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

[JustRandy]

Yeah but don't bother measuring the gap.  Just loosen it and see if it starts.  You can run a 1/8 inch gap.  If that's the problem, it will eat through .001 in no time.

I used to run 1/8 gap at the start of the day and by the end it had eaten it up.  Most of the time I didn't bother to find TDC, I just loosened the lash however much and went.

I'm almost positive that's your problem.

[JustRandy]

Your valve probably looks like this:

[Hagbard]

Loosened the intake lash and managed to get it to run for a second or two if I held my palm over the intake. But then it dies.

[JustRandy]

That sounds like a jet is plugged.  Did you change something while trying to get it started?

[Hagbard]

Did that a couple more times and it roared to life. Thanks! So it seems that purchasing that head for $55 was a good idea 😂 

[JustRandy]

So loosening the lash fixed it?  Now you have to figure out about how much of the valve is worn so you know how much time you have left.  Basically you're at the end when the adjuster screw is flush with the bottom of the rocker, so if it has a long way to go then the valve is just starting to wear.

Once it's warm it should start, so you could loosen the lash to get the engine warm then tighten it again to keep the valve from wearing.

What's happening is the valve isn't contacting the seat, so it can't hold the compression.  Somehow that doesn't matter once it's warm.

[Hagbard]

Wonder if thermal expansion opens up the seat enough to function when warm? There appears to be a lot of adjuster screw left above the nut, it seemed kind of “tall” to me in comparison with others I had seen. I bet that one of the recent PO’s did a halfassed valve job on it.  Do you think switching the current cam over into that one and installing it would correct the issue?

[JustRandy]

The intake valve is open all the time whether hot or cold, but it only affects starting when cold.  I can only guess why.  Maybe it has something to do with the propensity of the gas to ignite.

5 minutes ago, Hagbard said:

There appears to be a lot of adjuster screw left above the nut, it seemed kind of “tall” to me

The screw above the nut is what's used up.  Eventually you'll have to take the screw all the way out.  So however many threads are below the nut is how much you have left.

Switching cams wouldn't change anything because it's the part of the cam with no lobes that would affect it.

Now I see why they sold it cheap.  Things are starting to make sense.  Luckily it won't take much to fix it.

[JustRandy]

I was thinking that I wouldn't blame those guys too much because I can't remember how many intake valves I've installed without cutting the seat, but I always attributed the wearing to bad air filtration.  Finally after making the same mistake over and over it dawned on me that there is no way to replace a valve without cutting the seat.  No one told me that in all my reading.  I mean, I might have seen it suggested, but not emphatically necessitated.

Any wearing at all on the seat is not going to mesh with the new valve and all that's needed is to wear the hardness off the valve and it's gone.  It's imperative to have the valve and seat at exactly the same angle.  It's also important to have the contact patch in the center of the valve footprint.

In light of that, I bought my own cutter.  So far I've used it once, so it hasn't paid for itself yet lol.  But after using it I discovered that I'd likely not trust anyone else to do the job.  They could cut corners and most people wouldn't know.

[Hagbard]

I legit laughed out loud at “it hasn’t paid for itself yet”. 😂

Got it mostly put back together tonight, still have some odds and ends to sort out but it’s almost resembling a real quad again. 
 

Cut out some circles of ABS and riveted them over the spots where the fender screws to the rack and cracks 

[Hagbard]

This look like anything worth a crap?

https://www.ebay.com/itm/164349125071

Keep in mind I don't shy away from buying specialty tools at Harbor Freight - IO generally only need them to work once =P. Don't be fooled by the overflowing Snap-On box in the background  

[JustRandy]

8 hours ago, Hagbard said:

This look like anything worth a crap?

https://www.ebay.com/itm/164349125071

Now that you mention it, I think I bought that one or one like it and sent it back.  Seems like it didn't have the cutter I needed because the sizes lie.  So I bit the bullet and bought the pricey one.  https://www.ebay.com/itm/264215390009

And the pilot https://www.ebay.com/itm/263155791974

If I had bought it in 2007 it would have paid for itself a few times by now.  I think that cutter would do every valve on every machine I ever had, except maybe cars.  The cutting teeth adjust in and out to fit a range of seats.

