Modern Buddy

Posted: **Fri Apr 09, 2010 11:34 pm**

Well, I have the dubious honor of announcing that my intake valve and piston have joined forever in holy matrimony. I witnessed the moment they first kissed, I swear it was explosive. Since they'll now be moving out of their current residence inside my engine, I'll be looking for new ones. Bother.

<img src="http://www.voodoo-buddy.com/head.jpg" width=50%>
<img src="http://www.voodoo-buddy.com/piston.jpg" width=50%>

Posted: **Fri Apr 09, 2010 11:43 pm**

Ouch.

That sucks.

Posted: **Fri Apr 09, 2010 11:48 pm**

Pretty sure the busted one is your exhaust valve?

Edit: See signature

Posted: **Fri Apr 09, 2010 11:49 pm**

Anachronism wrote:Pretty sure the busted one is your exhaust valve?

Edit: See signature

<--- checks again.

Ohh. Yeah. That would be the exhaust valve.

There's nothing wussy about blowing a piston AND head up at 55MPH

Posted: **Fri Apr 09, 2010 11:57 pm**

Do you have any idea what caused this? You got me not wanting to buy my head now

Posted: **Fri Apr 09, 2010 11:57 pm**

GAK!

How'd that happen?! How many miles did you have on the kit? Could this happen from getting too hot and oil burning off?

Posted: **Sat Apr 10, 2010 12:15 am**

ScooterTrash wrote:Do you have any idea what caused this? You got me not wanting to buy my head now

Well, I'm tempted to think it was my new head. I've gotten about 2000 miles on it, and it was still requiring very regular valve adjustments. Though the valves are SUPPOSED to be NCY valves.

I'm a bit disappointed, as the head performed amazing.
The piston below the crown still looks fine, the rings don't look bad, and the cylinder survived without any damage at all.
That just leaves the valve for fault.

Posted: **Sat Apr 10, 2010 12:16 am**

jijifer wrote:GAK!

How'd that happen?! How many miles did you have on the kit? Could this happen from getting too hot and oil burning off?

The new head had about 2k miles on it, I installed the 161 kit about 20k ago. The kit didn't seem to be having any issues, the head just failed.

Posted: **Sat Apr 10, 2010 12:20 am**

Wait...what's your mileage at these days anyway, Kaos?

Posted: **Sat Apr 10, 2010 12:26 am**

Cheshire wrote:Wait...what's your mileage at these days anyway, Kaos?

28,300ish. I installed the 161 kit around 8k miles. Maybe a bit more, its been a while and I'm fuzzy on the details

Posted: **Sat Apr 10, 2010 1:10 am**

I've got the 150 stock head. It's all I've ever used with the kit. 1) the NCY head wasn't out on the market when I put this on 2) I was concerned that NCY was totally untested. No real reason but i knew the 150 buddy head worked well and that's what was tested at Genuine with the kit. Maybe you can get a used 150. I don't think that head needed nearly the modification either.

I am pretty sure you put that kit on after me so frick, you racked up miles slowly at first and crazily at second. I've had mine on since early May 09. When did you install this bad boy?!

Posted: **Sat Apr 10, 2010 1:19 am**

jijifer wrote:I've got the 150 stock head. It's all I've ever used with the kit. 1) the NCY head wasn't out on the market when I put this on 2) I was concerned that NCY was totally untested. No real reason but i knew the 150 buddy head worked well and that's what was tested at Genuine with the kit. Maybe you can get a used 150. I don't think that head needed nearly the modification either.

I am pretty sure you put that kit on after me so frick, you racked up miles slowly at first and crazily at second. I've had mine on since early May 09. When did you install this bad boy?!

Thats supposed to be a fairly good head. I'll likely port my stock 125 head and see if I can get my hands on some larger valves. If I can swing it, I might go for the NCY one.... Still working through the options.

Posted: **Sat Apr 10, 2010 1:25 am**

Blargh, that sucks!

Isn't that the head you've been testing out that's been custom ported and matched (NOT the NCY head)? How often have you had to reset the valves?

Did the retainers loose their shape, just out of curiosity?

Actually, I'm curious about the clearances that the head had in the first place. If it used mismatched valves, it could have much tighter tolerances than an off the shelf head. That would mean that the normal break in settling in would cause... well, you know...

Posted: **Sat Apr 10, 2010 1:32 am**

Lostmycage wrote:Blargh, that sucks!

Isn't that the head you've been testing out that's been custom ported and matched (NOT the NCY head)? How often have you had to reset the valves?

