1998 king quad 300 exhaust manifold glowing red

[goatman]

the e-clip is 7mm id, the shifter linkage is 8mm od and the e-clip fits into a groove

pulled the cylinder head cover and the timing marks on the cam are where they are supposed to be so it hasnt skipped a tooth.

so now what?

Trouble shoot the cdi?

[Mech]

Yeah. You need to use a timing light and check it's idle ignition advance angle, and that the ignition timing advanes as you rev it up.

It should probably have about ten degrees of advance of top dead center at idle, and should go up to between twenty-five and thirty degrees of advance at full revs. If it goes up by about ten degrees more advance than what it had at idle, then it should be ok...The flywheel is probably marked with a ignition timing mark, possibly full advance, and possibly idle advance. The manual should probably have specific figures..

[goatman]

went looking for a cdi tester and the suzuki pocket tool is $700, not doing that, they say you can only use their tester and not a normal DMM???

lowered the clip to the 5th groove on the needle, exhaust was hot right away and throttle crapped out. moved the needle clip to the 2nd groove from the top and throttle was alot better, still getting red exhaust under throttle though. ill try the top groove tomorrow.

 

[goatman]

need to buy a timing light with a digital display that shows rpm/degrees

the cdi is what adjusts the timing, correct?

 

INNOVA 3568 Digital Timing Light, Timing Lights - Amazon Canada

[goatman]

by carburetor theres 2 wires, 1-orange wire that is a female barrel connector and a white wire/black stripe male barrel connector. they could plug into each other but they werent connected so i didnt, i just put some heat shrink on the white/black connector. looking at wiring diagrams there is no white/black wire anywhere saying what it is

theres something else i just clued into. someone painted the motor black

do you think its possible that the paint is making the motor run hot causing a lean condition?

[Gwbarm]

Those wires down by the carb could have been for a carb heater that is no longer there. You might try following them to see where they go to get a better idea. Havent looke at a diagram on your bike but generally black and white go to the kill switch and orange goes to coil but you are running so not the coil wire.

[goatman]

the white and black came out by the speedometer  and connected to an orange wire that goes into the left hand controls, off/on, start and lights. i plugged them together and nothing happened. im starting to think the intake valve is toast. just going to go recheck the gap. right now it starts and idles, give it half throttle and it blows air out the intake by the gas tank and will die if i dont release the throttle. its not back firing. i can get it to go full throttle and its sucking a ton of air through the intake. its such a pita to try and set the gap on these things, getting ready to lose it on this thing lol

[spock58]

Check for a leaking intake manifold, could be cracked or missing an o-ring??

[goatman]

i checked that by spraying maf cleaner around everything while it was running to see if it would rev up but no leaks. i just did a compression test with the valves backed off and the psi was jumping from 35 psi to 50 psi. im thinking it needs new intake valve or something. im just going to tear into it and see what i find.

[Gwbarm]

I agree you should probably pull the head and check the valves out, compression seems low even with a compression release . Then you can check the timing before you pull the chain off to see if it has jumped time.

[goatman]

got it off, lots of carbon but when i sprayed cleaner in the valve ports nothing leaked out. got some paste coming from amazon to lap the valves and put it back together. 

[goatman]

the headgasket looked they just used permatex ultra black. would you spray the steel gasket with copper coat instead of the ultra black. i realize there is an o-ring on one of the studs that needs ultra black but for the steel gasket id rather copper coat it than use the caulking

[Gwbarm]

I never reuse head gaskets i would replace it and replace the o rings.

[goatman]

im in Canada, the only gaskets i could find was a top end rebuild kit. cylinder, piston all the gaskets for about $1000 cad delivered. if lapping the valves works ill bring in a top end kit from ebay in the USA, theyre only $200 cad delivered. ebay is also Namura brand

https://atvcylinders.com/en-ca/products/1991-2000-suzuki-king-quad-kingquad-300-cylinder-piston-top-end-rebuild-motor-engine

[goatman]

this ebay https://www.ebay.com/itm/154318957476

[Mech]

Yup, replace the head-gasket and a new O ring doesn't need sealer.

