Vintage Dirt Bike Q & A

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 Post subject: Re: Poor performance
PostPosted: Mon Apr 07, 2014 9:34 am 
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Joined: Wed Aug 01, 2012 9:55 am
Posts: 24
Hi Ray,
yes I have put the original OEM ignition back on and it runs shit hot!! it's just this new uinit does not have a position mark on the stator for mounting on the actual engine.
The only marks are for the timing, one on the stator and one on the rotor these 2 line up at ignition point 2.3mm BTDC.
I haven't given up yet I'm determined to get this running as I intended.

stiff upper lip and and that stuff i'll keep ya informed


Regards Malcolm

P.S. it is only a matter of tenths of mm for or backwards on the stator. :idea:

_________________
1976 Yamaha TY80 X 2, 1977 Yamaha TY250 X 2, 1976 & 1978 Honda CR125 Elsinores, 2013 Harley Davidson 48 Special.
Range Rover Vouge Black Edition, a Little Smart four two and a shed load of other shit!!


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 Post subject: Re: Poor performance
PostPosted: Mon Apr 07, 2014 10:03 am 
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Joined: Tue Jul 29, 2008 11:02 am
Posts: 47
Location: Nashville, TN
Do you have a dial indicator you can set up on top of the piston to find true TDC and 2.3mm BTDC? I had to do the same thing with the PVL ignition on my MR250. Set it once, not a problem yet. Bike starts pretty easily and runs great! Their instructions give you a window of 70-85 thousandths of an inch BTDC, I set it right in the middle of that and tapped the rotor on to the crank. Then I had to tighten down the rotor on the taper, there's no key way anymore. Then adjust the stator so the marks line up. Had to re-set the piston to .077" BTDC to make sure I was still in the right spot after tightening down the crank nut, then line the marks up. Started after 2 slow priming kicks to get the fuel going on the first go.


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 Post subject: Re: Poor performance
PostPosted: Mon Apr 07, 2014 2:39 pm 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
Quote:
Their instructions give you a window of 70-85 thousandths of an inch BTDC, I set it right in the middle of that and tapped the rotor on to the crank. Then I had to tighten down the rotor on the taper, there's no key way anymore. Then adjust the stator so the marks line up. Had to re-set the piston to .077" BTDC to make sure I was still in the right spot after tightening down the crank nut, then line the marks up.

My friend bought a Powerdynamo CR125M ignition after seeing your pics and installed it on his MR175 using t.read's procedure above. I thought having no keyway would be a real problem since the OEM MR flywheel damn near cuts them in half, but it hasn't so far.

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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 Post subject: Re: Poor performance
PostPosted: Mon Dec 14, 2015 9:25 am 
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Joined: Wed Jul 27, 2011 12:31 pm
Posts: 38
Hey guys, sorry to dredge up an old topic, but I was interested in how that ignition ever worked out. An aftermarket ignition that keeps a lighting circuit for the mr series certainly has my attention. I've got a '75, '76 MR175, and a '76 MR250. I very much would like to maintain (and improve) the lighting of both of them, but really don't want to add a battery to do so if I can avoid it.

Thanks


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 Post subject: Re: Poor performance
PostPosted: Mon Dec 14, 2015 10:44 am 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
My friend installed the Powerdynamo ignition (looks identical to yours) on his 'MT175' (MT125 frame for road legality, everything else either MR175 or CR125M). Long story short, the motor felt very low on power compared to his other MR175 with CR ignition, so he began a dialogue with PD to try and figure it out. It turns out PD makes an optional advance unit (IMO absolutely vital for decent performance, I feel it's the main benefit of electronic ignition systems) with selectable advance curves for their CR ignition, which my friend bought but has yet to install. I don't have a direct link for the advance unit at the PD site, my friend said he really had to look to find any mention of it.

A modern laptop-type battery could be mounted to the seat pan with a charging cable accessible from the airbox, and would power a wicked-bright LED lighting setup at max output for at least 6 hours straight before needing a charge; it would also remove several pounds of weight from your crank and substantially reduce magnetic drag. Just sayin' :)

It's amazing the battery-powered things that are available these days - this one's in my garage right now (sorry, couldn't help myself):

http://i399.photobucket.com/albums/pp74 ... 202014.jpg

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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 Post subject: Re: Poor performance
PostPosted: Mon Dec 14, 2015 11:02 am 
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Joined: Wed Jul 27, 2011 12:31 pm
Posts: 38
I guess I'm just looking for a unicorn them, ha :( Oh well, I do see the PVL ignition kits for sale as well that have been out a few years in the $400 range, and fit the mr175, but I wonder if they also fit an MR250? as of recently, I've got an MT250 in the wings as well. (you can probably see where I'm going with this) The $400 price isn't as scary as it was a year ago since my home machinist business is starting to gain momentum as well. I suppose I'll just bite it and go the drop in route, and do the recommended battery for LED lights.

Thanks


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 Post subject: Re: Poor performance
PostPosted: Mon Dec 14, 2015 11:36 am 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
Apparently PVL makes an MT250/MR250 ignition, without lights (70032). I'm not sure if their CR250M units would fit, I'd probably go that route if the CR setups had more aggressive advance curves than the MT/MR ones.

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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