225 first ride report

[Lutz]

Well, I finally got the bike fully together and running over the weekend. To update what I have on the done to the engine: Eric Gorr 225 kit, mo-better-everywhere porting (a little bit more focused to mid and top end), Pro-Circuit pipe and silencer, Moto Tassinari V-force delta 2 reed cage (low tension setting), stock 35mm carb (40/CEL#3/160) airbox lid removed. Gearing is 13/48.

My first ride impression: WOW! The power is absolutely awesome. I started off riding slow for break in purposes, and found that the bike has some pretty amazing low end power. I was able to lug the bike in first and second gear (no clutching needed) to get through some really muddy and/or tight spots on the trails, chug-a-chug-a chug-a-chug-a. This is with the Pro-Circuit pipe and porting that is focused toward mid and top! At this point I was very happy, but I hadn't even opened it up yet.

After some slower riding I went out onto a dirt road and accelerated using about half throttle to six gear. The motor pulled very hard all the way, and cruising at half throttle the bike was going very fast, and begging for more. Even at half throttle, the bike is just begging to pull another gear past six; several times I tried, but just couldn't find seventh!

Finally, the time had come to open it up! Again, I was on a dirt road. I got on the gas hard, and the bike pulled hard through first and second gear...then I started to get some traction. Third gear greeted me with a slight loft of the front tire, and fourth gear provided an all out power wheelie, with acceleration to match. Through fifth and sixth...pull, pull, pull. Top speed is very fast; I can't make a direct comparison to stock, but it seems to have much more. Topped out in sixth, the bike is begging for a higher gear; it wants to go MUCH faster.

Acceleration from part throttle to full throttle is very good. Twist and go. Pulling the front end up in sixth gear is also not a problem: a little bit of body english and a feed of throttle-brahhp the front tire is airborne. All of this is "out of the box." I haven't changed jetting at all yet, so I expect nothing but improvement from here on.

Now the bad news: There were times that I heard some pinging :( I believe it was a result of a very cool day and lean jetting. No big deal, just something I need to correct when I get to home again. But that won't be for three weeks, and after finals!

In conclusion: two thumbs up! The new mods (225 kit and V-force reed cage), in conjunction with the mods I'd already done, make for an awesome power package. It can be lugged through the goop, flat-out screams when opened it up, and it pulls as hard as you want in between. Throttle response is great and the power is very controllable everywhere. I'm going to need a suspension revalve really soon, or I may get into trouble! ;) Also, I have my eye on the RB carb mod!

Regards,
Lutz

 

[Mac]

We have a very similar setup and I'm very interested in your jettting. Your bike is way richer than mine and you heard pinging?? I am running a 152 main with stock needle in mid position and 35mm carb. I also had the mo better porting and run the FMF REV pipe.
I also heard something at WOT but thought it was my heart beating or something.
I haven't had a chance or the location to do a WOT plug chop yet have you? I heard this mod wouldn't require any jetting changes but now I'm nervous.
I'm not sure what I heard at WOT but it prompted me to let off, thought It was gurgling (rich) causing a missfire.
Anyone know exactly how to describe what pinging really sounds like?
The bike ran GREAT btw pulling increadibly strong which made me think the jetting had to be close. When I originally had the 155 main installed the bike drank fuel like no tomorrow which also made me think I was too rich.
Maybe a quick PING test would be to add some anti-knock liquid like 104+ octane boost or trying some race fuel, any thoughts. After I dropped the main to a 152 the noise was still there but the bike seemed to run better?? Very confusing.

 

[Lutz]

I'm not absolutely positive that it was pinging that I heard, and it wasn't at wide open throttle; it occured in the midrange and not constantly. It seemed to happen when I was cruising in a high gear at part throttle (seemingly a high load situation), or sometimes if I would let off at part throttle then get back on the gas. I couldn't find an absolutely consistant situation where the sound would occur, but I also didn't put a lot of riding time in.
I did do a WOT plug chop, twice, and I can't get any color in the plug. I'll check it again when I get to ride again, to make sure I wasn't doing it wrong. I'm looking way down at the base of the porcelain, which seemed to remain white, and with the riding I did do, when I was done, the plug was still basically white, not super dry bone white, but not at all tan.
I agree that from what I've read that 160 is pretty rich, even for a modified KDX, so I am a bit suspicious.

