Planet Minis

76fifty · 05-11-2008, 07:59 AM

I took some pictures of my z50 swingarm next to my xr75 swingarm. I wanted to show some other people a side by side of the length of the swingarms and the amount you need to trim to make the xr75 arm fit a z50. The stock swingarm is 11 1/4 inches long from the center of the swingarm pivot bolt and the XR75 is 15 1/4.
You can tell from the pictures that the shock mount is not a full 4" back from a stock swingarm. The stock shock mount is 9 1/8 inches back from the swingarm pivot bolt and the XR75 shock mount is 12 1/8 inches back.
I trimmed 3/16 of an inch off the inside of the xr swingarms inside mounting points. I also cut off the XR's stock brake stay rod bracket.
I also put some zip ties on to hold the XR75 swingarm where a 13" shock would put it. Quite a big difference over the stock setup. I'm going to take a couple inches out of the swingarm so the wheelbase isn't so long.
Has anyone shortened a XR swingarm and if so how did you do it?

Here's some picture's:

mxr33 · 05-11-2008, 08:14 AM

nice looking z, i really like the yellow. i have been thinking about this myself. i think it would be easier to lengthen the stock swinger. cut it between brace and eyelets. add in 1" or 2".

arlindsay1992 · 05-11-2008, 06:36 PM

Very common route you're taking. Easy, cheap, and Honda strength. To shorten it, you'd just cut it, find a pipe with an OD same as the ID of the swingarm, then weld it together and grind/file it until it's flat. Don't forget your brake stop on the right side. You need to weld on a tab just like on the Z50 swingarm unless you choose to use the brake torque arm like on the XR75 or CT70. Before you decide to shorten it, ride it to make sure you want to shorten it. You may find the extra wheelbase to be very comfortable. I really like it. It handles so much better.

Also, when you extend the swingarm more than 2 inches on the older Z's, the rear fender looks like it's mounted wrong since it is mounted to fit the stock swingarm. When you extend the swingarm, the rear fender is not far back enough. On the +4 swingarm you need to move the rear fender back 2 inches to make it look right.

See attached:

76fifty · 05-11-2008, 06:45 PM

Arlindsay

I read a post where you said you extended your fender 2" but I didn't realize how you did it.
My reason for taking a couple inches out is I'm not sure how it will wheelie with that extra 4" and an 88 kit. Maybe I'm too worried about it. Also, if I leave it at 4" will 305mm shocks work o.k. or will they bottom out. I weigh 185 lbs and a buddy is going to be building a track. The 305's seem like they would work good with a 2" extended swingarm but maybe not so much with a 4".

arlindsay1992 · 05-11-2008, 07:02 PM

I don't know how 305's would work because I never had them and I never had a +2 swingarm. If you want it to wheelie with the +4 it's hard. If you want to avoid wheelies, then the +4 is good because it puts the rear wheel way out behind you. I am sure someone will post up what length shocks work good with what length swingarms. But I know for a fact that 335 works good with +4 swingarms. But I weigh 140 so my perfect suspension would be soft for you.

patman · 05-11-2008, 09:06 PM

I wouldn't shorten it.Bolt 'er up and go.I have an XR80 swing arm on my street legal Z and it rides great.Wheelies really well too.I'm running Kitaco 330mm shocks.

76fifty · 05-12-2008, 06:46 AM

O.K. I'm going to try leaving it at 4".
I read that arlindsay has ct70 shocks on his bike. Does anyone know if the ct70 shocks are going to have as stiff of a spring as the Kitaco's?
I noticed the Kitaco's have a collar at the bottom of the spring.
Does it control the preload on the spring?
Also, how long of a chain do I need to get?

Thanks, you guys have been alot of help.

patman · 05-12-2008, 08:16 AM

The Kitaco's are adjustable.If you ask me they are a bit stiff,but I ride on the street.You'll probably want them stiffer for the dirt.I weigh about the same as you do,180-200.I'm not sure how much weight I put on this winter Haha.I used the chain off of my XR50 and I'm not sure how long it is.I could count links if you want.Or just order a chain.You'll probably have to cut it down any way as most come plenty long.

arlindsay1992 · 05-12-2008, 09:53 AM

The CT70 shocks from Honda TB are 335mm and just about right for me. I am 140. You may find the Kitaco shocks are better sprung for you. They have adjustable preload but nothing else. Get a new 420 chain which is usually 120 links then figure out where you need to cut it to make it fit. Also remember the brake rod extender.

