Jump to content

Honda 200 engine modified...........!

Recommended Posts

No transmission or clutch, modified for 1/2 midgets.  Powroll did some of these a number of years ago with sand cast cases. This is a later version with machined cases done by another outfit.  This is what the top end cam Powroll sold was designed to be used in.  I'd  like to find one of these to install in a racing kart chassis, using a kart type clutch.

 

Old school Al

Kart engine.jpg

Edited by Old School Al
  • Like 1

Share this post


Link to post
Share on other sites

Hey Al....Interesting.....what is the output gear ratio running directly off the crank??

Share this post


Link to post
Share on other sites

I have no idea how they gear these and that could change with conditions.  Actually "output off the crank" would be 1.1 as there are no gears wouldn't it?

 

Old School Al

Edited by Old School Al

Share this post


Link to post
Share on other sites

Al, got any idea what size pumper carbs Pete was using?  Still no progress shown on the Powroll web site!

Share this post


Link to post
Share on other sites

I don't Swiss.............I'm going to try and get some more info on it this winter.  

 

Did you notice the size of the crankcase vent by chance...............? ;)

 

Old School Al

Edited by Old School Al

Share this post


Link to post
Share on other sites

You need to release a LOT of air with the small case and the amount of air these engines are capable of pumping through the case vents!  No reason not to be turning that engine upwards of 12,000rpms!

 

Swiss

Share this post


Link to post
Share on other sites

Wouldn't that be getting into CRF rpm territory...........?  Where does the rev limiter stop the CRF's that are designed for high rpm......?

 

Old School Al

Edited by Old School Al

Share this post


Link to post
Share on other sites

Al, don't own a CRF so don't know about their rev limiters.  The XR200 stock stroke is the same length as the early XL250 Honda 4-v engine.  Paul at Powroll took an XL250 and set it up for Flattrack racing and they were running it at 13,600rpms on the dyno and track.  Bigger and heavier valves than the XR200 runs as they used XL350 valves in a hogged out 250 head.  Not much difference in the valve spring pack specs for racing springs between the XR200 and the XL250/350 heads...  The 200 head neads about a .150" spacer underneath it and you can actually run the 250/350 springs.  I had some of the new design Beehive springs made up for me by RD Springs for my XL350 and with the spacer, they fit the 200 head.  The Beehives don't have a harmonic rpm frequency that will cause valve float and they are a single spring design which eliminates the interference/rubbing and heat generation that the dual spring sets cause.   

 

The main problem with the 200/230/250 engines trying to run at 12,000rpms is breathing through the stock 2-v head.  The CRF230 head has larger valves and could possibly make good power well past 10,000rpms.  Need to make sure that you have a good oiling system and a stock stroke 200 crank with a big bore piston between 69-70mm would probably work well.  That will give up to 222cc and the same power as the stroker cranks.  Long strokers with short rods do NOT make more power than a good equivalent big bore engine.

 

The real advantage of the CRF engines is the ones that have the 4-v head.  At least for making power and rpms.. 

Share this post


Link to post
Share on other sites

I realize you don't have CRF's, but with all the research you do I figured you may have some idea.  On the stroker vs big bores, short stroke large bore is going to make more power with more power strokes per minute.  In some applications the more usable delivery of the (lesser) power of a stroker is a advantage though.  In this application I would not want a stroker for a couple reasons.  I wouldn't get too carried away on this engine at  first and see how it stayed together.  Lots easier and cheaper to start off mild and work up to find the limits.  While the old two valve head may be limited, it will still perform well enough to surpass what the rest of the engine will handle.  I agree on the CRF engine........if I was going to go high rpm, I'd go with a CRF engine that is designed for it. :thumbsup:   

 

Old School Al

Edited by Old School Al

Share this post


Link to post
Share on other sites

OSA,

 

Back in 1971 I was moved to Alaska by my "employer" the US Army.  I took along my SL125 that I had confiscated from my then wife as she had forced me to sell my dearly loved Norton P-11.  I began drilling holes in the frame and various other pieces which earned me the nickname Swisscheese from my Army buddies!  That was my "racebike" back then and I ran a big Norris cam and sent the head off to Jerry Branch to have ported and put the 1" spacers in the front forks for more travel etc..  But at the local MX track I met a Honda Shop Mechanic from Anchorage, AK (we were in Fairbanks) who was racing an earlier SL100 with the 175 piston and full race cam and running on methanol etc...   I talked with him and asked him what kind of rpms he was turning with the little 49mm stroke 117cc engine?  He said that they had run it up to 14,000rpms and did so regularly on the track.  He also said that they didn't bother to run an air filter, just a velocity stack and that the engine was so cheap to rebuild they didn't worry about it.  They just ran it until it came apart and then rebuilt it and went back to the track!  HA!HA! 

Well, I was not a shop employee, sponsored by the owner and had to pay for my parts so I ran air filters and such on my engines but still took the little 125 regularly to over 12,000rpms, bottoming out the tach and then shifting.  Fairly reliable for the time and never blew the engine until I was drag racing an XL250 and running some Nitro 9 in the fuel tank along with a Powroll stroker crank and a Yosh piston.  But that bike would pull right off the bottom end with the biggest Megacycle cam they made and I could play Trials rider all the time! 

