RM-370 project

[whenfoxforks-ruled]

Worked out perfect. I had my ears off about the rehearsal tomorrow? Wedding Saturday. My oldest son Ryan, and in 4 years Seth (bun in the oven)will need a PW50! 370, I did find out the swingarm is stock. Just the forks, sure look like 79 caps? Thanks Mike!

 

[2strokerfun]

Anyone do business with AMS?

I've bought quite a bit of stuff from them. Good plastics, seat cover, seat foam and other stuff. Good people and quick delivery.
Call them and talk to them. I believe there is a lag time on some of the exhaust hardware, if they have to fabricate it. But they will tell you. They are one of the few places I've found for aftermarket '75-'76 250 elsinore exhausts, so I'll be placing an order myself sometime before summer months expire.

 

[_JOE_]

LOOOOOOOOOOOOOK Bob!!!!!b You can still get 'em!

http://amsracing.com/fox_forx.php

 

[whenfoxforks-ruled]

Well, hook me up with a set? I would be ever so grateful! And a swingarm, anyone want an RM370 swingarm, with buddy peg mounts?

 

[whenfoxforks-ruled]

Well, the parts are about accounted for. Except the air box, pipe and silencer. I am getting a new kick starter, for a 78 sp370, what the hell was that? Well the numbers look about correct, man the cross referencing? Vintage has the glass air box, some guy in Australia has hand made pipe combos, 680 dollars delivered? AMS has a new pipe for 209, or some junk off fleabay for $$, but, the silencer? And yes Joe, I want a longer muffler, that bike has enough bottom end?

 

[dirt bike dave]

The SP370 was a four stroke trail bike. I did not think it was made as early as 1978. That must have been the first year...

 

[whenfoxforks-ruled]

Lets see, THE MOTOR RUNS! The sp370 kick starter must be held on by a really huge flanged bolt, no pinch bolt. The motor, I think I could duct tape a concrete point to it and use it as a jack hammer. I hate to think about welding and balancing, but thanks to KTM Mike, I have a back up. Unless someone has some solid mods, I have not bugged Eric for a while, but sealing off that by pass for the compression release, raising the compression for race gas, and shoving some of that torque on top. I seen a nice long national silencer! Then there is the suspension, for what it will cost to put something usable for me, I am thinking 1,000 bucks. I may know a guy, with a 2000 rm rolling frame, a lot cheaper! And too bad I know them forks are the same as 2009 1500 dollar KYB racing forks, after Jeremy puts some voodoo in them. Or would it fit in a 125? I could use them radiator shrouds to direct air atop the engine? Good suspension, DISC BRAKES, and extort that torque out of that little monster. I am looking more to local races, but still hang on to something for ARHMA type racing. I really like the idea of putting that sucker on the line this fall in a plus 50 class, in district 17 or 14. Remote reservoir shocks with a shrader valve are pretty easy to come by. The 78 400 forks look fun? I almost had a set of fox airs for the back, but they were 18". Soon as I get all that hardware store paint off, media blast, then I will take some more pics.

 

[KTM Mike]

Cool - sounds like you are making progress! On compression bypass - I forget which was which but one year or the other, 76 or 77 had it, the other did not. You could try tracking down the other year clyinder?

Slap some works performance shocks on the rear, new seals in the forks, dial in fork oil weight and height, get proper springs rates, go racing for way less than $1000!

 

[dirt bike dave]

Not sure if Race Tech makes a cartridge fork emulator that will work in those forks, but if they do, then add that to all the things Mike recommended. Should work good enough!

 

[whenfoxforks-ruled]

I had to look at the specs twice about the forks, 20-20 motor oil? Leaky seal, put some motor honey in them? The clymers did not specify that either or had the bypass, I need a Suzuki shop manual, without 33 year old brittle paper? May be that fork thingy would help them old forks, and the thickest fork oil I can get my hands on.

 

[TRexRacing]

I have RT emulators in my '80 YZ with '82 490 43 MM forks.Very nice improvement.Well worth the effort and cost.Now I just need a shock.

 

[SMarquez]

http://i245.photobucket.com/albums/gg50/captmoto/074.jpg
http://i245.photobucket.com/albums/gg50/captmoto/075.jpg
http://i245.photobucket.com/albums/gg50/captmoto/079.jpg
Race Tech has some Gold Valve Settings for YZ shocks now. They are working on correct spring lengths too. Mine has a special spring collar and a dual rate spring set-up. This a friend of mine at Perris Raceway in California. I can't believe how fast he goes and how he clears a 90' table there. He is surprised at how the suspension worked there too. They are now really getting into Vintage Evo stuff. Check them out to replace the CC shock or maybe they can rebuild it.

 

[SMarquez]

Thanks everyone, and Yes, Joe hates them short throw away silencers! I was watching some ding bats running up one of the forestry approved(at the time) silencers, its over 150 dollars!!! Sure see the extended left rail Mike, and good thing I moved my laptop above droool level, awesome restores!!!! The ex-naked city enduro? Ahhh to bash some trees, and cellulite ridden nudists? They moved across the street! There was a time I lived on part of their property, wifey did not like me paying rent in person? I have been watching stock beat up pipes going for 3 digit figures? Anyone do business with AMS? The 78 has a lot of similar parts, after that forget it? Anything Mike, and I would go to the ends of the earth, no lie! My eldest is getting married Saturday, but Sunday is open! Give me a reason to skip down to Roselawn, because its Sunday? My camera and my dog will go for it anyways! I will find it.