I am going to call Eric Gorr to get his take on my situation, and I'll get back.

Regards, Lutz

 

[canyncarvr]

Thanks for the input! Certainly sounds lean. No color at all is beat out (bad-wise) by a couple other things..shiny bits or a dull aluminum color. Well...and complete stickage.

A side note...BOTH tassinari cages were called 'VForce'. The original is black (for one thing) and the II is gray. If you have adjustable tension, it's certainly a II (that said for other's info..I'm sure you know what you've got).

I haven't tried lo tension setting yet. Plan to after a couple more rides with them set at 'high'. Want to get a good feel for it now.

Please DO get back to the forum on the pinging (maybe) and the jetting.

I'm sure BRush has posted his jet selection...haven't looked for it yet.

 

[BRush]

Eric's kit sure can breathe some life into the old KDX :) I have not had trouble with pinging on mine. My typical jetting is

152, 42, AEK-4, #7 slide, and AS 1 to 2 turns out depending on ambient temperature. That's using Mobil premium pump gas and Mobil MX2T @40:1

Remember this is with the RB Carb, Boyesen power reeds, FMF Torque pipe (K35). I'm one of the hold outs still using the AEK needle instead of the CEJ, CEK, etc. as per the long jetting thread last fall. 99% of my riding is single track technical and that combo has resulted in an electric motor with lots of grunt and no big hits anywhere. A penalty is paid in the form of a minor flat spot as the slide clears the divider plate. This winter I did a little high rpm sand-pit riding and were I to do much more of that, I'd rejet

 

[Lutz]

Examining possible noise sources

BRush,
Thanks for the info. When you got your top end back, did you notice any play in the main valve when the valve was in the open (high RPM) position? In mine I noticed that the flap could hang down slightly into the exhaust port when it should be in the full open position; I think it is because the roof of the exhaust port is raised and the powervalve linkage is only mechanically able to lift the valve up to where the roof of the exhaust port was stock. It seems that exhaust pressure will force the valve against the roof of the exhaust port though, so that shouldn't be a problem in terms of flow restriction. I'm just wondering if the other 225's, and ported motors in general, are the same way; I would assume that they are.

Now to the point: I was thinking that maybe it is possible that the noise I heard was the exhaust valve slapping from the slack position against the roof of the exhaust port and back. I haven't talked to Eric yet, but when I do I'll relay his input. I haven't ruled out detonation, but I would rather the noise be something as simple as the exhaust valve making extra noise.

By the way, the gas I am running is Citgo premium pump gas mixed with Amsoil 2000 somewhere this side of 50:1, the same mix (source and ratio, not the actual fuel) I've been running for a long time with no previous problems.

canyncarvr,
Yep, it's a delta II, just bought new. For reference, it is indeed light gray in color. On the contrary to your experience I haven't tried the high tension setting yet; that's something I'll do when I get some more riding time and feel for how the bike runs. Let me now the relative power characteristics if you try switching your settings. I've read elsewhere on DRN that the Delta II's work better in the low tension setting, despite claimed shorter reed life. As to my plug readings: no sign of engine damage i.e. aluminum bits, etc. It does appear lean to my eyes, but I didn't have a light to really iluminate the inside of the plug. From what I could see in natural light on the trail, the porcelain of the plug appeared to remain white, but the metal at the base of the porcelain had taken a dark blackish color. At the end of the ride I would describe the porcelain color as "off white" to the naked eye. I do plan on doing a closer investigation when I get home; hopefully the temperatures will be a little less frigid by then.

Any other input?

Looks like an all nighter of Strengths of Materials homework for me so GOOD NIGHT :ugg:
Lutz

 

[BRush]

There has always been a bit of play in the power valve and it tends to rattle at times. I think that’s just a KDX thing, since mine did it before the big bore kit . I don’t worry about it since it does not seem to affect reliability or performance. I just did a top end and PV inspection after a year on the big bore kit and everything was fine.

