Planet Minis

Turbo Supra · 08-31-2009, 08:27 AM

So I picked up an xr100 about 1 month ago for $50. The man that sold it to me said the motor was dead and would need to be replaced. I cleaned the carb and bam... ran like a champ.

Anyway the bike is burning a good amount of oil. So I bought some rings (standard bore) and an intake valve grommet.

Here enlies my problem.. The first piston ring (the top) will not fit into the slot on the piston. I got the second (from top) one and oil spacer installed with ease, and the middle. But the top I cant figure out... I asked the honda dealer for stock bore specs and thats what he said he gave me. Do i need a compressor or something?

I'm a car guy.. dont know alot about these bikes.

any help is much appreciated!

Turbo Supra · 08-31-2009, 11:53 AM

I should specify, I dont think it matters but its a 1992 xr100r.

Turbo Supra · 08-31-2009, 07:40 PM

bump for some help

spiz5 · 08-31-2009, 10:49 PM

Seems odd. I would just replace with a new piston and ring set and be done with it. Maybe at some point somebody replaced it already with an aftermarket piston and thats why the oem ring isn`t fitting?

Turbo Supra · 08-31-2009, 10:54 PM

Quote:

Originally Posted by spiz5

Seems odd. I would just replace with a new piston and ring set and be done with it. Maybe at some point somebody replaced it already with an aftermarket piston and thats why the oem ring isn`t fitting?

could be... the previous owner said he had multiple people work on it. One guy even said he "fixed" the oil burning problem. When they went back to get a refund he had skipped town. Why they didnt start the bike upon leaving the store I dont know.

I may do that. The Clymer manual says remove a pin to remove the piston.. I don't see this pin. Could you guys provide some insight for a noob?

also, what are the dimensions of the stock bore. We aren't looking for a big bore kit... just to get it running well again. any suggestions on places to purchase?

thanks spiz.. much appreciated.

kawik01 · 09-01-2009, 07:51 AM

Thats the wrist pin and it doesnt stick out of the side of the piston. its up in it where you basically have to look at it straight from the side and there should be two little rings that hold it in place. grab your snap-ring pliers and pop em out and the pin should slide out with a little help. your piston should pop right off after thats of and you can have a better look at it.

BlackBeard · 09-01-2009, 08:45 AM

replace the piston, its cheap enough insurance to instill long life reliability again, While your at it buy a cheap ball hone and clean up the bore while you have it apart. If it was smoking before takedown I wouldnt dare re-assemble it without lapping the valves in and installing new valve seals.

-hope this helps

Turbo Supra · 09-01-2009, 01:27 PM

looks like I get to learn how to lap valves... its simply polishing it with the surface of the head right?

BlackBeard · 09-01-2009, 01:58 PM

its simple, just go to your local quality auto parts store and they should have a valve lapper, its a piece of wood with suction cups on either end. make sure you get on that has cups small enough for your valves. While there pick up a tube of lapping compound. then simply remove the valve springs, coat the face of the valve that contacts the head with the compound and simply spin the valve back and forth against the head mating the two surfaces together. review the work periodically and when it looks smooth simply clean it off and install.

Turbo Supra · 09-01-2009, 02:25 PM

sounds simple. Thanks a million!

I looked today and the numbers on the top of the piston indicate an OEM piston... at least I think so, I'm gonna ask at a local honda dealer later this week.

Anyone here know how to determine an OEM piston versus aftermarket?

Thanks for all the help guys.

Turbo Supra · 09-06-2009, 06:21 PM

Quote:

Originally Posted by Turbo Supra

Anyone here know how to determine an OEM piston versus aftermarket?

anyone know? Thanks guys!

Turbo Supra · 09-06-2009, 06:23 PM

also written on top of the piston:

"BOOK 4

4666M05400

XE
|
V

"

Turbo Supra · 09-09-2009, 11:14 AM

I gave wiseco a call... turns its their piston.... and a 54mm bore. +1 over stock.. So I ordered rings from them.

I also took apart the head today.. the intake valve grommet was on the exhaust side. Pretty big fail on the mechanics end. I imagine thats where my oil burning issue is coming from. Because if I am correct, the intake valve is the only one with the little green grommet on the xr100??????? correct me if im wrong...

schofell84 · 09-09-2009, 07:41 PM

dude, you have to file the end gaps.

are you saying the rings are to wide to fit into the ring lands? or they wont fit in the piston bore because they are too long.

Turbo Supra · 09-09-2009, 10:30 PM

no, its an over sized piston. Thus, different size rings. That was an old problem, until I figured out the piston was not OEM.

anyone know where that little green valve grommet goes on a '92??

