DT1 Flat Track Race Bike

Mr_Dunev

I have no idea what I am doing
Been working on this bike for a few months and decided I might as well do a build thread.

I bought this bike a few months ago, to give either Vintage MX or Flat Track a try. I decided to go with flat track for now. I'll build an MX bike later.

So far here is a list of the mods.

Webco Head
GYT Cylinder
Ceriani front end
Koni Shocks
Torque Engineering Pipe (Soon to be swapped out for a low pipe)
Engine dropped 2"








I couldn't wait to test her on the track so I cleaned the carbs, replaced the crank seals, replaced a sheared woodruff key and took her out and raced her in the Open Knobby Class at the 1/8 mi dirt track.

Here is a video of her in my alley way before the race
https://www.youtube.com/watch?v=ccnyZO0Rdpk





Had a blast racing, but didn't do very well against modern CRF450's and YZ250's. Out of a dozen bikes there were only 2 "older" bikes that were in my class. A 90's DR350 and a '72 RT2MX-360. Needless to say I didn't win ;D

With knobby tires I can only race the Open Knobby class, but with flat track tires I can race the Vintage 250 class.

I decided I wanted to race it properly so I decided to start doing some shopping for parts.
Here are some parts I bought last month at an AHRMA swap meet.





The wheel I bought had a hub that was 7.5" so I had to sell it and buy another one. But that one also ended up being wrong, so I am on the search for a Barnes quick change Hub laced to a 19" aluminum rim. Then I have to mount a rear disc brake, which will probably be off of an RD400.

It's my birthday this weekend, and I wanted to race so I have been working on my bike all week trying to get her into race mode!

I bought a 19" Aluminum spooled front wheel on ebay, and slapped a Maxxis DTR-1 tire on her. I still haven't changed the rear wheel so it stock and put a Dunlop K70 on that i had lying around.






Pulled the head to check the top end and it doesn't look good. So I am using a spare top end that I have for the weekend. I already honed the cylinder and it should be going on the bike tonight. I'll have the original top end rebuilt in the next couple weeks.

Here are some photos of the old top end. Looks like it might have soft seized once or twice ;D



I had AMS Racing overnight some sprockets to me. The sprocket on the bike was a 44 and I went up to a 52 since I am only racing 1/8 mile still. I plan on also racing 1/4 mile, but i'll worry about re-gearing the bike for that later.




Changed out the sprocket in the back of my truck last night. P.S the harbor freight Dirt bike stand is WAY too high for a lowered flat track bike.



I don't have the tools to put a new chain on so the bike she is at a shop down the street having one put on. Tonight I am putting the New(ish) top end put on, and then i'll do a compression check to make sure everything is in working order. Wont be able to get the Champion seat/tank painted for a while so I am sticking with the old seat and tank. I'll probably paint something on the tank in the next day or so, just so it isn't so plain.

Tomorrow a buddy is coming over to help me weld up and fix the low pipe i have, so fingers crossed i'll have it done before the race on Sunday. I also still need to cut and re-weld the brake lever as it is much too high.

I'll keep posting updates as I go.
 
Re: DT1 Dirt Tracker

So on Friday night 2 days before my race I decided to put a spare top end on that I had lying around. But to my surprise the Cylinder was FROZEN to the studs. It took me 2 hours of banging it with a rubber hammer, prying, pulling and yanking before I finally got the cylinde to budge. Even after I broke the seal it took me 30 minutes to get the Cylinder off the studs. However in the process a bunch of rust and dirt fell down into the crank and pretty much locked it up. :'( So i pulled the motor out and started filling the crankcase with carb cleaner and dumping it out. It took almost all of Saturday (my birthday) and 7 cans of carb cleaner to get 99.9% of the shit out of my crank.

Then I find out that the extra top end is different than the one on my current bike, and that the one on my current bike is a GYT cylinder. So I decide to just hone my current cylinder and put it back together since I had a race on Sunday. It was a HUGE pain in the ass, that pretty much had me back to wear I started. Anyways it was a lesson learned. I will be fully dissembling the motor soon and getting my cylinder honed with new piston and rings etc. Also will be looking at the gears and crank to make sure everything is in order.

Here are some photos from this weekend.

New sprocket and chain







During one of my races the Carb top/slide unscrewed itself completely and was bouncing around inside my carb body. It was pretty scary not gonna lie. I'll add that to my list of things to check before each race ;D


Vintage 250 class



Had a blast racing and I can't wait to get out there again. I low-sided twice, so I'm still learning. I am currently running a K70 on the rear, and I plan on putting a MAXXIS DTR-1 on once I get my 19" quick change rear wheel sorted out.
 
Judging by the guy next to you at the start, you clearly are not big enough for the Vintage 250 class.
 
deviant said:
Judging by the guy next to you at the start, you clearly are not big enough for the Vintage 250 class.

That guy and his buddies brought more than 12 bikes. He raced a bunch of classes if I recall.
 
Dude, that guy has got to be pushing at least 250.


Sent from my iPhone using Tapatalk
 
deviant said:
Dude, that guy has got to be pushing at least 250.


Sent from my iPhone using Tapatalk

I have no clue, but he had a BIG heart, He helped me with my tire pressure :)
 
Actually I forgot, a photographer Judd Neves sent me some photos from the last race.

Also a Video of the last race.

You can see my bike at
0:21
0:29
0:51
https://www.youtube.com/watch?v=FQo6s4Isrbo






 
Here are some photos from the July 25th race. I was the ONLY one in the Vintage 250 class :'( I was racing Vintage 360's and a semi modern YZ250. New top end ran great, but the bike kept popping out of 3rd gear for some reason, so I have some work to do before the NEXT race on the 15th :mad:













I did get some video, but it is pretty embarrassing, so I wont post it. Once I have a 3rd gear, and I get a little better at racing I'll post a video or 2
 
Are those guys running a smaller rake on their bikes than you are on yours? It seems like you have a much larger rake. I'd expect the short wheel base would do much better on an oval flat track, taking some load off the front wheel and allow you to throttle into the turns better.
 
deviant said:
Are those guys running a smaller rake on their bikes than you are on yours? It seems like you have a much larger rake. I'd expect the short wheel base would do much better on an oval flat track, taking some load off the front wheel and allow you to throttle into the turns better.

Yes they do. I think the optimum rake for flat track is 26 degrees or around there. My bike it stock rake.
 
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