Another one back from the dead (1997 King Quad 300 LT-FWDX)

[Hagbard]

I have most of a 160 motor to do with as I please.  no rocker cover, but I have a head with a broken exhaust valve in it, and everything below that. Suzuki is terrible with cross referencing, and stamping the same part with different numbers just to make life fun, but I suspect there's more interchangeability than parts numbers and diagrams let on...  Wondering if that scrap 160 head would be useable? Ozark cam looks like it has a "D" on it.

Edited September 27, 2021 by Hagbard

[JustRandy]

The 300 cam has a D on it so that's the same grind as you have now.

I don't know about 160 heads.  I suspect it would have smaller valves and that angled exhaust.

Also I think the heads and valve covers are matched sets.

[Hagbard]

Sh** you're right about the matched set thing. Judging from the blue RTV I see peeking out around the valve cover, I suspect someone else may already have sailed that particular ship past the point of no return. I don't see any evidence of leaking around THAT half-assed gasket job, but it flows out of the inspection caps, and they're already pre-rounded with what appears to have been Vise-Grips or Channel Locks... perhaps they started out with a handy old Crescent wrench. Song remains the same. I have some new caps on the way (originally from a 77 SP370, speaking of undocumented interchange) which I figure I can at least tighten enough for the o-ring to seal. 

As far as a head and valve cover, I found this candidate for rebuild, think it's suitable?

https://www.ebay.com/itm/234056625049?hash=item367edcab99:g:GI4AAOSwhw9gzNXv

(Sorry to pester you if you have better things to do feel free to tell me so  )

[JustRandy]

A lot of RTV makes me think some was squished into the cam bearings.  Go light on the goop man.

People tighten those caps too much so they end up rounding them off.  Inspection caps and oil pan plugs don't need to be torqued commensurate with their size, but that's what people do.

The intake inspection cap is where I pour the oil in.  A long skinny funnel fits right through the frame into the inspection hole making it real convenient.

I knew a guy with a SP370.  It was a torque monster!

The head on ebay looks ok to me.  I'd buy it.  The bearings are a little rough but I've ran worse.  Buffing wheels for dremels would shine those up in no time.  Put new valves and cut the seats and it should be a good head.

Oh yeah other questions will have to wait til tomorrow.  Hopefully it won't hold you up much

[Hagbard]

Just found this one. I think I'm going to grab it. for $40 I can't beat it.

 

https://www.ebay.com/itm/224522065109?hash=item34468ed4d5:g:kMEAAOSwNq9g4q0x

[JustRandy]

Looks good!

[Hagbard]

I pulled the trigger on it last night/early morning. Figured I could turn around and sell the carb boot alone for half of what I just paid for the head. And I might be lucky and it already has the heavy springs. Turns out that even though the rocker cover was in one of the pics, it was a separate auction, so I ended up paying another $15 for it. I WAS ROBBED I TELL YA! 

So just for the sake of argument, would this head equipped with a 250S piston bolt up to a 230E block that's sitting in a 160 frame?? Asking for a friend who is tenting his fingers like an evil genius and muttering something about "power to weight ratio" and "lengthen the swingarm"

[JustRandy]

It's still a good deal.  If you desperately need a head it would be $200 or so.  I should buy another, but I'll wait until you're done raping ebay

No man, the 250S and 300 have 17mm wrist pins.  Everything smaller has 16mm.  That's why the 250S engine is worth its weight in gold.  The head will fit, but not the piston.

[Hagbard]

Heard. I figured it was too good to be true lol. I'll just keep saving my pennies while I look for a bargain bin special on the cam. If nothing comes up I'll just suck it up and buy the $140 one with my Christmas booty (If I have any left). About to go use the KQ to mend some split rail fences in exchange for a near mint '04ish CR80R. I figure it's a good trial run for the KQ, and I can buy a LOT of wheeler parts for what that dirt bike is worth.

