Murray mini ?

[ccarruth]

I just picked up two Murray Track 2's. One is in good condition the other had an engine fire and is going to need a bit of work. Since it's in this condition I'm planing to hot rod it just a little. I've got a Briggs Animal engine with a few goodies that I'm going to put on it so it may just be a sporty little ride.

The problem I'm having is that the neck headset bearings need to be replaced and they are an odd size. The only 1.5" bearings that I've found are threadless which will not work. I've looked at everything form motorcycle bearings to BMX and mountain bike bearings and nothing has matched up yet. Does any one know where I can get these bearings?

The only thing I can think of so far is to sleeve the neck and use some bike bearings that are easy to find. If anyone has any ideas please throw them out here and lets kick them around to see what would work best. Thanks guys.

Corey

 

[george3]

all bearings have ID. Go to a bearing house and get an exact copy

 

[supernova]

Be careful not to overpower this minibike as the rear sprocket gearing is extreme! 2days ago I rode my buddy's murray with a 6.5 HF and pulled the front wheel up at speed 35mph+ (throttle wheelie) with no tourqe converter! Seriously be careful, I love going fast but when that wheel came down it wabbled bad! I dont scare easy as I have ridden 2stroke street bikes for years! I am also not an alarmist but dude be careful!

 

[ccarruth]

If it were just the bearings I could do that but I also need 1 bearing cup and the nut. The guy I got it from tried to take it apart to fix the bearing, he lost the the nut and washer. On top of that the let his kid keep riding it like that which broke the cup. That's why I was looking for a headset kit to just replace all of it.

Yes, the rear sprocket on this thing is huge! I haven't counted the teeth yet but I know it's too much gear for what I intend to do with the bike. I'll save it for a spare for the other bike. Thanks for looking out though. You never know if someone has thought all the way through a project before they start swapping parts and making test runs.

Thanks for the info guys.

Corey

 

[ccarruth]

George3, you don't want to part with your Powell Phantom 7 do you? I'd give it a nice home so you wouldn't have to worry about it. That's the only one I've ever seen and I like it. Very cool bike.

Corey

 

[minibikedude]

If it were just the bearings I could do that but I also need 1 bearing cup and the nut. The guy I got it from tried to take it apart to fix the bearing, he lost the the nut and washer. On top of that the let his kid keep riding it like that which broke the cup. That's why I was looking for a headset kit to just replace all of it.

Yes, the rear sprocket on this thing is huge! I haven't counted the teeth yet but I know it's too much gear for what I intend to do with the bike. I'll save it for a spare for the other bike. Thanks for looking out though. You never know if someone has thought all the way through a project before they start swapping parts and making test runs.

Thanks for the info guys.

Corey

72 tooth rear sprocket with 41 size chain, 10 tooth front sprocket is the stock set up on Murray's, I swapped mine out for a 35 chain size in 66 tooth. I got it at manufacture supply. They have 60-66-72 tooth sprockets with 2 inch center hole and 2-7/8 holes across, fits right on the Murray bike. I,m running a 6.5 also.

 

[RON]

Here's a couple pictures of my mini.
http://www.oldminibikes.com/forum/general-minibike-talk/698-rons-orange-mini.html

 

[ccarruth]

At least I know who to blame for this now! When I started looking for a mini bike project I ran into the pics of your orange Murray and said that's the one I want to start with. I guess it's the shape of the frame that got me. It's so different from all the rest of the mini's. You did a great job on that bike Ron. Did you replace the bearings in the neck? I measured the one good cup and bearing that I have and have tried to cross ref. it with everything I've found and still nothing!!! I was told that Murray used non standard neck bearings in their bicycles and such so that may be the case with the mini's.

If I don't find anything in the next week or so I'm going to take a neck off something with bearings that are easy to find and weld it to the Murray. I don't know what else to do. I've spent hours searching the net and have found nothing that's even close to the specs of the Murray.

Corey

 

[george3]

how about rupp

 

[RON]

At least I know who to blame for this now! When I started looking for a mini bike project I ran into the pics of your orange Murray and said that's the one I want to start with. I guess it's the shape of the frame that got me. It's so different from all the rest of the mini's. You did a great job on that bike Ron. Did you replace the bearings in the neck? I measured the one good cup and bearing that I have and have tried to cross ref. it with everything I've found and still nothing!!! I was told that Murray used non standard neck bearings in their bicycles and such so that may be the case with the mini's.

If I don't find anything in the next week or so I'm going to take a neck off something with bearings that are easy to find and weld it to the Murray. I don't know what else to do. I've spent hours searching the net and have found nothing that's even close to the specs of the Murray.