The 77 tank mounted different from the 78-80, bolt on vs. slip fit. Circle F in Texas quoted me $35 for a silencer for a 77 RM250. Send the a pic of the muffler on the bike and what you are looking for. [email protected] Maico Only might have a pipe for you too. I think he builds the Retro Rocket pipes for Vintage Iron. Good luck

 

[whenfoxforks-ruled]

Thank you SMarquez! Most silencers I have been looking at are well over 100 dollars, and iffy on the fit. The stock ones came in about a 4 inch and 8 inch choice. I want 1 about 12 inches or longer! The DG national silencers look good, but not till the early 80's. Not a big race tech fan(MXTech) but, if they are all up on helping these old dogs manners, I will check them out! My back will appreciate it!

 

[whenfoxforks-ruled]

Been a while. Arrgh! My worst of fears. I finally got around to taking the 370 apart. First up, a nice 1/2" crack on the intake skirt. I am told that they were good for this? The wear pattern directly at the bottom of the skirt is shinier, like the entire piece was forcing out? Or, some meat head stuck some blocking under the skirt and torquing the clutch??? The off center head is wild, but how does it seemingly start corroding away? Then there is the crank, thrust washers, what thrust washers???? The micro fiche shows them, and the book shows them? I remember placing them on the 77 cr125 crank, many times. I am pretty sure, when the crank starts to come apart, the thrust washers get thrust-ed alright! No signs of this though. The piston and ring, wiseco, is pretty clean. Good thing I have 2 early 78 rm400 bottom ends. Seemingly exactly the same. Well the first one, same thing???? Now, I am a little hesitate about taking the 3rd one apart to see its condition. New guy figuring has me wondering, what if I take the best rod, which is the part I can not get new, and replace the rest of the parts? Anyone have an idea where to get the actual rod dimensions? Like the bearing ID's, and width at the journal? They have a dimension for the crank width at the rod, subtract proper clearance? What is a good clearance for a rod needle bearing? Same as the top? The auto fender bolt, with a piece of inner tube, shoved in the left sprocket cover post hole was classic, the jb weld and black paint also. Sure looks like someone shoved a liner in the 370 barrel, what a hack job on the ports! I will have a house shake down, I need a camera. The last one was last seen on the bank of the Salt Creek near Valporaiso In. Anyone finds it, let my son know? "Oh Dad, you should have seen this fish that got away, it was this big! Well where is the picture?" It was a classic look on the lads face to say the least! I have the stock pipe in some what usable shape, made it out of 2 pipes. The home made mini super trap silencer that someone made, out of some really thick metal, over an 1/8th" thick, what a joke. The POS stock Chinese pit bike had a 1" muffler on it, put 2 stroke packing in it and call it done. Wiseco has taken the 370 and 400 pistons off their web site, Not Good, oem and fleabay it is.

 

[Uchytil]

I feel your pain! My house remodel has taken over my moto-life. I just about have the wiring&heat/cool runs roughed in. The bathroom has not even started other that electric. I have to drop a ceiling downstairs to accomodate the piping, arghh! And, I still have to find, and replace, all the windows. My Maicos just sit near my new bead blaster waiting for proper attention. At least I did get the 440 frame/swingarm done to final coat. I need new rims/spokes for both bikes and, of course, engine kits. Everything else (new) is just collecting dust. So much for my plus 50 debut at the races this summer (bummer). BTW, that camera is probably toast ort in some salmons stoamch :nener:

 

[whenfoxforks-ruled]

Dang walking salmon!

 

[holeshot]

Yep - I had a '76 RM370 back in the day (bought new). The '76 was a first year model.... the '76 did not have remote shock reservoirs (I'm pretty sure the '77 had shock reservoirs). Also, the '76 had a problem with the clutch not disengaging properly - when you were sitting on the starting line for too long in gear with the clutch pulled in, the darn thing would take off by itself. The '76 also had an issue with the primary drive gear (on crank end) coming loose. Not sure if this was simply a matter of improper tightening at the factory or something more chronic.

The '77 had those little issues resolved, so it's the better year to own. I only had my '76 for a few months and sold it with low hours, so I didn't do much "intimate" wrenching on it.

 

[whenfoxforks-ruled]

Back in business! Seemingly the 370 and 400 has thrust washers for the needle bearing, not the bearing and rod. The rod floats over the washers. Thank you magnifier and light!

 

[_JOE_]

Here's a good parts bike for you...........http://erie.craigslist.org/mcy/1402501039.html

 

[whenfoxforks-ruled]

Thanks for getting me drooling already this morning Joe. If! That is a smoking deal, minus the Pa. thingy? I do know a guy, him and his wife make a living, criss-crossing the country, delivering bikes! CHEAP! 10 hour trip one way, he picked it up and 1 box of goodies for 200 dollars, unfriggingbelievable! Man I love the U.S., just not big business or the gov.! They would make a way to shut him down.

 

[_JOE_]

I wish I could justify buying that thing. It would be a fun project, and I know this guy who's been working on one who could tell me what to look for..........

 

[whenfoxforks-ruled]

The 370 parts are a lot harder to come by, than the 400. What the heck, a year is a year! The 78 400 will drop right in my frame. The only difference is the stickers and 20 cc's more bore. The 78 1/2 is different, it matches nothing. The 79 and 80 has plenty of parts, and a rod still available. The water cooled years are still pretty good, but I want 1 air cooler. If that thing ran like it did, with a cracked skirt, shot left main bearing, the worst sleeve and porting job I have ever seen, and a set of bad crank seals,,,, I can not wait! I do have a pile of not using parts Joe?