[JustRandy]

I'm starting to wonder if I should get another cam for a spare before they're gone or the price goes up.

A mint CR80 for mending fences?  Yeah I'd take that deal!  Those little things are fun for a couple days.

[Hagbard]

You have no idea the restraint it is taking me to not buy this. My excuse is that it's still plus $22 shipping. This is called foreshadowing. I will live to regret this oversight, and have conveniently documented it here for posterity.

[JustRandy]

Can you make an offer?  I know shipping costs are going up with the labor shortage.

[Hagbard]

Nope, no "Make an Offer" option on the listing. They just sent me a discount offer since I "watched" it.  I have a couple of quotes out on boat covers, maybe if one of them pulls the trigger, I'll splurge.

[JustRandy]

The best things come to those who wait, they say.  You could also be on the lookout for a 70mm ish piston with a 17mm pin.

Did you talk to the paint guy?  What did you find out?

[Hagbard]

I found out that it's not worth the money to spend on clearing a single stage paint that I didn't buy from him ROFL   He did confirm the thing about flex additives for me, something I would never have even seen painting bikes - it's only for flexible plastic bits, mainly bumpers, said it would be great to use on ATV plastics if I were using the complete primer/base/clear system. Flex should go in the primer and clear, he said it wasn't necessary for the color coat though.

 

Is a 70mm like .5 over?  

[JustRandy]

I probably wouldn't clear it either.  Seems like a lot of paint to me.  I've seen bumpers crack the paint and flake off so I don't know what is gained by thick piles of paint.

I thought stock was 68.5,  I have a 69.5 Arias piston.  I'd try to avoid wiseco if I could because it's a lot of weight that can't be shaved off since the pin is too long.

Honestly I'd like to find a 70mm stock compression piston then mill the jug down to boost the compression.  There's a good 1/4  inch of dead space above the piston.

[Hagbard]

19 minutes ago, JustRandy said:

I probably wouldn't clear it either.  Seems like a lot of paint to me.  I've seen bumpers crack the paint and flake off so I don't know what is gained by thick piles of paint.

I thought stock was 68.5,  I have a 69.5 Arias piston.  I'd try to avoid wiseco if I could because it's a lot of weight that can't be shaved off since the pin is too long.

Honestly I'd like to find a 70mm stock compression piston then mill the jug down to boost the compression.  There's a good 1/4  inch of dead space above the piston.

The flex additive is what keeps the flaking and cracking from happening   But this Farm paint is pretty elastic from what I can see so far.  If it gouges or scratches, I can always touch it up or re-spray them considering how cheap the paint is. Comes in other colors too - there's a "Ford Blue" and "Massey Red" that bear a resemblance to the OEM fenders that were on this thing, but I really liked the look of the JD Yellow. The orange is a bit too brown to match the "Winning! Orange" or I would have made this beast match my LT185 from 10 years prior.

I can't keep all the bore and stroke sizes straight, been looking at parts for 4 or 5 different motors and remembering which is which is a formidable task lol.  As far as Wiseco, I love the look and feel of them, but yeah, they are heavy. I have a keychain from them that I assume is a miniature replica of one of their pistons, and it weighs a ton.

Ex-FIL is a machinist who's into classic cars, guess I shouldn't have pissed off his little girl.  Then again, he might still be willing to do a little chipping for me.

[JustRandy]

There is probably an optimal amount of flex to add before the loss of adhesion outweighs the benefits of more flex.  But the thicker the coat the more it must flex to prevent cracking.  I don't know how thick the layers are, but the top layer would be flexing the most since it's at the end of the radius of curvature.

I think the bore and stroke are 68.5 x 76.  The stroke is monster.  Everyone thought the 67mm stroke of the quadsport was a lot.  With a 76mm stroke every little hair of diameter you can gain makes a big difference to the overall displacement.  I don't know how I remember these numbers... maybe I'm not lol

I think the 230 is 66 x 67 and the stroke is longer than the bore.  The 250 is 68.5 x 67.  The 300 flips the 6 and 7 for 76mm and uses same piston as 250.  So if you can remember the 230 then you can figure out the rest.  68 is +2 over on the 230, so 68.5 is the next bigger sleeve used in the 250.

