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RD350 performance upgrades/projects

47K views 62 replies 18 participants last post by  woodsman 
#1 ·
I have been dumping some money into my RD350 again, and I thought I'd ramble about it just a little to help keep me motivated to get it back on the road. It turns out that I had the automatic oiler "turned down" too low, so I have been slowly starving the motor for oil for quite some time.

I ordered up a fresh set of Banshee pistons, wrist pins and pin bearings, and I am waiting for those pistons to arrive. I really liked these M&H forged pistons I got last time. They held up very well to extraordinary abuse, and I experienced some real power gains. If the shoe fits, wear it. So I got another set:

EDIT: I purchased a third set of these pistons in Jan 2010. these are a new batch from the manufacturer, and the quality had seriously decreased. There are conspicuous slag deformation around the ports, and the factory machining is over all very sloppy. I no longer recommend these pistons.



Several months ago I bored out my intake to support big banshee reed blocks. I believe the RD350 suffers from a foundational performance bottle neck through the restrictive stock reeds, and the big ones instantly made a HUGE improvement. I was getting happy little roll-on third gear wheelies before I started soft seizing motor up b/c the engine was oil starved. Looks like an absence of oil also serves as a foundational performance bottle neck.... [8D]

The other day, on a whim, I dropped a low-ball eBay bid on some of the famous Delta V Force reed blocks -- these are well known performance parts for Banshees. It turns out no one else bid, and I got them at a fair price. They arrived yesterday, new in the box, and I am looking forward to see how much more metal I will have to remove to make these bad boys fit.


Another substantial problem with the RD350s is their infamously poor ignition systems. It is a standard breaker points system, but the coils blow, the charging system can't handle much more than stock, and they foul plugs like they're going out of style. To counter this I have been experimenting with running car coils on my RD. You know, the good old fashioned canister kind. They actually worked well, but the didn't last. I have gone two sets. The first were old, free hand-me-downs, so their original condition was unknown. The second pair were HUGE 60,000v cheap Chinese crappy ones, and they failed pretty quickly. I guess you get what you pay for.
This time I sprung for a pair of new Accel chrome ones (ACCEL #8140C).

I will be running a pair of dual 1.4ohm external ballast resistors with each coil which will let me experiment from 1.5ohms to almost 3ohms for each coil. Coupled with an intentionally resisted secondary ignition, I am pretty sure I've finally figured out what it takes to make something like this work.

Running big coils creates two immediate problems. The first problem is that car coils basically rape the points. The second is that my bike's crappy charging system is insufficient to continuously power them along with the headlights and everything else. (I have already upgraded the lighting from wimpy stock 35w bulbs to the amazing brightness of a 55w H4 'Sylvania SilverStar Ultra' bulb (I think these are the best). This is already straining the fragile charging system.)
To address the second problem I simply run the bike with no lights 90% of the time, saving the juice for night time. I did buy a 35w 'true HID' headlight setup, hoping to help address my unsustainable wattage addiction, but I think that once again I got what I paid for, and the crappy Chinese kit I purchased off eBay actually sucks a whole lot more power than its advertised 35w. Plus, when the power gets low with these you can't limp home in the dark -- there is no dimming action, and they simply turn themselves off. YUCK! I might spring for another conversion kit. I think I'd have to look for one that is of substantially better quality, maybe one of the German made kits. It would be rad if I could find one that does what it is supposed to do.

*To address the first problem*, I have been researching transistorized ignition boosters. I'm pretty excited about this! Called by many different names, these are clever little devices that effectively work like a digital relay that fits between your points and your coil, accomplishing several very handy things all at once. First, and most importantly they operate like a relay for my coils: They take the heavy voltage dump that the coils normally would drop through the points, and it redirects it directly to ground. The points instead get a greatly reduced micro voltage for triggering the coils. What this means is that the points do not have enough voltage to arc, so there is almost no wear, and a correctly adjusted, fresh set of points can effectively last almost forever with minimal adjustment. At the same time, coils work best with a nice crisp triggering signal, which points do not deliver, but the transistorized ignition delivers perfectly. And finally the coils also will run better because they will have a better ground than what the points can deliver. I intend to open my spark plug gap up to a whopping 0.060" to add a little fire to the fuel. So all around, if you are going to run breaker points, a transistorized ignition booster is a fantastic upgrade, offering some real BANG for your buck. I think this represents one of the final missing pieces to successfully run car coils on my RD350.