I paid $114 and $24 from the same seller 2 years ago so that's how much prices went up.

Man those plastics look sweet!  I'd be afraid to get any mud on that jolly rancher lol

[Hagbard]

So I have to give a whole lot of credit to whoever decided what jets to supply with this carb. They sure aren’t anywhere near what is called for in the manual, and I suspect there may be internal differences in the carburetor that have been accounted for with these jetting choices. The main is a 145, the pilot is unmarked but looks to be somewhere in the 12.5 or smaller range by eyeball😳 but lo and behold, once I got everything straightened out and got it running reliably, putting those jets in made it go like hell and idle nicely. Keep in mind this was a carb that sold for $50 on Amazon, which I got from Amazon warehouse for $20.18 ¯\_(ツ)_/¯ 

[JustRandy]

What carb?

[Hagbard]

The BST31-133 I got that I was cursing just yesterday. Runs like a charm now. 

[JustRandy]

Oooh ok.  It didn't work because of the intake valve.  Are you going to keep it or buy one without the diaphragm?

The jets could be numbered differently and the fact that the pilot doesn't have a number suggests it was a rebuild kit.

[Hagbard]

For now I’m going to keep it. Almost all of the headaches I was attributing to it were the intake valve issue.

[JustRandy]

Looks like I'm consistent over a decade lol

  

On 10/19/2012 at 5:53 PM, JustRandy said:

I guess I need to find a 28mm carb somewhere. That's probably about right for this engine.

 

On 9/30/2021 at 12:08 PM, JustRandy said:

The 230S and 250S had 26mm carbs, so 28mm is probably right for a 300 (280).

[Hagbard]

LOL I was browsing through some threads and saw your old posts that sounded EERILY like the problems I was having lol.  Was thinking today... how about I help you make that seat cutter pay for itself?    I don't want to blow the money on a tool I have zero clue how to use properly, and you seem to know WTF you're doing. I'd just as soon spend the money with you if you don't mind doing the work. If not, say so, and I'll try to track down someone local-ish.

[Hagbard]

So back to camshafts...  Still digging around and I found that the "Hot Cams" upgrade for the LT230S is the same part# as the one for the LTZ250.  Specs listed below along with interchange info. LT250S is notably absent, but I know the same cam *should* fit, right?  I can't find any specs about stock cams i.e. lift, duration, etc. so I don't know if this would be an upgrade or not. But not necessarily the HotCams product - think a stock LTZ250 cam would be any good? Thinking more about putting it in the 230 at this point and leaving the KQ alone. I dunno.

 

Part 2066-1

FITS MODELS	LT 185 QuadRunner (84-87); LT 230 E QuadSport (87-93); LT 230 G (85-86); LT-4WD 250 QuadRunner (87-98); LT-F 250 F QuadRunner 4x4 (99-02); LT-F 250 Ozark 2x4 (02-09,12-14); LT-F 250 QuadRunner 2x4 (88-01); LT-Z 250 QuadSport (04-09)
SPECS	Stage: 1 Exhaust Cam Lobe Center100.750° Exhaust Cam Lobe Duration at 1mm237.500° Exhaust Cam Lobe Lift7.570mm Exhaust Cam Valve Lash0.360mm Intake Cam Lobe Center103.500° Intake Cam Lobe Lift8.940mm Intake Cam Valve Lash0.150mm Intake Lobe Duration at 1mm235°

Nevermind. Stock cam is the same "D" version.  At this point I'm wondering about getting the cam reground.

[JustRandy]

16 hours ago, Hagbard said:

how about I help you make that seat cutter pay for itself?

