Hawk 250 swing arm bushings

[pete]

Originally Posted by ben2go

There are roller bearings that will replace those.Tho I'm not sure what size.I've never had one, so I'm not sure exactly how the rear swing arm is set up.The bearings need an inner race,aka sleeve,to ride on, and for the bolt to clamp down on, so the swing arm doesn't bind up as it travels up and down.

So you are saying that the swing arm bushes/eyes are machined to the correct inderfearance fit & alinement for a needle race...

but you also say yer NOT sure what size & never had one...

confusing post....

what is needed is someone to measure them... not with a ruler or calipers..
get a snap gauge & micometer... So yer can check for round/ tapper /weld destortion
then it would be possable to see if a needle races can be fitted..
as a rubber bush even with a outer sleeve can be pushed in to any hole near the right size
but not so with a needle race...

Anything ealse is just quess work...

the japs line bore theres after welding/ casting so true is true...
i surspect the rubber bushs are used to stop the need to line bore
just jig welded...as the rubber is very forgiveing to misalinement...
by misalinement we are talking points of a millimeter at the eye which would
be millimeters at the other eye...



...

[Ariel Red Hunter]

Originally Posted by pete

So you are saying that the swing arm bushes/eyes are machined to the correct inderfearance fit & alinement for a needle race...

but you also say yer NOT sure what size & never had one...

confusing post....

what is needed is someone to measure them... not with a ruler or calipers..
get a snap gauge & micometer... So yer can check for round/ tapper /weld destortion
then it would be possable to see if a needle races can be fitted..
as a rubber bush even with a outer sleeve can be pushed in to any hole near the right size
but not so with a needle race...

Anything ealse is just quess work...

the japs line bore theres after welding/ casting so true is true...
i surspect the rubber bushs are used to stop the need to line bore
just jig welded...as the rubber is very forgiveing to misalinement...
by misalinement we are talking points of a millimeter at the eye which would
be millimeters at the other eye...



...

Pete, not only do I agree with you, but roller bearings are not the best answer for a reciprocating load. Bronze bushings are best for that use. At least 1 1/2 inches long on either side, with a spacer between them, and a shim or washer between the frame and the swing arm, both sides. Grease fitting in the middle is a good idea. Roller bearings are great for rotating loads.

[Mudflap]

If you use bronze bushings, do you use a steel sleeve around the pivot bolt or just leave the pivot bolt loose? Wouldn't a loose pivot bolt cause wear to the frame?

Wonder if the Lifan rubber bushings would fit. Mine have lasted 9 years and 50,000+ miles so far.

IMO the best set up is tapered roller bearings like many street bikes use.

[Ariel Red Hunter]

Originally Posted by Mudflap

If you use bronze bushings, do you use a steel sleeve around the pivot bolt or just leave the pivot bolt loose? Wouldn't a loose pivot bolt cause wear to the frame?

Wonder if the Lifan rubber bushings would fit. Mine have lasted 9 years and 50,000+ miles so far.

IMO the best set up is tapered roller bearings like many street bikes use.

No the pivot bolt is held firmly in place. The bearing surface is between the pivot bolt and the bushing. The only real downside to using bushings is that they have to be greasable. I had greasable swing arm bushings on both of my A.J.S.'s, and they lasted with no measureable play for the years I kept them. In fact, I've never heard of AJS/Matchless SA bushings ever going out, even if they only got greased once a year or two.

[ben2go]

Originally Posted by pete

So you are saying that the swing arm bushes/eyes are machined to the correct inderfearance fit & alinement for a needle race...

but you also say yer NOT sure what size & never had one...

confusing post....




...

Sorry about the confusion.

I do not currently own a CB.So I have no way of knowing if the roller bearings are an option, or what may work.I was trying to say that they could be an option.

All of my Japanese bikes have the needle style roller bearings in the swing arm and shock linkages.I've never had one fail.

[Ariel Red Hunter]

Originally Posted by jeffrey

These bushings look like bushings in a control arm in a car but the tube is not supported in the center. So when tightend down it pushes the tube in and the swing arm rubs the frame. It needs a center tube in there.

Yes, they are like the bushings in a control arm. Alfa-Romeo sports cars had (I don't know if they still have) all bronze bushings in the A-arms and even the anti-roll bar of the front end. It made for a very tight handling sports car. It does the same thing for a motorcycle with a rear swing arm.

[ben2go]

Originally Posted by jeffrey

These bushings look like bushings in a control arm in a car but the tube is not supported in the center. So when tightend down it pushes the tube in and the swing arm rubs the frame. It needs a center tube in there.

I've never seen a bike that didn't have an inner swing arm spacer.It my be a quality control issue.

[chinatoys]

My Hawk did not have a center pipe in between the swing arm bushings and the frame could be tightened down on to the swing arm. The CRF230 swing arm bearing kit works great once you machine the swing arm pivot inner diameter from 25mm to 26mm to accept the new bearings. I had it machined for a .001" interference fit.

[hertz9753]

Originally Posted by chinatoys

My Hawk did not have a center pipe in between the swing arm bushings and the frame could be tightened down on to the swing arm. The CRF230 swing arm bearing kit works great once you machine the swing arm pivot inner diameter from 25mm to 26mm to accept the new bearings. I had it machined for a .001" interference fit.

Do you have link and the year of the CRF230 bearings that you bought?

[ben2go]

Originally Posted by chinatoys

My Hawk did not have a center pipe in between the swing arm bushings and the frame could be tightened down on to the swing arm. The CRF230 swing arm bearing kit works great once you machine the swing arm pivot inner diameter from 25mm to 26mm to accept the new bearings. I had it machined for a .001" interference fit.

That's good info right there.

[ben2go]

Originally Posted by hertz9753

Do you have link and the year of the CRF230 bearings that you bought?

If I'm not mistaking,they're all the same.

[chinatoys]

They are all the same 03-15 CRF150f and CRF230f. I bought this set on ebay. http://www.ebay.com/itm/331501807999

I ended up using four bearings instead of two. I didn't have the swing arm machined all the way through, just deep enough for two bearings on each side.

[Wolftrax]

Originally Posted by chinatoys

They are all the same 03-15 CRF150f and CRF230f. I bought this set on ebay. http://www.ebay.com/itm/331501807999

I ended up using four bearings instead of two. I didn't have the swing arm machined all the way through, just deep enough for two bearings on each side.

Thanks, just ordered one.

[ben2go]

Originally Posted by chinatoys

They are all the same 03-15 CRF150f and CRF230f. I bought this set on ebay. http://www.ebay.com/itm/331501807999

I ended up using four bearings instead of two. I didn't have the swing arm machined all the way through, just deep enough for two bearings on each side.

Just under $24.That's a good price.

[Ariel Red Hunter]

Originally Posted by ben2go

Just under $24.That's a good price.

Yes that is, and only requiring a simple machining job on the swing arm makes it even better.