Did the retainers loose their shape, just out of curiosity?

Actually, I'm curious about the clearances that the head had in the first place. If it used mismatched valves, it could have much tighter tolerances than an off the shelf head. That would mean that the normal break in settling in would cause... well, you know...

Yeah, its the one that I've been testing. I was just getting ready to review it too :/

I've not looked at the retainers, I'll do so in a sec.

The valves were 28mm/23mm valves.

I was adjusting them about every 150 to 200 miles. Which seemed like a LOT after the first 1 or 2.

Posted: **Sat Apr 10, 2010 1:37 am**

Whoa! That's WAY too often... something's wrong with that picture.

Posted: **Sat Apr 10, 2010 1:39 am**

Lostmycage wrote:Whoa! That's WAY too often... something's wrong with that picture.

Yeah, I'm thinking something didn't seat right at break-in, which resulted in failure.

Posted: **Sat Apr 10, 2010 1:40 am**

I've got 10k mine. Theses are notes on the invoice regarding the head install:

TAP AIR INJECTION PASSAGE ON NEW HEAD, INSTALL
GRUB SCREW TO BLOCK PASSAGE, CHECK
PISTON, RING, SQUISH CLEARANCES, INSTALL
CYLINDER AND HEAD, SET VALVE CLEARANCE,
MODIFY TOP CYLINDER SHROUD FOR NEW
STYLE CAM CHAIN TENSIONER,

is that what you did? I don't think my valve required any additional testing. Originally the WRONG valves were sent with the head but it was obvious to my mechanic and he said the valves sent were for the 125 and would never fit the head. But that was the last I heard of valve problems.

Posted: **Sat Apr 10, 2010 1:43 am**

jijifer wrote:I've got 10k mine. Theses are notes on the invoice regarding the head install:

TAP AIR INJECTION PASSAGE ON NEW HEAD, INSTALL
GRUB SCREW TO BLOCK PASSAGE, CHECK
PISTON, RING, SQUISH CLEARANCES, INSTALL
CYLINDER AND HEAD, SET VALVE CLEARANCE,
MODIFY TOP CYLINDER SHROUD FOR NEW
STYLE CAM CHAIN TENSIONER,

is that what you did? I don't think my valve required any additional testing. Originally the WRONG valves were sent with the head but it was obvious to my mechanic and he said the valves sent were for the 125 and would never fit the head. But that was the last I heard of valve problems.

I followed that more or less. I followed the same steps I did to install my 125 head. Some of those don't apply, as the 150 head has EGR stuff, while the 125 and this head didn't. But its not the first head I've done, scooter or otherwise

Posted: **Sat Apr 10, 2010 1:44 am**

Those are the directions for adapting a 150 PGO head (with the emissions plumbing). It's a totally different head and doesn't really apply to Kaos' head which is a performance head without the emissions connections.

Posted: **Sat Apr 10, 2010 1:52 am**

my bad. you didn't use the NCY or PGO head? This failure is on something else, huh? My PGO 150 is doing ok (i'm not gonna say 'great' since my prima pipe cracked the last time I bragged) I'm going in for a "tune up" and have them look at all the stuff again since it's been 10k. Seems like a grub screw could shake loose and screw stuff up

Posted: **Sat Apr 10, 2010 1:56 am**

jijifer wrote:my bad. you didn't use the NCY or PGO head? This failure is on something else, huh? My PGO 150 is doing ok (i'm not gonna say 'great' since my prima pipe cracked the last time I bragged) I'm going in for a "tune up" and have them look at all the stuff again since it's been 10k. Seems like a grub screw could shake loose and screw stuff up

Nope, I've been testing an Endrigo Racing head on the Buddy.

they basically took a stock head, shaved it 2mm, did a FANTASTIC port and polish, matched it to an intake, and stuck big valves in it. It should out perform most heads out there, and is setup well. Now if we can just sort this failure out, we'll see if I still recommend it

Posted: **Sat Apr 10, 2010 2:14 am**

That sucks, Kaos. I hope you're able to get back on the road soon. If you're unable to ride, at least the weather continues to suck.

