Planet Minis

CrawlerD

I have a bunch of older Zs and a couple Cts and I hate points. I have never seen a very good description and a breakdown of the possibilities. I don't know if this is possible anyone have any info?

Dan, I know you hate points too. How are you planning on converting your atc 70?

Z

Here's the easy way and these supposedly work pretty good.

eBay Motors: HONDA CT70 ATC70 SS50 Z50 XL70 CDI Electronic Ignition (item 120252327971 end time Dec-19-08 19:59:50 PST)

I'm going to run one of the above soon and will do a full writeup after I do the conversion along with pictures. Give me a month and I'll give everyone a report. They have good reviews from the ATC crowd, but I see the Z50 crowd being no different.

While I'm running that piece, I'm going to pick up a Honda TRX70 engine that are 12V CDI from the factory and build one of these bad boys up for a big-displacment build for the ATC.

You can also grind your inner cases to clear a CDI pickup and run a Stator from a CRF50 from Ricky Stator and convert the 6V motor to 12V if you want to purchase a crank adapter or swap in a 12V crankshaft.

The tapers on the cranks are different between the 6V and 12V engines if you weren't aware of that.

That's my 2 centavos on the subject.

mexicanyella

That Ebay seller doesn't mention different crankshaft tapers between the
3-speed and 4-speed 6V motors. Hopefully he sorts that out for the buyer while he's sorting out which tailor-made CDI box he's including in the kit, but other than that it looks like a pretty slick setup.

Any of you points haters are encouraged to PM me with offers to sell a 4-speed points ignition with spark advancer. I love points. I also love centrifugal force, and when my favorite kind of force is used to alter a timing curve in which my favorite mechanical current interrupter is activated...I just live for that. I've got at least one need for one of those ignitions right now, so let me know if you'd spare one in your panicking haste to rid the world of mechanical contact breakers.

Z

The overseas guy has 4-5 different setups to address the Hitachi, Mitsuba and other flywheels along with the L and S crank tapers.

For me, this is just a quick fix until I install the Honda 12V CDI setup out of a TRX70 with the 12V TRX crank and add the 12V lighting and voltage regulator for night riding.

mexicanyella

What are the L and S tapers? I've seen the Hitachi (3-speed fixed timing, I thought) and Mitsubishi (4-speed w/spark advancer). Are there yet more variations, and are they in 6V?

Z

S cranks are the 3 speed 6V cranks. L cranks are your 4 speed H 6V variants. Type R cranks are the 12V cranks. There was also a G crank that was produced on some 6V Honda monkeys overseas between the L and the R cranks.

When I'm motivated, I'll post up some pics showing the different tapers.

Here's a rather large pic of my ATC70 flywheel. This slighly differs from the 3 speed and the 4 speed "H" engines. The bolt holes are for the pull start bracket.

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CrawlerD

If you are the "Super Hero protector" of the points then I am the super villian he11 bent on the destruction of all points and won't be satisfied until "CDI" rules the the world. DESTROY ALL POINTS! Haha

CrawlerD

Not to hijack my own thread, but -Dan is it possible to lose the pull start on a 86, 87 trx? My guess is the cases are totally different and flywheel too wide for covers, and no provision for kickstart output shaft, but haven't studied one to look closely.

Z

If you had a complete 86-87 TRX70, there is no provision for a kickstart since there is no hole. This would easily be remedied by using your Z50 or CT70 clutch side case, but you would have to find a kickstart shaft and gear to match the TRX70 gearbox.

On the flywheel side, you could use a 12V CRF50 side cover and cut off the gear indicator shaft or drill a hole in the case where it sticks through. Look at the above pic and you'll see the N on the case with the shaft.

CrawlerD

Oh forgot about the indicator.

I have a line on one and think I might pick it up. I like those 12v motors.

Thanks for your help guys.

mexicanyella

regarding the indicator shaft, on my late 70s ATC 70 motor the shaft itself appears to be a weird bolt that just screws into the shift drum where there'd normally be a normal hex bolt and rubber plug. I haven't split the cases yet, but that's what it looks like to me.

I don't theeeeeenk the ATC flywheel is different in size once you unbolt the pullstart cage from it, but I don't know if replacing the indicator shaft with a regular shift drum bolt would allow a bike cover to bolt on. I suspect it would, though.

Regarding ridding the world of points, just think of me as the director of a large, remote points containment facility in the rural midwest. Sending that stuff to me just makes sense, especially when you factor in the small, negotiable points surrender reimbursement that's at hand.

While I take great pains to operate this facility in an eco-friendly fashion, and am dedicated to spreading goodwill throughout the legions of points disposers out there, I will be fiscally unable to reimburse EVERYONE who surrenders a points ignition to my facility for disposal. But I am prepared to discuss reimbursement with the first few, as an incentive. The early bird gets the worm, as I'm sure you know.

dirtbkr188

Here are two pics of a TRX70 engine converted for use in a bike. I used a Z50R kickstarter shaft (22T pinion), removed the indicator and replaced it with a bolt and rubber plug, and used regular XR/CRF clutch and ignition covers.

Z

It appears I'm an ATV engine noob. Good info Tim.

mexicanyella

Okay, now how about someone who's successfully modified a 6V case half to accept the 12V ignition pickup? Anyone who's got photos to show what needs to be cut, ground, drilled, tapped or whatever?

(In the event that you had swapped a 12V crank into 6V cases...)

thorwarrior915

Tim must have missed this one... I'm sure he has pictures. All you have to do is grind away some of the "webbing" near the countershaft sprocket to clear the pickup coil for the 12V stator plate. Its a minimal mod for an awesome upgrade.