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Discussion Starter #1
My 95 KTM 300 has started up in reverse a couple times, so I decided to check the timing. The bike does have the SEM ignition. The manual says 13 degrees (1.2mm) BTDC. I found TDC with my dial gauge. The problem I'm running into is that once the flywheel is rotated clockwise and pinned to the stator, I can't get 13 degrees of rotation. My dial gauge is in inches so I need .047". I'm can only retard the timing .02". What am I missing/not understanding? Please help.
 

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You are probably correct to suspect timing issue causing reversed engine rotation.Your timing will not move itself. It should not go out of adjustment unless moved or caused by defect. I suspect your trouble is a defective ignition module. SEM ignition is a well known piece of crap substitute for a decent ignition system. I wouldn’t be bit surprised to find your module is the problem. But check for loose or broken trigger. If you are unable to bring base timing to spec without slotting trigger I would not hesitate to replace that high priced module. Good luck
 

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Any leads on where would be a good replacement for the ignition?
If allowed (Admin remove if not allowed...) I have found KTMWORLD a brilliant, non expensive and fast place to get bits for any model of KTM.
 

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Discussion Starter #5
So a little off the typic of timing. The pawl gear eyelets on my kickstarter broke, locking the kickstarter the kickstart gear. So since I had to drain all my fluids I decided to check out my top end. This is what I found:

"X" dimension on the piston was .15 (with a torqued down cylinder), manual say max is .1 before torqueing.

Piston looks brand new, aside from the heavy carbon from the jetting I've been chasing. No blow by on the rings.

Piston ring gaps were .13 and .15. Manual lists the max at .4.

The flapper valve in the PV assembly appears to be from a 96 or 97. More than likely a 97 KTM 360 (that's what my donor bike is). Not sure if that's a big deal but there are differences, main bearings on a 95 vs bushings on a 97. When I assemble the PV everything fits snug and there is no side to side or up and down movement, just axial movement like what's needed.

I had replaced the o-rings on both the flapper and control valves. When I inspected the control valves, it appears that the springs are doing nothing. In fact, I put a straight edge on the control valve sides and you could see like between it and the top of the o-ring. I think this helps explain why I had a virtual wind tunnel coming out of these two points during my leak down test. I'm not sure how or if this needs to be remedied.

The rod has no up and down movement at the crank, and almost no side to side.

So my plan of attack is to get a complete engine gasket kit, and stator side crank seal. I've already replaced the clutch side, thanks to some findings from my leak down test. I'm going to shim the cylinder per manual specs. Replace cylinder studs, nuts, and head bolts. They looked a little shady and neglected.

I've fixed the kicker starter my parts from the donor bike, but I think I'm going to replace the kickstarter spring and ratchet spring. I really don't want to pull the clutch again due to aged parts.

I've set the "Z" dimension, however, I'm a bit lost on what the true height is for a 95 KTM 300 MXC. My manual says it's for a 91 thru 97 and gives 46mm. I have a manual for a 96 and it gives 48mm for 300 SX and MXC. I went with 48mm and will check during assembly that there is no issues with the flap and piston/rings.

Now as for the control valves, what do I do about the o-rings? The o-rings I put on are KTM OEM parts. However, when I did my leak down test, I could get it to pressurized to 6psi but once I took the air away I'd drop to 0 in less than 10 seconds. This is the only remaining leak I can detect.

Last question/issue, would anything listed above add to or mask itself as jetting issues?

Sorry for the long post, I'm trying to process a lot of small issues I "inherited" from the previous owner's project short cuts. Please be gentle if you have to correct me for any ignorance in my info above. I don't want my kids to see their dad crying over a dirt bike.?
 

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Just a thought

I’m just wondering about your original post and your recent revelation about your mishmash of motors causing your original reverse running motor. My thoughts here would be that if your ignition trigger is measuring crankshaft rotation based on your flywheel input but your piston travels actual position is not where it is supposed to be you are in effect mis-timed. Sorry to confuse a confusing problem, but I thought it may be worth a mention. I wondered if the 300 and 360 rotor diameter may affect your timing question. TDC is always at top of stroke but smaller rotor would retard ignition timing. Good to check this stuff while motor is apart. Check back as needed for additional help??as needed. And don’t worry about crying in front of the kids. They saw you crying when the little crumb snatchers climbed up your lap and used your balls as a diving board :surprise:
 

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Discussion Starter #7
And don’t worry about crying in front of the kids. They saw you crying when the little crumb snatchers climbed up your lap and used your balls as a diving board :surprise:
I got six and I can tell you time does soften those memories. Given how deadly kids are with those knees and elbows, it really is a modern miracle I made it to six.

Good point about the crank. I'll have to look into that.

Augiedoggie, any insight into the control valves and o-rings?
 

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Almost forgot

Sorry almost forgot. My eyes were clenched tightly in sympathy for that nut crunch I lost my concentration. Your power valve o rings and covers are not air tight and will drop pressure when air tested. I like to perform cylinder leakdown with piston at TDC and air introduced to spark plug hole. You can use plastic wedge or flattened copper tubing rotated gently into crankshaft primary gear to lock piston. I will try to post picture if possible. Crankcase pressure testing is complicated by power valve air leakage. This test will require constant low(10-15psi) to perform crank seal testing
 

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This is the copper tubing used to lock piston @ TDC for leakdown testing. Can also be used to lock crank or clutch for other purposes, but too much torque can break gear teeth off or damage shaft bearings if used with excessive torque. Have to be careful.
 

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Discussion Starter #10
I understand that the PV components are not air tight, but from what I've read I understanding that I should expect 1 psi of pressure loss about every 20 seconds or so. I lose all pressure in like 5 seconds.

