New Guy with RM400

Awesome you're getting back into it. I prefer buying a helmet and boots at a shop so I can try them on.

should be fun, I will post up some pics of the bike later. Just want to be as safe as I can, I presume equipment has changed and or improved since I rode back in the 70's. Hoping to find some old guys my age (late 50's) to ride with. I am having to relearn all about break in, types of oils,routine maint etc...

get yourself some decent bars to control that beast. I cant tell for sure from the pics and I could be way wrong it looks like someone stuck cheapie ebay shock on that fresh 400. Florida isnt know for smooth tracks. At very least get the least expensive Works Performace shocks.
I got in the best dice at an open practice on a guy with a RM400 and I was on my new 250f. Ever since that day I have wanted one bad

Max those look like ohlins which you can't get much better! Great bike, a 1980 or 79 is on my bucket list. Helmet, boots, chest protector at a minimum.

Bike looks sweet, what's the story on it?

Have fun, be safe, the ground is harder now!

Story is found on Craigslist as is. Don't know much about what it takes to restore a bike, so went with the already done route.
For sure be safe! older and I hope wiser, a man got to know his limitations (Dirty H mag force).

My other hobby

https://www.youtube.com/channel/UCxMsHgfGwCVtyRrqXVtll-g

I figured it was time to diversify some.

Your first and foremost concern should be suspension. I cannot overstate this enough. I think those shocks you have are Ohlins, which are great shocks, but I would search the internet and look for a guy I think is out of VA who sells and rebuilds them and have him set them up for your weight and riding style. I would send the forks to Race Tech and have the same done. I rode one of those bikes back in 78 when I like 100lbs (it lasted for about 2 laps…then I fell hard), so power is not an issue so i would leave the motor alone. But your having been away so long, i can tell you that bad suspension on a bike with that much motor can go south pretty quick while properly sprung and set up suspension will inspire confidence. Good luck. Mike

Next question, oils.

The bike has a fresh top end. I used to run a castor based oil, Bel ray IIRC in a tall white bottle back in the 70's.

Is this still the best way to go?, or has there been a lot of changes since then. I see MC-1 full syn oil advertised a lot.

Also I used straight 30w in the crankcase back in the day, now I see 85wt trans oil which if I understand is the same viscosity as 30w motor oil.

Lastly does it matter about using one kind of premix for break in vs regular use? like break in with the castor then go to syn for regular riding? I seem to recall something about sticking with one brand to prevent gumming up the works, not sure about that, like I said its been over 35 yrs since I looked into this.

I installed a 2" draw tite receiver on my 92 ford EX, so now I am looking at a hitch hauler. That should make for some interesting driving with that old Ford Explorer.

Just pick a synthetic and go with it. I'm sure the Suzuki guys have a favorite transmission oil but all of them are good. My advice is pick what is most available local to you as availability is important otherwise it's not super critical. Break in I run it a little rich at 32:1 otherwise I run 40:1 based on the oil I use against 5 gallons of gas.

Fuel is a bigger concern than oil. Use a quality synth oil like 450exc115 said and you'll be ok.

The important thing is to mix only what you will use right away because modern (pump) fuel has qualities that make it susceptible to problems if it sits for more than a couple of days. If the bike is going to be parked for very long, you must train yourself to drain the carb and the tank, it's not like the old days where you could let it sit for a month and have no problems, especially in a humid climate.

vet323 wrote:

Fuel is a bigger concern than oil. Use a quality synth oil like 450exc115 said and you'll be ok.

The important thing is to mix only what you will use right away because modern (pump) fuel has qualities that make it susceptible to problems if it sits for more than a couple of days. If the bike is going to be parked for very long, you must train yourself to drain the carb and the tank, it's not like the old days where you could let it sit for a month and have no problems, especially in a humid climate.

understood. I will make sure to only mix up what I plan to use. I got some Bel-ray MC-1 and some gear saver 80wt oil for the crankcase.

Dave, come out to Tampa Motocross his Sunday. The Sunshine State Vintge MX Club will be racing. Lots of knowledgable and friendly people will be there to help you. We have a couple 78 RMs in the club.

edgo897 wrote:

Dave, come out to Tampa Motocross his Sunday. The Sunshine State Vintge MX Club will be racing. Lots of knowledgable and friendly people will be there to help you. We have a couple 78 RMs in the club.

sounds like fun, I will do my best to get out there!

I have been looking around for a club, would be great to meet some folks.

Great you are getting back on it, the RM looks very nice. Have fun!

tomorrow going to check out a hitch carrier, its alum tilt up style. I have read some reviews some good some bad, so I will take a close look at the quality of construction and go from there. I like the way track tilts down and the bike rolls up transfers the weight as it goes. Not sure I like the alum constructions though. Anyway will check it out.

I have a aluminum and steel fixed hitch mount for when I'm not racing and needing the enclosed trailer. All I did was replace the crappy Chinese bolts with real bolts that had strength to them. Works great and was less than $100 bucks.

vet323 wrote:

Fuel is a bigger concern than oil. Use a quality synth oil like 450exc115 said and you'll be ok.