08-31-2009, 08:27 AM	#1 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	XR100 Smoking.. any help appreciated. So I picked up an xr100 about 1 month ago for $50. The man that sold it to me said the motor was dead and would need to be replaced. I cleaned the carb and bam... ran like a champ. Anyway the bike is burning a good amount of oil. So I bought some rings (standard bore) and an intake valve grommet. Here enlies my problem.. The first piston ring (the top) will not fit into the slot on the piston. I got the second (from top) one and oil spacer installed with ease, and the middle. But the top I cant figure out... I asked the honda dealer for stock bore specs and thats what he said he gave me. Do i need a compressor or something? I'm a car guy.. dont know alot about these bikes. any help is much appreciated!

08-31-2009, 11:53 AM	#2 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. I should specify, I dont think it matters but its a 1992 xr100r.

08-31-2009, 07:40 PM	#3 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. bump for some help

08-31-2009, 10:49 PM	#4 (permalink)
spiz5 PM Newbie Join Date: Feb 2004 Location: Frankfort Il Posts: 18	Re: XR100 Smoking.. any help appreciated. Seems odd. I would just replace with a new piston and ring set and be done with it. Maybe at some point somebody replaced it already with an aftermarket piston and thats why the oem ring isn`t fitting?

09-01-2009, 07:51 AM	#6 (permalink)
kawik01 1st Gear Member Join Date: May 2009 Location: ky Posts: 203 My Mood:	Re: XR100 Smoking.. any help appreciated. Thats the wrist pin and it doesnt stick out of the side of the piston. its up in it where you basically have to look at it straight from the side and there should be two little rings that hold it in place. grab your snap-ring pliers and pop em out and the pin should slide out with a little help. your piston should pop right off after thats of and you can have a better look at it.

09-01-2009, 08:45 AM	#7 (permalink)
BlackBeard "ZBBT" Join Date: Oct 2007 Location: 50 riders Posts: 1,836 My Mood:	Re: XR100 Smoking.. any help appreciated. replace the piston, its cheap enough insurance to instill long life reliability again, While your at it buy a cheap ball hone and clean up the bore while you have it apart. If it was smoking before takedown I wouldnt dare re-assemble it without lapping the valves in and installing new valve seals. -hope this helps

09-01-2009, 01:27 PM	#8 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. looks like I get to learn how to lap valves... its simply polishing it with the surface of the head right?

09-01-2009, 01:58 PM	#9 (permalink)
BlackBeard "ZBBT" Join Date: Oct 2007 Location: 50 riders Posts: 1,836 My Mood:	Re: XR100 Smoking.. any help appreciated. its simple, just go to your local quality auto parts store and they should have a valve lapper, its a piece of wood with suction cups on either end. make sure you get on that has cups small enough for your valves. While there pick up a tube of lapping compound. then simply remove the valve springs, coat the face of the valve that contacts the head with the compound and simply spin the valve back and forth against the head mating the two surfaces together. review the work periodically and when it looks smooth simply clean it off and install.

09-01-2009, 02:25 PM	#10 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. sounds simple. Thanks a million! I looked today and the numbers on the top of the piston indicate an OEM piston... at least I think so, I'm gonna ask at a local honda dealer later this week. Anyone here know how to determine an OEM piston versus aftermarket? Thanks for all the help guys.

09-06-2009, 06:23 PM	#12 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. also written on top of the piston: "BOOK 4 4666M05400 XE \| V "

09-09-2009, 11:14 AM	#13 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. I gave wiseco a call... turns its their piston.... and a 54mm bore. +1 over stock.. So I ordered rings from them. I also took apart the head today.. the intake valve grommet was on the exhaust side. Pretty big fail on the mechanics end. I imagine thats where my oil burning issue is coming from. Because if I am correct, the intake valve is the only one with the little green grommet on the xr100??????? correct me if im wrong...

09-09-2009, 07:41 PM	#14 (permalink)
schofell84 2nd Gear Member Join Date: Feb 2007 Location: Ogdensburg Posts: 278	Re: XR100 Smoking.. any help appreciated. dude, you have to file the end gaps. are you saying the rings are to wide to fit into the ring lands? or they wont fit in the piston bore because they are too long. Last edited by schofell84; 09-09-2009 at 07:43 PM.

09-09-2009, 10:30 PM	#15 (permalink)
Turbo Supra PM Newbie Join Date: Aug 2009 Location: Cincy, OH Posts: 35	Re: XR100 Smoking.. any help appreciated. no, its an over sized piston. Thus, different size rings. That was an old problem, until I figured out the piston was not OEM. anyone know where that little green valve grommet goes on a '92??

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