Author Topic: Is this a RC Adjustable Swingarm? (Read 1380 times)

newday777 · « **on:** March 18, 2024, 03:43:35 am »

Edit: answered. It's not a RC swingarm. Thanks George.

Hey all
I'm looking at what someone is advertising as a RC Engineering Adjustable Swingarm and need confirmation of what it is as he has none. I tried using the internet searching but didn't find any hits.

1. Does anyone have a RC Engineering Adjustable Swingarm to confirm this is one?

Or is there an old catalog on what RC offered back then?

Did they use a special axle or just a stock axle as it doesn't have one with it?

It has busted welds on the end cap, and wondering if maybe that might have caused a tweek in the Swingarm when it got busted? Can it be welded without problems?

I don't remember seeing one back when I was parts manager or one in the catalog.

madmtnmotors · « **Reply #1 on:** March 18, 2024, 04:34:06 am »

Don't know about whether it is RC or not, but the busted welds on the one end cap looks like someone cranked down on the adjuster either without loosening the axle first or cranking the adjuster beyond the limits of the axle slots. Looking at the end cap at the corner where the "weld" was you can see that there was almost no penetration of the weld into the cap. There's also the possibility that something might have fallen over onto the adjuster bolt or the swingarm could have been dropped on the adjuster bolt hard enough to pop the cap. That probably would have bent the bolt but the bolt could have been replaced. If I were selling it I would have at least welded the cap back on.

newday777 · « **Reply #2 on:** March 18, 2024, 04:57:02 am »

Quote from: madmtnmotors on March 18, 2024, 04:34:06 am

Don't know about whether it is RC or not, but the busted welds on the one end cap looks like someone cranked down on the adjuster either without loosening the axle first or cranking the adjuster beyond the limits of the axle slots. Looking at the end cap at the corner where the "weld" was you can see that there was almost no penetration of the weld into the cap. There's also the possibility that something might have fallen over onto the adjuster bolt or the swingarm could have been dropped on the adjuster bolt hard enough to pop the cap. That probably would have bent the bolt but the bolt could have been replaced. If I were selling it I would have at least welded the cap back on.

Yes those are possibilities on how it broke the welds

MRieck · « **Reply #3 on:** March 18, 2024, 07:05:30 am »

That has got too be an old .....emphasis on old.....RC swingerarm. I remember fitting one on Sam's automatic drag bike. I'm no fan of those pieces.

Don R · « **Reply #4 on:** March 18, 2024, 08:34:48 am »

If I was in the market for one, I wouldn't let the cap weld get in the way. I have a similar piece that has the clubfoot on the outside left. I've collected the collar and pivot bearing pieces to make it a swinger type, I haven't found anyone yet to do the machine work.
Check the front pivot to be sure it isn't intended for use with a set of struts.

newday777 · « **Reply #5 on:** March 18, 2024, 09:34:01 am »

Thanks guys.
Don
Did they come with roller bearings for shocks then? What's the difference for struts?

newday777 · « **Reply #6 on:** March 18, 2024, 09:34:56 am »

Quote from: MRieck on March 18, 2024, 07:05:30 am

That has got too be an old .....emphasis on old.....RC swingerarm. I remember fitting one on Sam's automatic drag bike. I'm no fan of those pieces.

I probably won't get it, was just thinking.....

Don R · « **Reply #7 on:** March 18, 2024, 12:10:47 pm »

Quote from: newday777 on March 18, 2024, 09:34:01 am

Thanks guys.
Don
Did they come with roller bearings for shocks then? What's the difference for struts?

Mine has bolts for the pivot point holes, it wasn't intended to swing, I'm not sure if that one was or not.

newday777 · « **Reply #8 on:** March 18, 2024, 12:14:33 pm »

OK thanks Don. I'm thinking I'll pass on it.