The important thing is to mix only what you will use right away because modern (pump) fuel has qualities that make it susceptible to problems if it sits for more than a couple of days. If the bike is going to be parked for very long, you must train yourself to drain the carb and the tank, it's not like the old days where you could let it sit for a month and have no problems, especially in a humid climate.

Dave M wrote:

understood. I will make sure to only mix up what I plan to use. I got some Bel-ray MC-1 and some gear saver 80wt oil for the crankcase.

Consider running aviation fuel. The 100LL works great at staving off detonation, smells good and will last for months on end if it's stored in a sealed metal container. Just drain the tank back into the gas can when you're done riding for the weekend.

Hey Matt, did you ever get an RM400 for yourself? I seem to recall us both wanting to get one someday .. Although I'm rapidly becoming too old for many more bikes other than a couple I'll be buying from friends, it would be great to see a 70s big-bore Suzie build here!

barkhard696 wrote:

Hey Matt, did you ever get an RM400 for yourself? I seem to recall us both wanting to get one someday .. Although I'm rapidly becoming too old for many more bikes other than a couple I'll be buying from friends, it would be great to see a 70s big-bore Suzie build here!

Not yet. There's been a 79 (I want an 80) here on CL for the last several months, but at $2800 I'll pass. I have too many irons in the fire and am focusing on work right now. Besides, I'm down from 15 bikes to 7 and the wife would not be too happy to see that trend reversing. Of course, if the right deal presented itself....

Ok got the carrier home, works well with the bike.

Now back to the handlebars, I have had another mention the handlebars as an issue.

I don't recall back in the day having aftermarket bars, is that something that is just more available now? The guy I got the carrier from mentioned that the steel ones bend easy. I just don't remember this being an issue before. I did some reading up on it though and there is mention of less shock/fatigue transmitted to the rider from alum. Also if I need them is there a 'prefered" brand, I see some on ebay for 45$ that fit the RM400 from 1978.

I've been very happy with Mika bars. mikametals.com

The old 1 1/8" Pro-Taper bars were excellent, but won't fit your 7/8" triple clamp without adapters. Personally I'm not much of a fan of the Renthal bars.

DC plastics sells a set of MSR bars for just under 50 bucks that are decent.

Started it up, took a a while, geez I forgot how hard it is to start these beasties, at least until I get the hang of it.

Holy smokes is it strong, I don't think I will be getting out of 2nd gear much, I cant believe how strong it pulls.
I sure don't recall my 76 RM250 being anywhere like this (of course it was a 250 and not a 400).

I have got to get some boots, my work shoes (old running shoes) do not give any protection from the kick started, OUCH.

I can see lock tite will be my friend, on of the pinch bolts on the upper triple tree vibrated out, and the muffler support gave up pretty quict too.

I got some 110 leaded race gas and MC1 at 20:1

Its running pretty rich which given the shocking power is fine by me

Ok just took the bike carrier out for test ride with the bike on board, I used two straps on each side, I dont know if that is how others lash the bike down, but I figured if one of the straps lets go the other is a safety.

I also found I could pull the carrier off and stow IN the explorer, so if I go to an open field I don't have to worry so much about it getting ripped off.

Next I am just looking for an open trail nearby to do some break in runs. I went around the block but I know the neabours will freak if I keep this up.

I see some trails out just north of champions gate off US 27 heading towards clearmont. If you of you locals now the deal pls let me know. Looks like there is a trail right off a parking lot of a big box store from the aerial map.

Dave M wrote:

Started it up, took a a while, geez I forgot how hard it is to start these beasties, at least until I get the hang of it.

Holy smokes is it strong, I don't think I will be getting out of 2nd gear much, I cant believe how strong it pulls.
I sure don't recall my 76 RM250 being anywhere like this (of course it was a 250 and not a 400).

I have got to get some boots, my work shoes (old running shoes) do not give any protection from the kick started, OUCH.

I can see lock tite will be my friend, on of the pinch bolts on the upper triple tree vibrated out, and the muffler support gave up pretty quict too.

I got some 110 leaded race gas and MC1 at 20:1

Its running pretty rich which given the shocking power is fine by me

I would think that 20 to 1 is way too much oil. My air cooled 414 Montesa is run at 32:1 and that is plenty. With these modern oils, you can probably run 40:1, especially with light loads.

At the least, I'd cut it back to 25:1.

That's just my opinion, of course.

RB

Dave,

I run one strap on each side to the handlebars. They are good quality protaper straps. I also run a strap ocover the swingarm to keep the back from hopping and a short bungee around the tire and rack.

20:1 is super rich. I'm at 40:1 on all of my vintage bikes.

Yeah, Dave- 40:1 is the way to go.

roger, I will cut it with 2 more gallons of gas, so it will be 6 gallons of fuel with 2 12.8 oz bottles of MC-1. That should get me to 30 to 1. I was a bit nervous with it since its a brand new set of rings. Just need to find a station that sell straight gas, not mix with alcohol.

I prob ran 4 oz of fuel thru it so far so I don't think I will have gummed up the works (once around the block).

another question, air forks.

the manual says not to exceed 15psi.
they are sitting at 0 right now per my cheap tire gauge.
any recommendations on air pump? I assume a simple hand pump like the kind used for basketball inflating since I don't want a lot of pressure.