The shipping back n forth will eat into my profits or your costs and I'd hate to charge anything of substance because I know you're on a budget.  You could buy the tool and resell it on ebay.  I'm sure it would sell fast at the right price.  Just deduct the cost of having a pro do it and sell it for the remainder.  Or have a local pro do it and check their work.  Maybe they will do a good job.  If not then I'm sure they will fix it.

It's not hard to do.  What's hard is doing it long enough to be sure you've done it right.  You have to use paint or somehow determine where the contact patch is on the valve.  So you have to grind, paint, check, grind, paint, check, etc. and it's too easy to say "aw that's good enough."  Since your valve is already worn so bad, a lot of cutting will probably be needed on the seat (it was with mine).

You won't need the 60 degree cutter since your seat is already too big.  You'll use the 30 and 45 to move the contact patch back to the center of the valve.

About the cams, I'm not sure I'd trust any specs from hotcams.  If I remember right I think they were selling a stock cam with more lift with the wrong specs (some insane exhaust duration which couldn't have been right).  I'd rather have less lift with more intake duration.

If the LTZ250 cam were any good I wonder why no one was using it back in the day.  It seems like it came up in discussion but I can't remember what was decided.  That was way back in 2007, 8, 9.  I'll dig through my notes and see if I have the cam specs for all the cams.

[Hagbard]

14 minutes ago, JustRandy said:

The shipping back n forth will eat into my profits or your costs and I'd hate to charge anything of substance because I know you're on a budget.  You could buy the tool and resell it on ebay.  I'm sure it would sell fast at the right price.  Just deduct the cost of having a pro do it and sell it for the remainder.  Or have a local pro do it and check their work.  Maybe they will do a good job.  If not then I'm sure they will fix it.

It's not hard to do.  What's hard is doing it long enough to be sure you've done it right.  You have to use paint or somehow determine where the contact patch is on the valve.  So you have to grind, paint, check, grind, paint, check, etc. and it's too easy to say "aw that's good enough."  Since your valve is already worn so bad, a lot of cutting will probably be needed on the seat (it was with mine).

You won't need the 60 degree cutter since your seat is already too big.  You'll use the 30 and 45 to move the contact patch back to the center of the valve.

About the cams, I'm not sure I'd trust any specs from hotcams.  If I remember right I think they were selling a stock cam with more lift with the wrong specs (some insane exhaust duration which couldn't have been right).  I'd rather have less lift with more intake duration.

If the LTZ250 cam were any good I wonder why no one was using it back in the day.  It seems like it came up in discussion but I can't remember what was decided.  That was way back in 2007, 8, 9.  I'll dig through my notes and see if I have the cam specs for all the cams.

The LTZ cam is the same as the KQ 300 and the 250 4x4 “D” on the end

[JustRandy]

1 minute ago, Hagbard said:

The LTZ cam is the same as the KQ 300 and the 250 4x4 “D” on the end

That's possible.

All specs at .040 lift unless stated otherwise:

The 230 stock cam is 235/237 duration and .324/.290 lift.

The hotcams 1 is 235/337.5 which is a misprint that it appears they fixed.  So 235/237.5 is the stock duration.  Lift is .352/.298.

So hotcams is basically a stock 230S cam.

Webcams 1 is 251/256 and .340/.340

Webcams 2 is 257/262 and .360/.360

Webcams has a 3 but I don't have the .040 specs, but the .050 specs are 264/264 and .425/.425

Megacycle 1 is 236/240 and .4/.4

Megacycle 2 is 282/284 and .43/.43

The following are what I measured myself:

230S cam 235/235 and .336/.311 with 15 degrees overlap

LT4WD is 219/221 and .321/.286 with 2 degrees overlap (good cam for turbo)

250S is 252/236 and .339/.345 with 19 degrees overlap

As you can see, the 250S stock cam is pretty good and close to the Webcams stage 1.  I'm not sure the exhaust duration is that meaningful.

I don't have any notes on the 300 cam but I'm pretty sure it's different than the LT4WD cam.  I think it has a hair more duration.

 

[Hagbard]

To be honest, information like this and other stuff in this thread ought  to be in a sticky.

