Kdx 220 running issues again

[JZ05220r]

For those of you who may have seen my posts in the past about my 220 may recall some issues I have had (air leak at reed gasket, leak between case half’s just below the exhaust port). Well I got the engine leaks fixed. The bike is still displaying similar symptoms that I have had before. I have been through so many aspects of the bike in order to get it to run good. I am at a point where the bike just feels so zingy it’s almost like it’s simply overheating or heat soaked. The power is pretty radical like an on/off switch. Definitely missing a lot of smoothness. The one thing I haven’t messed with is ignition timing. If over heating is the issue with the bike would retarding the ignition help? Also I mentioned to Jeff Fredette in the past that I was running the RB head. He mentioned that Ron takes off more material then he does himself. Maybe I am just a bit to extreme with cylinder mods and cylinder pressures are too high for the stock ignition timing. I am running a lectron carb now as well. Weird because the bike was far more powerful and smooth the first time I took it out with the lectron and the refreshed/fixed engine. From there it gradually started to feel less and less strong as I have ridden it. I’m up to about 3-4 hours since getting the engine taken care of and the new lectron carb. Any suggestions. My engine has been to Jeff twice already due to the leaks I found and I’m not considering the mechanical components of the engine to be the culprit anymore. Thanks

[Molly's 70]

Check all your grounds. If your sure all your mechanicals are sound, then maybe it's electrical.

[JZ05220r]

Check all your grounds. If your sure all your mechanicals are sound, then maybe it's electrical.

I can double check those.

[kdxdazz]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220 until I stopped taking advice from others and started studying, yes I do realize the irony in me giving advice. What needle are you running ? I also have a lectron on my kdx, I also have an RB head and a stock head

[JZ05220r]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220 until I stopped taking advice from others and started studying, yes I do realize the irony in me giving advice. What needle are you running ? I also have a lectron on my kdx, I also have an RB head and a stock head

Hey so I have the lid on but no snorkel, it’s in my tool chest. Which air boot are you referring to? Pre carb or manifold? Did not check the squish band. I think I remember asking Ron to set it to run safe on 93 but I’m sure that didn’t make a difference as to how he does it. I am running a 3-2m metering rod. Thank you

[kdxdazz]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220 until I stopped taking advice from others and started studying, yes I do realize the irony in me giving advice. What needle are you running ? I also have a lectron on my kdx, I also have an RB head and a stock head

Hey so I have the lid on but no snorkel, it’s in my tool chest. Which air boot are you referring to? Pre carb or manifold? Did not check the squish band. I think I remember asking Ron to set it to run safe on 93 but I’m sure that didn’t make a difference as to how he does it. I am running a 3-2m metering rod. Thank you

Carb boot, also check you have the plastic insert in the reed block and nobody has dremilled it in anyway, carb boot has 2 seals witch are prone to flattening, once that happens it's impossible to get it to seal, I have a YouTube channel showing how to make a simple leak down tester using a blood pressure gauge, I was surprised by how badly my carb boot was leaking

[SS109]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220...

I don't know why you keep saying this as it's simply not accurate and I completely disagree with you on many points. When have I or anyone else that is a regular member here claimed they wanted the most peak power out of our KDX220's? Most want a smooth wide powerband and not to turn the KDX engine in to some peaky MX style engine. That is not playing to the strengths of the KDX 220 engine. My engine absolutely lugs like crazy, yet will scream pretty good up top, best of both worlds, but still not even remotely close to a peaky engine. I prefer the 220 engine over the 200 just because, when modded, it does have a much wider powerband than the 200 and I don't have to ride it like a 125 2T to get it to move. I'm not a fan of porting the 220 to make it behave more like the 200 either. The stock 220 porting is perfect IMO. That said, the RB head and carb, the FMF desert pipe, Boyesen RAD Valve/Vforce III reed setup really wake up the 220 without losing anything down low and, if it actually does, it's so little it's not noticeable to me.

