feetupfun Posted February 17, 2008 Report Share Posted February 17, 2008 I'm doing some renovations to my MAR and want to run the ignition wiring differently to where I found it (getting squashed between the bashplate and the engine cases) It seems obvious to run the wiring forwards and up the RH front downtube as I see was done to the MARs I see in photos with Mick Andrews riding. My query is how to route the wiring to the downtube. If I use the exsiting grommet slot directly underneath the flywheel but run the wiring forwards rather than backwards, I suspect it will get just as squashed as it did going backwards from that hole. If I make a new slot for the slide-in grommet at the 4 o'clock position, I fear that I will be weakening the crankcases in a critical spot (under the RH front engine mount lug). Another option is to cut a grommet slot in the magneto cover, but I think this might look a bit strange. Ideas, suggestions, comments please Quote Link to comment Share on other sites More sharing options...
tony283 Posted February 17, 2008 Report Share Posted February 17, 2008 David, I always ran mine forward and up the right tube. I encase the 2 wires in tubing (colour co-ordinated of course) for protection and there is JUST enough room under the Renthal Bash plate. Remember unlike the Yam the live wire is BLUE not BLACK. Mine had been wired A*** backwards! (Strong runner off e-bay!) Tony Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted February 17, 2008 Report Share Posted February 17, 2008 My first trials bike was an ossa andit ran ok till the first time I hit the bashplate. Think mine was then routed out the top ? is this possible? Quote Link to comment Share on other sites More sharing options...
woody Posted February 17, 2008 Report Share Posted February 17, 2008 (edited) Best way to route the wiring is out of the front of the crankcase directly under the right hand side of the barrel. Drill a hole through the front of the case (on the flat face inbetween the engine number and the first of the cooling fins - or whatever they are...??) into the ignition housing. If you look at the engine from the ignition side, this hole will enter the ignition housing at about 1 o'clock, just behind the top right ignition stator fixing point. The wiring coming out of the back of the stator can be run around behind the stator around the crankshaft from left to right and then up through the hole and up the frame downtube. To run the wiring behind the stator you will need to grind back the strengthening ribs on the casing in the ignition housing that span out radially from the oil seal housing. This gives the wiring space to sit behind the stator without getting pinched. The exit hole can be sealed with silicon sealer as the casing here is too thick for a grommet. Then just blank off the original exit point for the wiring - I welded mine up. No need to drill holes in ignition casing this way. Whether you have an early or later stator (ie; flywheel timing hole at 4 o'clock or 9 o'clock) will determine how far around the crankshaft you have to route the wires as the different stators have the wires exiting the backplate in different places. You can't go behind the top of the stator as there is no room behind the top of the backplate due to the transfer port. It is difficult to explain all this in writing but if you look at your engine whilst reading this you should see what I mean. Can't post a picture but I can email you one if you need. Also - question for Tony. Noticed you have what looks like a Mikuni fitted to your MAR in the picture. What model - VM26? Don't suppose you have the jetting/needle/slide numbers to hand do you? Edited February 17, 2008 by Woody Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 17, 2008 Author Report Share Posted February 17, 2008 Thanks guys. Yes I see that will work well - thanks Woody. I'll post some photos for future reference. Quote Link to comment Share on other sites More sharing options...
tony283 Posted February 18, 2008 Report Share Posted February 18, 2008 Woody VM26 150-160 Main 30-40 pilot all dependant on altitude, sea level to 8000 out here so change as required. These carbs are v expensive as it a flange mounted one, not quite enough room to use the original IRZ flange and a rubber! (I tried) Tony Quote Link to comment Share on other sites More sharing options...
mattylad Posted February 18, 2008 Report Share Posted February 18, 2008 Woody's reply is totally correct the reason the mod needs to be done is with the bottom exit the ignition cable is sometimes trapped between the sumpguard and crankcase which over time can cause a short circuit within the cable even if it is not externally visible. (source of advise Mick Andrews) Quote Link to comment Share on other sites More sharing options...
woody Posted February 18, 2008 Report Share Posted February 18, 2008 Thanks Tony, but if you are able at any time could you find the needle number and needle jet number that are fitted. This is the really tricky bit on Mikunis as there are so many combinations. The needle jets come in two different types, either a 182 or a 175, the 182 sits flush in the main venturi and the 175 has a D shaped shroud protruding into the venturi. They mix the fuel/air differently so both have different type needles from each other. Quote Link to comment Share on other sites More sharing options...
tony283 Posted February 18, 2008 Report Share Posted February 18, 2008 Woody, carb details: VM26 Slide 2.0 Needle 5F21 Needle Jet 182 with D shroud Main 140-160 Pilot 30-40 see "the Bulldozer from Spain" in the blog Tony Quote Link to comment Share on other sites More sharing options...
woody Posted February 18, 2008 Report Share Posted February 18, 2008 Love the Ossa SSDT story on the blog - very entertaining piece. I can relate to all the tales about reversing Ossas and engines coming back from the dead as I've experienced them all too - they are a great bike, still my favourite. Thanks for the carb settings but one more favour to ask - the needle jet number. 182 is the jet type as opposed to the size. The size is denoted by a letter and number and the range goes from O2 to O8 and then P2 to P8 so your jet should be somewhere in that range. If you could have a look next time your messing with the carb I'd be very grateful Quote Link to comment Share on other sites More sharing options...
tony283 Posted February 18, 2008 Report Share Posted February 18, 2008 Woody, Glad you liked the story, there are 2, also some more action in Guernsey (2 tales). Mikuni...... 182 N-8 Tony Quote Link to comment Share on other sites More sharing options...
woody Posted February 18, 2008 Report Share Posted February 18, 2008 Thanks for looking the info up Tony, I have a starting point now The tales are quite amusing, I'll be reading a few more over the next few days Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 29, 2008 Author Report Share Posted February 29, 2008 Here are the photos of how I did it for future reference Quote Link to comment Share on other sites More sharing options...
swooshdave Posted March 1, 2008 Report Share Posted March 1, 2008 Will you put a gloop of silicon over the opening? Quote Link to comment Share on other sites More sharing options...
woody Posted March 1, 2008 Report Share Posted March 1, 2008 Here are the photos of how I did it for future reference Yes, that's it exactly, glad you understood what I meant. So much better this way, no more split or mashed wires. I've always used silicon to seal where the wires now come out with no problems at all, it stays sealed. Quote Link to comment Share on other sites More sharing options...
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