Dynoed a stock 85' 200, modded 85' 200x and the stock 250 Big Red today

[Mickey Dunlap]

Did a truck load of dynoing today! lol

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First up was the mighty Big Red 250es, and it laid down a arm ripping 9.1 rear wheel HP! That will shock most people, but that's why you get a bench mark before and after mods. You will have to wait a few weeks for the 350cc big bore kit results, but it just goes to show you what the power loss is on a shaft drive bike.

Next up was the stock 200x, and it was real close to the 11 HP we made at Powroll some 32 years ago and that was 10.44 rear wheel HP. To be fare this bike had a bent axle and a bit of a loose cam chain which made the dyno graph look like it had a bit too much caffeine, but it was very close to what it should have been so I happy with the numbers so far.

Then I did the 200x with my .020 over 11.5:1 piston, trail race cam to run on pump gas, a big valve head with a 30mm carb kit I came up with that flows the same as my Powroll 28mm round slide Mic.. The only thing I wish I did was bring my Powroll pipe because the stock DG pipe is about 4 inches longer in the head pipe and has a longer tapper on the meg all which make power at a lower RPM then I would like to see for the cam I was running. So the end result was a 16.4 rear wheel HP engine that I felt should have made 18 HP. But those are the number, about a 60% gain. Also just so people know we drained the tank at the last run and put in some VP C-12 race gas and it showed no HP gain, it just richened it up a tad in the mid range so if you were racing it would run a little cooler and may pull a little harder under more of a load.


When I make my next trip up to the dyno I will be taking my 212cc Team Honda Powroll 200x up as I raced it, and a 4 inch shorter DG pipe just to get the numbers to see if I can make it work better then it did on the other 200x.

[Mickey Dunlap]

Wrong truck load of trikes! LOL

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[christph]

Wow, I'm really excited to hear about your 200X kit as I plan on doing some mods this summer. Regarding the 30mm carb, is that a bored out Keihin PD 27mm? I saw a picture of the engine on your facebook account. I already bought one from DG and am wondering if I can just send it to you to get bored out. I'm also using the XR 200 intake manifold. Is that what you are using too?

[Mickey Dunlap]

Wow, I'm really excited to hear about your 200X kit as I plan on doing some mods this summer. Regarding the 30mm carb, is that a bored out Keihin PD 27mm? I saw a picture of the engine on your facebook account. I already bought one from DG and am wondering if I can just send it to you to get bored out. I'm also using the XR 200 intake manifold. Is that what you are using too?


No this is a true 30mm that I mod the insides to get it to flow better, it works better then my Powroll 28mm did. I can't do much with the 27mm, I already tried.

[Keith Salyer]

Is that the engine combo for the 200X that will squash the 250R's on the tight indoor /rodeo tracks? Also how different was your setup when you were giving everybody fits in the big trike class.

[christph]

No this is a true 30mm that I mod the insides to get it to flow better, it works better then my Powroll 28mm did. I can't do much with the 27mm, I already tried.

Is it a Keihin 30mm? I didn't know Keihin made the PD in a 30mm.

I just came across this on ebay. It says it is a 30mm Keihin with an accelerator pump but the price suggests it's a Chinese knock off.

http://www.ebay.com/itm/KEIHIN-30mm-PZ30-Carburetor-Accelerating-Pump-Throttle-Settle-Cable-CB-CG-200-/191343317808?hash=item2c8cf35330&vxp=mtr

[Mickey Dunlap]

Is that the engine combo for the 200X that will squash the 250R's on the tight indoor /rodeo tracks? Also how different was your setup when you were giving everybody fits in the big trike class.

I didn't get to ride the bike much that this engine is in because it has big tires on it where I could only break it in in first gear, plus it has no foot pegs or brakes on it at all. Any way I ran a 218cc bike at Mickey Thompson races that had I think 24hp. The torque of it is what made it work. I don't think it's going to out run 250r's, this is just a pump gas play racer.

[Mickey Dunlap]

Is it a Keihin 30mm? I didn't know Keihin made the PD in a 30mm.

I just came across this on ebay. It says it is a 30mm Keihin with an accelerator pump but the price suggests it's a Chinese knock off.

http://www.ebay.com/itm/KEIHIN-30mm-PZ30-Carburetor-Accelerating-Pump-Throttle-Settle-Cable-CB-CG-200-/191343317808?hash=item2c8cf35330&vxp=mtr

That looks good but I don't think it will fit without cutting the frame. I was going to cut the frame because I have another 30mm with pump that I have flowing another 15cfm, but this one fits and flows as good as what I raced with but it's a oval bore vs. round bore and they perform better. This one also uses the stock cable for the thumb throttle with most people want that I talked to. All of the carbs with pumps need a twist. So I can sell the carb and manifold all modded ready to bolt on for $120. Great carb kit for the price.

[yaegerb]

You should put mine or xrider's 200x on your dyno :)

[whipit]

stingy dyno. not a dynojet I assume. any idea
what kind of numbers would something like a 450R pull on this particular unit?

[Mickey Dunlap]

You should put mine or xrider's 200x on your dyno :)

Bring it over.

[Mickey Dunlap]

stingy dyno. not a dynojet I assume. any idea
what kind of numbers would something like a 450R pull on this particular unit?

Not really when the stock 200x was with in a half of a HP of what I know it would have been.

[bkm]

I bet a high compression big bore with cam and good exhaust would do good against a 250r on a tight bull ring flat track. I raced basically stock 250r's last year on my bike and I was overpowering the tires and track with my 310. You put kart tires on a lightweight 200x with close to 20whp,and it will do very well against a 250r on a tight track.

[Mickey Dunlap]

I bet a high compression big bore with cam and good exhaust would do good against a 250r on a tight bull ring flat track. I raced basically stock 250r's last year on my bike and I was overpowering the tires and track with my 310. You put kart tires on a lightweight 200x with close to 20whp,and it will do very well against a 250r on a tight track.


I looked back over the dyno sheet and it was getting peak power at only 5000rpm, should be 8000. Pipe is 4 inches too long for this cam. Great trail pipe with my smaller cam. The 13:1 would help but it's not going to do much for HP, just torque.

[bkm]

Is 20whp possible without a stroker?

[oscarmayer]

With the right mods it could be possible. But the $ you would spend. Your going to be just shy of a full race motor minus the stroker crank. On the top end alone you can easily reach $1000 with machining, porting parts and such. And you could even spend more with seat replacement, and guide replacement as well as larger valves. So how deep is your pockets will determine that factor.


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[bkm]

With the right mods it could be possible. But the $ you would spend. Your going to be just shy of a full race motor minus the stroker crank. On the top end alone you can easily reach $1000 with machining, porting parts and such. And you could even spend more with seat replacement, and guide replacement as well as larger valves. So how deep is your pockets will determine that factor.


Sent from my iPhone using Tapatalk
Seeing that Mickey thinks the above engine should have made 18 with pump gas and a different exhaust, I don't think it would take a much more to make around 2 more hp.

[bkm]

I'm not sure if the big bore needs the case machined or not, but I would think a high compression big bore, race cam, carb, big valve ported head, and real exhaust should make 20whp? Money is not really the concern, I'm just wanting to know if it's now obtainable without a stroker.

[Mickey Dunlap]

Is 20whp possible without a stroker?


It is, with the higher compression and .080 over, good pipe and some different lobe centers.