Also, the air box lid is not designed specifically to help a linear power delivery. Yes, it helps accomplish that because it chokes the hell out of the engine so it can't help but be linear. It's primary functions are to quite down the intake noise and to help reduce water ingress to the air box.

As for squish on the head, the tighter you go the more overall (not peak) torque you can produce provided you don't raise the compression to a point where it exceeds the detonation resistance (octane rating) of your fuel. This is well known for any type of the normal internal combustion engines.

You talk about smooth power. Obviously, what you want out of your KDX is for it to be the absolute smoothest engine possible for your terrain and riding style. Well, I've learned the better I am with my clutch the smoother I am. Just something to ponder.

JZ05220R, what octane fuel are you running? IME with RB's head mod (3 different bikes now) you need to run 91+ octane with it or the engine would start to run hotter than normal and it would get that zingy feeling as well. I also wouldn't mess with the ignition timing until you know everything is working right first. The stock ignition should work perfectly fine with your mods. Hell, even with all my mods I can dial in more advance and still not have issues with 91 octane fuel in 100+F temps. A leakdown test I think is in order to eliminate any possible leaks. Double check your Lectron settings and make sure you have the proper needle in it that Lectron recommends for the KDX. Oh, how does the spark plug look down at the base of the porcelain? Got a pic of it?

[JZ05220r]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220...

I don't know why you keep saying this as it's simply not accurate and I completely disagree with you on many points. When have I or anyone else that is a regular member here claimed they wanted the most peak power out of our KDX220's? Most want a smooth wide powerband and not to turn the KDX engine in to some peaky MX style engine. That is not playing to the strengths of the KDX 220 engine. My engine absolutely lugs like crazy, yet will scream pretty good up top, best of both worlds, but still not even remotely close to a peaky engine. I prefer the 220 engine over the 200 just because, when modded, it does have a much wider powerband than the 200 and I don't have to ride it like a 125 2T to get it to move. I'm not a fan of porting the 220 to make it behave more like the 200 either. The stock 220 porting is perfect IMO. That said, the RB head and carb, the FMF desert pipe, Boyesen RAD Valve/Vforce III reed setup really wake up the 220 without losing anything down low and, if it actually does, it's so little it's not noticeable to me.

Also, the air box lid is not designed specifically to help a linear power delivery. Yes, it helps accomplish that because it chokes the hell out of the engine so it can't help but be linear. It's primary functions are to quite down the intake noise and to help reduce water ingress to the air box.

As for squish on the head, the tighter you go the more overall (not peak) torque you can produce provided you don't raise the compression to a point where it exceeds the detonation resistance (octane rating) of your fuel. This is well known for any type of the normal internal combustion engines.

You talk about smooth power. Obviously, what you want out of your KDX is for it to be the absolute smoothest engine possible for your terrain and riding style. Well, I've learned the better I am with my clutch the smoother I am. Just something to ponder.

JZ05220R, what octane fuel are you running? IME with RB's head mod (3 different bikes now) you need to run 91+ octane with it or the engine would start to run hotter than normal and it would get that zingy feeling as well. I also wouldn't mess with the ignition timing until you know everything is working right first. The stock ignition should work perfectly fine with your mods. Hell, even with all my mods I can dial in more advance and still not have issues with 91 octane fuel in 100+F temps. A leakdown test I think is in order to eliminate any possible leaks. Double check your Lectron settings and make sure you have the proper needle in it that Lectron recommends for the KDX. Oh, how does the spark plug look down at the base of the porcelain? Got a pic of it?

I’m running 93 octane. I can do another leakdown test. If I see any leaks I’m not going be extremely happy. Jeff’s split the cases twice in total already to do crank seals and because I found the crankcase leak externally. I do have the correct needle for the lectron. I’ll take my plug out after work today and see what it looks like. I’m wondering if this a temperature dependent leak that suddenly gives way and persists. I keep thinking about the possibly of an air leak between the crankcase and the gearbox. Not sure how to target that one. Whatever this problem is it’s not going away after a guy like Jeff Fredette split the cases twice. The idea of buying brand new oem cases has crossed my mind but I need to confirm every possible scenario. I just want to have fun, bottom line. This ain’t fun.

