centrifugal oil filter hawk 250

ectomite · 07-14-2018, 01:50 AM

Hey, guys got a problem my centrifugal oil filter fell off inside the engine. so now the end of the crankshaft threads are messed up I'm trying to find out what size the nut is that goes on the end of the crankshaft that holds the centrifugal oil filter on where I can get the right die to rethread. I can't find much info and what I got is confusing. I brought the nut to a local machine shop they measured 15mm on the inside. So I called ricky power sports and they said it's 16mm so I don't know. I will attach some pics if anyone knows I would greatly appreciate the help and thanks ahead of time.

Megadan · 07-14-2018, 02:17 AM

If the machine shop measured the inside diameter of the nut, then they didn't account for the depth of the threads cut into it. Metric thread sizes are based on the shank size of the bolt (crank in this case), so if if inside of the nut is 15mm, and the threads are .5mm deep on the crankshaft, this would make the nut an M16 (not a very good machine shop if they don't know this).

If you have a pair of vernier calipers (you can get some digital ones cheap at harbor freight) then you can measure the O.D. of those threads on the crankshaft. Obviously your reading won't be precise since the threads are damaged, but if it reads something like 15.8, just round up to 16.

So if we know it is an M16, then to get the thread pitch you will need to measure the distance between the thread peaks in a straight line on the crank shaft. If they are 1mm apart, then it is M16x1.0, If they are 1.5mm apart, they are M16x1.5, and so on. You can use those same calipers to approximate this distance as well. This link can possibly explain it better. https://www.boltdepot.com/fastener-i...iandpitch.aspx

If I had to guess by visual, then I would say it is an M16x1.5, but I would measure to know for sure.

It is unusual for this type of failure to happen, so the only thing I can assume is somebody at the engine factory installed the bevelled washer in backwards. The washer should have a stamp on it stating which direction is out. If it is installed backwards, there is potential for the nut to back off. example: https://www.cscmotorcycles.com/fckim...acement/28.jpg

pete · 07-14-2018, 02:21 AM

thread gauge will give you the tpi of the thread...

look like a small pack of saws... simular to feeler gauges...

..

Megadan · 07-14-2018, 02:28 AM

Quote:

Originally Posted by pete

thread gauge will give you the tpi of the thread...

look like a small pack of saws... simular to feeler gauges...

..

This also works if you can locate one locally.
example. https://www.lowes.com/pd/IRWIN-Metri...4aAoDaEALw_wcB

One of these can also be used, and is quite handy to keep around. https://www.ebay.com/itm/Screw-Bolt-...4383.l4275.c10

ectomite · 07-15-2018, 02:04 PM

Hey, thanks megadan and Pete u guys were very helpful I picked up the tools mentioned seems its a 16mm 1.0 thread depth. only thing now not sure to get a right or left tap to cut the threads. And ya Meagan I heard this is an unusual failer not sure witch way that washer was installed since everything was free floating. I tell ya I have had nothing but bad luck with this bike so far from dealing with the texas power sports crap and engine problems now can get a little frustrating.

Megadan · 07-15-2018, 02:40 PM

Looks like right hand threads to me. Standard Righty Tighty.

ectomite · 07-15-2018, 04:19 PM

Okay, thanks megadan looks like I'm good got the tap ordered appreciate the help from you guys.

Megadan · 07-15-2018, 05:15 PM

No problem, it is what this forum is about. Once you get everything sorted out you will be able to enjoy the bike. Stick with it!

Sullybiker · 07-17-2018, 01:23 PM

CSC state 60ft.lb of torque on that nut. I used an aluminum washer between the primary gears to lock them. It's not easy to tighten it otherwise.

ectomite · 07-28-2018, 11:59 PM

Wow did not know it was 60ft.lb. it does look hard to tighten wonder if I could just use my impact gun on it if I was carefull.

