350x locking up but not locking up!?!?

[jonny500]

ill try to make this quick, ive been looking everywhere and cant seem to find a solution or anyone else that has had this happen to.. i have a 85 350x and just recently tore it down to freshen it up. new wiseco 10.25 comp., 50 over, new d.i.d cam chain, valve seals, clutch, and a full dg exhaust...i ran it for a couple min. let it cool, and did it a couple more times. took it for a ride around the house and after about 1 min the motor started getting tight! took it out yesterday and rode about 2 miles down dirt road varying throttle and it seemed to be getting tight again. let off the gas in 5th at about 1/2 throttle and she came to a quick stop, pulled clutch and she quit. if i kick it over slowly it seems like its siezing but if i let it cool for a min. its fine!? SO i tore into it tonight and theres not one scratch in anything!! the only thing i can think of is the new cam chain getting tight when hot? or is this normal to do this when breaking in??

[wisconsinite]

sounds to me like the bore is to tight for the piston. definitely not normal break in.

[Dirtcrasher]

Does sound like the bore is tight, but I'd imagine something should rear it's ugly head. Something is getting hot, expanding and causing some binding.

The valve cover alone can do this if you use sealer in the wrong areas. It blocks oil galleries to the cam......

What sealer did you use and did you avoid the areas in the service manual??

[jonny500]

i used hondabond and followed the manual to a t. I had a machine shop boar and hone it and he said it was spot on. im going to have the clearance checked tomorrow. i didnt have to file the rings, the specs were .013 top but it was .017 and 2nd ring said .016 but it was .021 the box said piston spec is 0.051mm every bolt on this thing is right on with a snap-on digital wrench.

[jonny500]

shop said ring end gap was too small and to go another .010 on both. so like .027 top and .031 2nd ring?? do you guys remember what yours are at?

[tri again]

shop said ring end gap was too small and to go another .010 on both. so like .027 top and .031 2nd ring?? do you guys remember what yours are at?

I know nothing specific but wanted to keep the thread alive.
Frustrating for sure.

I lost the top of a piston in a single engine AIRplacne at 1800 feet.

The faa certified mechanic forgot to set the ring gap and it pulled the top of the piston off.

generally for aircooled lycoming was something like
10 thousandths for every inch of stroke.

Wouldn't it be nice if your fix was that simple?

Wishing you the best and sorry you had to go in 2x
but it will be worth it in the long run and
will soon be a distant memory.

Happy trails.

[Dirtcrasher]

I'd have to check but I believe Wiseco states .004 for every bore inch. 3" bore = .012

.027 and .031 seem large.........

[wisconsinite]

i would deffinitely check the bore diameter, also check top and bottom to make sure it's not tapered. perhaps your jug was not bored properly.

[beets442]

+1
i would deffinitely check the bore diameter, also check top and bottom to make sure it's not tapered. perhaps your jug was not bored properly.

+1 on checking ring end gaps

[ailll1]

I'd have to check but I believe Wiseco states .004 for every bore inch. 3" bore = .012

Right,
Directly from Wiseco: Recommended end gap is usually .004'' per inch of bore. (Example: end gap for a 3'' bore would be .012'') Additional end gap may be necessary for modified engines. (May include head/cylinder work, aftermarket exhaust, etc.)

That's for a liquid cooled 2 stroke though.

[jonny500]

could it be the lower rod bearing starting to go?? i filed the ring gaps to .021 and .030 and the motor still got REAL tight after about 5 min. pulled the clutch in and she died. tried kicking but it was locked up, waited 5 min. and it started right up and idled fine. no noises at all! and not a scratch on anything!

i can spin the motor over holding onto the rod and theres no play and it feels fine..

[Slingblade]

Doesn't really sound like a bearing. I've been on a 350x when the big end bearing went and it was jerk, jerk, ping, ping, clatter, knock sorta thing. No scuffs on the piston at all?

Are you absolutely sure you're getting oil to the topside?

[jonny500]

oh yea theres oil, i cracked the bolt to the head and to the top of the cooler and fired it up, oil was everywere! after closer inspection the rod small end has some dark lines in it and you can feel small high and low spots. like grooves, im thinking if the top bearing were to seize, the piston wouldnt be able to rock back and forth and it would scar the cyl. but the motor never really locked up solid, it would just start to lose all its power, thats when id let off the gas and pull the clutch and it would die. but something was tight. ive got too much into this trike to stop now, so i think im going to put a rod in it but should i replace the crank bearings? the manual says to, so i guess its a no brainer huh.. im going to get some pics so maybe someone else can shed some more light. everyone has been a great help, and ive tried it all but no luck yet..

[RubberSalt]

Is your case breather able to breath? Do you have enough oil?

Ring gap should be the same on both. 0.015-0.045mm. I'd set them both upwards of .032-.037mm. The extra compression creates more heat. Expands rings more than the book says.

I've had an issue where my clutches acted funky and locked my engine up. Nut fell off the clutch pack(wasn't me! ok it was). Drain the oil and see how it looks, check the filter, it could be plugged up somewhat.

[Dirtcrasher]

If your gonna split the case, you should def. replace the mains, the oil seals, check the clutch and measure the oil pump spec.

