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TrxPipUK

1992 350D Starting problems

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Everything looks to be in great condition to me @TrxPipUK! I'd lap those valves just barely enough to see that they are mating with the valve seats properly and put new valve seals in the head. Replace the o-rings on the ends of the rocker arm shafts too while ya have it apart. Those o-rings might not be leaking oil yet but they will someday if you don't take advantage of this opportunity.

 

Those rocker shafts can be difficult to remove sometimes. Once ya get them moving they're easy though. If you heat the rocker cover up in a shallow pan of simmering water before trying to pop the shafts out that might help.

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Here's the inside of the cylinder as I pull edit off the piston. A fair bit of oil. Is it meant to look like this? 

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No, but you may have added oil when you did a wet compression test if I recall?

 

Are any piston rings broken? What does the cylinder bore and piston skirts look like after the oil is wiped off? More pics... :-)

 

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4 hours ago, TrxPipUK said:

Here's the inside of the cylinder as I pull edit off the piston. A fair bit of oil. Is it meant to look like this? 

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is that mud I see on the cylinder wall ??.

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4 hours ago, retro said:

No, but you may have added oil when you did a wet compression test if I recall?

 

Are any piston rings broken? What does the cylinder bore and piston skirts look like after the oil is wiped off? More pics... 🙂

 

I never got round to doing the wet compression test actually lol. Not a great sign that oil is there then? I'll get some more pics tomorrow 🙂 What are the piston skirts?

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2 minutes ago, TrxPipUK said:

I never got round to doing the wet compression test actually lol. Not a great sign that oil is there then? I'll get some more pics tomorrow 🙂 What are the piston skirts?

I would put a top end kit on it. If your wanting a remanufactured engine n flow is the only one I'm aware of, contact them if you think the top end kit will be to expensive, I don't know your budget just giving you options.

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1 minute ago, F250 guy said:

I would put a top end kit on it. If your wanting a remanufactured engine n flow is the only one I'm aware of, contact them if you think the top end kit will be to expensive, I don't know your budget just giving you options.

Yeah I reckon a top end kit is the way forward. Not sure what it's like getting them over here in the UK though 🤔. Just to check I understand the meaning of a "top end kit"... You mean like new gaskets, piston rings and piston?

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12 minutes ago, TrxPipUK said:

Yeah I reckon a top end kit is the way forward. Not sure what it's like getting them over here in the UK though 🤔. Just to check I understand the meaning of a "top end kit"... You mean like new gaskets, piston rings and piston?

your correct, BUT !!!!!!!!!, YOU NEED TO CHECK THE SHAPE OF THE CONNECTING ROD FOR ANY PLAY AT THE TOP WHERE WRIST PIN GOES ?, AND AT THE BOTTOM WHERE THE ROD CONNECTS TO THE CRANK !. if any play is in either spot ?, well..now your looking as a full engine removal, split, tear down, because the rod must be correct !. 

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pretty sure this ^^^^ was covered some pages back ?, check rod play at top and bottom, mic cylinder for specs , if out of service limit ?, will require a bore job, larger size piston to match cylinder ( piston kit ). if rod is bad ?, now your looking at a complete engine tear down to change out the rod. to check rod play at top: take the wrist pin, slide it into the top of rod: JUST THE OUTSIDE END OF WRIST PIN FLUSH TO OTHER SIDE OF WRIST PIN HOLE IN TOP OF ROD !, now lift up, push down on outside of wrist pin, does it move any ?, if it does ?, your rod is no good at the top !. now grab the rod, while trying not to move crank, push down on rod, lift up on rod, feel any play ?, if so ?, your rod is no good, again..COMPLETE ENGINE TEAR DOWN TO REPLACE ROD !.

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1 hour ago, TrxPipUK said:

I never got round to doing the wet compression test actually lol. Not a great sign that oil is there then? I'll get some more pics tomorrow 🙂 What are the piston skirts?

 

Ok sorry, my mistake.... the piston skirts are the two longest sides of the piston. Take a pic of each side after the oil is wiped off so we can judge the wear on the piston. None of the three piston rings should be broken, each should be free to move and rotate in their respective grooves. If any of the three appear to be stuck in their groove in the piston (or broken) lets us know.

 

Once we get pics and info go ahead and take the piston off from the rod by removing the two circlips at each end of the wrist pin and pushing the wrist pin out of the piston. Then check the top and bottom of the rod for excessive wear as shadetree mentioned.

 

EDIT: See if you can take a few pics of the upper section of the cylinder bore after the oil is wiped out of it. Let us know if there is any vertical scoring or deep scratches visible in the bore.

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4 hours ago, TrxPipUK said:

Yeah I reckon a top end kit is the way forward. Not sure what it's like getting them over here in the UK though 🤔. Just to check I understand the meaning of a "top end kit"... You mean like new gaskets, piston rings and piston?