I'd find someone to do a good job boring it.  You want the bore to be tight so the piston doesn't flop around.

The problem with wiseco is the pin goes all the way across the diameter which makes both the piston and pin really heavy.  I don't know why they do that.

[Hagbard]

This is a pretty cool video I happened across, I think it might be right up your alley.

[JustRandy]

That was interesting.  I wonder what gas they use to harden the sand.

[Hagbard]

Most sand casting uses CO2 and a chemical called "Gasbond" that gets mixed in with the sand.  I'm wondering if they add an odorant to it like they do with propane (stinky eggs smell) so they know if there's a leak creating potentially lethal concentrations in the room. Would make sense from a "keep OSHA happy" standpoint. There's a foundry near me (or there was thirty years ago) that made some parts for a downrigger for my dad. They were some parts for a little jig that would "twitch" the rod via input from a little paddle wheel with a cog. The parts in question were made of a rather brittle plastic, and he glued the shattered remnants back together and LaPann's cast them in sand and made him some replicas from aluminum.  A few years ago I found out you can actually cast small bits yourself using a mixture of hi temp silicone RTV and cornstarch as a mold. I replicated one of the ancient Snap-On badges for my toolbox that way. Came out halfway decent.

[Hagbard]

So, back to the King Quad - I really, really, REALLY don't like this carburetor (BST31-SS) and want to just swap it out for a Mikuni VM round slide or anything else without the vacuum diaphragm.  Manual states stock jetting as 120 main, 37.5 pilot with the pilot screw 2 5/8 turns out.  When set up that way it is ridiculously hard to start, won't idle down without dying, etc.  I've experimented with swapping out jets but I think I'm really just shooting blind with this thing. The only adjustment screw (pilot fuel screw) on this thing is on the friggin BOTTOM of the carb where you can't physically access it to adjust without removing the carb from the intake boot and flipping it over. What a jackass arrangement.  I did some searching for anyone who has successfully swapped out to a different carb on this machine and come up dry. Any ideas? 

[JustRandy]

12 hours ago, Hagbard said:

I'm wondering if they add an odorant to it like they do with propane (stinky eggs smell)

In the video they all backed away from the apparatus so maybe.

There are some videos on youtube of people in india making some neat castings while barefoot with rudimentary tools.  Almost makes me think I could do it, but probably not lol.

46 minutes ago, Hagbard said:

Mikuni VM round slide or anything else without the vacuum diaphragm

Yeah when you said you replaced with a diaphragm carb I kinda cringed.  That sort of balancing act is the first thing I wanted to be rid of.

I think I finally settled on a carb from a 250 dirt bike or something.  You don't want a new carb or you'll be back in the same boat figuring out the jetting.  If you buy used it should work.

I think this is what I have: Carburetor Suzuki GS125 GS250 GS300 Motorcycle Carb PZ30 Intake 30mm

53 minutes ago, Hagbard said:

When set up that way it is ridiculously hard to start

Hard starting when cold can indicate that the intake valve is not closing all the way.  And sometimes sparkplugs can act like carb problems.  I try to remember to at least swap the plug before tearing a carb apart.  I've had brand new plugs not work right.

56 minutes ago, Hagbard said:

adjustment screw (pilot fuel screw) on this thing is on the friggin BOTTOM of the carb

I have some short stubby screwdrivers for that.  Sometimes a screwdriver bit for drills can work.  I think they put it there so people don't tinker with it.

[Hagbard]

I have a VM26-606 sitting new in a box on my shelf, but I suppose a 30mm would be a better match.  I guess got super lucky with the eBay mikuni I got for the LT185, it was literally good to go right out of the box. I think I had to move the air screw like 1/8 turn. I'll see if I can find a used dirt bike carb tho, because this diaphragm thing is for the birds.