[SS109]

Sorry you're having so much trouble with your bike. KDX's normally aren't much of an issue to keep running well for years on end.

Yeah, gotta do the leak down again. Never trust anything and always confirm. If there is a leak between the engine and trans areas the leak down will show it. Of course, locating exactly where it's at is another story. Check everything externally and if nothing there then it would have to be between the crank case and trans. Don't even trust the new stuff like the crank seals. Check it all!

[JZ05220r]

Sorry you're having so much trouble with your bike. KDX's normally aren't much of an issue to keep running well for years on end.

Yeah, gotta do the leak down again. Never trust anything and always confirm. If there is a leak between the engine and trans areas the leak down will show it. Of course, locating exactly where it's at is another story. Check everything externally and if nothing there then it would have to be between the crank case and trans. Don't even trust the new stuff like the crank seals. Check it all!

I assume I should remove the clutch basket to check the right crank seal. Remove the flywheel to check the left one. When installing the flywheel is it safe to hold the flywheel with my flywheel holder tool while tightening the nut or can this possibly cause the key or key way to sheer? I’m sure it’s fine but just want to double check. Also what would the fix be for the crankcase and gearbox compartment leak if that was the case?

[Slick_Nick]

Sorry you're having so much trouble with your bike. KDX's normally aren't much of an issue to keep running well for years on end.

Yeah, gotta do the leak down again. Never trust anything and always confirm. If there is a leak between the engine and trans areas the leak down will show it. Of course, locating exactly where it's at is another story. Check everything externally and if nothing there then it would have to be between the crank case and trans. Don't even trust the new stuff like the crank seals. Check it all!

I assume I should remove the clutch basket to check the right crank seal. Remove the flywheel to check the left one. When installing the flywheel is it safe to hold the flywheel with my flywheel holder tool while tightening the nut or can this possibly cause the key or key way to sheer? I’m sure it’s fine but just want to double check. Also what would the fix be for the crankcase and gearbox compartment leak if that was the case?

That’s what a flywheel holder tool is for.

[JZ05220r]

Sorry you're having so much trouble with your bike. KDX's normally aren't much of an issue to keep running well for years on end.

Yeah, gotta do the leak down again. Never trust anything and always confirm. If there is a leak between the engine and trans areas the leak down will show it. Of course, locating exactly where it's at is another story. Check everything externally and if nothing there then it would have to be between the crank case and trans. Don't even trust the new stuff like the crank seals. Check it all!

I assume I should remove the clutch basket to check the right crank seal. Remove the flywheel to check the left one. When installing the flywheel is it safe to hold the flywheel with my flywheel holder tool while tightening the nut or can this possibly cause the key or key way to sheer? I’m sure it’s fine but just want to double check. Also what would the fix be for the crankcase and gearbox compartment leak if that was the case?

That’s what a flywheel holder tool is for.

Yea that was dumb. In the past i remembered using the clutch basket holder on other machines I have owned

[JZ05220r]

The spark plug. The transmission fluid level is halfway up the window. I started it above the window on purpose. I may talk to Jeff about this. I would split the cases and fix it myself but this is clearly going over Jeff’s head and surely would mine. I wonder if he can make some kind of exchange deal.

[SS109]

Wow, that's black! Either you're running pig rich or you're sucking trans oil. Of course, it could be both!

I wouldn't worry about pulling the flywheel or right engine cover unless you do show a leak you can't find through the normal methods. No the leakdown again and see what you find.

[Slick_Nick]

Yea that was dumb. In the past i remembered using the clutch basket holder on other machines I have owned

It's the same thing. The pegs to hold the flywheel are on the backside of the clutch hub holding tool.

