Building my own two-stroke "Mongrel" - Inspired by CharlieT & TedT

BillyGoat4130

Been Around the Block
Hi Guys,

A little back story first. I have been a life-time rider in the dirt. Started on 3wheelers when I was a kid, rode quads, dirt bikes. Didn't get into street riding until about a year ago. I have had ATC250R 3wheelers for about 15 years now, and they are great machines. I must give credit where credit is due - I stumbled onto some pictures and build thread of CharlieT / Checkered Past Cycles' "Mongrel" build where they took an ATC250R frame and engine, and put a Buell Front end, CBR F2 rear end on it, and made a very cool 250cc road machine....

https://www.youtube.com/watch?v=I3J7LO79CwQ
http://www.dotheton.com/forum/index.php?topic=53028.msg669086#msg669086

Ever since I saw this thing, I had to have one.


I have built 3wheeler and quad parts for myself for a long time, I am handy with a tig welder and I know enough machining to make myself a danger to my own health...:)

My dad and I finished up a project engine for an ATC250R about 2 years ago, and ever since that was completed I've been kind of day-dreaming about building a 2wheeler to put this custom power plant in we built. It started life as scrap ATC250R engine cases. I procured a Skidoo Summit 800 cylinder and head, and long story short basically welded/machined/hacked those parts to make myself a 410cc counter balanced 6 speed 2 stroke engine (with custom pipe...)

(my dad holding the exhaust when we finished it 2 thanksgivings ago)


So, this gives you a little idea of what kind of crazy shit I dream up and throw together....lol



So, the plan on this beast I am building is an 85 ATC250R frame, with an old clapped out motor to begin with before I put the rotax conversion in it. The front and rear end are SV650 units I have already bought. The frame is titled MC. The SV650 front end parts should be here right before Christmas and should allow me a few days to do a little mock up and see how much modification to the steering neck and steering stem areas will need to be done.

Should be a pretty cool machine!
 

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Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

The humble beginnings of the 2 wheeler project....
 

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Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

The Mongrel is a beast. I am in.


Sent from my iPhone using DO THE TON
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

Holy crap! There's our bike!Billygoat, that is so freaking awesome. I'm so stoked to see another one coming together.

One thing you're going to find is that the stock neck is waaaaaay too steep to work as it is. We added 12 degrees to it to slow down the steering, and also to get clearance for the front end. We braced the tube internally while we were at it.

Trust me, you are going to freaking love that thing. So light, so responsive. Anything we can do to help, let us know!


Sent from my iPhone using DO THE TON
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

That bike is very cool in person. CharlieT is too.

Sent from my SAMSUNG-SM-G920A using DO THE TON mobile app
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

Yiiiiiiissssssssss!!!!! Finally on here.
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

Woohooo. I'm watching
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT

Holy hell !!! I will be watching this build. :eek:
 
Wow, the mongrel on steroids! Charlie and Ted are a great pair of guys and the mongrel is rad in person, this thing actually scares me LOL.
 
Ha! I've inspired a few people in the past, but it usually ended up with citations being issued or trips in the back of a squad car! Good luck with the build and can't wait to see it progress.

A sneak preview of one of our latest projects here in the shop. Mongrel II, or M2 for short....when 250cc just isn't enough, a 1984 CR500. Like they say, go big or go home!

15424679_10104511206966992_207977069_n.jpg



Or perhaps we should name it the Death Wish.
 
Wow, thank you so much for all the enthusiastic (and many!) replies already folks. Super cool to have Charlie and Ted here in the thread as well. Ted PMed me a few tips and pics of their bike that'll definitely be helpful for me.

It is has been too long since I had a big project like this, and my real job has been driving me insane lately. I figured the best cure was a new project in the shop to occupy some of my time and the space in between my ears :)



More pics and information soon as it comes together!
 
I remember the picture of Pops with the pipe,classic! Looks like you fellers have the skills. Primary gearing for quads are short, so you'll have to go big on the countershaft and small on the rear sprocket. But you already know that. Can't wait to see the progress.
 
Small little update - over the weekend I worked in the shop and did some clean up and organizing since its been 2+ years since I had a real project in there. Degreased and pressure washed the frame, got it up on the work table, rolled the SV650 rear end into place. Whacked off the bottom linkage tabs of the frame. Swingarm fits width wise in the frame very nicely - minimal bushing required. Will need to reduce down to a 15mm swing-arm pivot bolt (same as frame).

The biggest challenge I had not really noticed before is that the SV650 rear shock and linkage is offset to the left, which is terrible for my carburetor and air filter clearance. Especially with the big motor I made, I barely stuffed it all in there with a center mount shock, and it should have really been offset to the right. I suppose the SV is offset to the left to make room for the exhaust collector in that region on the bike. I'm currently leaning towards just welding a new mount onto the swingarm and going linkageless with another shock. Utilizing that stuff is going to be pretty tricky with the frame placement.

I'm waiting on a 520 conversion rear sprocket for the SV back wheel, and then I'm gonna set my motor in and see what I need to do on my chain alignment before I make any other decisions with the shock/linkage scenario. I'd like to keep the linkage and stuff if I can, but its in a terrible terrible place.
 
Re: Building my own two-stroke "Mongrel" - Inspired by CharlieT & TedT

A few mock up photos for your viewing pleasures.

Sent from my SM-N910V using Tapatalk
 

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