05-11-2008, 07:59 AM	#1 (permalink)
76fifty PM Newbie Join Date: Apr 2008 Location: Edgewood, WA 98372 Posts: 9	z50a to xr75 swingarm camparison I took some pictures of my z50 swingarm next to my xr75 swingarm. I wanted to show some other people a side by side of the length of the swingarms and the amount you need to trim to make the xr75 arm fit a z50. The stock swingarm is 11 1/4 inches long from the center of the swingarm pivot bolt and the XR75 is 15 1/4. You can tell from the pictures that the shock mount is not a full 4" back from a stock swingarm. The stock shock mount is 9 1/8 inches back from the swingarm pivot bolt and the XR75 shock mount is 12 1/8 inches back. I trimmed 3/16 of an inch off the inside of the xr swingarms inside mounting points. I also cut off the XR's stock brake stay rod bracket. I also put some zip ties on to hold the XR75 swingarm where a 13" shock would put it. Quite a big difference over the stock setup. I'm going to take a couple inches out of the swingarm so the wheelbase isn't so long. Has anyone shortened a XR swingarm and if so how did you do it? Here's some picture's: Attached Thumbnails

05-11-2008, 08:14 AM	#2 (permalink)
mxr33 1st Gear Member Join Date: Dec 2007 Location: indepMo Posts: 197	Re: z50a to xr75 swingarm camparison nice looking z, i really like the yellow. i have been thinking about this myself. i think it would be easier to lengthen the stock swinger. cut it between brace and eyelets. add in 1" or 2".

05-11-2008, 06:36 PM	#3 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: z50a to xr75 swingarm camparison Very common route you're taking. Easy, cheap, and Honda strength. To shorten it, you'd just cut it, find a pipe with an OD same as the ID of the swingarm, then weld it together and grind/file it until it's flat. Don't forget your brake stop on the right side. You need to weld on a tab just like on the Z50 swingarm unless you choose to use the brake torque arm like on the XR75 or CT70. Before you decide to shorten it, ride it to make sure you want to shorten it. You may find the extra wheelbase to be very comfortable. I really like it. It handles so much better. Also, when you extend the swingarm more than 2 inches on the older Z's, the rear fender looks like it's mounted wrong since it is mounted to fit the stock swingarm. When you extend the swingarm, the rear fender is not far back enough. On the +4 swingarm you need to move the rear fender back 2 inches to make it look right. See attached: Attached Thumbnails

05-11-2008, 06:45 PM	#4 (permalink)
76fifty PM Newbie Join Date: Apr 2008 Location: Edgewood, WA 98372 Posts: 9	Re: z50a to xr75 swingarm camparison Arlindsay I read a post where you said you extended your fender 2" but I didn't realize how you did it. My reason for taking a couple inches out is I'm not sure how it will wheelie with that extra 4" and an 88 kit. Maybe I'm too worried about it. Also, if I leave it at 4" will 305mm shocks work o.k. or will they bottom out. I weigh 185 lbs and a buddy is going to be building a track. The 305's seem like they would work good with a 2" extended swingarm but maybe not so much with a 4".

05-11-2008, 07:02 PM	#5 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: z50a to xr75 swingarm camparison I don't know how 305's would work because I never had them and I never had a +2 swingarm. If you want it to wheelie with the +4 it's hard. If you want to avoid wheelies, then the +4 is good because it puts the rear wheel way out behind you. I am sure someone will post up what length shocks work good with what length swingarms. But I know for a fact that 335 works good with +4 swingarms. But I weigh 140 so my perfect suspension would be soft for you.

05-11-2008, 09:06 PM	#6 (permalink)
patman 3rd Gear Member Join Date: Aug 2006 Location: Minnesota Posts: 2,211	Re: z50a to xr75 swingarm camparison I wouldn't shorten it.Bolt 'er up and go.I have an XR80 swing arm on my street legal Z and it rides great.Wheelies really well too.I'm running Kitaco 330mm shocks. Attached Thumbnails

05-12-2008, 06:46 AM	#7 (permalink)
76fifty PM Newbie Join Date: Apr 2008 Location: Edgewood, WA 98372 Posts: 9	Re: z50a to xr75 swingarm camparison O.K. I'm going to try leaving it at 4". I read that arlindsay has ct70 shocks on his bike. Does anyone know if the ct70 shocks are going to have as stiff of a spring as the Kitaco's? I noticed the Kitaco's have a collar at the bottom of the spring. Does it control the preload on the spring? Also, how long of a chain do I need to get? Thanks, you guys have been alot of help.

05-12-2008, 08:16 AM	#8 (permalink)
patman 3rd Gear Member Join Date: Aug 2006 Location: Minnesota Posts: 2,211	Re: z50a to xr75 swingarm camparison The Kitaco's are adjustable.If you ask me they are a bit stiff,but I ride on the street.You'll probably want them stiffer for the dirt.I weigh about the same as you do,180-200.I'm not sure how much weight I put on this winter Haha.I used the chain off of my XR50 and I'm not sure how long it is.I could count links if you want.Or just order a chain.You'll probably have to cut it down any way as most come plenty long.

05-12-2008, 09:53 AM	#9 (permalink)
arlindsay1992 "High Speed Record Guy" Join Date: Mar 2006 Location: Northern Virginia Posts: 4,369	Re: z50a to xr75 swingarm camparison The CT70 shocks from Honda TB are 335mm and just about right for me. I am 140. You may find the Kitaco shocks are better sprung for you. They have adjustable preload but nothing else. Get a new 420 chain which is usually 120 links then figure out where you need to cut it to make it fit. Also remember the brake rod extender.

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