FYI, transistorized ignition thingies apparently don't actually exist anymore. Rumor has it that Accel used to sell one, but I was unable to verify this. Fortunately there are $20 kits out there so you can build your own. HERE is one of the cheapest places where you can buy a 'K2543 Electronic Ignition Module Kit.' And HERE is a top-secret .pdf of the instructions to build the same kit if you think you could save money by sourcing all the parts yourself. You need to use one per coil.


Having said all that, Mark "HondaMan" from the SOHC forum makes and sells an updated 'plug and play' ignition booster which is similar to the kit, but if you use his you only need one unit and it should be significantly better. There is a 16 page forum discussion around its development HERE. I just purchased one from him for a little less than $100, and that includes shipping, special components for my particular application, plus a fancy alloy box to make it look pretty and aid with cooling.

(HondaMan's image)

Since it is being custom made (and he had to mail order the red alloy box), it probably will be a few weeks before it arrives. I am pretty excited, and I will post some more info/pics when it shows up.

All in all, I am hoping that all this fun stuff, combined with a significant amount of other work I have dumped into this little bike, will help make my happy little RD350 one of the faster ones in town.

On a side note, Snorklefork and I are pretty good friends, he also has an RD, and we have some friendly ongoing competition to see whose RD is faster. Um, Snork, watch out! You're about to get spanked. ;)

So now I just need to patiently wait for the last few pieces to arrive in the mail. Then I need to make a new seat, and replace the rear rim with a nice alloy one, and paint and install those chambers, and, and, and..... :D

peace and grease,
-fang
 
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#27 ·
Fang's ignintion only uses the points to trigger his ignition. No big amps go thru them so they won't wear out. The benefit is when on a long ride, or at the track, if his ignition fails (which i doubt it will) you can swap two wires and run the stock points setup like normal.
So Fang has a hot ignition setup that doesn't drain too much, and won't require lots of maintenance.

For coils btw, the stock CB750 coils have a really really good long dwell from what Mark was telling me. They are hard to beat. The Dynas had more volts, but shorter dwell. That long dwell goes long way in topend power. That Mark is a really knowledgable nice dude.
 
#28 ·
Fang's ignintion only uses the points to trigger his ignition. No big amps go thru them so they won't wear out. The benefit is when on a long ride, or at the track, if his ignition fails (which i doubt it will) you can swap two wires and run the stock points setup like normal.
So Fang has a hot ignition setup that doesn't drain too much, and won't require lots of maintenance.

For coils btw, the stock CB750 coils have a really really good long dwell from what Mark was telling me. They are hard to beat. The Dynas had more volts, but shorter dwell. That long dwell goes long way in topend power. That Mark is a really knowledgable nice dude.
 
#29 ·
Unga, that updated rectifier/regulator is on my short list of near future updates. FYI, I am about 90% sure that the HVC unit to which you linked is made by Tony over at Oregon Motorcycle Parts, where it is sold for a little less money. Brad at HVC is a good guy, but I REALLY like Tony at Oregon MP -- old retired hippy electronics guys living out in the mountains, making amazing products from their home always have a soft spot for me. Kudos to him!

Also, like Pampadori said, my system is redundant -- if it fails while I am out and about, I can quickly and easily convert it back to stock operation on the side of the road with no tools. I am not familiar with any Dyna-style electric ignitions that are capable of any performance gains over the one I have assembled, and mine costs around $150-$300 less. But most importantly, mine is authentically retro cool!


EDIT:
HERE is a link to some of Oregon Motorcycle Parts' regulator/rectifiers. The one for the Yamaha 2-stroke twins costs $115, and is called a 'VRREM7-YRD.' It looks the same and has the same part number as the one HVC sells. ;)


peace and grease.
-fang
 
#30 ·
Unga, that updated rectifier/regulator is on my short list of near future updates. FYI, I am about 90% sure that the HVC unit to which you linked is made by Tony over at Oregon Motorcycle Parts, where it is sold for a little less money. Brad at HVC is a good guy, but I REALLY like Tony at Oregon MP -- old retired hippy electronics guys living out in the mountains, making amazing products from their home always have a soft spot for me. Kudos to him!

Also, like Pampadori said, my system is redundant -- if it fails while I am out and about, I can quickly and easily convert it back to stock operation on the side of the road with no tools. I am not familiar with any Dyna-style electric ignitions that are capable of any performance gains over the one I have assembled, and mine costs around $150-$300 less. But most importantly, mine is authentically retro cool!


EDIT:
HERE is a link to some of Oregon Motorcycle Parts' regulator/rectifiers. The one for the Yamaha 2-stroke twins costs $115, and is called a 'VRREM7-YRD.' It looks the same and has the same part number as the one HVC sells. ;)


peace and grease.
-fang
 
#34 ·
Hi guys. I dropped the cylinders and pistons off at a new machinist almost two months ago, and he botched up one of my jugs.

