Treats puch-hobbit head hard to impossible start?

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I've been super hung up on this mild build's starting issues. I got ahold of the treats 44 mm puch- Hobbit head with the slotted stud holes which I enlarged for the m7 studs I have in their. Currently the mallosi m7 97 mm which works for a stock or this Puch head. The bike occasionally started with the treats head. Fat blue spark. Hpi mini with 300 g wt. Stock shocko. Worked for years before the pull start and head. Put back the original head which is an old motzig squished oem head and presto fires right up runs great but then not and changed to another spark plugs and and fires right up.

Not sure if this is some kind of heat fouling of multiple plugs or is there some aspect of this treats head that makes it even harder to start. I didn't measure the relative volumes of each combustion chamber. I should though.

Has everyone with this head had smooth sailing?? I enclosed some pics of putting a sharpie ink on the head and lightly sanding on plate glass to demonstrate it doesn't seem warped. A leak down is such a pain to.perform.

And yes I also have Graham's newest head but that requires 126 mm studs and.before I do that I still am trying to understand what's up with this. Im trying to be done with the build to move onto a water cooler but I don't want a garage full of non runners.

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Re: Treats puch-hobbit head hard to impossible start?

Why are you using an es plug?

Re: Treats puch-hobbit head hard to impossible start?

You do know you have to fully rejet when changing heads right?

A correct combustion chamber will be more efficient. A shit decomp head will be much less efficient.

Re: Treats puch-hobbit head hard to impossible start?

yeah^your piston crown maybe just touching your spark plug electrode, stuff ever so slightly expands when hot hot. remember to retorque head nuts n make sure the threads aint bottoming out to no threadness...

Re: Treats puch-hobbit head hard to impossible start?

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B6hs. Did I mistype ? Pat the electrode to Piston crown is brilliant and could explain all this misery!! But it seems so far away from the sealing surface. But the kit was milled to give a tight squish on the milled oem head. The stock shocko piston isn't excessively dome shaped.

Jbot : I can assure u I've tried all kinds of settings and slides.

I think if the old head continues to work I will change out the studs and give the dog cycles motzig jailing head a go. I want this to reliably run cool. Putting that jailing head on is a major bear. One suggestion is to pull the motor mount get the head on without messing with the petcock. Ugg. With no idea if im missing something on this build and now an an additional adventure.

Re: Treats puch-hobbit head hard to impossible start?

That plug is sitting way too far out.

You shouldn't see threads. Add a washer or 3 to the plug.

Re: Treats puch-hobbit head hard to impossible start?

And wtf are you doing running a 6?

Always an 8 on any kitted hobbit

Re: Treats puch-hobbit head hard to impossible start?

One additional question. I've got a 15 or 16 Sha on this. It's been on for years. When it's been running and I turn it off and then pretty quickly restart it will catch usually right up but if I wait a.while it's a harder start and often it wants to start with the slide fully up. After starting it has a great low and even idle. Is there some little starting passage that possibly got some kind of blockage.

Re: Treats puch-hobbit head hard to impossible start?

Dirty30 Dillon /

Your piston is a dome, so the straight edge is moot

Re: Treats puch-hobbit head hard to impossible start?

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to

Yea im collecting them!!

Top is the treats Athena 47.6

Middle is supposedly the 44 mm

Below is the perfectly executed jailing at a tad below 44.

So the squish band overlaps the head gasket !?

Re: Treats puch-hobbit head hard to impossible start?

Wow....ya get rid of that plug.

Re: Treats puch-hobbit head hard to impossible start?

Dillon I know it's a dome but it's number of mm above the top.of the jug isnt as great as the depth to the plug of that head even with it sticking out into the head as jbot noted.

And is it a known fact that it's bad for the plug to extend onto the head that way! I understand cosmetically and ethetically it's not nice.

I took a ride with the old head with the decomp and yeah it got pretty heat soaked. 450 plus. Forget that , the only way that's ok is if I live in antartica. But because the bike ran semi ok otherwise, this evening im going to try and get the jailing on the bike using the remove the frame to.motor bolt and lifting the frame up. It's possible though that the too deep plug on the treats head is overheatingthe plugs and heat fouling each and every one that I get the engine to fire up with. So I could instead of replacing the head bolts to 126mm I could try the jbot washers and perhaps that's the whole problem. And Pats observation will be accommodated with washers. I assume I need to find 14mm washers???

Re: Treats puch-hobbit head hard to impossible start?

Josiah Radebaugh /

Slap a short thread (8?) Plug in there

Re: Treats puch-hobbit head hard to impossible start?

So is there a suitable spark plug with a thread length shorter than say a b8hs? What is the brand and number ?

Re: Treats puch-hobbit head hard to impossible start?

Josiah Radebaugh /

Re: Treats puch-hobbit head hard to impossible start?