[JustRandy]

What I really like about the 250 cam is it holds the intake valve open longer.

Both cams open the valve about the same time, but the 230 reaches .040 closed at 35 degrees after bottom dead center while the 250 is at 60 degrees after.

Holding the valve open nearly 30 degrees longer allows porting of the intake to take advantage of the inertia of a column of air to keep filling the chamber even though the piston is moving up in the bore.  It's a powerful supercharging effect that effectively makes the engine bigger than it's static displacement (ramming 300cc of air in a 250cc volume).

I don't know to what extent exhaust duration matters and I'm fairly convinced that lift over stock doesn't add anything except stress.

[JustRandy]

3 minutes ago, Hagbard said:

To be honest, information like this and other stuff in this thread ought  to be in a sticky.

There was a "vault" on atvconnection that had everything in it.  https://atvconnection.com/forums/suzuki/226867-85-88-suzuki-lt230s-quadsport-help-2.html

Looks like it may be gone  https://atvconnection.com/forums/suzuki/226867-85-88-suzuki-lt230s-quadsport-help-1269.html#post3447760

I guess it was hosted by a guy who got tired of paying for it.

[JustRandy]

I guess webcams is the way to go but you have to send in your cam and rockers for welding which is hard enough to shred anything that isn't just as hard.  Plus webcams will grind any profile you want.

A lot of guys ran webcams stage 2 back in the day.

Instead of doing all that it's just easier to get a 250S cam which I already know boosts power without sacrificing lowend and it preserves the longevity of OEM.

A stage 2 webcam might be a bit more power but when dealing with 1/4 liter engines it wouldn't be so much that rider skill couldn't makeup for.

A guy I know had a 660 raptor and I ran off n left him all the time on trails with an essentially stock 250S on a modded frame.  I was actually trying to blow the engine so I had excuse to rebuild it, but never could.  The 660 is too heavy and too much power to negotiate curves.  Keeping the front tires on the ground so it could steer was the biggest challenge.  If I had a 660 the first thing I'd do is put bald tires on it, but he had holeshots that were way too aggressive.

Too many people buy into looks and names instead of what works (the jeet kune do of quading lol).

[Hagbard]

So, I think I’m gonna keep the king quad barely stock, but utilize all this info and put a 250S cam in my 230motor/160 frame Frankenquad. It’s smokes like a son of a bi***, so I’m going to redo the top end anyway, might as well use those nice heavy valve springs I got, and that hot cam.

[JustRandy]

I guess you could put the 230 cam in the 300.

230s are notorious smokers.  I figured it was due to the wrist pin wiggling in the rod end.  What separates 230s from any other quad engine is the bore/stroke ratio.  The stroke is so long that the rod is at a sharp angle causing the piston to press hard against the side of the bore.  The 250S added a longer rod to mitigate that effect.  Shorter rods increase the acceleration at TDC (which is good if you want a strong intake charge) while they decrease it at BDC.  Longer rods spread the acceleration out more.  The 250 also added a 17mm rod end because 16 is just not enough to hold the piston on while slinging violently from extents of that huge stroke at high rpms.  Adding a heavy wiseco just makes the problem worse.  The small end bore of the rod stretches into an egg shape and I'm assuming that a piston flopping around in the bore is what causes the rings to wear and the smoking.

So in light of that about all you can do is make the bore as tight as possible to hold the piston straight and make the ring gaps as big as possible to be sure the rings never bind.  Also keep in mind the inherent weakness when riding.  You may have to learn to live with the smoking until you find a 250S engine or some other quad.  There are too many things wrong with the 230S to make them worth building.  The 300 on the other hand is a good candidate.

Honestly I'd probably beat the snot out of the 230 until I saved up enough to find something better to invest in.

[Hagbard]

Fair enough. Appreciate the insight and advice. Found a local powersports shop that does machining in-house, and come highly recommended by the local dealer as well. Water pump on my Tundra just sh** the bed last night, so I currently have a MUCH bigger fish to fry.