[goatman]

ill look at it tomorrow to see if ill re-use it. im in Canada, parts arent readily available and to get gaskets will cost as much as a top end rebuild kit from ebay USA. ill probably slap it together and if it doesnt work ill order a top end rebuild kit.

[Mech]

Ok. It's your money your money.

For anyone watching and interested, and for their future reference..  Engines, single cylinder engines, that only have 35Lb compression, don't start. They start getting real hard to start when they get down to about 80Lb. Also, if an inlet valve is leaking, then they don't like idling..  This engine we are discussing both starts and idles.

The most likely reason for such a low compression reading is either that the throttle was closed while doing the test, or the gauge is faulty.

The one thing that has the most dramatic effect on exhaust temperature is ignition timing being retarded or not getting advance. That will cause it even at low revs or little throttle settings. Lean mixture can cause exhausts to get hotter, but they have to be ridden with the throttle open to do that, and even then you seldom notice the exhaust red hot unless it's night time. A red hot exhaust in daylight is ignition timing..

Edited July 28, 2025 by Mech

[goatman]

if i understand correctly, the flywheel is fixed in place by a keyed shaft, the coil pick up is fixed in place. theres no adjustments that can be made in the gear case. the cam shaft is in time with the flywheel, no adjustments can be made, mechanically the engine is in time. so what you are saying is the cdi is pooched? thats the only thing that says when to fire the spark plug correct? 

so at about 1200 rpm we should have 10 degrees btdc to fire the plug and at full throttle about 30 degrees btdc, i understand that

i saw in the manual that they said the throttle needs to be open to compression test it, i did not do that

it was still blowing air out the intake at about 2000?rpm

i still think there is a valve problem

today will be my last day of working on it, if it doesnt work, it can sit for a month while i wait for parts and spare time 

[Gwbarm]

I understand i admit i have reused head gasket in a pinch i would use the copper stuff, but be advised it is not a permenant fix it may work for a month or two but it will fail, look over the gasket very well before reusing it to see if you can see where its failed . If air is coming out the intake i would say it has jumped time somewhere or you have a bent valve inspect the valves very carefully to see if they are OK .

[goatman]

i cleaned the head gasket up, got all the black compound they use off it and sprayed it well with copper, the head gasket didnt blow, lapped the valves and got all the carbon off them. they spin nice and are not sloppy, timing chain tensioner seems to be working just fine. got it all back together just waiting for the Permatex Ultra Black to set up on the head cover.

i wanted to take it up to a mining claim i have this weekend, hopefully this works and ill see if i can do a proper compression test with throttle open

[Gwbarm]

Wow! You have been busy! Valves look good i dont see any pitting. I would maybe lap the top one a little more you want it shiny all the way around like the bottom one. Double check the timing also sometimes the shaft that the timing gear attaches to can move so it will appear to be in time but check the cam lobes to make sure they are both pointing in the right direction.

[goatman]

the foot shifter cable came in from amazon that measured 26.77" and it fits.

cam lobes in right direction?, i didnt look at the lobes. i made sure the "A" stamped on the cam was in the same position as it was when i took it out.

-A-

guess ill find out soon enough

 

[goatman]

i compression tested it with the carb off 110 psi

do they have rev limiters?

 

[goatman]

this is where the quad got stuck on the van

 

[Gwbarm]

The rev limiter is a small screw up by the thumb throttle. Did what you did help any thing

[goatman]

yes, i can accelerate through the throttle, before at 1/4 throttle it would bog out so if i wanted to move the quad in high gear it would stall so then i would shift into low to get it to move, now you can see it powers all through the throttle and i can move forward in high gear. ill play with it more tomorrow. when the throttle is pinned it sounds like a rev limiter to me

[Gwbarm]

It does sound good ! Relly nice low throaty growl, i always liked that 300 engine.

[goatman]

a person mentioned to me it sounded like the exhaust valve isnt completely seating. ill increase the exhaust gap a little more tomorrow and see if that helps.

[goatman]

went to 0.006 on the exhaust valve didnt do much of anything except a slight ticking sound