 

[Lutz]

Thanks. I'm hoping that is the source of the sound. We'll see.

 

[canyncarvr]

...powervalve linkage is only mechanically able to lift the valve..

All that (flapper fit etc.) is something that is advertised as being massaged as part of the big bore process. Hopefully it wouldn't be pollyannish to expect it to be correct?

HHmm...'strength of materials' study. Anything over 5.0 is usually pretty good, tending toward a strong #1 hop (bittering). Watch your AAU% cuz this year's crop is a bit on the low side (chinook going from 17% to 10.8%!)
;)

 

[Mac]

Keep us posted Lutz I'm hoping this is also the sound that I'm hearing. I only seem to hear it at 3/4 to WOT.
I do hear the powervalve open with a metallic clink but this is dependent on RPM not throttle position, If I maintain mid-high RPM and blip the throttle I can hear the PV open and close in sync with the front end lifting but that is not the noise I'm worried about. The noise I am concerned with is when I hold WOT I hear multiple ticks in sync with a slight power loss, not sure if it's pinging or plug missing.
BRush is running the RB carb mod with a torque pipe so his jetting will be way different. I think the kg-35 requires leaner jetting than the kg-30 expecially at WOT so I can't use his jetting for comparison. I only hear the problem when my RPM is topped out at WOT so maybe if I had a torque pipe that didn't rev as high I wouldn't have the problem either. :think:
Anyway I was hoping the jetting would be close but it looks like I should just start over from the beginning, only problem is finding a place to hold this thing at WOT for 30 seconds since the quads tore up the railroad bed. :|

 

[Lutz]

I talked to Eric this afternoon and asked him about the powervalve. As I expected, he said it is normal for the powervalve to hang down a little in the open position and that it will be pushed fully open under exhaust pressure. He also said that he doubts that one would be able to hear the valve fluttering.

All that (flapper fit etc.) is something that is advertised as being massaged as part of the big bore process.

Right, but the powervalve mods that are done in conjunction with the big bore kit only involve cutting the valves so that they don't potrude into the cylinder and hit the piston; I think it would be hard to modify the valve to lift higher than it does in stock condition, based on how the job is done, but maybe worth looking into in the future. Regardless, it seems that the powervalve probably isn't the problem.

Which brings us back to detonation: Eric told me that I should try richening the needle (remember my problem is in midrange) and/or retard the timing. Those are the two things that I figured on trying anyway if necessary, and Eric's input reinforced my thinking.

Mac, for your problem, I would try richening the main jet first and check it with plug chops; if that doesn't work, then try retarding the ignition timing. Also, have you checked your float level? Come to think of it, I haven't checked mine... As general information, when my bike was stock other than the PC exhaust, I tried running a 152 main jet, and it left the plug bone white lean lean lean. Of course I wasn't running oil in my air filter then, so I think that made my jetting requirements a bit different than others'. Still, it doesn't seem unacceptable that a 152 main could be too lean on a ported 225 with a rev pipe. Then again, maybe your jetting is close and the problem lies somewhere else. I would expect the bike to use a lot more gas than stock, regardless of jetting: more power=more gas. I think that it might be interesting to try some octane boost just to see if the noise dissappears (I wouldn't run the stuff for any other reason or length of time); if the octane boost did fix the problem, I would try retarding the timing for sure.

I wish I didn't have to wait so long to get back to my bike and sort the problem out, but I guess them's the brakes :whiner: Keep on with any updates everybody.

HHmm...'strength of materials' study. Anything over 5.0 is usually pretty good, tending toward a strong #1 hop (bittering). Watch your AAU% cuz this year's crop is a bit on the low side (chinook going from 17% to 10.8%!)

Still laughing about that one!

Good day,
Lutz

 

[Lutz]

I was digging through info on the internet to find the correct way to read a spark plug and I found a site that gives some really good information on spark plugs, ignition timing, and most importantly in this case, a cutaway picture of a spark plug that shows exactly where to "read" the plug color at. Click www.strappe.com/plugs.html for the sparkplug site.
I found the first page linked off of this one: Macdizzy.com. This page is an awesome source for information on two stroke engines, among other things.