Cylinder also, ya gotta have yours bored out. Best if the ATV machine shop you choose, send them your cylinder and Piston so they'll have the starting measurements. Then they'll bore it, match it send it to you. Or at least that's how G&H does it here in the states. 

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12 hours ago, F250 guy said:

Cylinder also, ya gotta have yours bored out. Best if the ATV machine shop you choose, send them your cylinder and Piston so they'll have the starting measurements. Then they'll bore it, match it send it to you. Or at least that's how G&H does it here in the states. 

I hear g&h went china parts now ??. if so ?, best to look elsewhere !..lol.

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Awesome thanks guys. 

Just been out and wiped down the oil off the cylinder. Got some pics to show you lot as well 🙂

The piston rings definitely aren't free moving. They were all stuck snug in the piston, I started pushing and poking the rings and one popped out. You can see this in the pictures. 

I looked at taking the piston off the rod but I can't see how you do it? Is there a special way to get the circlips off to get the wrist pin out? 

Thanks 

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stuff a rag under the piston around the rod, in that little loop under the cir-clip, take a small screw driver, pry it up out of the groove on the piston end, be careful not to drop it down in the engine !. the cylinder does not look like it has deep grooves in it from looking at your pics ^^ ?, you may get by with a hone, new rings. IF !!!!!!!!!!, YOUR ROD IS OK ?, and your cylinder is not over service limit ?. right now you need to get the piston off the rod, and check it like it was said above ^^^^^^^^. if your rod is bad ?, it time to pull engine, split it, because you will need a new rod on the crank. in the future ?, IF YOU EVER HAVE AN ENGINE THAT THE SPARK PLUG HAS BEEN LEFT OUT OF IT ?..DO NOT CRANK IT OVER AN OVER !!. more than likely rings and cylinder will be rusted over ?, and all your doing Is damage to the cylinder when you do this !!.

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Those are all good pics! As you have learned the reason why there was low compression is because the piston rings became stuck in the ring grooves due to rust expanding the rings and bore. Rust particles were scrapped off from the cylinder bore which jammed those rings tight into their grooves when the motor was cranked over. Great job!

 

To remove the wrist pin, use a narrow blade screwdriver or a pick to pry up under them enough to get the end of those clips started out of the groove and walk them out using your pick as soon as you can grab the free end of the clip with needle nose pliers to control them. They are made of spring steel wire, so they will fly away if you lose control of them. Wear eye protection just in case. Make sure that your rags are stuffed tightly around the connecting rod and into the top of the motor cases.

 

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The piston was in excellent, like new condition before this rusting event happened. Notice the tiny circular knurled grooves surrounding the piston diameter (the piston is knurled at the factory so those tiny grooves will hold lubricating oil) from the crown down to the bottom of the skirts. Those knurled marks still being present indicate that the piston had very little wear. The scuffing on the thrust side (exhaust side) of the skirt was very minimal until the rust particles tore the piston and bore up a bit.

 

But I think you are going to need to rebore that cylinder due to heavy rust pitting around the top of the bore, with other several small rust pitted areas scattered about the bore, along with some scoring visible on the thrust side of the bore. Photos are never definitive proof though.... so have a machinist look at the cylinder and measure it for you. Let the machinist make that call... whether the bore can be salvaged by honing or not?

 

Take a pic or two of your method as you are checking the rod clearances using the end of the wrist pin if you can.

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Stuff a rag down around the cam chain right away too! You don't want small parts, gasket materials and dirt to fall into the motor cases while you work. You will learn more about the cleanliness of the bottom end when you remove the right side cover. Don't buy any parts yet.... you're almost there though.

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@retro and @shadetree thankyou!! I can't thank you enough for your help.

 

Don't worry, I stuffed rags down there as soon as those pics were taken and when the cylinder was removed.

 

So next step is to remove the wrist pin and check out the rod. What kind of movement am I looking for on the rod and where abouts should I be looking? 

 

It's a shame about that piston. But oh well, guess it couldn't of been helped. I'll try and find a motorcycle or ATV mechanics shop and take the piston and cylinder over. Would I be looking to get a new piston and the cylinder bored out then? 

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3 hours ago, TrxPipUK said:

So next step is to remove the wrist pin and check out the rod. What kind of movement am I looking for on the rod and where abouts should I be looking?

 

Once the piston is off the rod, take the wrist pin and slide it into the top of the rod just far enough that the pin begins to poke out of the other side of the rod. In this manner you'll have a long section of the pin in your hand that you can use for leverage. Lift the pin straight up and down several times to cause it to rock in the wrist pin bore of the rod. There should be little to none play there.... if you see and feel any play at all it should be barely perceptible. Any excessive play in the top of the rod will be noticed right away.

 

Repeat the same lift/drop procedure to verify that there is no play in the bearing on the bottom of the rod. The bottom of the rod should have between .015" - .030" of end play (slides side-to-side), but with no perceptible vertical play at all in the lower rod bearing. Let us know the results and take a pic so we'll know that ya did it right.