@josiah...thanks for the help. U r extremely helpful. I wish I was as amazing as you. Such wisdom. Keep it up...actually don't .

Re: Treats puch-hobbit head hard to impossible start?

Josiah Radebaugh /

Or you could slap some washers on. b8hs(edited)

Re: Treats puch-hobbit head hard to impossible start?

I looked for 14 mm washers at Ace and they are super wide. But if jbot says it's possible then the appropriate washers must exist. I want to definitely figure out if the extension of the plug into the chamber is causing early very early heat fouling

Re: Treats puch-hobbit head hard to impossible start?

Josiah Radebaugh /

Maybe, temporarily you could cut a piecec of 12-10 gauge copper wire and roll it to make a washer.

Re: Treats puch-hobbit head hard to impossible start?

Dirty30 Dillon /

Re: Treats puch-hobbit head hard to impossible start?

are you sure that is a B6HS plug and not a B6ES? it looks super long in the pictures, like an ES. that is what everyone posting thinks is happening.

you can just take the compression washers off a couple burned up plugs and stack a few of them- poor mans index washer. It works ok but it isn't ideal.

you're looking for 12mm SAE washers at the hardware store but i don't think that is a good idea either.

Re: Treats puch-hobbit head hard to impossible start?

A lot less screwing around if you simply stop and buy the right plug .

NGK 5510 B8HS Standard Plug

https://www.oreillyauto.com/detail/b/copper-core-4441/ignition---tune-up-16776/spark-plug-12874/b14eb31b13d7/ngk-copper-core-spark-plug/5510/4537085

Re: Treats puch-hobbit head hard to impossible start?

> Graham Motzing Wrote:

> -------------------------------------------------------

> are you sure that is a B6HS plug and not a B6ES? it looks super long in

> the pictures, like an ES. that is what everyone posting thinks is

> happening.

>

> you can just take the compression washers off a couple burned up plugs

> and stack a few of them- poor mans index washer. It works ok but it

> isn't ideal.

>

It's a lot closer to ideal at least, but ideal is not using washers, and getting a proper plug, is that just milled that deep to make the dome? maybe you do need washers, but it's not OK as-is... your entire purpose running that head is to improve the squish, squish velocity, mixing, gas/air proximity all actively efficiently compressed at the plug, I mean the advantages to a properly cut head are being significantly affected by a giant wall of plug sticking out into the head. (yes I know most of the effect is at the edge of the band but still).

Also high comp proper squish is by design tight tolerances and your plug could totally be hitting. I don't really understand what you're looking for with this post still, everyone's been in pretty much agreement from the beginning that your plug is extending too far. And second that if you're fouling a lot, which it sounds like has been the case also, you are either not sparking consistently, a really real possibility if your piston's nearly dining on your plug, or your plug's too cold, or both. I mean people run 7's on stock bikes - a hotter plug that fits your head is a consistent recommendation, please don't ignore it, get that squared away and report back!

Re: Treats puch-hobbit head hard to impossible start?

Yes it's a b6hs. And now a b8hs

Yes it's a shitty head because the short reach plug projects into the dome

Yes unless this is an anomaly don't buy this position

Yes I have Graham's jailing here to go to next if I can't get the plug flush to the top of the dome.

Yes the title of the post is if anyone else has tried this exact treats 44 mm head and what is their experience.

Re: Treats puch-hobbit head hard to impossible start?

It's not the head man.

It's you and your setup.

You assume a lot and don't look at individual variables.

Put the head on and get it to run.

Stop swapping back and forth.

That's just ridiculous.

Re: Treats puch-hobbit head hard to impossible start?

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Ok this is now flush. Im going to mount it and see a) what the compression is

2 if I want it higher I will fill the base of this Frankenstein POS head.

3 then see what if it works.

4 the stock head is 120 psi

Re: Treats puch-hobbit head hard to impossible start?

Mill not fill

Re: Treats puch-hobbit head hard to impossible start?

Pushrod Fifty /

That washer on the plug wont seal, your going to have an air leak. Is that red sealant silicone? If so, it wont hold up to temps and gas. Use Hondabond or better a gasket and figure-eight the head and barrel top on a granite stone or cooktop glass with 320 wet sand or emery sheet. For a custom build a leak down test is a good idea.

Also some mower and chainsaw plugs have shorter threads, you can match something close in a hardware store just to try out as the spark should be in the right place in the chamber. Too close to the piston and it will see less atomized fuel and foul out.(edited)

Re: Treats puch-hobbit head hard to impossible start?

Pushrod Fifty /

Any sealant not impervious to gas will end up in a blob between your piston crown and top ring and it will sound like a score on a ring.

Re: Treats puch-hobbit head hard to impossible start?

Looks like you need a 3/8" thread reach .

NGK BM7A might do .

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