Megadan · 07-29-2018, 02:11 AM

You could also thread some small rope through the park plug hole and turn the engine by and until it stops the piston in place to hold the crank still. Obviously, make sure the rope can be pulled back out lol. Also a handy trick to hold up valves if you want to change the valve stem seals without pulling the head.

ectomite · 07-29-2018, 10:12 PM

Thanks megadan for the tips very usefull information. I just stuck a penny between the gears I was in a hurry to get going again seemed to work so there is another way to stop the crank for future reference for everyone.

07-14-2018, 02:17 AM	#2
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,053	If the machine shop measured the inside diameter of the nut, then they didn't account for the depth of the threads cut into it. Metric thread sizes are based on the shank size of the bolt (crank in this case), so if if inside of the nut is 15mm, and the threads are .5mm deep on the crankshaft, this would make the nut an M16 (not a very good machine shop if they don't know this). If you have a pair of vernier calipers (you can get some digital ones cheap at harbor freight) then you can measure the O.D. of those threads on the crankshaft. Obviously your reading won't be precise since the threads are damaged, but if it reads something like 15.8, just round up to 16. So if we know it is an M16, then to get the thread pitch you will need to measure the distance between the thread peaks in a straight line on the crank shaft. If they are 1mm apart, then it is M16x1.0, If they are 1.5mm apart, they are M16x1.5, and so on. You can use those same calipers to approximate this distance as well. This link can possibly explain it better. https://www.boltdepot.com/fastener-i...iandpitch.aspx If I had to guess by visual, then I would say it is an M16x1.5, but I would measure to know for sure. It is unusual for this type of failure to happen, so the only thing I can assume is somebody at the engine factory installed the bevelled washer in backwards. The washer should have a stamp on it stating which direction is out. If it is installed backwards, there is potential for the nut to back off. example: https://www.cscmotorcycles.com/fckim...acement/28.jpg __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	2

07-14-2018, 02:21 AM	#3
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,262	thread gauge will give you the tpi of the thread... look like a small pack of saws... simular to feeler gauges... .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
	2

07-15-2018, 02:40 PM	#6
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,053	Looks like right hand threads to me. Standard Righty Tighty. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	0

07-15-2018, 05:15 PM	#8
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,053	No problem, it is what this forum is about. Once you get everything sorted out you will be able to enjoy the bike. Stick with it! __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	1

07-29-2018, 02:11 AM	#11
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,053	You could also thread some small rope through the park plug hole and turn the engine by and until it stops the piston in place to hold the crank still. Obviously, make sure the rope can be pulled back out lol. Also a handy trick to hold up valves if you want to change the valve stem seals without pulling the head. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
	1

07-15-2018, 02:04 PM	#5
ectomite Join Date: Mar 2018 Posts: 32	Hey, thanks megadan and Pete u guys were very helpful I picked up the tools mentioned seems its a 16mm 1.0 thread depth. only thing now not sure to get a right or left tap to cut the threads. And ya Meagan I heard this is an unusual failer not sure witch way that washer was installed since everything was free floating. I tell ya I have had nothing but bad luck with this bike so far from dealing with the texas power sports crap and engine problems now can get a little frustrating.
	0

07-15-2018, 04:19 PM	#7
ectomite Join Date: Mar 2018 Posts: 32	Okay, thanks megadan looks like I'm good got the tap ordered appreciate the help from you guys.
	1

07-17-2018, 01:23 PM	#9
Sullybiker Join Date: Dec 2016 Location: Western PA Posts: 363	CSC state 60ft.lb of torque on that nut. I used an aluminum washer between the primary gears to lock them. It's not easy to tighten it otherwise.
	1

07-28-2018, 11:59 PM	#10
ectomite Join Date: Mar 2018 Posts: 32	Wow did not know it was 60ft.lb. it does look hard to tighten wonder if I could just use my impact gun on it if I was carefull.
	0

07-29-2018, 10:12 PM	#12
ectomite Join Date: Mar 2018 Posts: 32	Thanks megadan for the tips very usefull information. I just stuck a penny between the gears I was in a hurry to get going again seemed to work so there is another way to stop the crank for future reference for everyone.
	0