Author Topic: RT2 Ignition--need a cuppa & a lie down. (Read 8564 times)

OverTheHill · « **on:** May 11, 2015, 08:12:41 pm »

Building a dunga out of bits that are 'past their useby' date [by 40 years or so]--anyway, story is i had no points primary source coil so was going to go total loss battery & points with an RD type secondary coil. Then got thinking, i have a yz stator plate from the 1980's that bolted straight on [3 slotted screw holes] but was stuffed in the main source coil although ok in the other [trigger coil--looks the same but slightly smaller]. Had a rotor of a very early YZ with two little magnets out near the edge but the big magnets lined up where they should. Tested & got about 10 [peak] volts at a good turn of kick start so had a battery powered cdi box of a kxf90 quad which luckily i'd written down what wires go where etc. Then thought it possibly doesn't need a battery powered secondary coil seeing it's called cdi [even though battery powered] & not tci. So hooked up a kdx200 plug coil & sparks great. Ran the battery through a 5 amp meter just to see how much the box draws & actually hardly moves the needle--actualy thought it wasn't moving at all initially. So still not sure if i'm onto something [time will tell]. If it 'does run' it looks on the face of it like you'd charge the battery once a year [yeah rite]. Got more 'jack ups' to do before it's a runner but watch this space. It'll be 'so' ugly but just thought--i think there's enough bits to get 'one more' running so i've gone too far to not carry on now. Cylinder has a YZ400F [82mm] piston in it--stock std ports]. Bottom end, gearbox etc is unknown--just found it wrapped in a rag in my junk shed, feels ok but who knows. Set the piston at 2.5mm btdc as a starting point then put a degree wheel on & marked the spot then turned the rear wheel & strobed it then moved the rotor to get it right. Just thought though [bugger it] the kxf90 is a 4stroke so should advance up heaps which i don't want--so 'stand back'--she might blow. If all else fails i'll revert to the flywheel & points with battery--needs a heavy flywheel realy!!. I've seen cheapy performance 2 stroke [i hope battery powered] cdi boxes on trademe & ebay so might have to chase one. Anyway--long story about not much [yet] sorry.

jimson · « **Reply #1 on:** May 12, 2015, 12:46:05 am »

I like the sound of this build. I'll be watching & might even have a spare Cdi unit for you Overthehill. Jimson

OverTheHill · « **Reply #2 on:** May 12, 2015, 08:36:53 am »

Thanks Jimson, i have a few cdi option i'll try if all else fails. If i 'realy need a flywheel to tame it for easy kick starting then i'll look for a cdi source coil to [hopefully] fit the DT1 stator plate & if it produces 150/160 peak volts it should fire a secondary coil with built in box like of a LT50 quad or JR50 two wheeler. Did that once on a DT125 watercooled trail bike that had destroyed the trigger coil [screws fell out of lighting coil--bought it not running]. Didn't even have to alter the firing point as was spot on. Anyway--getting way ahead of myself. With this bitza somebody has chopped out the left front downtube damn it but will worry about that last. Never intended to use this frame but is my last one & looked totaly unmolested till someone did that. Cheers.

OverTheHill · « **Reply #3 on:** May 19, 2015, 12:31:58 pm »

Finaly got this total cock up running [not a pretty sight so ignore it or have a laugh at my expense lol]. Fired it up just now--you know how it goes, the exitement of the first start up not knowing if it's going to go!!. My ignition system worked a treat BUT as i suspected might happen [or the oposite actualy] it retards off big time. Idles perfect then climbs the wrong way so reversed the pulse coil wires thinking she'll advance now but no--just the same. Box is from a Rh side set up & this is left side so spinning back to front sort of. What i wanted was [is] a box that stays static in the timing!!, next trick if i can't overcome it is to use the box of my long retired toyota grande "82 two litre which had a mechanical advance destributor. Anyway BUGGER!!, having a cuppa & a think--yes dear i'll go & mow the @##$%%^ lawns before it rains.

Iain Cameron · « **Reply #4 on:** May 31, 2015, 12:20:54 pm »

I know its a weird question but what has happened to the frame down tubes . Iain

OverTheHill · « **Reply #5 on:** June 01, 2015, 06:18:01 pm »

Quote from: Iain Cameron on May 31, 2015, 12:20:54 pm

I know its a weird question but what has happened to the frame down tubes . Iain

Hi, probably weird answer lol. This is how i bought it. Came with other related RT1/2/3 stuff many years ago. Apart from that problem the frame looks good & unmolested. Would be interesting to know the reason but the old chap has long departed this world unfortunately. Got given a very rough parts motor last week with a mag on it & a few other handy bits but still going to persevere with the crazy ignition system till it gets beyond me. Haven't had a chance to get back to it lately but hopefully soon. Cheers. ps, must remember the frame before i start pulling wheelies up the road--if i get that far.

