Looking for tech advice about Vape Ignition installation on a 1975 RD250B

[Economy Cycle John]

The Yamaha spec on that bolt is 18 ft lbs, I run them at 20, no issues. I realize its on the upper end but these rotors can tend to slip if the taper's not engaged. The bolt I include in the kit will take the 18-20ft lbs (I've tested them), won't snap and does a great job of holding the rotor.

[Dvsrd]

Making a peg spanner is pretty easy, if you have access to a drill press and hand files or angle grinder.

[RDryan]

Making a peg spanner is pretty easy, if you have access to a drill press and hand files or angle grinder.

Yeah I thought about that and that's  probably what I should've done. So today with the aid of the forum I took into consideration everyone's input and here's how it went. Since I don't have a drill press never mind a proper piece of metal stock to make a peg spanner out of I decided to pull the clutch cover and lock up the primary gear like Chuck suggested. Had a bit of a struggle getting the cover off because I used that Yamabond on the crankase side of the gasket and boy does it hold...She finally gave free and the gasket came out of it in pretty good shape except for a couple minor breaks, we hope. Took my time with the razor cleaning off all that dried sticking Yamabond. Cleaned all mating surfaces to let em dry. Then I locked up the primary gear with a rag and proceeded to fasten/torque down that rotor bolt with the Economy Cycle hardware kit. There's a split type lock washer, one of three washers along with the longer bolt in the kit and it didn't work so well. For what every reason as I was tightening the bolt the split washer wanted to expand at the split and it dug into the face the bolt leaving burrs on the bolt. I just kept tightening it and really wasn't getting 10 pounds of torque nevermind 20 because that washer wanted to eat into the bolt. No big deal though. I just loosened it all up substituted the split lock washer for the supplied Vape washer. I figure with the additional length of the bolt in the hardware kit even with the three washers in there there is still much more threads engaged than with the shorter Vape bolt.  Crept up to 17 ft. lbs.  of torque and really it felt very tight at that. Could you put 20 ft. lbs. of torque on it? I suppose but it felt very tight creeping up to 17 plus I gooped a generous amount of the blue loctite on it. I'd be surprised if the bolt were to come loose or even the rotor slips.

So I took my time with it and did the best I could with what I had. Probably would have been nice to have a proper holding tool as I kinda created a lot of extra work for myself but I could see how holding that rotor with a strap wrench may actually put enough force on it to damage the magnets within. I got the idea from this You tuber who goes by the name Lucky Yogi. She made a neat video series on this rd350 bike build and her partner used this rubber strap wrench in one the videos to hold it. Seemed like a good idea and probably ok to do but you never know and after seeing that Vape tool link it definitely made me think better of it. 

[m in sc]

sounds like you got it. suggestion? put  witness line across the bolt to the rotor, that way if you ever have a running issue you can visually see if the rotor has slipped. im 98% sure you got it though. 

[RDryan]

sounds like you got it. suggestion? put  witness line across the bolt to the rotor, that way if you ever have a running issue you can visually see if the rotor has slipped. im 98% sure you got it though. 

That's a great idea, I'll do it. Noticed you did that reading the HPI ignition thread and that's a trick looking magneto. How do you like that compared to the Vape?

[m in sc]

the both have their benefits. the powerdynamo/vape has  much stronger charging output, so for running other stuff, like a stepper tach, constant lights at idle, and the zeeltronic ignition box, i think its better (if not just easier). the HPI is definitely lighter, simpler. however, it has 60w of output vs the 200w of the vape, so you have to get creative to run a full compliment of electronics.

i think the vape is more user friendly and has a big flywheel, so it helps keep the rps up during regular rides between shifts, whereas the HPI is so small, winds up (and down) much faster. installation difficulty between the 2, in my opinion, is about the same. i think the spark output is about equal. i'm running one of each both on ported and piped motors with big carbs, etc, and neither lacks.

if you are looking for a super minimal build id say the hpi is the best option, the powerdynamo is good for that as well, but has more'creature comforts' and is def more flexible, for lack of a better term.

hope that makes sense.

i'll also mention this for posterity:

if you dont want to delve into the wiring as much, the dyna that vintage smoke sells is absolutely bulletproof, i have one on my r5. its def good for those looking to run basically a stock setup. these would eb restorers, or stockish bikes with pipes and some light work done.