From what I've read, I think I was doing my plug readings wrong: specifically looking even higher on the porcelain of the insulator than I should have, plus I didn't have good enough light to actually see the base of the insulator well. In hindsight, I think my WOT plug reading might have actually been telling me that my main jetting was OK, or even too rich. I can't say for sure without doing another plug chop. What I do know is that the metal around the base of the insulator was covered with soot, but I couldn't tell if or how far the "mixture ring" went on to the insulator. I'm thinking, from what I can remember, that the jetting was rich.

I also plan on checking my ignition timing. I don't think now that it is too advanced, but it might possibly be too far retarded. And I'm very much under the impression that my pinging was just a result of having the needle in too low a clip position. I think moving it form #3 to #4, along with the expected much warmer weather, should fix the problem...time will tell.

Anyway, check out those web sites and enjoy! You'll probably learn something along the way, too.

Regards,
Lutz

 

[Mac]

Thanks for the update Lutz.

I have no desire to run race fuel either, only thought it would be a good test. I'm still not sure it's even detonation. I remember when my Talon tsi had a detonation problem (after I played with the boost) It was very obvious. It felt like someone was jamming on my brakes off and on real fast like the ABS went crazy. I guess my question is how hard would detonation feel on a 2stroke? What I felt was very mild but sounded bad.

I agree, better to be safe than sorry, think I'll throw the 160 back in and work my way down. Hopefully I'll get out this weekend to do some testing, I'll post any results.

 

[Lutz]

I have no desire to run race fuel either, only thought it would be a good test.

Not running race fuel isn't really what I meant: I would love to have the money and supplier to run race fuel all the time, but it's just not practical. What I meant was I wouldn't use an octane booster unless I absolutely had to; there are quite a few threads on why octane booster isn't good and race gas is, so I won't go into the reasons here. That said, it might still be a good test to try octane booster to see if it solves the problem (race gas would be even better); but I think it is important to make sure your jetting isn't too lean first. Race gas would probably prefer leaner jetting anyway, but I don't think octane booster would.

I had never really heard detonation before now (maybe a few times in cars), but I'm pretty sure that's what it is: a loud metallic "pinging" sound. I have a feeling that the pinging sound is something that you will "just know" if you've heard descriptions of it. For the most part, nothing bad feeling happened when I heard it, but it sounded bad. In your Talon, I doubt it was the effect of the detonation you were feeling directly; your car, especially since it has a turbo, will have a knock (detonation) sensor that is linked to the computer to prevent damage from detonation. When detonation is detected, the computer retards the timing until the detonation quits, then returns to the original setting, or something on that order. Anyway, the resulting fluctuations in power probably what caused the surging feeling you experienced; because our bikes don't automatically retard the timing when detonation occurs, we probably won't feel as drastic a power loss.

While I was trying to figure out a repeatable situation where I would hear pinging in my bike, I also noticed that the power seemed a little bit flat, i.e. lean, around the area where the pinging would occur. Once again the pinging would occur when I was cruising at part throttle in a high gear (which is actually seems to be a high-load situation, on the contrary to my first description of when it would occur.) So once again, I assume that my jetting is just slightly lean there when under a higher load, resulting in detonation. It sounds like you have a similar situation; if you feel like there is a slight loss in power when you hear the pinging, it probably means the jetting is getting a bit to lean under the high load of WOT. By all means, go to the 160 main and work from there. You may not be far off right now, but from what I've read, there is a fine line between the jetting that gives top performance and the jetting that begins to cause detonation; I think that's where I'm at with my needle clip position right now.

I appologize if I get to long winded in my posts, but this is a learning experience, and I think I should be as thorough as possible to get the most out of it.

Mac, good luck if you get to do any testing this weekend.

Regards,
Lutz

 

[Mac]

Thanks Lutz, tried to give you some MOJO but I don't think it worked. Cdave?? Anyone?? I just get a white blank screen. Can anyone give Mojo or is it admin only?