Honda CX 500 Forum banner

Clueless seller

6342 Views 55 Replies 11 Participants Last post by  wmw
No interest on my part, but if you're looking for one, you won't find this one by doing a search.

FleaBay Ad "CBX Turbo"

Check out the description, Honda is so safety conscious it makes me feel all fuzzy.
1 - 16 of 56 Posts
Thanks for the lead on the bike. I bought it to race in the production class at Bonneville. Since I am planning a complete rebuild, the $4000 I saved over most 650's will go to good use. Ed
The bike would run in the production, pushrod, supercharged 750 class. It has to appear stock from the outside, but the inside can be modified. With such small production numbers hardly anyone has modified these things for speed. With an outdated fuel injection system and an out of production engine, it will be interesting trying to improve on this thing. The computer will limit both boost and rpm, so that will be much of my challenge. Having to have virtually every speed part custom made will be another challenge. Oh well, this is a much easier sale to my wife than trying to build a 250 mph, $50,000+ Hayakawamaha. It is costing me a bundle as I had to buy her a new car to ease into this....

Any and all performance ideas will be greatly appreciated. I am going to try to pick Jim L's brain for ideas and try to locate the other guys who have run these at Bonneville too.
Thanks for the tip, I have an e-mail out to him right now.

There are Four reasonable performance mods that you can do to these bikes.

Mill the heads (a little).

Smooth the the Exhaust ports.

Run a Boost valve.

Run a Blow Off Valve.

If you want to make a drag bike, you could run Nitrous, but you will fuck up your engine.

Anything else you try will be a futile attempt, a very expensive attempt, and the only thing you will accomplish in the end is to fuck up a perfectly good bike.
Thanks for all the suggestions guys. The bike has to appear stock, so bodywork, fairing, tank, seat, exhaust etc. need to appear stock as in the manual. The engine can be played with so I really need help from the fuel injection experts, the turbo experts, and the electrical guys. I have the basics for horsepower pretty well figured out, it is just a matter of making it work in this nearly 30 year old package. I will be trying to dyno the package as it is developed and add and subtract things as they prove themselves on the dyno. I think the bike needs a little more compression, possibly more cam, better headwork, more fuel, more boost and a few more rpm. Assuming I don't blow it too many times, we should set a record or two. Understand I am not trying to offend the purists here. My Ebay 500t and 650t are far from being showboats, besides that is what the Barber Museum is for. I want to stretch the performance envelope in something a little different. Anyone can go fast on a new Suzuki. Buy that and the latest turbo kit and there is record waiting for you. Read JimL's build story on his bikes (CX500)and you get the picture. I want to honor these bikes and show how this "failed" design can still be a winner, nearly three decades later.

See less See more
Hi Ed, in what respect(s) do you consider the CXT's a "failed" design?

My "failed" design comment was kind of a tongue in cheek reference to the turbo bikes in general. I first put a turbo on my 750 Honda in 1976. I also own three Kawasaki 750's and a CX500 and 650 turbo. Needless to say, I think the idea is pretty cool, they just were not much in the way of commercial successes. Honda really showed off with the technology in 1982. If you look at the Mercedes Ilmor engine that won Indy a few years ago it is pretty similar, except with two valves per cylinder. Those engines were designed to run at 10,500 rpm for 1200 miles, pretty good proof that racing improves the breed.
The production class at Bonneville is hardly a 1/4 mile dragstrip. Any bike is elevated in stature if it does well at Bonneville.

And exactly what is the difference between running at Bonneville and maybe throwing a rod or ?, and running a circular track and throwing a rod or ?. Or being parked and hit by a car, caching fire in a trailer or getting broadside on a public road, results the same. Six of one, half a dozen of another. At the price this thing sold for, most would have used it as a parts bike or parted it out, at least it'll cut through the wind again.

There are still a relatively large number of these bikes around vs production numbers, and few purists out there willing to pony up the $$$ it takes to keep them unmolested and stock.

