74.5 Mint 400 help with the correct serial numbers .

[Jaan Ojala]

I placed a wanted for a 74.5 Mint 400 ..
can anyone help me with the correct serial numbers for both the frame and the motor?
I have had a couple of guys who replied to my wanted but didn't know for sure if they have a regular 74 400
or a 74.5 Mint 400 ?
and a second question, is a 75 frame the same as a 74.5 Mint 400 (except for the serial number)
thanks again !!

[Daniel P. McEntee]

  The '74.5 and '75 frames are pretty close. Both have multiple lay down shock positions and I think the biggest improvement for '75 was maybe in the forks?? I have been down this road a bit and if you search the subject, the late Mike Winters did a lot of research into this as he was in possession of what he thought was the oldest '74 250 frame at that time. I have a 400 that I think was originally built up from parts in the Atlanta area back in '75 or so, and It could have gone either way. In '76, they went to a different frame all together for the MC bikes, and maybe a different frame number system to be in line with the rest of the imports. There is a listing of frame numbers and corresponding years here on the POG list that should tell you what you need to know or at least get you very close.
  Welcome to the group,
    Dan McEntee

[Jaan Ojala]

Thanks Dan for all the information. the last time I raced was back in 1995ish on a Penton 250 that I restored.
I did real well with it !
Now its time for me to get another Penton and to the track.
And if I going to build a Mint 400 I want it correct and legal for the 74 and prior vintage class!
 I do need to get confirmation that a 74.5 Mint 400 is legal for the vintage class ?
I live in Oregon.
thanks, Jaan

[Cal Alexander]

Here's my two cents worth from somebody who has enjoyed these bikes for the past 50 years. I have a 74 1/2 Mint 400 and a 75 250 (original owner). The main difference between the two is the rear brake stay, chain guard and motor supports. The early Mints used the older steel version and in 75 switched to the updated slotted Aluminum brake stays and motor supports, the chain guide was also eliminated on the 1975 model with the updated rear brake stay. There were no frame changes between the two years and no suspension changes. It's possible late in the year KTM updated the suspension but I've never seen an original 1975 model with anything but Ceriani front and rear suspension. As for the vintage class, most races I've attended will allow you to run your 74 with the shocks in the upright position, sometimes they will also measure the travel and use a spacer to limit it to 3 inches. Hope this helps. Welcome to the POG Jaan, I live close by in Utah if you run into any questions or issues with your bike.

[Jaan Ojala]

Thanks Cal,
thats the information I needed.
Whats your thoughts on the ahrma tech inspectors allowing me to race in the 74 and earlier class with myself having a 75 frame numbers ?

[Cal Alexander]

There is no discernible performance difference between a 74 1/2 and 75 Mint. Just small changes with the chain guide, brake stay etc. My experience at the Ahrma events is that they pretty much focus on suspension travel for this era of bikes. Unless your Ahrma official is a Penton aficionado they won't know the difference as the 74 1/2 and 75 bikes are identical suspension and performance wise. Penton and KTM didn't pay much attention to model years. John Penton wanted the latest and greatest innovations and best equipment on all of his bikes. They would make upgrades continually during a model year. That's what endeared Penton to so many of us in the early 1970's.

[Jaan Ojala]

Thanks again Cal.
I just need to find a core or build one from parts.