Posted: **Sat Apr 10, 2010 2:21 am**

Kaos wrote:
jijifer wrote:my bad. you didn't use the NCY or PGO head? This failure is on something else, huh? My PGO 150 is doing ok (i'm not gonna say 'great' since my prima pipe cracked the last time I bragged) I'm going in for a "tune up" and have them look at all the stuff again since it's been 10k. Seems like a grub screw could shake loose and screw stuff up
Nope, I've been testing an Endrigo Racing head on the Buddy.

they basically took a stock head, shaved it 2mm, did a FANTASTIC port and polish, matched it to an intake, and stuck big valves in it. It should out perform most heads out there, and is setup well. Now if we can just sort this failure out, we'll see if I still recommend it

man, you're so lucky this you can do this stuff yourself. I'd be curled up in a ball and crying if this happened to me. I paid nearly $400 to get that thing installed and well, that's not something I can throw down all the time.

Posted: **Sat Apr 10, 2010 3:27 am**

You're posting, so I'm guessing you are OK.

The lost time sucks.

The loss of your ride until it's fixed sucks.

But, this is freaking awesome! It looks like a big silvery bug on the windshield!

Posted: **Sat Apr 10, 2010 3:27 am**

jijifer wrote:
Kaos wrote:
jijifer wrote:my bad. you didn't use the NCY or PGO head? This failure is on something else, huh? My PGO 150 is doing ok (i'm not gonna say 'great' since my prima pipe cracked the last time I bragged) I'm going in for a "tune up" and have them look at all the stuff again since it's been 10k. Seems like a grub screw could shake loose and screw stuff up
Nope, I've been testing an Endrigo Racing head on the Buddy.

they basically took a stock head, shaved it 2mm, did a FANTASTIC port and polish, matched it to an intake, and stuck big valves in it. It should out perform most heads out there, and is setup well. Now if we can just sort this failure out, we'll see if I still recommend it
man, you're so lucky this you can do this stuff yourself. I'd be curled up in a ball and crying if this happened to me. I paid nearly $400 to get that thing installed and well, that's not something I can throw down all the time.

Heh, I wouldn't have gotten my bike near as far as it is now without doing it myself. Shop time gets expensive!

Posted: **Sat Apr 10, 2010 3:32 am**

Syd wrote:You're posting, so I'm guessing you are OK.

The lost time sucks.

The loss of your ride until it's fixed sucks.

But, this is freaking awesome! It looks like a big silvery bug on the windshield!

Heh, yeah. Scared the poop outa myself but nothing actually happened ride wise other than a big bang and the motor stopping. It didn't seize up or anything.

Now that you mention it, it is kinda interesting looking. Essentially the valve splatted against the piston head, so you're not too far off on the bug analogy

Posted: **Sat Apr 10, 2010 9:36 am**

Is your timing belt/chain (don't know what GY6's use) ok?

Here is my theory- Larger exhaust valve is actually just slightly hitting the piston as it is opening just after TDC. Because the piston is going down at that point, no catastrophic failure, but the contact starts to bend the valve.

Eventually the valve bends to the point where it no longer seals, and so you have to keep readjusting until the head pops off the valve.

Either that or broken valvespring, but I would guess there was a slight clearance issue there.

Posted: **Sat Apr 10, 2010 2:34 pm**

Anachronism wrote:Is your timing belt/chain (don't know what GY6's use) ok?

Here is my theory- Larger exhaust valve is actually just slightly hitting the piston as it is opening just after TDC. Because the piston is going down at that point, no catastrophic failure, but the contact starts to bend the valve.

Eventually the valve bends to the point where it no longer seals, and so you have to keep readjusting until the head pops off the valve.

Either that or broken valvespring, but I would guess there was a slight clearance issue there.

Hmm, thats an interesting theory. I'll check it and see. There ARE valve cutouts in the top of the piston, but that doesn't guarantee it missed the valves.

Posted: **Sat Apr 10, 2010 4:36 pm**

Kaos wrote:
Anachronism wrote:
Hmm, thats an interesting theory. I'll check it and see. There ARE valve cutouts in the top of the piston, but that doesn't guarantee it missed the valves.
Yes, but the valve cutouts may not be large enough for the head with the nifty bigger valves.

Not saying this is what happened, but I just don't see valves snap the head off like that unless there was some kind of contact. If the timing belt is ok, and the valvespring is ok, that leaves clearance.

Posted: **Sat Apr 10, 2010 5:38 pm**

I just realized something thanks to the last couple posts. PMing you Kaos

Posted: **Sat Apr 10, 2010 8:12 pm**

if the timing chain happens to break on these things, would the valve and piston hit? or is this because you had an aftermarket head?

Posted: **Sat Apr 10, 2010 9:47 pm**

gearhead wrote:if the timing chain happens to break on these things, would the valve and piston hit? or is this because you had an aftermarket head?