You are right about land speed racing. The biggest appeal to me is it works for amateurs and prize money is not the issue. My road-racing days are well behind me, but I can still have fun out on the salt with a bunch of other old guys and gals. The courses vary from one mile at Texas to 1 1/2 at Maxton or Loring and up to seven miles at Bonneville. Acceleration isn't an issue on the longer courses so you can shift about like you would on the freeway. I think JimL said they hit top speed around 9500 rpm, so you probably aren't stressing the bike too much more than a lot of guys do on Friday nights on the street. Racing improves the whole breed. JimL has ordered pistons from CP so a new better designed piston is available for less money than a NOS Honda part. Others in the UK and Australia are finding bearings and other parts to substitute for impossible to find Honda parts. Assuming we can still locate engine blocks, the aftermarket will allow us to keep these motors running for many years.

I do not have anything against collectors or even speculators. I feel bad for someone that buys a bike because of its perceived collector's value. They are better off buying gold or an index fund if they want to make money. Buy a bike to have fun. As to blowing motors what difference does it make if the bike is too stressed and it blows or if some dummy lets it run low on oil and it blows, either way you are out some bucks.
See less See more
If your work is going to result in the creation of replacement CP pistons and main bearings, go for it.

I'll support you 100%.

I do wonder, however, where you are going to get rings?

I have heard of an Audi oil ring being used to replace a bad oil ring, but no replacements for the main rings.
Part of the challenge of these things is finding better parts at a cheaper price. Honda CRF 250's had 78 mm pistons for many years and there are over bores as well. The Hayabusa uses 83 mm and there are some others too. Bearings are just a matter of finding a good parts man to match sizes. My dream combination would be a disc piston like the CRF and a steel or titanium rod to make up for the length. If I can figure out how to raise the rpm I will look at beehive valve springs and ti valves. If the ignition won't let me pull the rpm, there is no point. Jim L got 11,000 rpm without going to titanium or beehive valves, so 11,500 or 12,000 could be possible.

You guys need to listen to Turbo Tim. He is making some serious horsepower. When I drag raced cars in modified production in the 70's we ran 10.30 but only ran 132mph. He is hitting 135, that is a lot of hp for a 673 pushrod, twin. The only way he will find the limit is by occasionally losing an engine, but even then we learn something.

I am not sure of our ultimate configuration. The dyno and the wallet will decide (er...Paypal).

As to modifying bikes, I do have a stock RG500 Suzuki. It is a blast to ride and does pretty well stock. I do have one museum looking at it and may part with it, if we agree on things. But the point is I bought it to ride and have fun. During its time it terrorized GSXR's like nothing else. On our hilly, winding roads in the mountains, that little 500 does the trick. Now I hear it is worth about $12,000+ and I am scared to ride it.

Guys we are not in a rivalry. This not stocker vs. racers. Lets trade ideas, help each other with parts, help fix each other's bikes and supply those unabtainables that Honda can't provide. We will celebrate victories and console our buddies when they blow a motor or wreck. Save debates for Replicans vs. Democrats....

Ed H
See less See more
I think higher RPM's is the method for NA engines and 1/4 mile drag bikes. With a turbo charged engine I think some of those goals get discarded or minimized. Predetonation, timing, turbo mapping; head flow, boost level etc etc come into play equal to or greater importance than acheiving high RPM.

HP is just a mathematical function of measured torque. These 650's in stock trim made 80ft lbs from 4000-8000 RPM's. And that from a 40 cubic inch engine. That is where they got their acceleration rate. Not from being able to wind 50 ft lbs from 7000 to 12,000 and make bigger HP. A 650T will still accellerate with stock 600/750/900's crotch rockets of today, but top speed will be limited due partly to gearing.

Increasing torque by increasing boost while not inducing pre-detonation and altering gearing to allow that peak boost to get to the ground would be my personl goals. HP is just an RPM factor requiring lower gearing to maximize the torque available at that higher RPM.

I think the NA 500's and 650's are redlined for piston speed considerations and not neccessarily valve float. I think they also had some considerations for cam lobe configurations and cam ramp angle.

When they went to the 650 NA engine, they reduced the RPM due to the slightly longer stroke of the 650 which increased the piston speed.