 

3 hours ago, TrxPipUK said:

It's a shame about that piston. But oh well, guess it couldn't of been helped. I'll try and find a motorcycle or ATV mechanics shop and take the piston and cylinder over. Would I be looking to get a new piston and the cylinder bored out then?

 

Yeah its a shame... that piston may have been replaced recently judging by its like new appearance. But the bore is worn some and does not look like it was honed recently.

 

Take the cylinder and piston to a machinist so they can be measured and follow his advice. Worse case scenario you may need to buy a new piston kit then return to the shop to drop off the new piston and cylinder to be bored out and honed. Let us know what the machinist advises and we'll help ya source your new parts and gaskets.

 

After you have checked the rod on both ends you can begin to remove the right side cover. Let us know when you are ready and we'll share some tips about getting that side torn down. Keep a smile on! :-)

 

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hats off to ya digg'n in bro !, outstanding for willing to learn all of this !. may seem like a tough job ?. but honestly ?, it will only be tough when you start buying new parts ?, then the crying starts..lol. live and learn bro, hang in there...yu'll get-r-done !.

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16 hours ago, shadetree said:

I hear g&h went china parts now ??. if so ?, best to look elsewhere !..lol.

Really?? I didnt know. Wow!!!

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4 hours ago, retro said:

 

Once the piston is off the rod, take the wrist pin and slide it into the top of the rod just far enough that the pin begins to poke out of the other side of the rod. In this manner you'll have a long section of the pin in your hand that you can use for leverage. Lift the pin straight up and down several times to cause it to rock in the wrist pin bore of the rod. There should be little to none play there.... if you see and feel any play at all it should be barely perceptible. Any excessive play in the top of the rod will be noticed right away.

 

Repeat the same lift/drop procedure to verify that there is no play in the bearing on the bottom of the rod. The bottom of the rod should have between .015" - .030" of end play (slides side-to-side), but with no perceptible vertical play at all in the lower rod bearing. Let us know the results and take a pic so we'll know that ya did it right.

 

 

Yeah its a shame... that piston may have been replaced recently judging by its like new appearance. But the bore is worn some and does not look like it was honed recently.

 

Take the cylinder and piston to a machinist so they can be measured and follow his advice. Worse case scenario you may need to buy a new piston kit then return to the shop to drop off the new piston and cylinder to be bored out and honed. Let us know what the machinist advises and we'll help ya source your new parts and gaskets.

 

After you have checked the rod on both ends you can begin to remove the right side cover. Let us know when you are ready and we'll share some tips about getting that side torn down. Keep a smile on! 🙂

 

Does it have to be nessicarily a motorcycle machine shop, just curious I always thought motorcycle ATV has to be that type of shop for rebuild. Regular machine shops at least far as I know have 0 experience with motorcycle stuff. Plus the bore and honing machines wouldn't go that small I don't think, may be wrong but never hurts to ask.

Edited by F250 guy
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5 hours ago, retro said:

 

Once the piston is off the rod, take the wrist pin and slide it into the top of the rod just far enough that the pin begins to poke out of the other side of the rod. In this manner you'll have a long section of the pin in your hand that you can use for leverage. Lift the pin straight up and down several times to cause it to rock in the wrist pin bore of the rod. There should be little to none play there.... if you see and feel any play at all it should be barely perceptible. Any excessive play in the top of the rod will be noticed right away.

 

Repeat the same lift/drop procedure to verify that there is no play in the bearing on the bottom of the rod. The bottom of the rod should have between .015" - .030" of end play (slides side-to-side), but with no perceptible vertical play at all in the lower rod bearing. Let us know the results and take a pic so we'll know that ya did it right.

 

 

Yeah its a shame... that piston may have been replaced recently judging by its like new appearance. But the bore is worn some and does not look like it was honed recently.

 

Take the cylinder and piston to a machinist so they can be measured and follow his advice. Worse case scenario you may need to buy a new piston kit then return to the shop to drop off the new piston and cylinder to be bored out and honed. Let us know what the machinist advises and we'll help ya source your new parts and gaskets.

 

After you have checked the rod on both ends you can begin to remove the right side cover. Let us know when you are ready and we'll share some tips about getting that side torn down. Keep a smile on! 🙂

 

Thanks @retro. I'll try getting those circlips off today and get the piston off. I'll get some pics of testing the rod as well.

Thanks again man 🙂

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4 hours ago, shadetree said:

hats off to ya digg'n in bro !, outstanding for willing to learn all of this !. may seem like a tough job ?. but honestly ?, it will only be tough when you start buying new parts ?, then the crying starts..lol. live and learn bro, hang in there...yu'll get-r-done !.

Thanks man! Yeah it's great to learn this stuff I think... especially about a machine I'll be using lots once its running. 

Just gotta keep saving the £$£$ lol. Thanks for your help as always man 

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