I've been in a holding pattern since he told me things were screwed up -- about two weeks.

Otherwise, things are buttoned up and ready to go.

Needless to say, I'm pissed.

-fang
 
#60 ·
Once you start seeing pistons with holes in the skirt, you know you are in experimental territory and trial and error is an expensive way to figure out where and what shape to drill holes in a piston skirt. Scavenging ports can be cleaned and polished to reveal a few more horses, but once you start changing the shape and dimension of those ports significantly you better have a stack of spare barrels on the shelf.

Case in point:
Hi guys. I dropped the cylinders and pistons off at a new machinist almost two months ago, and he botched up one of my jugs.
I've been in a holding pattern since he told me things were screwed up -- about two weeks.
Otherwise, things are buttoned up and ready to go.
Needless to say, I'm pissed.
-fang
 
#37 ·
I was on the 2nd to last over bore, and he opened the cylinder too much. Remember that these cylinders have the intakes ported for a bigger reed box, so that makes them a little special.... Really, it would not be a big deal, but the pistons I want are out of stock. I've put it off for a little while, and now its time to make things happen.
 
#38 ·
that really sucks that he botched the cylinder... :( I always watch these 2 stroke projects with eager anticipation
 
#39 ·
Thanks Raven, but nah.... It really is not the end of the world.

We decided that since I was originally going to pay $100 for the work, he will cover any expenses that go beyond $100 and do everything else for free, plus some extra freebies. Fortunately I have a set of spare 'junk' cylinders that Snorkelfork threw my way, so It looks like the best solution is to buy a set of pistons and do all the prep work on these other cylinders. He will let me use his superior equipment to open the intakes again, and he will weld up the windows I make, deck the heads, help me with a spark plug thread repair (helicoil gone bad), and stuff like that -- all at the original cost.

The only real problem right now is that a set of replacement pistons will cost about $150 - $200, and I sadly am suddenly too broke to pony up the cash. Once again I am in a financially motivated, indefinite holding pattern; the story of my life.

Thanks all for the interest. Basically all I can do is bitch and wait. So I'll keep my peace in this thread until I have some pictures showing off how things are getting done.

Peace and grease,
fang
 
#40 ·
My pistons arrived in the country. Now only a few more days for the to get to me, and then back from the machinist. The pistons are the same as the ones in the pics in the first post, + a few thousandths larger.

Maybe back on the road next week? That would be the cat's meow.

peace and grease.
-fang
 
#45 ·
A couple quick updates. Yesterday my machinist came by the workshop and picked up my pistons, promising that the cylinders will be ready by Friday (tomorrow). How long has this been drawn out?

Also in similarly related news. The 6mm (4th overbore) pistons I got from Turbo1Racing this time around (my third set) are really of disappointingly poor quality. I edited my first post to mention this too. I believe that these most recent pistons are from a fresh batch, and the forging is sloppy, the ports are full of slag, leaving them misshaped, they weigh about 3.7 grams difference between the two, and the factory machining is unnecessarily sloppy. It took a lot of time to 'dress' (machine) the pistons just so they could be used. I think they will work, and if they last few sets had not performed so well, I would have thrown them away when they arrived. I can't recommend them until this gets sorted out, that is unless you are looking for a piston upon which you intend to do some machining to make it fit.

I emailed my contact at Turbo1Racing this morning to share this stuff also.

Peace and grease,
fang
 
#48 ·
I guess I am (1) a lazy bastard, (2) just don't care enough to send them back, and (3) probably don't expect that anything would have happened even if I did. Plus these pistons cost me about $70 less than the set of PRO- X I almost bought.

Either way, if the alloy is otherwise the same, they should end up being fine pistons for me. I thought I was buying plug and play pistons, but these required some extra work. Oh well. Besides, I have been waiting for MONTHS now on this BS cylinder bore job, and I am sick of it. It should have taken one day. Two days tops. I'm ready to move on with what I've got and chuck it up as a learning opportunity.

I'm sure I'll feel differently if a month from now my pistons have blown up and ruined the bottom end. Then again if a year from now things are still ticking along nice and tight, then we'll know it was no big deal. There is no way to know right now, so I might as go with what I've got.

peace and grease.
-fang
 
#49 ·
Cha-Ching! I came home from the Monastery last night around midnight, and voila! My machinist finally came through -- he actually delivered the parts back to the workshop, clean and ready to go. Kudos to him! I will come back, edit this post and fly a few pics a little later. but right now it is time to down some Saturday morning coffee and hit the wrenches.

peace and grease,
fang
 
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