Yeah, breaking a timing chain could do that too, though thats not what happened in this case. I'm fairly sure it had to do with the head, I'm still not totally sure WHY though. I think Anachronism's theory is probably the most likely. I'm not sure at this point how I'd prove that though.

Posted: **Sun Apr 11, 2010 3:54 pm**

good luck on your search for finding out what had happened. If you are using a stock head, is there enough valve clearance in the event that timing was off or it broke that it would still hit?

Posted: **Sun Apr 11, 2010 4:05 pm**

gearhead wrote:good luck on your search for finding out what had happened. If you are using a stock head, is there enough valve clearance in the event that timing was off or it broke that it would still hit?

I think the issue was I was NOT using a stock head. I was testing a very new head that had mostly been used on GY6 buggies, and they were trying to push into the scooter market.

Posted: **Sun Apr 11, 2010 4:26 pm**

interesting. Im going to be doing the 161 kit on my gf's buddy and was thinking while im in there, do the head... but i guess i'll wait till some reviews come out and what people are saying.

Posted: **Sun Apr 11, 2010 4:30 pm**

gearhead wrote:interesting. Im going to be doing the 161 kit on my gf's buddy and was thinking while im in there, do the head... but i guess i'll wait till some reviews come out and what people are saying.

People have had great success with the 150's head, or the NCY head. I was running a seriously worked racing head.

Posted: **Sun Apr 11, 2010 5:28 pm**

Kaos;

That is definitely a catastrophic failure – glad you didn’t get hurt.
What are you going to do now?
By the way; when you replaced the head with the larger 150cc head, did you replace the barrel gasket, I believe the 161 kit comes with two gaskets, thick gasket for the 150 head, and the thin gasket for the 125 head; because it certainly looks as if the exhaust valve hit the piston, but that may have been when it self destructed.
Anyway I hope it all works out for you and you don’t stay down for long, maybe a chance to get the Ural you talk about.

Posted: **Sun Apr 11, 2010 5:35 pm**

thats what you get for using it to tow your camper on your road trip.

i'm sure it made it most of the way though.

Posted: **Sun Apr 11, 2010 6:47 pm**

rajron wrote:Kaos;

That is definitely a catastrophic failure – glad you didn’t get hurt.
What are you going to do now?
By the way; when you replaced the head with the larger 150cc head, did you replace the barrel gasket, I believe the 161 kit comes with two gaskets, thick gasket for the 150 head, and the thin gasket for the 125 head; because it certainly looks as if the exhaust valve hit the piston, but that may have been when it self destructed.
Anyway I hope it all works out for you and you don’t stay down for long, maybe a chance to get the Ural you talk about.

I asked him the same thing via PM as I also thought the 150 gaskets were thicker. Scooterworks website states that the thinner gaskets are for the 150 head. He didn't change the gaskets, if scooterworks is correct then he should have had more clearance. I'm checking with my rep to find out for sure

Posted: **Sun Apr 11, 2010 7:57 pm**

ScooterTrash wrote:
rajron wrote:Kaos;

That is definitely a catastrophic failure – glad you didn’t get hurt.
What are you going to do now?
By the way; when you replaced the head with the larger 150cc head, did you replace the barrel gasket, I believe the 161 kit comes with two gaskets, thick gasket for the 150 head, and the thin gasket for the 125 head; because it certainly looks as if the exhaust valve hit the piston, but that may have been when it self destructed.
Anyway I hope it all works out for you and you don’t stay down for long, maybe a chance to get the Ural you talk about.
I asked him the same thing via PM as I also thought the 150 gaskets were thicker. Scooterworks website states that the thinner gaskets are for the 150 head. He didn't change the gaskets, if scooterworks is correct then he should have had more clearance. I'm checking with my rep to find out for sure

Yeah, my understanding was that the 150 gasket was thinner to keep the compression the same with the larger chamber size. We'll see what Scootertrash finds out.

I'm going to do one of a few things when I rebuild.

Option 1 is another 161 piston, with some heavy port and polish on my 125 head, which will get me more or less back where I was.

Option 2 is a Akunar dometop piston with a heavy port and polish on my 125 head, which will get me a higher compression 161 setup.

Option 3 is to buy a CH250 horizontal from the year of Honda Helix that had them, or a CN250 from one of the 250cc scooters and bolt that in

I like option 3 the best but the family accountant(my lovely wife) says it'll be more than likely option 1 or 2

Posted: **Sun Apr 11, 2010 8:07 pm**

Kaos wrote:Yeah, my understanding was that the 150 gasket was thinner to keep the compression the same with the larger chamber size. We'll see what Scootertrash finds out.

