OZ ATV :: The Australian ATV Forum

[Mart 300r]

Gday people chasing a complete wiring harness to suit an 85r.reason is ive put the stator and flywheel into my 500 engine and i need a harness with the round plug to fit the cdi i have.I wired an 84r cdi into it and it backfires and let me tell you if youve ever had a 500cc 2stroke kick back let me tell you it fu*ckin hurts nearly put me through the shed roof lol.I think the advance in the 84r must be very different to a watercooler one or something is a miss way to advanced an keeps kickin back.Any help with a harness or even just the male part of the round plug would help me out cheers.heres a few photos any way of what ive done so ya can get abit of an idea of what im rambling on about.





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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[HaggLE]

You cannot use a 250 cdi unit on a 500! Even a water-cooled one.
The 500 has totally different spark requirements than a 250 and different rev ranges. You need to use the 500 cdi unit

[bullet]

Maybe a degree or so less than what they run in the std 500 bike engine will help deliver smoother down low operation and definitely help avoid some kick back on start issues.
Put a timing light on it and see what you have for initial timing.
Check whatever literature you can find on the 250 and 500 initial timing.
Then check advance curves too... or retard curves... some 2 strokes idle with more timing and then retard with rpm.
So i agree with the just throwing a 250 set up on there, it might be quite a bit different.

If your pick up mounting holes are slotted, you might be able to manually adjust out your problem.
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Can-Am X Team
Bullet #Y12. MrsB #Y18.

[Mart 300r]

Ive spoke to alot of different people on this an belive it will work.As said above will just be a different power curve i think my issue is with the 84r unit i have because i know i have a few dodgy ones an id dare say ive picked up a shitty one.An yes my pickup plate i made is slotted an i retarted it heaps and it fired but i just wann get the cdi that matches this stator.I have no doubt it wont work as its fired but well see.

Thanks for the info bullet as said im not the best when it comes to electrics.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

Last edited by Mart 300r on Mon May 30, 2011 5:56 pm; edited 1 time in total

[Mart 300r]

HaggLE wrote:

You cannot use a 250 cdi unit on a 500! Even a water-cooled one. The 500 has totally different spark requirements than a 250 and different rev ranges. You need to use the 500 cdi unit

Where did you find this information have you had any experiances with it?
You cant use a 500 cdi they are digital or some sh*t and completey different.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[HaggLE]

The cdi will advance and retard as the rpm changes, in a 250 the variation wil be different to the 500 but more importantly it will happen at different rpm as the 500 revs no where near as high as the 250. It may be close enough, you just don't know. If the timing is too far wrong you will have meltdown which I know you know. I've seen to go wrong before with the wrong cdi setup and have had a programmable box programmed and seen the difference it makes.

But to answer your question... My brain.

[Mart 300r]

I understand the cdi's are programmer to advance an retard.but I can't see how it will be a big enough reason not to make it work as you stated in your first post.the reason for doing this is to help smooth the engine out.the same as all the atv manufactures engines I've played with have large heavy flywheels. Deffinately not doing this for performance. Oh well if it don't wrk I'll put it back stock. the bikes u wouldve done it on were on a dyno and on a race track where every ounce of performance is an edge.I'm not heading for a race track I'm just playin on a beach so as long as it runs I'm happy lol. I think you'll find a 500's redline wouldn't be to different to the 250 at guess I'd put both at around 9000-10000 rpm that's talkin 250r an cr500.not some off it's head road bike 250 or 500's that get raced with ur ol boy.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[HaggLE]

I don't doubt it will run, just keep an eye on the signs of internal heat.
U can't run the 500 pickup?

[Mart 300r]

Nah its all wired different ay.Heat is deffinately the worry if its advancing to far when it shouldnt be most of the time you can hear it but underload its gunna hurt it.sometimes i wish i just built a big 250r engine lol
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[Mart 300r]

After doin a heap of reading on this today ive found a big mod for cr500 owners is to modify the cr250 stators so they can run cr250 electrics and it makes a huge diff some are even using the 125 cdi's for different performance.So i cant see it being a big problem at all.And as i said above i thought the 500's cdi was digital but they arent they are analog.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[4stroker]

yeah the hot ticket for 5 hungeys is to run an '01+ digital CR250 ignition.

Mart sorry if i missed it but why arent you running the stock 500 setup?
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2002 SE Banshee

[Mart 300r]

4stroker wrote:

yeah the hot ticket for 5 hungeys is to run an '01+ digital CR250 ignition. Mart sorry if i missed it but why arent you running the stock 500 setup?

Gday mate how are ya?Yeh after doin a bit of reading up i found that was the ticket for the 500 hunge dudes.

Reason for doin mmmm dunno really lol,The counter balancer was workin sweet i was havin dramas with the outer cover comin loose, but i think it was due to a few factors with the studs and the shaft and the nuts i was using.They are all sorted now and they shouldnt come loose fingers crossed.So at the stage i had the engine pulled apart and hadnt done anything to it for ages(was flat out workin on trikes lol)But now the bug has bitten again.I think i wanted to see if it would help with vibes by adding a large diameter flywheel like most atv 2 stroke engines have.I was goin to run it without balancer setup to see if it made a difference that way i could help alot of people out by doing the mod.I know alot of 500 riders put the stealthy flywheel weights on their engine and seems to help with vibes alot but obviously lose the kick in throttle response.I dunno mate really if it dont work i can change it back without to much dramas.Also it gives me a lighting coil to so thats a bonus being a quad and we do heaps of night duneing.
At the end of the day i love trying different unique things whether they work or not its all in good fun, most of the stuff i know has been from trial and error mostly error lol but no harm in trying ay
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[4stroker]

furry muff mate!

extra flywheel weight should definitely be handy in a heavy quad chassis.

bit off topic, but what carb have you got on it?

most blokes on the bannedcr500 site seem to be pretty happy with modding the head, adding the 01 cr250 ignition, 39 pwk carby and fmf pipe.

i know you are trying the 85 ignition for different reasons, but yeah, thats what id be doin if i had a 500.

i reckon itd be the smick set up for in the dunes.

MX or trail riding though id probably look at what you are trying to achieve with the extra FWW.
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2002 SE Banshee

[4stroker]

just went up and looked at the pics again, looks like youve already got the 39 pwk!
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2002 SE Banshee

[Mart 300r]

Yeh 39pwk mate havent ran it yet brand spanka lol,fmf pipe stock head.It went hard with a bloody 34mm pj and a 250r ct pipe on it lol pulled like a train they are deffinately torque monsters.All im aiming for at the moment is reliability really,Then if all's good ill go searchin for more grunt.
Next mod will be decomp valve in the head an make reverse kicker gears but deffinately way to much compression without the decomp valve just smashes gears lol.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE

[Mart 300r]

Sweet just fixed the prob wired in my 85 r cdi wouldnt start couldnt get spark.Then finally remembered that that cdi shat its self just before i did the 500 conversion.(i shouldve remembered cause it was a massive push off the beach lol)Any way i thought bugger it this 84r cdi has to work tried everything retarted it another 12mm still kickin back hard.Then i picked a family friends brain lol and he said swap the pickup wires around green to blue.Bang first kick and away she went what i didnt think of was the 84r's flywheel is on the right hand side of motor therefor spins the opposite direction lol.So stoked i still do need a cdi out of a watercooled so if anyone has one that would be good let me know.
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1984 ATC 300R, 1986 TRX 500R,1984 ATC 200X, ATC 70 WITH CUSTOM LAYDOWN 250R ENGINE, 125CC CUSTOM THUMPSTER TRIKE