1972 Rupp Nitro 400 ???'s

markxx800
Senior Member

Posts: 106

1972 Rupp Nitro 400 ???'s Mar 4, 2011 9:26:09 GMT -6

Quote

Post by markxx800 on Mar 4, 2011 9:26:09 GMT -6

I have a decent 72 400 Nitro. Doesn't run all that well and I've heard the crank bearings cry a few times. This Summer I want to pull the motor. I got a complete NOS Bottom End from Brandt. I did a compression test and have 150psi on both cylinders. I'll need a new topend gasket kit of course. Would you just swap the topend over to the new bottomend? or at least put new rings in it? Also,would you put in new wrist pin bearings?
Also, it would be nice to find a NOS stator. I HATE Points/ignition problems.
I also have a 73 40HP American that I'd like to restore,but it needs a track and all idler/drive wheels. Maybe take the CDI Ignition from the American and put it in my 400???
The track and drivers are good on my sled but I'd like a set of those red Hifax.
The drive clutch on my sled seems to stick alot. I guess it's common. What drive clutch is a good replacement. 102 Comet?? Or is there replacement parts to make this one work correctly?
I have a NOS rebuild kit for the Kiehin carb too as the carb seems inconsistent(Maybe bad crank seals aren't helping?)
Were can I find the parts I need?
I'm open to any other ideas also. This sled is going to be a nice rider,not a trailer Queen.
Thanks!!

Mark

racingelvis Rupp Racers Posts: 1,738	1972 Rupp Nitro 400 ???'s Mar 4, 2011 10:09:14 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by racingelvis on Mar 4, 2011 10:09:14 GMT -6 pm sent, b.s.171

markxx800 Senior Member Posts: 106	1972 Rupp Nitro 400 ???'s Mar 4, 2011 17:56:51 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by markxx800 on Mar 4, 2011 17:56:51 GMT -6 Thanks Bill and Greg for the info! Mark

yellowlab2 Silver member Posts: 595	1972 Rupp Nitro 400 ???'s Mar 4, 2011 19:37:11 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by yellowlab2 on Mar 4, 2011 19:37:11 GMT -6 Nice lookin' Nitro! '73 handlebars look cool on it, too!
	Just the Rupps: '69 Rupp GT300 '69 Rupp GTX 295x2 '70 Rupp Sprint 29 '71 Rupp 440 Magnum '71 Rupp Sprint 23 '71 Rupp Sprint 44 '71 Rupp Sprint 29 Racer '72 Rupp Rogue '72 Rupp Nitro 295 '72 Rupp Nitro 400 '72 Rupp American 30 '73 Rupp Nitro 295x3 '73 Rupp Nitro 340 '73 Rupp Nitro 400x2 '73 Rupp Nitro 440 '76 Rupp Sport 340x2 '76 Rupp Rally '76 Rupp Nitro 340 '76 Rupp Nitro 440 etc...

markxx800 Senior Member Posts: 106	1972 Rupp Nitro 400 ???'s Mar 4, 2011 21:37:34 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by markxx800 on Mar 4, 2011 21:37:34 GMT -6 Yes, it has the 73 offset spindles and those 73 Handlebars. My Rupp Buddies have offered a set of Correct 72 bars for the 73's,but I find them more comfortable, so I'll keep them. lol Mark

markxx800 Senior Member Posts: 106	1972 Rupp Nitro 400 ???'s Mar 20, 2011 20:55:06 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by markxx800 on Mar 20, 2011 20:55:06 GMT -6 RacingElvis, you have a PM From me Mark

racingelvis Rupp Racers Posts: 1,738	1972 Rupp Nitro 400 ???'s Mar 21, 2011 12:40:50 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by racingelvis on Mar 21, 2011 12:40:50 GMT -6 got it,.. thanks,..b.s.171

kronnikracing
Silver member

Posts: 609

1972 Rupp Nitro 400 ???'s Mar 21, 2011 13:36:49 GMT -6

Quote

Post by kronnikracing on Mar 21, 2011 13:36:49 GMT -6

I would definatly put some new rings on it while you have it apart, pretty sure that the bare minumum for compression according to tohatsu for the 400 is right around 130 - 135, according to the chart in our shop, seems like most of the tohatsus we have messed with are always in that 170 plus range for compression.

Addicted to racing!

1badnitro Senior Member Posts: 100	1972 Rupp Nitro 400 ???'s Mar 25, 2011 16:18:54 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by 1badnitro on Mar 25, 2011 16:18:54 GMT -6 You've been holdin' out on me Mark. I didn't know you had that. Nice sled!! Percy

markxx800 Senior Member Posts: 106	1972 Rupp Nitro 400 ???'s Mar 25, 2011 20:38:00 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by markxx800 on Mar 25, 2011 20:38:00 GMT -6 Percy, I have lots of Goodies around here. Sorry I have been a bad influence on you-LOL Mark

1badnitro Senior Member Posts: 100	1972 Rupp Nitro 400 ???'s Mar 26, 2011 8:31:35 GMT -6 Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by 1badnitro on Mar 26, 2011 8:31:35 GMT -6 LOL!! I know, I think I need therapy!! I've got a little something coming from Elvis soon that I can't wait to show you........ Percy

Rupp Luver: I've been gone for so long,my account was closed.I'm doing my last Rupp build,you can follow it on Vintagesledders.com on Face Book.Yes Rick,its the end of the line! Nov 16, 2023 17:17:20 GMT -6

Rons Rec. Parts: Hi. We've been cleaning House. Back in the 60s-70s we were a Rupp dealer. We found 10 pallets of new Rupp Snowmobile parts & plastic buried in the warehouse. We would like to sell the whole lot if possible. If interested contact Dwaine @ 907-262-5235 Dec 20, 2023 16:39:32 GMT -6