RM370 rebuild

[EL Sammo]

003 (4) by EL Sammo, on Flickr

Ta Da! Damn these are a good looking bike! Two years for the build, dad fired it up and ran the motor but waited for me to come back for the first ride.

009 (2) by EL Sammo, on Flickr

Very pretty, like a girl dressed up for a night on the town, you know shes going to hurt you and cost you money at some point but you still have to jump in and enjoy it while you have the chance.

[EL Sammo]

004 (5) by EL Sammo, on Flickr

[EL Sammo]

20160323_134201 by EL Sammo, on Flickr


I'm excited by how it looks so i can only imagine the kind of sir up these must have produced when they were first released. Dad tells me how much of a improvement they were over the TM range and how good they were to ride with a wonderful power curve but i wonder how much of that is just rose tinted glasses looking back into the past? Lets find out!

With a drum of premix and a box of sparkplugs we were out to a local flat track to test run the old girl. Its difficult t say if mechanical items have a soul but if it does i am sure she would be happy to once again be out and tearing up the countryside.

20160323_131850 by EL Sammo, on Flickr

That's myself and Dad, I'm the one without grey hair! haha Has been a really nice project to keep me and Dad in touch and chatting to each other, its easy to let life get in the way and lose touch with people in your life even if neither of you wants that to happen so something to work on together can be really cool.

[EL Sammo]

The Rm was not supposed to idle so once it fires you can just keep it running with a few blips, off and around the paddock for a few laps i was pleasantly surprised! The brakes and suspension were much better then i expected, new cables, shoes, machined drums etc means everything is working as intended. The last Vintage MXer i rode was a totally flogged out shitbox so maybe gave me bad impressions! Probably quite a few people have the same.

A few more laps then pulled in for a checkover and Dad told me stop being a pussy and get stuck into it, i was trying to run it in a little but he said get the revs up it will be fine. Really impressive motor on these a mid size two stroke is a good thing, you can lug it around a bit and it pulls with torque and you can scream it out like a 250 also so very usable.

IMG_4139 by EL Sammo, on Flickr

[EL Sammo]

rm3701 by EL Sammo, on Flickr

rm3702 by EL Sammo, on Flickr

20160324_144706 - Copy by EL Sammo, on Flickr

Took it to the local sandhills and had a great day blasting around the dunes.

[EL Sammo]

<iframe src="https://player.vimeo.com/video/166373177" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
<p><a href="https://vimeo.com/166373177">RM370 RESTORATION</a> from <a href="https://vimeo.com/user1312663">Sam Bennett</a> on <a href="https://vimeo.com">Vimeo</a>.</p>
<iframe src="https://player.vimeo.com/video/166373177" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
Made a video! Hope you enjoy.

[EL Sammo]

20160328_160930 by EL Sammo, on Flickr


Alas i also killed it too, on my last day of riding it some friends were taking their new 450f Finke desert race bikes out to a local test track. I didn't know at the time but they gear for about 160kmh on the finke bikes and the straights on the whooped out sand test track were huge.

Stock gearing and jetting on the 370 meant i was wide open by half way along the straight clocked at 145kmh by a ktm450 i was racing with, but it was wide open for too long, i could have backed off but was locked in a battle with the ktm450and two stroke honour was at stake so i kept it pinned.

I didn't back off the throttle at the end of the straight but instead kept it wide open and used the killswitch to bring it down but the damage was done, i felt the motor go off and pulled over to let it cool. Once it cooled there was the horrible feeling of no compression.

Back to dads and after some sucking of air through clenched teeth the top end was off revealed the front edge was detonated off the piston but the bore and bottom  end was totally fine.

Some CSI style questions from Dad about how long i had it wide open for were answered sheepishly, and we decided to change from the standard #310 main up to a #360 for next time to be on the safe side with a #340 also there.

A new genuine piston and she was up and running again, a little bit of a rough getting to know each other period but that's ok! Next time i am back i plan a bit of a test session to sort the jetting and keep it a little on the safe side, also no more wide open desert test tracks i want to get onto some proper VMX tracks around the place.

Hope you all enjoyed the build and will likely meet some of you at VMX events around SA or VIC if all goes well in the next few years!

Have a great day.

[Lozza]

Sand dunes are very hard on a bike especialy air cooled (big loads high rpm and low speeds) , you need to jet up and run a colder plug same goes for Finke style desert races.
Bike looks a treat.

[oldyzman]

Nice story El sammo,
OK it ended up with a very lucky blow up.
Feels nice to know that you used it though. Rather than sat around getting dusty or rusting..
good on you!
Brett

[80-85 husky]

cant believe you poohed it great bike, great build by your dad.

[EL Sammo]

Thanks guys, we're really happy with how it turned out. Next time back a bit more run in and testing time will be good and then off to find somewhere to race it.

Whats the cutoff year at VMX events? I'm rebuilding a 1996 cr125 also that is up in brisbane and was hoping to take both bikes out. Also got a 1980 RM125 but it needs a full restoration also so may be some time away.

[KTM47]

QVMX run Pre 95, so a 1994 model is the newest.  Pre 95 isn't in the MA rule book yet and probably won't be for at least another two years.

[alexbrown64]

Very well done ElSammo.  And a few siezures, bit of paint rubbed off and the rest of it are all part and parcel.. Bike looks great and i bet it was a blast to give the other boys a run.
Well done,
Cheers,

[shelpi]

Well done, a top rebuild, sorry about the WOOPS, I'm inspired as Ive been getting a RM370 together over the last couple of years.
cheers

[EL Sammo]

Bill CR by EL Sammo, on Flickr


Thanks guys! My brother in law just finished a CR250  81 build also so we are going to go racing together again, last time was back on 125s around 1996, not sure how it will go but should be a load of fun.