[JimmyB]

Leak down test is in order if you are losing tranny oil to find if its the main cases, crank seals or a common area with these motors the cast steel inserts for the crankshaft main bearings. There are 3 slots both on the flywheel and clutch side where the aluminum sometimes was cast thin and can expose the steel sleeve for the bearings, causing a air leak on the flywheel side or oil(tranny) to be drawn into the crankcase on the clutch side. Fill these slots with JB Weld(Original 24hr cure formula)if this is the case, I usually did this both sides as a preventive measure on the first rebuild.

[JZ05220r]

Leak down test is in order if you are losing tranny oil to find if its the main cases, crank seals or a common area with these motors the cast steel inserts for the crankshaft main bearings. There are 3 slots both on the flywheel and clutch side where the aluminum sometimes was cast thin and can expose the steel sleeve for the bearings, causing a air leak on the flywheel side or oil(tranny) to be drawn into the crankcase on the clutch side. Fill these slots with JB Weld(Original 24hr cure formula)if this is the case, I usually did this both sides as a preventive measure on the first rebuild.

I have heard of this but I thought it was for the e series bikes only. This is the 220. Thanks

[JZ05220r]

Wow, that's black! Either you're running pig rich or you're sucking trans oil. Of course, it could be both!

I wouldn't worry about pulling the flywheel or right engine cover unless you do show a leak you can't find through the normal methods. No the leakdown again and see what you find.

Ok yea I’m sucking in trans oil. Aside from that it looks very white like I may have an air leak. Seems like their is a possibility I’m getting extra air and transmission oil introduced to the combustion chamber

[kdxdazz]

I often go against the grain on here and I will do again, most people on here give advice about top end power but completely leave out the pleasure of riding a smooth linear power delivery, first thing I would do is put the airbox lid on and snorkel, it is specifically designed to help give a linear power delivery, I plan on making a video soon to explain this, you will need to do a leak down check to check that air boot, it is extremely problematic, don't mess with ignition timing, did you check the squish band, don't run is so tight, I had nothing but problems with smooth power on my kdx220...

Also, the air box lid is not designed specifically to help a linear power delivery. Yes, it helps accomplish that because it chokes the hell out of the engine so it can't help but be linear. It's primary functions are to quite down the intake noise and to help reduce water ingress to the air box.

this is one of those kdxrider myths that is often repeated but i don't think people give it much thought when repeating it, most bikes (excluding motorcross bikes that are purely focused on top end power) run airbox lids and snorkels regardless of noise requirements, even my 12hp cbr125 runs a snorkel, the airbox and snorkel absolutely is designed to give a linear power, yes airbox noise is reduced and thats why there are no sharp edges on a snorkel,as sharp edges create noise ,big holes create more power in an internal combustion engine and small holes create more torque, for those that have found a way around these laws of physics please patent it now and become a millionaire .kdx's in the USA run a none compliant exhaust system right? unlike many other countries run a full legal exhaust system yet the usa kdx version runs airbox lid and snorkel for noise requirements? doesn't make sense right , but its not always about what makes sense its about following the crowd to feel part of the group, this response is not for you as no amount of evidence will change your mind,just an informative response for others that may be reading, as a gesture of more evidence i run a snorkel from a kawasaki boss which is about 10 percent larger than the original kdx snorkel. it is neither 10 percent more noisy or 10 percent more powerful

[John_S]

I’m sorry to hear you’re having issues again with this engine. I wouldn’t remove the flywheel or right side cover just yet.

When you do the leak down test make sure to remove the radiator cap to see that no bubbles are coming up through the radiator and also check the vent line that runs up to your air box. If it’s got an internal leak between the combustion chamber and transmission, or it’s the right side crank seal, the air should be coming out that hose. I saw a guy spray a little soapy water down that vent line, pump up the engine and it was blowing bubbles.