OverTheHill · « **Reply #6 on:** July 25, 2015, 06:16:27 pm »

Forgot to tell ya ][not 'that' exiting lol] i finaly got my old 'bitsa' going, gave up with the silly battery cdi nightmare & put an original mag on it i got given. [easy way out]. Anyway, headed off down the road only to find top gear is poked [bent selector & rounded off dogs slipping or barely touching in this case. Apart from that it goes like hell--for a petty much std motor albeit bigger piston & carb. Couldn't face pulling it apart just yet so geared it higher front & rear to avoid 5th. Welded a tube in,-in place of the missing frame tube but will weld it better when i take the motor out [just used waterpipe]. Used it down to the farm every day for a while & just love riding it as plenty powerful in an almost lazy kind of way but like everything around here it'll always be 'work in progress'. Mag came off a complete rusty corroded motor a mate gave me [just at the right time] but now i'm thinking if i just had 'one more' frame i think i've got just about enough bits to do another one--or not--.picks to follow, for a laugh.

OverTheHill · « **Reply #7 on:** July 25, 2015, 06:21:34 pm »

OverTheHill · « **Reply #8 on:** July 25, 2015, 06:30:17 pm »

Note the DT2MX clutch lifter which was a lucky score off ebay which of course had the split plastic worn as they all do in the end but is working good enough. Also you might spot the RH fork slider is back to front [only had two left side forks lol] & you 'won't spot' the steering head main bolt is the crank pulley bolt out of my Honda Vigor parts car [Honda Vigor No4--True, it's an illness, like RT/DT's].

OverTheHill · « **Reply #9 on:** July 25, 2015, 06:39:31 pm »

Iain Cameron · « **Reply #10 on:** July 25, 2015, 07:29:16 pm »

Nice , you have got to love these old girls and once they are in your blood that's it your addicted . Whats the carbie to air cleaner off . Iain

OverTheHill · « **Reply #11 on:** July 25, 2015, 08:29:31 pm »

Carb--trying to think, bing obviously but about 35 years ago a guy gave me two, a 36 & 38 & think he had an ossa or montessa, don't think a bully--anyway, 38 was on loan for a few years then he needed it back but left the 36, measured it the other week & is 37+ & can just remember boring it at work. Only has one float too & never misses a beat. Had it on a DT1MX top end along with the airfilter [inside a homemade cover] on a a YZ250A bottom end & YZA frame [long story] might have a pic of that nightmare--actualy was damn good to ride but since sold.

jimson · « **Reply #12 on:** July 25, 2015, 08:43:04 pm »

Looks good,I like a dirt bike with character.looks lived in & has a history cool

jimson

Momus · « **Reply #13 on:** July 26, 2015, 12:33:56 am »

You like a good earth when welding I see.

Is that new down tube nothing fancier than 1/2" NB water pipe with the gal. sanded off arc welded in?

I hope so. Anything fancier will hurt that bikes venerable character.

OverTheHill · « **Reply #14 on:** July 26, 2015, 02:43:15 pm »

Quote from: Momus on July 26, 2015, 12:33:56 am

You like a good earth when welding I see.

Is that new down tube nothing fancier than 1/2" NB water pipe with the gal. sanded off arc welded in?

I hope so. Anything fancier will hurt that bikes venerable character.

Are you sure you weren't sneaking around while i was 'performing this faultless repair'. Galve pipe de-galved [hate welding galve] bend was nearly right so in the vice with a fork leg tweaking it, flared the frame slightly & tapped the pipe in a bit so not exactly butting it as to avoid blowing holes. Anyway, it worked, & don't have to worry now when pulling wheelies up the road [which i forgot about the frame in the initial exitement of the maiden voyage [immediate wheely lol] then--jeez--the frame--creep home. When i get around to fixing the gearbox [top gear--overdrive on these boxes] i'll weld the frame up better & overlap the joints with probably a couple of bit of handlebar cut longways arc them up. It'll work, for what it is [whatever it is].

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