Don R · « **Reply #9 on:** March 18, 2024, 02:15:58 pm »

I have a nice, modified stock +2" swingarm on the Rat Race bike, I don't really notice it when I'm riding, it turns pretty nicely, it did lay down the shocks, so the shorties came off and I put on a set of DOHC Honda shocks.

gschuld · « **Reply #10 on:** March 18, 2024, 05:59:31 pm »

That is actually an MTC Engineering 6” over (Pic from a 1975 MTC catalog). It’s very similar to an RC Engineering arm, but there are subtle key differences. Most obvious is the bracket for the shock mounts is square on both ends, where the RC arm has tapered ends.

George

gschuld · « **Reply #11 on:** March 18, 2024, 06:01:11 pm »

RC Engineering version from the 1977-1978 ish RC Engineering catalog.

George

Don R · « **Reply #12 on:** March 18, 2024, 06:39:49 pm »

They both appear to be bearing ready to work with shocks. The RC one is chrome moly too.

Tracksnblades1 · « **Reply #13 on:** March 18, 2024, 06:41:37 pm »

Well Done George…😁

newday777 · « **Reply #14 on:** March 18, 2024, 07:02:16 pm »

Very cool.

madmtnmotors · « **Reply #15 on:** March 19, 2024, 04:49:14 am »

That actually looks like a serviceable unit. If the price was right I might be willing to give it a go, but shipping would probably be the deal breaker.

newday777 · « **Reply #16 on:** March 19, 2024, 05:13:25 am »

Quote from: madmtnmotors on March 19, 2024, 04:49:14 am

That actually looks like a serviceable unit. If the price was right I might be willing to give it a go, but shipping would probably be the deal breaker.

He wants $400 for it. I'm out.

madmtnmotors · « **Reply #17 on:** March 19, 2024, 05:18:17 am »

Quote from: newday777 on March 19, 2024, 05:13:25 am

Quote from: madmtnmotors on March 19, 2024, 04:49:14 am
That actually looks like a serviceable unit. If the price was right I might be willing to give it a go, but shipping would probably be the deal breaker.

He wants $400 for it. I'm out.

Yeah, that would be a deal breaker for me, even before shipping!

Sam Green Racing · « **Reply #18 on:** March 22, 2024, 08:36:45 am »

Quote from: madmtnmotors on March 19, 2024, 05:18:17 am

Quote from: newday777 on March 19, 2024, 05:13:25 am
Quote from: madmtnmotors on March 19, 2024, 04:49:14 am
That actually looks like a serviceable unit. If the price was right I might be willing to give it a go, but shipping would probably be the deal breaker.

He wants $400 for it. I'm out.

Yeah, that would be a deal breaker for me, even before shipping!

Newday777, what model/year are you planning on fitting it to ?

newday777 · « **Reply #19 on:** March 22, 2024, 09:18:28 am »

Sam
I have a few projects of 74-76 Ks. But I was just chewin and that didn't look right is why I was asking.

Sam Green Racing · « **Reply #20 on:** March 22, 2024, 10:24:57 am »

Newday777, I fitted one to my bike and was told it was an RC one, but after seeing the 2 pictures of the RC and MTC catalogs that George posted, mine must be one of the MTC ones.
The reason for me asking, these arms were made for the early K models and although they fit to the frame, nothing lines up if fitted to the later Auto, Late K, or F2 frames.
I hope this helps as when I did it, I ran into all sorts of problems with chain alignment and the same with the left hand shock. Instead of the shock, I had an offset strut made and spacers behind the rear sprocket to make the chain line up.

Sam.

Sam Green Racing · « **Reply #21 on:** March 22, 2024, 11:01:01 am »

Here's a picture of my bike.

newday777 · « **Reply #22 on:** March 22, 2024, 02:36:31 pm »

Thanks again Sam.

Sam Green Racing · « **Reply #23 on:** March 22, 2024, 02:55:18 pm »

My pleasure my friend, me making my mistake let's me help others so they don't make the same mistake.

Medyo Bastos · « **Reply #24 on:** March 30, 2024, 10:57:32 am »

Sammy can message me and let me know what 4/1 you used? Donka dude!

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Author Topic: Is this a RC Adjustable Swingarm? (Read 1380 times)