You mentioned being afraid to ride your 12K bike and yet people ride 20-30K bikes on the road all the time. Thus your reluctance to ride your RG500 is not likely due to it's monetary value alone, but due to it's intrinsic value and rarity. But yet if you'd put another thousand in the 650 turbo bike as is, you'd end up with up to a 5 to 6k value (likely).

And it's likely as or more "rare" than your RG500.

The RG500's production numbers were approx 7500 in '85; 1500 in '86 and 500 in '87. Thus only if you have a '87 is your rarity greater than the 650 T that you have now.

From Wickipedia concerning the 650T

You can indeed do what you want with it; but it would be equally interesting and challanging to take a NA 650 engine and bike and install a turbo on it or modify it to it's maximum potential. You'd have to decide if the engine block and crank would take it. There are already several guys doing this with CX series bikes and thus you'd have company.

You stated that some of your goals would be to facilitate the fabrication of replacement and performance parts for the 650Turbo's. That and similar approaches have been found unmarketable and basically unwanted. Dan Topping discovered this perspective. There simply is not enough of the bikes manufactured and still remaining to mass market any type of performance upgrades. And most owners seem content with the performance for street riding as it is. If they wold want to spend 10,000 for performance upgrades AND for daily riding; they'd likely opt for a newer motorcycle also.

Many though would be appreciative though if stock replacement parts (such as sidecovers) wouild be sourced and manufactured. But even those are resellable to a very limited number of people.

Only a few of those cabaple of affording extreme parts to modify a 650 Turbo would actually have an interest in doing so. So your likely in a world of a very few modifiers such as Tim the dragracer and yourself.

Someone had even made a intercooler for the turbo, but couldnt' get it dialed in. That would be another performance upgrade that may net 20 HP.??
Tony G

I agree with much of what you say. My goal however is top speed alone. On any bike the top speed will be limited by the rpm's it can pull. If a 500t runs out of spark or fuel at 9,000 there is not much sense in building one to pull 11,000. It doesn't matter if you have 80 hp or 120, the rpm's will limit you. Gearing is our limiting factor with these bikes. True you can juggle trannies, drives and tire ratios, but that is about it in production racing. In the altered classes you can twist the engine and use sprockets to fine tune your gearing. We used to race a factory BMW in the late 70's and had the luxury of four rear end ratios to use, but that is not the case with the Hondas.

I am not trying to do anything commercial. My cousin had a pretty successful race shop (Reher Morrison Racing Engines) and won a bunch of titles in Pro Stock drag racing, but they did it for the love of the sport, not to make money. You might make a bit tuning Suzukis or dirt bikes, but not too many people get rich at that. I would simply like to be able to help with problems. There are guys on this and other forums who have addressed cam problems, valve train wear, wastegate issues, sensor problems, and fuel injection issues. These are tremendous resources as Honda has pretty much grown past these bikes and unless there is an old mechanic at a dealer, no one has heard of these things, much less able to give advice on them. Body parts should not be an issue. Everything but the gas tank could be duplicated pretty easily with basic fiberglass skills. I was making side covers for my CB750 back in the 70's when it was easier than buying the part at the junk yard for $10. Find a website on making molds for fiberglass parts, or a book, you would be surprised how easy it is.

As to my RG500, it is pretty darn rare in the US. Rick Lance might have an idea how many there are, but I would be surprise if there are a hundred in the entire country, much rarer than any turbo bike. Most have been brought in from Canada (like mine) and we seldom see them in the south. I just do not want to butcher that bike as it is run to ride as is and I do not intend to race it.

I like the idea of converting a NA to turbo. For a modified or altered bike this would probably be preferable so as to use a modern ignition and injection system. Yes you would have to engineer the bottom end to take it, but the basic materials are out there now.

I would like to look at an intercooler and or a water injection system. These things do not always work the first time. We learned this in drag racing when we heard that someone tried a camshaft and it did not work. Then we tried it and picked a 1/10th. Trial and error is pretty much a given when you are trying to out engineer the manufacturer.

See less See more

Just wondering if your reconsidering your racing project with the 650T due to our discussion.