Should the control valve o-rings touch the cylinder, or at least protrude above the surface of the control valve?

Also, thanks for the insight. You're like the KTM Jesus, saving one poor wreched 2 stroke at a time. ?
 

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The standard compression on common o rings is .010 in. Sorry i dont speak metric. some kits may have gypsy o rings or non standard o rings. You can probably find industrial o ring chart and use bore size and shaft size and order viton o rings from industrial supply distributer. I found the wiseco top end kits were complete with correct size and material o rings. I dont get too hung up on the power valve leakage. I know some guys do, and maybe they know something i dont here, but my logic was a slight leakage at low pressure and temperature will amount to zip after motor warms up and everything grows to normal size and exhaust pressure is much higher than test pressure.
 

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Augie is good at this sh-t, your in good hands.
All those side control rollers on the power valves on an older bike leak a bit, often the left over 2 stroke oil/splooge leaking through semi seals the oring's good enough.
If your worried, buy a thicker viton oring from a hydraulic shop, but you wan't those little rollers to move freely.
As for the bike firing backwards, is the stator sitting on the backing plate in the correct position?
I think from memory the 3 bolt holes are evenly spaced apart, could it be put on 120 deg out?
 
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Discussion Starter #13
I'm not sure about backing plate being 120° out. The plate has a straight cut side on the rear side and a hole cut out in the front for the stator wires to pass through. I attached a snip of the diagram to show what I'm talking about. I'll double check it to see what might be possible. There are two sets of holes on the backing plate (~1/4" apart) so you never know.

Now in regards to the crank. When I look up cranks for a 95 KTM 300, the part finders list it as "54630318300 Superseded by Multiple Items 300'93" (searching on AOMC web page). So it appears that the 95 KTM 300 used a 93 KTM 300 crank. The problem is I can not verify this. KTM part finders online only go to 1994. I called AOMC and they verified that 94 thru 97 list the same crank. Can anyone confirm that the crank for 93 thru 97 are the same?

I really don't want to split the crank, but I think the only way to identify the crank is to find a part number. I can't think of any other way to verify the crank that is in the motor.

Lastly, is it bad that this part of a rebuild seems to be almost, if not just as much, fun as riding the bike?
 

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You’re a sick puppy

I had to laugh at your last comment. I also find it very rewarding and fulfilling to work on motorcycles, cars and anything else with nuts and bolts. Few people understand this except for gear heads like us. I go a bit bats trying to solve complicated problems in my work but I find these challenges sharpen our skills. I think the 300 uses a 250 crank and larger cylinder and the 360 uses 300 cylinder and different( increased ) stroke. My suggestion was based on a theory. I’m not certain this is relevant to your symptom but wanted to suggest checking. Not sure that disassembly is required as you may be able to identify pertinent parts by part number and find common part numbers of the suspected problem causing parts. And compare the part number to the ones required. Keep at it
 

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Discussion Starter #15
The rod is stamped with a "542". I'm going to make a little assumption here. A "542" engine stamp indicates a 250 MC. I know that a 1995 250 and 300 utilize the same rod, the hubs are different. On the crankshaft/piston diagram, the repair rod is item 30. So I'm going to assume that the crank is correct, and that the 542 stamp on the rod is indicating it's for a 250/300. So for now, I'm going to hold off on splitting the case. If I start Jonesing to look at a transmission I'll defer to my donor 360 motor (it's already split, I can get my shiny gear fix from it).

I was hoping to run and grab the top end gasket kit today but got distracted with yard work and milling wood in my driveway. I'm sure I pissed off a few neighbors with the barrage of noise from my planer and table saw. Boy won't they be happy if I can figure out this KTM 300 riddle. I may sit for the entire first day just brap brapping.
 

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I have to say, I definitely enjoy riding them a lot more than working on them.
I suppose it depends on what you're working on.
Just did a front diff rebuild on a nissan patrol including swivel bearings ect. Dirty sh-tty, time consuming job, And I couldn't care if I never do one again.
If you're stator wires line up to the hole in the backing plate and the grommet in the cover you should be right.
If you're piston is not tapping the head, but is still doing a complete stroke in the bore, and you're not slapping the crankcase anywhere then wouldn't that be alright?
Still trying to work out why you're donk is firing backwards
Ive only ever seen the magnets dislodge out of the flywheel, but could they have spun?
 

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Discussion Starter #18
I have to say, I definitely enjoy riding them a lot more than working on them.
I suppose it depends on what you're working on.
I agree with you on that. If it's a project, it's fun. If it a repair to a daily driver, I take it to my buddy who is a mechanic. I have enough deadlines at work, I don't need another because a starter went out.

One thing I notice about my flywheel is that it does not have the two holes like the parts diagram and manual show. I think that might be part of the problem. I need to look into this more.

Augie is definitely good. Hell of a lot more help than my local dealers. I've gone to my local KTM dealership and the young guys are all about fuel injected fourstrokes. Try talk jetting with them and they look at me like I have a d*ck on my forehead. It's harder to find someone who know the older bikes than most parts.
 

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Discussion Starter #19
So I finally got some free time today to tinker with the 300. I have a kokusan 2k2 from the donor bike. I decide to rough hook it up and test for spark. It sparks! The problem is that the 95 frame does not have the attachment points for the CDI and coil. The stator tests good, so worst comes to worst I rig it in place. I still can't make heads or tails regarding the SEM flywheel. Hoping I can slip away from work early tomorrow to go get the top end gasket kit and the other parts I've mentioned before. Cross fingers for this weekend.
 

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This is good!
Kokusan k2 ignition is 10 times better then sems.
You will find a way to bolt the coil and cdi on even if you have to make up a couple plates.
Definitely worth it.
Good luck, hopefully that 2 banger fires straight up for you.
 
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