[atc007]

Kind of ashamed I can't tell you what's going on here ! It ran ok before?? Smoked,I assume,but you had rode it? you should absolutely be able to SEE what's going on inside there!! The info above is right,tight bore,your piston should be scratched,more on the intake side. Egged cylinder ??,it happens,no matter what machine shop did it. Rod end,wrist pin, scratches ??,,usually they will seize on the piston as much as the rod. You said you used Honda bond,only on the cam cover correct?? Oil spraying out of the headbolt does not mean that it is GETTING everywhere it belongs inside. But Again,,you would SEE oil starvation!! I would run it a little more ,,especially if you're going back in again anyhow!! Never thought you'd be this addept at tearing into a 350X huh?! Keep us posted!

[jonny500]

the new wiseco pin looked like it started to get hot, the top rod had some wear to it like it too had gotten hot.... so heres what i did. took a brake caliper hone and lightly hit the rod just to polish it up then i buffed the stock honda pin with 2000 grit sandpaper and slapped it back together (at about 1:30 this morning) got out of work early so i finished putting everything back together, fired it up, let it get warm and started doing laps around the house. everything seems to be going good so far! ill find out wed. ive got the day off so im going to hit the dirt roads....couple questions..im still hearing a slight squeal when i tap the gas but i think this was happening last year also, how hot does the head get?? i know its gonna get hot becouse its air cooled and a little hotter because of the new high comp. piston but after about 5 min of riding it will sizzle water off the head.. THANK YOU everyone that replied to help me keep this thing together and not go to the boneyard! ive had a bunch of toys over the years and rebuilt most of them but this one just still has me stumped

[Dirtcrasher]

Mines a crate motor with a 10.5:1, Supertrapp (13 discs), megacycle cam and 93 octane 150 main/52 pilot. Doesn't get hot in 5 minutes and your in Maine, not the desert.

Did you break this in at all? or just hop to it and let it get hot and stay hot?

What size main jet and is the AB lid off??

Sorry if you stated so before...........

[wisconsinite]

5 min of running shouldn't get the head that hot, in my opinion. do those motors have a camshaft bearing? perhaps that's where the problem lies, what with the squealing noise...
did you check the ring gap at the top and the bottom of the cylinder? this will tell you if the bore is tapered. hope you get it worked out...

[atc007]

No bearings on the cam,,just metal on metal! I was gonna suggest honing your rod when I got in tonight! You read my mind. Yes ,the head will get that hot,tat soon?? MAybe sitting still w no air moving over it. Breaking in is simple as this,don't bog it,and don't overrev it. I like putting 4th 5 th gear. LOTS of speed and air moving,low rpm's. I think you might have it,,but the whine has me worried,,you may be diving back in ONE more time!! I'd keep riding it till it sounds bad or acts real bad,it should show you where it is this time! Good luck,

[Flossyb20]

I know it may be trivial at this point, but it sounds to me like your timing was off a tooth on you cam . This would cause all the problems you've been having, as running it with the valve events off will cause it to run pretty damn hot. Sounds like you've taken care of everything else that could be wrong, so maybe this could be it. Stop me if Im wrong Dirtcrasher...

[Dirtcrasher]

He claims he followed the manual "to a T" so I can't see that being the issue.

I still wanna know what the jetting is and at what altitude. Mine was lean until I got up to a 150 main from a 142 and a 45 pilot is now a 52.

Did it run low on oil at oil? Is the filter in backwards? How long was the 1st ride and how hot?

I rode mine 2 minutes and could feel the heat so I stopped and jumped way up on the jets. Let it cool and now I ride it maybe 10-15 minutes and let it cool down for an hour or so. I've done numerous heat cycles at this point but because of the motor being all new and the cam, I want to take it easy before I romp on it too much......

[jonny500]

jetting is 152 main and i think 38 pilot. ill have to check later, im not home now. i just had a friends dad check the piston to cyl. and he said 3.5 thousands, 4 was a little tight, im going to call wiseco in the morn. to find out for sure. had it out yesterday and got about 8 min. on it and she did it again!! i was toolin down the road in 5th varying throttle and it started getting tight, let off the gas and the damn thing locked up! tore it down last night and now i can see small scratches on the front and back of the cyl. but not 1 on the piston. this will be the 4th time ive built this motor so if this isnt the prob. im gonna give someone a helluva deal!

[Dirtcrasher]

I can't try and help you if you don't address specific questions...... Please read my post again.

.003-.004 is fine for a 4 stroke. A 38 pilot is very lean and could cause overheating issues.

[jonny500]

sorry about that, the pilot is a 42..and ive heard too many horror storys about the filter being in backwards and causing damage so i make darn sure its in right. ive had this trike for a couple years and have never let it get low on oil (it only takes a min to check)

every time i put this thing back together i let it run till it gets hot then let it cool before i fire it up again for the first ride.

today while looking at everything i think i found the problem! i had polished the piston pin right back to chrome.. the pin now has quite a bit of wear in the middle but a new mark way to the left, then i look at the piston pin hole and theres a matching one on that!

i think the pin is starting to sieze causing the marks in the pin bore and the scratches in the cylinder..SO.. today i orderd a new rod kit, both crank bearings, mag seal, and all the needed gaskets. the only reason im throwing all these parts at it is because i take care of a couple car-washes that are owned by a honda dealership so i get a killer deal on parts

[Dirtcrasher]

45 is the stock pilot, you should probably be at least at a 48 with that DG pipe.....