In particular, wondering if you've changed your perspective of the rarity of the Gamma 500 in comparison with the 650T?

You are probably right about the production numbers on both bikes, I won't dispute that. The Gamma was surely produced in bigger numbers, but was never sold in the US. I have probably seen about a dozen over the last twenty years. The turbo bikes were sold by a lot of dealers. I remember looking at them on all the dealer's floors in the early 80's. It seems like they either were presold, bought for the dealer's collection, or sat forever in the showroom. Very few dealers in the US sold more than two or three. I would not butcher an old classic that was in great shape. I have had my RG500 for about 15 years and it is still in near showroom condition. I had planned to race it too, but never got around to it. Now I could sell it and buy a GSXR for the same money. Honestly I don't ride as hard as I did 30 years ago, but I do still get a kick out of going fast and being competitive. The CX bikes run in a pushrod class, so you really do not compete against the newest technology. I have four CX's and would only consider one of them a collector' bike. The others are somewhere between fun riding bikes and plain ugly. I don't have any problem modifying a bike that most people would part out. If you saw the "before" pictures of some of the bikes I have built, you would be surprised they ever ran again. It would cost a few thousand to restore one and that is never worthwhile when you can buy a nice one for less money and effort. I would not buy a $10,000 CX turbo to race when I can buy an ugly one for a fraction of the price. I just like motorcycles and admire the guy who restores a CB350 to showroom condition and enjoys it. I will say again that I don't like the people who buy the bikes to speculate or just to try to run up the prices. Look what happened to Harleys in the 90's, it was just a game of hot potato as people bought marked up bikes and tried to resell them at even higher prices.

I am on this forum to get some ideas from other owners about maintenance, parts, and bikes that are for sale. I am not trying to sell anything, or sell a service. I enjoy motorcycles and find that working on them and riding them is pretty relaxing for me.
See less See more
And there are several on the forum who find dislike for those who might purchase a rare bike and turn it into a racebike with likely no future possibiltiy of being returned to stock. Althouh not a speculator or trying to 'run the price up'; even those type are permitted to do with their bike what they desire.

There is likely a balance between those who dislike investors and 'stewards' of motorcycling history who keep them in riding or restorable order (even for someone else) and those who take such rare bikes and destroy them by racing them or parting them out.

The Harley phenomenon had little to do with rarity of bikes. Perhaps there were rare editions made, but even very few of these editions have collector value. It was done more on the status of owning a harley.

These are not peoples lives that we are talking about though and the importance of such material issues can sometimes get taken beyond its appropriate perspective.

I simply wished to expose to you the inconsistency of your felt value of your Gamma vs the 650T and correct you on your error of the rarity of the Gamma vs the 650T.

What is smarter, to buy a clapped out bike and get it running again or to part it out and double your money? Or better yet, spend $6000 on it to make it a bike you can sell for $4000?

I bought my RG500 many years ago for about $3000. It is now worth $10 to 12,000. I am not going to race it or modify it and only ride it occasionally. Seems smart to take the money and put it back into something I will enjoy or have fun playing with.

As to rarity how many RG500's have you seen advertised in the US lately? I see two or three 500Ts or 650's advertised virtually all the time on Craigslist or Ebay, yet seldom see an RG500. If the RG's are more common they must not trade very often and when they do it is always at a higher price than the turbo bikes. If there were a lot of RG's in this part of the world they would certainly sell cheaper.
See less See more
Edh - Did you see this engine on craigslist? Engine is serial number RC16E-2001347. Possibly not far from you in the I'm not sure where in Arkansas you are located. Price seems like it is a little high considering what it is missing and also that its true status is unknown. Its been for sale for a while though, so maybe you could check it out in person and then negotiate. Anywho, just though I'd pass along...
Thanks for the tip. It is about two hours away, but they have good BBQ there. I have to pass through there to pick up the bike in Illinois anyway. Price is a bit high, but like you said he may budge on it a bit. Shipping is about $200, plus crating costs, so local pickup is his best bet to try to sell it.

How did you find the engine, most of the Craig search things are kind of worthless now?
1 - 16 of 56 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.