HL's are better than Maico's

[GMC]

Okay, now that I have your attention

Can anyone tell me when maico changed from the conventional spring mounted exhaust springs to the single large spring over the single long bolt into the barrel?

I thought they started the single spring / bolt on the 79 models.

can anyone confirm please.

Cheers,
Geoff

[Mick D]

Hi Geoff

The 250, 400, 440 all used the expansion spring type exhaust manifold part#467, on all years up to and including 1980

The 1981 model 400, 440, 490 were changed to bolt on compression spring manifold part#6893.

Except for the 250's which still uses a stretched expansion spring to hold the chamber on, but from 1981 onwards the arrangement was changed to a spigot manifold that is a part of the alloy cylinder casting.

[Mick D]

68 125 is an expansion spring, although it looks like a handyman conversion

69 125 roadie is a bolt and compression spring.

74 MC125 GP is bolt and compression spring.

75 Gs 125 is bolt and compression spring.

[GMC]

Well I guess the 79 I jigged from had the wrong manifold on the barrel as it was the bolt & compression spring type.
I just had to change a 79 pipe today to the expansion spring type.

Thanks Mick

[250 Magnum]

US Maico Service Bulletin dated March 9 1979 states that a bolt and bush has been installed instead of a tension spring on the exhaust. It also gives the engine numbers from where this change will take effect.

Danny 

[Mick D]

It is a common mod to retro fit the bolt type. It simply is more reliable especially as for as leakage is concerned. The mere fact they made a change shows there was need for improvement. But all factory parts lists support what I have stated.

I would love to add a copy of that Service bulletin amendment to my Maico library, if you wouldn't mind throwing it up please Danny. 

[Mick D]

All of my part lists are factory and appear identical to these examples in active web addresses.

78 part list

79 part list

80 part list

81 part list

All of my engines share the same exhaust flanges as these factory lists.

[250 Magnum]

I have a copy of the service bulletin ready to send, PM me with your email address and I will send it to you.

I would post it here but it is far easier to split the atom than it is to put a photo on this site.

Danny

[GMC]

Thanks for your help guys.
I guess the question needs to be asked of the customer everytime I build a pipe for these models.

I would post it here but it is far easier to split the atom than it is to put a photo on this site.

Check this out

http://ozvmx.com/community/index.php?topic=17785.0

[TM BILL]

I have a copy of the service bulletin ready to send, PM me with your email address and I will send it to you.

I would post it here but it is far easier to split the atom than it is to put a photo on this site.

Danny

Splitting the atoms easy  just send it through the post marked FRAGILE PLEASE DONT BEND 

[Canam370]

Splitting the atoms easy  Wink just send it through the post marked FRAGILE PLEASE DONT BEND  Grin

 

[Mick D]

I have a copy of the service bulletin ready to send, PM me with your email address and I will send it to you.

I would post it here but it is far easier to split the atom than it is to put a photo on this site.

Danny

 

Great stuff Danny, I will send that PM now, cheers.

[Mick D]

I have a copy of the service bulletin ready to send, PM me with your email address and I will send it to you.

I would post it here but it is far easier to split the atom than it is to put a photo on this site.

Danny

Thanks Danny, I nearly went insane last night, it wouldn't upload to Photo-bucket

In the sober light of today, It finally dawned on me that the file was too large in megabyte size.
I finally figured how to reduce it, and Bingo



They say if you learn something everyday, it should be  a good day.
Got me stuffed, but thanks for the education Danny and addition to my library.

Thanks for your help guys.
I guess the question needs to be asked of the customer everytime I build a pipe for these models.

[/quote]

Cheers, Mick.



 

[Mick D]

This time I have printed it and the shot it with the camera a couple of times, that's the quickest and best I can do, no more. I WILL be needing a Valium or something now.

[250 Magnum]

No Worries Mick, sorry about the big file size, next time I will try saving it as a PDF file and see if that makes it easier to handle.

Danny