Planet Minis

Flarry · 08-09-2008, 02:45 AM

Anyone know what bolt size the engine mounts on 03 xr50's use? I measured mine and it seems to be 9mm, my frame uses m8 bolts and Ive got m8 bolts but theyre very loose when I put them in and the previous owner has allready welded a crack in engine mount.

So whats the standard size? Are my cases worn or somthing, they dont look worn though..

Flarry · 08-09-2008, 08:36 AM

Oh and should I just use the smaller M8 bolts or will the engine casing/mounts crack?

ROBINSONDB22 · 08-09-2008, 08:38 AM

I think but don't quote me on this it is a 14mm head with a 10mm shaft I'd measure mine but thats a lot of work!

dirtbkr188 · 08-09-2008, 12:21 PM

The stock Honda frame uses 8mm engine mount bolts.

Flarry · 08-09-2008, 07:27 PM

Quote:

Originally Posted by dirtbkr188

The stock Honda frame uses 8mm engine mount bolts.

ok, should i just put my 8mm bolts in even though they're too loose in the crankcase mount? i really wanna do somthing about it before i put the engine back in, but i'd either need some metal sleeving 1mm thick to fill the gap, or a 9mm bolt, both very hard to find.

dirtbkr188 · 08-09-2008, 08:17 PM

That's strictly a judgment call on your part. I have no idea what type of riding you do, or how much punishment your bike can take.
If you're in doubt, just get another set of engine cases and swap everything over. If you try to insert any type of sleeve to make up just 1mm, chances are, you'll probably ruin the integral strength of the engine mounts by drilling them out. Drilling them out to take a 10mm bolt will probably weaken them, as well.

Flarry · 08-09-2008, 08:30 PM

Quote:

Originally Posted by dirtbkr188

That's strictly a judgment call on your part. I have no idea what type of riding you do, or how much punishment your bike can take.
If you're in doubt, just get another set of engine cases and swap everything over. If you try to insert any type of sleeve to make up just 1mm, chances are, you'll probably ruin the integral strength of the engine mounts by drilling them out. Drilling them out to take a 10mm bolt will probably weaken them, as well.

well I hit my backyard ramp, jumps at tracks, I dont often go reaally big though, i guess I'll just put them in and tighten them up, if it breaks or cracks then it'll be time for new cases. One other option is i could put rubber or garden hose or somthing in there?? I guess that wouldnt really stop any movement though. Thanks for the help.

RIDE~4~LIFE · 08-09-2008, 08:41 PM

Go to SA bearings they will prob hav an idea of how to fix it

thorwarrior915 · 08-09-2008, 09:14 PM

you could also figure out the standard equivalent thats a smidge bigger... just enough to take up the slack.

Flarry · 08-09-2008, 09:31 PM

Quote:

Originally Posted by thorwarrior915

you could also figure out the standard equivalent thats a smidge bigger... just enough to take up the slack.

Yeah i tried that but the closest i could get was too big, i dont really wanna drill out my frame to fit bigger either, or any other frame if I want a new one.

RIDE~4~LIFE · 08-09-2008, 09:52 PM

just go to SA bearings they usualy have ideas for all that stuff i know they hav helpd me out a bit with stuff like that a few yrs ago

firepower354 · 08-09-2008, 09:55 PM

I drilled my old RM125 to 3/8' and used grade 8 bolts. They were notorious for shaking loose. Never a problem after that.

08-09-2008, 02:45 AM	#1 (permalink)
Flarry PM Newbie Join Date: Sep 2007 Location: Australia Posts: 82	Engine mount bolt size?? Anyone know what bolt size the engine mounts on 03 xr50's use? I measured mine and it seems to be 9mm, my frame uses m8 bolts and Ive got m8 bolts but theyre very loose when I put them in and the previous owner has allready welded a crack in engine mount. So whats the standard size? Are my cases worn or somthing, they dont look worn though..

08-09-2008, 08:36 AM	#2 (permalink)
Flarry PM Newbie Join Date: Sep 2007 Location: Australia Posts: 82	Re: Engine mount bolt size?? Oh and should I just use the smaller M8 bolts or will the engine casing/mounts crack?

08-09-2008, 08:38 AM	#3 (permalink)
ROBINSONDB22 3rd Gear Member Join Date: Feb 2007 Location: KILLumbus, Ohio Posts: 2,469	Re: Engine mount bolt size?? I think but don't quote me on this it is a 14mm head with a 10mm shaft I'd measure mine but thats a lot of work!

08-09-2008, 12:21 PM	#4 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,007	Re: Engine mount bolt size?? The stock Honda frame uses 8mm engine mount bolts.

08-09-2008, 08:17 PM	#6 (permalink)
dirtbkr188 3rd Gear Member Join Date: May 2004 Location: New Jersey Posts: 2,007	Re: Engine mount bolt size?? That's strictly a judgment call on your part. I have no idea what type of riding you do, or how much punishment your bike can take. If you're in doubt, just get another set of engine cases and swap everything over. If you try to insert any type of sleeve to make up just 1mm, chances are, you'll probably ruin the integral strength of the engine mounts by drilling them out. Drilling them out to take a 10mm bolt will probably weaken them, as well.

08-09-2008, 08:41 PM	#8 (permalink)
RIDE~4~LIFE 2nd Gear Member Join Date: Jun 2008 Location: S.A, Australia Posts: 885	Re: Engine mount bolt size?? Go to SA bearings they will prob hav an idea of how to fix it

08-09-2008, 09:14 PM	#9 (permalink)
thorwarrior915 3rd Gear Member Join Date: Dec 2003 Location: Malone, NY Posts: 4,483	Re: Engine mount bolt size?? you could also figure out the standard equivalent thats a smidge bigger... just enough to take up the slack.

08-09-2008, 09:52 PM	#11 (permalink)
RIDE~4~LIFE 2nd Gear Member Join Date: Jun 2008 Location: S.A, Australia Posts: 885	Re: Engine mount bolt size?? just go to SA bearings they usualy have ideas for all that stuff i know they hav helpd me out a bit with stuff like that a few yrs ago

08-09-2008, 09:55 PM	#12 (permalink)
firepower354 3rd Gear Member Join Date: Oct 2006 Location: Flint MI Posts: 6,266	Re: Engine mount bolt size?? I drilled my old RM125 to 3/8' and used grade 8 bolts. They were notorious for shaking loose. Never a problem after that.

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