I went out and looked at the "150" gaskets (labeled on the bag) pretty sure they are the thinner gaskets, hard to get much thinner than that

Posted: **Mon Apr 12, 2010 2:45 am**

Wow, that is some pic. Glad you ok, but you got yerself some arht werk!

Hope you're back in the saddle soon. Yet another reason to have more than one motorized two-wheeler.

Posted: **Mon Apr 12, 2010 2:49 am**

siobhan wrote:Wow, that is some pic. Glad you ok, but you got yerself some arht werk!

Hope you're back in the saddle soon. Yet another reason to have more than one motorized two-wheeler.

Yeah, I'll use the piston as a nice pen holder on my desk at work, right next to the Mopar 383 bigblock one that's already there from a race blow up

A friend of mine was awesome enough to loan me his Bajaj. Its pokey, but at least its two wheels!

Posted: **Mon Apr 12, 2010 3:05 am**

Checkout this oddball find, I found a *3* valve head for the gy6

http://www.racemotorparts.com/products.php?id=1436

Posted: **Mon Apr 12, 2010 1:44 pm**

Kaos wrote:Checkout this oddball find, I found a *3* valve head for the gy6 http://www.racemotorparts.com/products.php?id=1436

That's odd...

Posted: **Mon Apr 12, 2010 2:20 pm**

Oh man, that's biblical! Make sure to do some good motor forensics. Don't want to repeat this mess. Based on the experiences of others (including myself) the the 161 kit and stock 150 head, head failure could be an option but a valve all of a sudden making proper nice nice with the piston seems a bit extreme without warning of such impending doom.

Posted: **Mon Apr 12, 2010 2:22 pm**

djelliott wrote:Oh man, that's biblical! Make sure to do some good motor forensics. Don't want to repeat this mess. Based on the experiences of others (including myself) the the 161 kit and stock 150 head, head failure could be an option but a valve all of a sudden making proper nice nice with the piston seems a bit extreme without warning of such impending doom.

Yeah, thats the odd part. Other than needing very regular valve adjustments, this thing has been running AWESOME. The head made a TON of power and it was a blast to ride. Up till the end, when it was LITERALLY a blast to ride

Posted: **Mon Apr 12, 2010 2:25 pm**

Kaos wrote:
djelliott wrote:Oh man, that's biblical! Make sure to do some good motor forensics. Don't want to repeat this mess. Based on the experiences of others (including myself) the the 161 kit and stock 150 head, head failure could be an option but a valve all of a sudden making proper nice nice with the piston seems a bit extreme without warning of such impending doom.
Yeah, thats the odd part. Other than needing very regular valve adjustments, this thing has been running AWESOME. The head made a TON of power and it was a blast to ride. Up till the end, when it was LITERALLY a blast to ride

OK, the oddly too regular valve adjustments should be a good clue. I'd look for cracks or damage to your rockers that could have been throwing the adjustment off that bad. Even tiny stress cracks could throw those out of tolerance.

Posted: **Mon Apr 12, 2010 2:26 pm**

djelliott wrote:
Kaos wrote:
djelliott wrote:Oh man, that's biblical! Make sure to do some good motor forensics. Don't want to repeat this mess. Based on the experiences of others (including myself) the the 161 kit and stock 150 head, head failure could be an option but a valve all of a sudden making proper nice nice with the piston seems a bit extreme without warning of such impending doom.
Yeah, thats the odd part. Other than needing very regular valve adjustments, this thing has been running AWESOME. The head made a TON of power and it was a blast to ride. Up till the end, when it was LITERALLY a blast to ride
OK, the oddly too regular valve adjustments should be a good clue. I'd look for cracks or damage to your rockers that could have been throwing the adjustment off that bad. Even tiny stress cracks could throw those out of tolerance.

Hmm, thats not something that had occurred to me. I'll check that.

Posted: **Mon Apr 12, 2010 2:32 pm**

Kaos wrote:
djelliott wrote:
Kaos wrote: Yeah, thats the odd part. Other than needing very regular valve adjustments, this thing has been running AWESOME. The head made a TON of power and it was a blast to ride. Up till the end, when it was LITERALLY a blast to ride
OK, the oddly too regular valve adjustments should be a good clue. I'd look for cracks or damage to your rockers that could have been throwing the adjustment off that bad. Even tiny stress cracks could throw those out of tolerance.
Hmm, thats not something that had occurred to me. I'll check that.

Ok, took a look nothing that I can see. I might take some high-res photos when I get home from work just to double check though.

Modern Buddy

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