1978 air box ?

[gooddirt]

Does the 1978 have the roundish metal air box? When did they go to the plastic type?

[454MRW]

The 1978 GS-6 uses the metal airbox like the 76-77 MC-5, but the 1978 MC-5 is the first year with the plastic one. The original KTM airbox has a cage that is held in place to the airbox with integral studs that protrude through the front of the airbox with nuts on either side of the boot, which are difficult and tedious to remove to service the air filter. Hi-Point made an upgraded airbox with a quick removal airfilter cage assembly with a pin and clip arrangement that simplified servicing. I have at least one of each style. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[gooddirt]

Thanks Mike , is the type of air boot and air box same as or close to the 1980 250 mx older motor model. I have around 6 types of air boots 1976-80.

[454MRW]

If this is an MC5, the boot is similar to the offset ones in 3rd or 4th one pictured on this site. I can't copy the pic and post it due to their website restrictions. It actually has an angled flange a little similar to the first one pictured on page 4. The GS-6 uses a longer offset airbox boot which is more readily available on eBay.
I just today installed one on the 78/79 MC5/MX6 bike that I am working on for a friend today, and boy, what a tough install! Mike
http://vintagedirtbikeparts.net/AirBoots2.htm
Here is a pic of the actual boot I used on the MC5/MX-6 250 and the 2nd pic is more commonly used on the GS-6 and metal airbox Pentons. This same airbox boot was used on my 1980 MC250. The 2nd style boot CAN be used IF you change to a shorter intake manifold. Mike




Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[garrettccovington]

Mike the 1st picture looks exactly like the boot for my 79 KTM.

G



72 six-day
79 KTM MC80 250

[454MRW]

Almost, but what is not evident in my only pic of the boot before I installed it is that there is a very pronounced "angle" to the boot starting from where it necks down until it mates up to the carb, which is also angled toward the airbox, closer on the left hand than the right hand side of the airbox. In other terms, the smaller diameter section of the boot is almost twice as long on the right hand side than the left hand side, where yours is the same length on all sides. I will take some pics of it on the bike when I get home Thursday after work. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[sixdazed]

Larry/Mike,A guy is supposed to be bringing me a 78 mc5-he said cheap.Not sure how complete or condition but i said bring it on.If it's not a keeper(for me anyway)i'll let you know in case you need any parts.Later,
                Ric

[454MRW]

I might be looking for a better 230 slide for the 54/38/107 38mm Bing carb if this one doesn't work good enough. Strangely enough, the 78 & newer MC5 250's use a 38mm carb, while the GS-6 still use the 36mm Bings. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[454MRW]

Here are a few pics of the angle of the carb/intake combination and the angled offset of the airbox boot as best I can show it. If anyone has these availble, I would grab them up if possible, because they are fairly hard to find and I could use some myself. Mike



Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[gooddirt]

I will post some pics of what I have in few days.