[JustRandy]

26 is a little small but it might work.  It would be easy to tune by having plenty of vacuum.

I originally designed mine for a 32mm, but the 32 I used was designed for a 2-stroke and was impossible to tune.  I finally decided I didn't have a big enough engine to produce the vacuum required to get a 32 tuned right so I stepped down to a 30.  I really didn't care about performance anymore and just wanted it to work.

I'm of an opinion now that smaller carbs are better.  My Honda 250 (229cc) has a teeny weeny 22 or 24 or something ridiculously small, but doesn't seem to have problems revving.  That is the most reliable quad I have.  Always starts in any weather (by virtue of the strong vacuum on the carb).  It's a pushrod engine with no oil filter.

A 28 is probably about right for you.  I'm overbored 1mm with the 250 cam with some exhaust mods so maybe that justifies a 30.

Just keep in mind the bigger the carb the harder it will be to tune.

[Hagbard]

Just checked, and the spigot size is a bit smaller. Found a great writeup here, apparently the DR200 uses the same carb and is as reviled there. https://thumpertalk.com/forums/topic/1373576-dr200-carb-conversion-info/ 

He says the 30mm slide carbs were too much for the stock bike, and ended up with a PWK 24 that worked really well, so I just need to find something in the 24-26mm range with the right size spigot I suppose.

Just looked at my plug, and it's (DR8ES) colder than what's called for (DR7EA) and I'm thinking that might be an issue. Might even go down to a DR6EA for a hotter spark.

[JustRandy]

Yeah 30 is way too much for a 200.  30 may even be a lot for my 300 with mods.  The 230S and 250S had 26mm carbs, so 28mm is probably right for a 300 (280).

My carb has fallen off a couple times in 5 years.  Not sure what intake boot I have though.  Like I said I originally designed and ported everything for the 32 then backwards engineered it to work with the 30 out of frustration.  I'm not sure if I did more port work in 2019 when I rebuilt it again or not, but I know I still have trouble with the carb falling off sometimes.  Not a big deal, but it happens.  Probably a better hose clamp would fix the problem.

I doubt you'll notice any difference in a 7 and 8 plug.  I have 6s, 7s, and 8s and unless there is oil burning or carbon then it probably doesn't matter.  I was just suggesting to change plugs to be sure the problem is not the plug.

[Hagbard]

So today we're back to no-start. Cranks, is getting fuel in the cylinder, plug is wet. There is spark when I check, have tried three different plugs. Have pulled off the intake boot and installed a new o-ring and gasket, got a tighter hose clamp. Eliminated unmetered airflow. What's next? Stator? Rectifier? .30-06?

[JustRandy]

Are you sure the intake valve lash is set right?

Take the inspection cap off and after you see the intake rocker move, stick a screwdriver in the sparkplug hole to feel for TDC.  It won't be far and it's easy to go past it.  Then once you're sure it's TDC, feel the rocker to see if there is a gap.  If there is no gap, that is your problem.

If in doubt, just loosen the lash just to see if that's the problem.  You can always reset it later.

It's possible that you have an intake valve that is wearing down.  If so, you will have to reset the lash every few days.  Hard cold starting is how I knew it's time to loosen the lash.  You can do it for a long time before the valve finally pops through the head.

Someone may have installed a new valve and didn't cut the seat.

[Hagbard]

Brother, I think you're onto something. I mentioned the RTV on the valve cover, but did I ever tell you about the dings inside the intake inspection cap? I switched the caps to see if it was a persistent condition, and it appears to have been in the past. So, someone has definitely been in there to address an issue with the intake valve, and left a trail of blue goo on the way out. I replaced the caps and o-rings yesterday, I'll go pop them back off and check the lash again. intake .001-.003 and exhaust .005-.007?