Corey

The part # on the Head Bearings are 750755 (2 required), the part # on the Head Race is 750753 (2 required). Repair parts were sold through central parts distributors, there (were) 10 of them in the US. One of them is Engines Southwest in Shreveport, La 1-800-388-6995. I have other numbers. Like already suggested, caliper the I.D., O.D. and thickness and go to a bearing warehouse. Look in the yellow pages. God bless.

 

[ccarruth]

Thanks for the part #'s Ron. I took the one good bearing and cup to both of our local bearing suppliers and they could not match it. That's what I get for living in small town USA. I'm going to try to get to Huntsville or Birmingham next week so I should have better luck finding them there.

How well does your Murray handle the extra power and Tav2? I'm starting to think that the Briggs Animal may be a little much. I may just use a stock 6.5hp with the Tav2 and save the Animal for another project. Thanks again.

Corey

 

[RON]

How well does your Murray handle the extra power and Tav2?

Corey

Great - except for wheelies.

 

[supernova]

That orange murray is sweet and fast as hell I bet! I can relate to the wheelie thing, you got a crazy big rear sprocket. Those murrays' are pretty quick with a 3.5 B&S, my buddy has one with a HF 6.5 and it will throttle wheelie with no TAV yours is probably dangerous! In a good way though!

 

[ccarruth]

I finally found the bearings and cups that I needed. Thanks again Ron for the part numbers! I run into a guy that had a part time bike shop and gave him the #'s and a good set. He was able to get me everything that I needed. After 4 different bearing suppliers found nothing all it took was a small business owner who was glad to help. After I collect a few more parts I'll start a build thread and throw in some new pics. Thanks again guys.

 

[minibikedude]

Any spec or number for the bearing you got, I should get a spare set for my Murrey.

 

[MiniBike Paul]

I love this Murray thread. And, hi Ron, it has been a while.

In November, I went to Indianapolis and got the 2 Murrays i bought and brought them back home; I think i am about the only Murray owner in California! (If there are others hope they contact me!)

Other projects will keep me from them for a few months, but i will follow these other builds with interest!! I still like the Jim Fallon "AMA Flat-tracker" look and will do 1 of mine in that style, i think.

As for gearing, I prefer #41 chain and figure I will leave the rear sprocket and if necessary use a jackshaft with a step-up! Most minis I have riden are geared to high; the result is that the torque can never really be used. I think lower gears combined with higher rpm is the way to go! It does sacrifice some top speed, but the pulling power (acceleration) from stand still thru high mid range is WAY better!! If top speed (or a lower rock crawling gear)is wanted, with a jackshaft quick gearing changes can be made!

Keep the Murray stuff coming!! Wonder who else is building a Murray!!

 

[minibikedude]

I got one in the works with a 6.5 clone.

 

[ccarruth]

He did not give me any part numbers when he gave me the bearings. I can get you the specs if you like. He said that he went through his old Murray stock and matched them up. Murray was one of the bicycle builders that used non standard bearings in their stuff.

I'm tearing down the worse of the two bikes first. The guy's kid somehow set fire to the gas tank and it made a mess. :hammer: I decided to throw a set of drag bars on and snap a few pics. I think they are what I'm going with for now.

My plans are to build a tank that shows the back bone for the split tank look, build a rear sub frame, possibly stretch the rear 6-8", and add some kind of front suspension. If I stretch the rear a little it should take the power of the Animal/Tav-2 better and make it more stable/safe to ride. I love over powered toys but I hate pulling gravel out of my :censure: even more! Here are a few teaser pics. When I start the build I'll get some more pics. Let me know what you guys think so far.

 

[minibikedude]

The Murreys are some well built minibikes, I was impressed with how soild they are. I do not think I would strech the frame if i was you, I would regear it. I have a different rear sprocket 66 tooth front 12 tooth, 35 chain size., I should be at 5.5 gear ratio, I see how it runs this spring when the snow gone. I love the seat suspionsion, I thought of getting a bobber seat like the on X-90 rider has on his bobber.

 

[ccarruth]

If I stretch the frame I'm not planing on cutting it. My Idea was to cut some plate and just extend the rear mounting area and machine out some aluminum struts that would bolt on for strength. Make it look like a swing arm. That way if I don't like like it I can cut it off and put it back to stock.

I haven't ridden one of these yet, does the seat shock really ride/work that good? If it works that good I may not need to go all out on the build. Do the band breaks on these things work that well or do I need to make plans to go to disk? Thanks