thinking about taking the motor out for a run this year and leave the body at home.

[Maicojames]

Freaky, a good friend of mine raced a 73 SC500 here in Texas vintage in 92-93, with two class championships. He holeshot every moto as well. The bike was as bought in 91 with an aftermarket weight on flywheel. I think even the counter balancer was removed. Only problem was, we found an NOS 2 nd over piston, bored it and ran new piston. It ran great with about 6 thousanths clearance on the worn out bore, but seized in moto two with new piston and 3 thousanths clearance. It was a beast with fresh top end-he used up clutch plates in it, though.
Anyway, we installed a spare MX360 engine, and he won the remaining races.
It was fun to see him smoke everyone on that "pig". I raced the bike with both the 500 engine, and 360 engine. With the 500 it was more like a 440 Maico with less fylwheel, the 360, I think is one of the best engines ever. BTW another club member raced another 73 SC500, at the time. It was immaculate, though he didn't ride it hard-he never had problems either.

 One concern is the very low hrs engine you have- it may not like to be spun far or long. I would be concerned about harming the engine to your potentially quite valuable bike. The bike Allen had was trail ridden several years, I think this lossened up the bore-we should have left it alone. Allen got a YZ250A after that, but never managed to do well on it-in fact he went better on my 74 250 Penton( KTM). For my experience, the SC500 gets a bad rap-it is as capable as the MX360, and this may piss off a few, but the MX360, and MX250 are as good as anything of the era( excusing the insanely expensive YZas, rare Monty VR250s, and more expensive 400-440 Maicos).
The MX Yammies are the best value you can have for Vintage classes in MX.
I hope you race it and have fun.

[evo550]

Freaky,
this link should get you into yamaha parts catalogue, follow steps 1,2,and3 and it'll get you into alot of info on tech upgrades yamaha produced 'in the day" for your SC including air leaks this model was notorious for, and piston mods on top of other things.
http://www.yamaha-motor.com/sport/parts/home.aspx