 

Basically, Paul and Pete at Powroll tuned the XR200s for low to mid-range power not because they would not rev to 10,000+rpms but because the typical rider didn't take good enough care of his engines to keep them reliable when running like that.  Just like their 13,600rpm XL250 engine, they could build you whatever kind of race engine you wanted but the warranty went away!  HA!HA! 

 

I thought that it was interesting that when Honda built the XRF250R engine with FI they used the same 50mm unit that they had used on the CRF450R!  Sure would be neat to see a dyno chart on that built up XR200 top end built for racing. 

  • Like 1

Share this post


Link to post
Share on other sites

Fascinating discussion.  Thought you guys might get a kick out of this - XR200 with one-fourth of a 4-valve CB750 head.  Keith Leighty in El Paso built this just because somebody told him it couldn't be done.  I think he spent a year on it ...  He's mostly retired now and building Honda motors for the AHRMA road course guys, but he's the one that built me that super-trick XR200 in the CR125 frame a while back.  All his stuff is museum worthy.

 

XR200wCB750headside_zps088ea07b.jpg

XR200wCB750headfront_zpsee0eb868.jpg

200left03.jpg

  • Like 1

Share this post


Link to post
Share on other sites

Keith has always built custom trick bikes, from back in the days when he and his brother owned Lone Star Honda in the '70s and '80s.

 

Swiss

 

It would be interesting to know what adding the DOHC head did to the engine weight?

Edited by Swiss

Share this post


Link to post
Share on other sites

Cool that you know of Keith.  I bought one of the first CR125 Elsinores in the country from Lone Star in November of 1973.  Keith let me make payments on the down payment until I had enough to take it home.  I used to stop by the store at 6 AM every day on the way home from my paper route just to look at it through the window.  Keith was putting tricked-out 4-stroke motors in Elsinore frames from Day 1.  His bikes have won their class in Baja, Tecate and Barstow more than once.  One bored and stroked XL175 in an Elsinore frame he built ran an honest 97 mph on the dry lake beds, and caught the eye of a guy named Malcom Smith who came over in the pits and asked, "What the heck is that thing that's keeping up with me?" 

  • Like 1

Share this post


Link to post
Share on other sites

hey guys ,i knew keith back in late 70s early 80s.bought several bikes from him out of el paso.i lived in alamogordo nm and was competitive with texas enduro circuit.i don't know how many times people paid the 50 bucks at enduros to protest his engines at these races.he would teardown engine to have piston measured and could do it in a very short time.i often thought he loved doing this to piss people off and get gas money to go back home! i would like to visit him if any one has contact info.

rimtrail105

jimmy birdwell

mayhill,n.m.

Share this post


Link to post
Share on other sites

hey guys ,i knew keith back in late 70s early 80s.bought several bikes from him out of el paso.i lived in alamogordo nm and was competitive with texas enduro circuit.i don't know how many times people paid the 50 bucks at enduros to protest his engines at these races.he would teardown engine to have piston measured and could do it in a very short time.i often thought he loved doing this to piss people off and get gas money to go back home! i would like to visit him if any one has contact info.

rimtrail105

jimmy birdwell

mayhill,n.m.

Hey Jimmy,

 

Last time I put his info into the address book was in 2004 so I can't say if he will still answer any of it.  He had a small shop in the back of an Auto Race Shop in El Paso.  Called his shop Kustom Works.  His shop phone # was 915-598-8823 and his email address was kleighty1@elp.rr.com

 

None of this may be current, last time I saw him was about 5 years ago at that shop.  Working on a variety of stuff, mostly older bikes. 

 

Swiss

Jim Schneider

PDMC

Share this post


Link to post
Share on other sites

That contact info is correct.  A few years back, he expanded and moved the shop.  He's mostly retired now, and finally "getting to work on my own stuff"...in his words.  He's really active in vintage road racing.  In fact, he just got back from some east coast events.  His knowledge and fabrication skills are unmatched.  You should see some of the stuff in his private museum.  Unbelievable. 

  • Like 1

Share this post


Link to post
Share on other sites

Hey Jimmy,

 

If you set up a weekend trip down to visit, let me know and I will be happy to ride down with you.

 

Swiss

Share this post


Link to post
Share on other sites

Well I found a fairly trick older kart chassis...........with Yamaha KT100 engine.  Now I need to find a good deal on the special 200 engine lower end etc............I have lots of top end parts.

 

Old School Al

kart 001.JPG

Kart engine.jpg

Edited by Old School Al

Share this post


Link to post
Share on other sites

Just rebuilt one of those cart motors a few months ago. Basically a 12-1 stock stroke(due to class cc limits back when they were made) Ported head with a #40 Megacycle cam. Had some with Web Cam also. Pete has a list of each one as they were numbered.

 

Girl that runs the cart is one of the top cart racers in nation. She just got new one with Yamaha R6 motor. Now that one I really want to drive

Share this post


Link to post
Share on other sites

Hey mcdirtclod, I am building a cr125 /xr200 for vintage motocross and came across your old bike. I am actually using the same year cr i got from a friend. I was wondering if I could pick your brain on a few things? I am planning on doing some different motor mods than anything I have seen so far. I have rules I need to stay with in ,so I am staying with the stock bore and stroke , but doing extensive head work. It looks like the cumbustion chamber and valve size is for a 125cc. If you could pm me.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×