(old guy mode: on)
you could daily any of these or win races with any of these systems. its nice to be in an era where we have options, unlike 20 years ago having to hack up kz and cb dynas systems or try to resurrect old newtronics setups from the 80's.  (old guy mode off) 

[RDryan]

Hi all, thanks for the help and sorry for this delayed reply. I probably should've replied sooner but I kinda felt like I didn't have much to add without getting off topic. So I did get the bike running with it's new ignition and I ran into more problems, jetting problems. That was a week ago. Between my work schedule and the wet weather we've been having in New England it's a long process but hey at least I can rule out ignition regarding my bikes tuning/running state.

Now to get a bit off topic, I made a lot of changes at once which probably didn't help but seemed to make sense. Along with the Vape Ignition I added a set of DG chambers and ditched the stock airbox with K&N filter for just the y boot and K&N filter combo. Found out that 170 mains were just not enough for the extra air and since I really didn't know as it's my first experience jetting carbs....I actually went the wrong way playing with leaner jets/settings of the slide needle. As of now the bike runs great with 170 mains and the slide jet needle in the 4th richest position. However I had to put the airbox back in to achieve this current running state. I actually think I could go even higher on the main as the plugs look a bit too newish clean and lean. I did just receive more jets in the mail yesterday 180,185, and 190 sizes. I would really like to try to rejet again without the airbox but I wonder if 190 will be rich enough? Any thoughts on this?....appreciated.

It's a pretty standard setup FWIW. 1975 RD250B, Vape Ignition, DG exhaust and K&N filter attached directly to y boot. Stock otherwise with oem style carb intakes no crossover or reed valve spacers and no special porting. I do have Boyesen Reeds but I retained the stock metal stops to limit the reeds opening. 

[m in sc]

190-200 should be about right, probably wind up one lean on the needle when all is said and done. 

[RDryan]

Thanks, I'll try that. It's amazing to me just how much of a jump in main sizes it takes to get it right.

and this was at least for me one of those things that's hard to understand just reading a carb manual or talking about. I had a friend that's got experience racing dirtbikes come over and he just merely looked at the plugs and knew I was going the wrong way with jetting sizes. Honestly I feel like the K&N without the airbox is the way to go for more heavily modified bikes but I'm not sure there's much more performance to be had with mine. It seems like it runs really good with the stock airbox. I dunno I just feel funny not trying to make the new air filter work though.

[RDryan]

Oh yeah btw I got those 4290 Autolite plugs and was wondering what should I set the spark plug gaps at? I actually have em set at stock specs. between .5 to .6mm actually closer to .5mm

[m in sc]

i run mine at .038"

  regarding the y boot, i have one on my stock r5, it runs great. just jet accordingly it will be good. 

[RDryan]

i run mine at .038"

  regarding the y boot, i have one on my stock r5, it runs great. just jet accordingly it will be good. 

Ha,ha that's good to hear. Well laughing at the emoji, our options here are endless

It's funny my dirtbike buddy asked me about the gap I had and he said to open it up to .030", he mentioned it really needs to be bigger to get a fatter spark. Or I guess getting the most out of it. Not sure why that makes a difference but I do know that both the Autolite plugs and the NGK plugs come new outta the box with something like a .025" to .026"ish gap and I was just doing what the manual recommended but maybe that just makes the plugs foul easier?

[m in sc]

the autolites are gapped for older cars with shit ignition systems. a wider gap will, if the system can produce it, give a hotter spark for sure. remember, the spark plug is overcoming resistance to spark. therefore, it will take more energy to (literally) bridge that gap, when it does that greater energy is released and your hand is numb for 10 minutes.   

[RDryan]

Awesome, I totally didn't know that. So I am essentially under utilizing the capabilities of this newer more modern ignition system. Glad I asked. 

[RDryan]

So today I decided I would try to wire up the one wire kill switch and that was pretty easy to do but I also wanted to add this two prong toggle switch I got from Advanced Auto Parts as a hidden kill switch that I would have mounted inside the battery box. Not sure if it matters but it says it's 12volts and 35amps made by Motorcraft. I thought that if I had the hidden switch basically wired between the blue wire running from the coils and the one wire kill switch I mounted on the handle bar then it was as simple as that but it doesn't work. I guess I must being doing something wrong here. Any ideas?