Heron Suzuki RM500

[firko]

Here are some shots of the trick Heron RM500 flyingdg Doug is building. DouG will, I'm sure fill supply the history and specs before long. Note rare centre port RM500 cylinder to suit the RM250 frame.
                                                               
                                                               
                                                               

[Rookie#1]

Wow very nice, alloy tank looks like it was modeled on a TT250 H/G tank?? 

Cheers, Brendan

[SON]

79 CR125 Alloy Tank
Great project I would love one of those barrells

[flyingdg]

This was a bike that I have been dreaming of building for years now but I couldn't figure out how to make the center port cylinder. This past fall I meet a fellow (Curt H) vintage rider that worked in a machine shop and was up for the challenge of turning a RM500 cylinder into a center port. This turned into a ton of work for him and he had to call in some favors from a friend (Bob B) that was a custom welder, he had to weld the exhaust port from the inside and part of the outside. Then I had to have a friend (Tim T) grind out the weld and port it. This thing was so much work that the friends have said never again will they make one. I also had (Tim T) make the custom Pipe. I have to give a big thank You to these three friends it was them that did it not me! The tank is a 79 CR125 that I was playing around with years ago I'm going to change the front so it's not so ugly. The bottom end is a 1981 RM465 5 speed with the 500 top end. I'm not a big fan of the RM500 4 speed I think it has some odd gaps in it. We are trying to get it done for a race on April 6th-7th and then this winter pull it back apart and rebuild it so it looks a bit better.         

[SON]

Great work,
Remember that 5 speed 465s broke their countershafts,
Start with a new shaft if possible,
Also take a little compression out of the motor
It will be easier to start
Nicer to ride

[flyingdg]

I had RK Tek cut a new combustion camber for it. The guy  that made the pipe and did the porting has a RM500 with a RK Tek head.....I rode it and it has one of the best power bands (he ported his and made a pipe) I have ever rode...I think it was better than my maicos. Do you think some of the counter shafts broke from running the chain to tight? If it is a problem I've got other motors.

[SON]

Back in 1990 I built a few RM 500 Motard bikes for the first Supermoto run in Australia,
With open rules I made the mistake of trying to get as much horsepower as possible,
I sourced a few 5 speed 465 bottom ends as we had found they worked better on Dirttrack,
I replaced both shafts just in case and from memory they were modified part numbers,
Chain tension was always a problem in the early LTR days,
But I think diameter of the shaft was the problem.

[shelpi]

hhhm Ive got one of those frames hanging in the shed, always wondered if a 465/500 donk would fit, was thinking of going that way but with a sidecar . would like to see underneath the tank

[JohnnyO]

Very cool bike DG..
The 5 speeds break as they are very narrow gears,  the 4 speed has much thicker and stronger gears. That is the reason they went to a 4 speed box..