OzVMX Forum

Marque Remarks => Spaniards (Bultaco, Ossa, Montesa etc) => Topic started by: crankpin on August 15, 2011, 10:28:54 pm

Title: '77 370 Bully
Post by: crankpin on August 15, 2011, 10:28:54 pm

Went for a spin over the weekend. Love the handling of this bike, just need to sort out the jetting (rich).

Was having a good weekend until a strange noise from the primary forced me off track to investigate...

Can you guess what happened?

There's a split in the primary cover between the oil drain and the stand mount  :(

If you click on the pics they blow up quite large...

http://circa74.lefora.com/2011/08/15/bugger-2/#post4

Title: Re: '77 370 Bully
Post by: Oppet on August 16, 2011, 01:43:36 am

Too bad  :-[
Something to do with transmission??

Title: Re: '77 370 Bully
Post by: crankpin on August 16, 2011, 02:43:34 am

Ate it's primary chain tensioner  :-[

Made a fair mess while it was at it...

Does anyone run without one?

I tried when I first got the bike but the chain rattled on the bottom of the primary cover.

Title: Re: '77 370 Bully
Post by: coza778 on August 16, 2011, 02:56:49 am

love your signature   crankpin  ;)

Title: Re: '77 370 Bully
Post by: crankpin on August 16, 2011, 03:05:46 am

 ;D

Title: Re: '77 370 Bully
Post by: Davy123 on August 16, 2011, 04:35:19 am

should have kept yer  C&J YAM...!!!

Title: Re: '77 370 Bully
Post by: crankpin on August 16, 2011, 04:42:03 am

Doh!

Came here ta get away from ye  ;D

Title: Re: '77 370 Bully
Post by: Moto on August 16, 2011, 07:50:55 pm

This model Pursang was the only one with a different primary ratio.
The clutch basket has a bigger diameter, it uses a chain with a half link and even a tensioner.It always seemed to scrape on the sidecover.
It is a problem that is fixed by fitting a standard Pursang basket and primary drive sprocket and new standard length primary chain.(as they used in the previous and later models) Dont use the tensioner they can't handle the Pursang RPM.

Title: Re: '77 370 Bully
Post by: crankpin on August 17, 2011, 12:56:43 am

Cheers Moto.

Will the adjusted primary ratio require final drive ratio changes also?

Title: Re: '77 370 Bully
Post by: Moto on August 17, 2011, 07:22:35 pm

 The secondary ratio's were not changed on the earlier or later models, they remained at 13 / 46. Your bike is listed as 12 / 46
 So the change in primary ratio doesn't seem to have had that big an effect.Changing up or down teeth on the countershaft is normal to adjust your gearing to a particular track.
 

Title: Re: '77 370 Bully
Post by: crankpin on August 18, 2011, 03:33:14 am

Quote from: Moto on August 17, 2011, 07:22:35 pm

Changing up or down teeth on the countershaft is normal to adjust your gearing to a particular track.
 

Not for me  ;D

Thanks for the info, been a great help.

Title: Re: '77 370 Bully
Post by: JC on August 18, 2011, 08:59:45 am

Std pursang primary ratio is 2.375 (16/38); 77 pursang 370 was 2.157 (19/41). Half-link in the primary chain was disastrous, as you found out.

Title: Re: '77 370 Bully
Post by: firko on August 18, 2011, 11:11:09 am

Another prodigal son returns...welcome back JC, I hope your health's on the improve matey.

Title: Re: '77 370 Bully
Post by: jerry on August 18, 2011, 03:52:41 pm

Didn't know you were crook John. Wondering where you had been. Good to hear from you. Keep the knowledge coming..... please. Cheers Jerry

Title: Re: '77 370 Bully
Post by: crankpin on August 20, 2011, 04:34:55 am

Quote from: JC on August 18, 2011, 08:59:45 am

Std pursang primary ratio is 2.375 (16/38); 77 pursang 370 was 2.157 (19/41). Half-link in the primary chain was disastrous, as you found out.

Thanks for the info, most useful.  :)

Title: Re: '77 370 Bully
Post by: crankpin on August 25, 2011, 07:27:49 pm

New ratio's and chain installed, works a treat.

Might finally get it into top cog now  ;D

Thanks for the info guys.

Title: Re: '77 370 Bully
Post by: JohnnyO on August 25, 2011, 07:29:49 pm

Got any pics of that bike cranky?

Title: Re: '77 370 Bully
Post by: crankpin on August 25, 2011, 07:34:13 pm

Yes but I haven't figured out how to post them  ??? or have I???

(http://circa74.lefora.com/composition/attachment/eaf6d15e2a219bac766fb36364266d61/937583/06062011737.jpg)

Title: Re: '77 370 Bully
Post by: crankpin on August 25, 2011, 07:36:15 pm

It looks a bit different now though.

Got a Circle F pipe, different rear springs and a better fitting seat cover.

Also looking a little battle worn  ;D

Title: Re: '77 370 Bully
Post by: crankpin on August 25, 2011, 07:38:06 pm

Here's the bike as I got it.

(http://circa74.lefora.com/composition/attachment/a665a40c08e8f596d79e9486a213f73f/914794/07052011721.jpg)

Title: Re: '77 370 Bully
Post by: JohnnyO on August 25, 2011, 07:38:32 pm

All i'm seeing is a red cross..

Title: Re: '77 370 Bully
Post by: crankpin on August 25, 2011, 07:51:48 pm

Bugger...

Sorry johnny, I could see it in the preview  ???

(http://circa74.lefora.com/composition/attachment/b94ce6c2a539e3cf8a4c563f96fce378/947030/P1050041.JPG)

Title: Re: '77 370 Bully
Post by: JohnnyO on August 25, 2011, 08:01:42 pm

Any pics on MX Trax?

Title: Re: '77 370 Bully
Post by: crankpin on August 26, 2011, 12:12:48 am

I'll post them on the circa forum and put a link here.

Title: Re: '77 370 Bully
Post by: crankpin on August 26, 2011, 12:58:41 am

As promised http://circa74.lefora.com/2011/08/25/mk10-bultaco-370/

Title: Re: '77 370 Bully
Post by: JohnnyO on August 26, 2011, 07:03:14 pm

That's a nice looking Bully mate, how does it compare against the '77 Maico's and Husky's?

Title: Re: '77 370 Bully
Post by: crankpin on August 26, 2011, 09:16:36 pm

I haven't ridden a '77 Maico, only earlier. The bully makes much nicer power and is easily equal on handling. It also feels lighter.

But compared to the 360/390 Husky, OMG that machine is an absolute animal, especially the 360. The Husky feels just as light as the bully and has slightly better rear suspension but the bully handles better and makes easier power to live with.

As far as looks go, the MK10 was the best looking bike of '77. Likewise the MK6/7 was the best looking bike of the early '70's.

Just my opinions though...

(http://circa74.lefora.com/composition/attachment/eaf6d15e2a219bac766fb36364266d61/992789/06062011737.jpg)