Profab Yamaha 500

[Tim754]

Hey Tony he did a curtsy for ya! Me I would have bowed.....................

[paul]

fallen over drunk  more like it

[GMC]

[GMC]

does anyone know how to remover the swingarm bolt, I was thinking it to be a one piece, but after looking and studing, it almost looks as if it is like a head stud bolt. 

The pivot bolt should be one long bolt with has a nut on each end, that's how NVT & I make the pivot bolts, not sure what Pro-Fab did.

It's probable just siezed in, the kids probably never heard of oil

[cblyx6]

   

 Wow, I am at a loss for words, I thought I might be able to get good info here, just didnt expect the amount of participation that is going on, thanks everyone for all the good info, gonna make this build so much easier.  I will try to post up pics as we progress. THanks again!!!!!!
 
 GMC, I just looked at the motorcross Action July 1977 ad that you sent via email and it clearly shows the swing arm pivot bolt as being one piece. Man I am gonna have a tough time getting it out. I guess the next step is an impact wrench and some heat, god I hate that. 

 Paul,  dude I am in awwwww with your old bike, cant believe u let it get away, awesome!!!!!!!!!!!!!!!!!!!!!!!     good luck on re-capturing it !!!!!!!!   When I look at your bike, I see you used a late model chain guide, how did that work for you?   And what was the length of your rear shock, your bike looks to have the correct stance for the HL500!!!!!

    A gratuities shot of my CR500AF, had a lot of fun building this bike, just finished it about a month ago, if anyone is interested in building one, just follow this link, tons of information!!!!!!  ( hope its ok to post links, if not, my apology)

 http://cr500riders.com/cgi/yabb/YaBB.pl?num=1219103792

 Best regards

 C. Bly

[LWC82PE]

i can probably find out the exact information/history of Pauls old bike (before Neil Collard had it) . A guy i know told me the exact history of that bike, where it was found, When it came into the country etc and what happened to it after Peter Stayt used it in Finke. I will see him in a months time and will ask if he can put it on paper as he told me a while back but i cant remember it now.

[cblyx6]

I am thinking that the rear shocks should be a round 17 to 17 1/2" on theAberg bikes, can anyone confirm that?  Reason is I am tying t oscore a set of Ohlins on Ebay and I sure would hate to buy the wrong length?

[paul]

mine were 16/,1/4  or 16, 1/2 i think

[LWC82PE]

the very early HL's ive seen with air shox dont look like they have very long shocks. they look fairly short compared to Pauls old bike and the one on the front cover of issue 2 of vmx. there is one pictured in issue 2 of VMX i think with KYB forks and fox air shox.

[cblyx6]

Would anyone have the article on the ProFab TT600 that RJ rode? I had that article saved in my favarites and now the link is bad, that article had a lot of technical data on his bike. Thats the look that I am after?   Thanks for any help.

[firko]

The suspension travel situation on an HL comes down to which particular era you are building the bike tto or what class you wish to race in. The original Husky framed "HL" appears to have around 8'' of travel maybe a bit more. The next generation featured either the Curtis/NV frame or Profab frames and had 10'' of travel using the available forks and Fox Shox of the 1977/1978 era. That bike is eligible to race in the pre '78 classes. The third generation is the later take on the bike usually using GMC replica Curtis/NV frames often using 12'' travel 43mm forks and overly long Ohlin or similar shocks. In my opinion HLs look better when built to the original pre '78 specs. They look too tall when using long travel later components in my view.

The original Husky framed HL with Bengt Aberg and Hallman and Enqvist

Aberg 1977 Profab HL

Ben Pennys GMC HL and genuine Curtis/NV bike both featuring later suspension components.

[GMC]

Shock lengths will vary depending on models.
I recomend 15 1/4" - 385mm for my frames. I know guys have used up to 17" but it raises the seat height nearly 2" compared to the 15 1/4" shocks
But this is for the 78 NVT based frame that uses a banana style swingarm.
The 79 NVT frames used a straight swingarm with the axle plate kicked upwards which seems identical to some of the Pro-Fab frames like CB has. They are so similar that I suspect Pro-Fab may have been making the alloy swingarms for the NVT frames.
Pro-Fab also had a banana style arm with 2 shock mounts, one at the rear & one around mid arm.
Sorry I can't help you much with your model as I am not sure of the geometry of the 79 NVT or Pro-Fab swingarms, other Pro-Fab owners may be of more help

[cblyx6]

 You guys are great,    I guess it is just a matter of what people prefer, I am 6'-2" so I may go ahead and try some long shocks,   Another question I have, I just purchased a 76 125c aluminum tank, no gas cap, what other model caps will fit this tank?   

Also the Australia based VMX magizine Issue # 4  had the article about RJ's bike, I just checked there website to see if it could be purchased and it was sold out, It had a lot of technical info on the bike, if anyone happens to have a copy and the means of scanning that article, it would certainly be helpful

Thanks again!

[VMX Andrew]

i think GMC sells the stainless  steel fuel caps for that tank....

[vandy010]

the feul caps are common to most yamaha MX~ers pre 76 and also the TY and early XT/TT yammie range as well and i have had no trouble at all in getting them over the counter at my local yammie shop.
although the billet alloy jobbie's do look good.
a US$500 Profab HL?
very, very jealous over here mate!