Flattrack racer build

[Champion750]

xpete, as the bike is sitting in the picture (off the stand of course) my magnetic angle finder shows a steering head angle of 24 degrees. That seems a little steep. Doug Horner at VMC frames said it's supposed to be set up to 26 degrees. I don't trust my angle finder because my stock framed TT500 with a "de-raked" steering head shows an angle of 22 degrees sitting on level ground off the stand.
Ass far as wheel base I'm going to have to drop a couple of plum lines from the axles and take a measurement. Let me get back to you on that.....

Thank you Signal for the great idea! That will help a lot.

 

[hooser]

Champions were originally set up at 25, also use 65 degree off set trees.

 

[Champion750]

I needed to do something about sealing the steering head bearings from dirt so I got a bearing guard from A&A racing for the top and had to improvise with the lower bearing with some dense foam.

As far as how the engine it's running....
Obviously its running a little rich! I've been leaning out the metering rods progressively and have got it running a little better. Right now tho, at small throttle openings, like say 1/4 throttle and lower, it's only running on one cylinder. The carb slides are pretty close to the same in height and I've got the temp reading on the exhaust pipes pretty even. I'm thinking maybe one of the plugs is fowling? I don't know. I have some more plugs on order so I can get a more accurate reading with fresh plugs. Later I'll invest in an air/fuel ratio guage so I can really get accurate. But for now I just need to get it running decent. It's a little disappointing that the carbs were so far off when I got them.

I also made an inner fender from .062" aluminum sheet.

Tomorrow I head out to the Lodi Cycle bowl to do some laps so we'll see how it goes. I'm hoping to make more progress in getting these carbs dialed in.

 

[zxpete]

Looking good. Have fun ripping tomorrow!! See if you can get a spectator to video this baby howling maybe!

 

[tonyc]

Good idea signal. When I take the cover off I usually change oil and filter.

 

[Champion750]

Well I got it dirty today and overall it ran really well. I was surprised. It's pretty much raceable. And like any framer I've ever ridden, the faster you go the better it handles. Next stop is The Sacramento Vintage/Amateur Mile on 5/31.

Sorry zxpete, I wasn't able to find anyone that would take a vid of me. There weren't a lot of people there. I should have a better opportunity next week.

 

[Jack]

Is there a possibility of another vid of the motor running with the bugs worked out? Good luck on the 31st.

 

[Champion750]

Jack I found a bike shop about an hour from my town that has a dyno. I'll be visiting them this week to talk about dyno time and once I have my air/fuel mixture guage set up, I'll be taking a few videos of the bike on the dyno along with a graph of the dyno results.

 

[zxpete]

bike looks like a blast!! thanks for posting this, your build is the inspiration of me buying an xs650 later today

 

[olddude13]

Just lay the motor on its side and slip frame in place, no need to lift motor

 

[Champion750]

I'm the sixth rider coming down the track in the video.

Rode the famous Sacramento Mile Sunday and the twin did pretty well all in all. It had teething problems but that's to be expected especially when I have zero experience with these bikes. The allen bolt in the pic seized and so I ended up holding the exhaust hanger on with safety wire. Then the mid mount on the exhaust (shown in the shop pic) lost it's bolt and I missed my heat race because of it. Got it fixed but had to start from the back row.
Also had a weird problem with the brake. When I was out on the track at speed the brake pedal would go all the way down like there was no fluid. Then when I came back in the brake would work normally. I talked to a few ppl and they said my brake pads were separating, maybe from vibration (?). Never had a problem like this before. I have to look into it.
Because I had no brakes on the track I had to slow down way early. Where I'm at in the video is how each lap went during the race. When I came out of the corner I swear I was gaining on those guys in front of me but then I'd lose them going in because of the lack of brakes.
One thing....the bike is fast! I can't wait to put it on a dyno

Here's the video. I'm going by at about 18 seconds in. One of the girls scoring took the video so it was the best I could get.

P.S. I got a third on my knight framed SR500 and made $100

 

[gggGary]

Lovin' it!

 

[TwoManyXS1Bs]

So you're the loner #6 behind the 5-pack? Listened to it several times, and I think there's a little more waitin' to be let loose.

Yeah, bad news about the fasteners. They're tryin' to hold on with all that vibration.

Nice trick with the rear brake, they don't know you're sandbaggin', potential threat next time out. Could check for disc runout, disc/caliper shoving during rear flex, looseness of caliper slider (not snug enuff for the vibration). Could just make a quick lap without brakes, coast to a stop, check if pads opened-up...

 

[racerdave]

Nice Champ. Been a long time, but I loved going to watch at the Springfield mile. Added to what 2many said, check the disc. Not tight,bent,not seated flat. It was time for a new summer wallpaper on my laptop, Your 2 Yam's in the pits is perfect. Thank's for the pic!

 

[hooser]

If you are running a floating rear break they will do that on a mile , not so much on 1/2mile. secure it so it won't bounce side to side opening up the pucks.

 

[Champion750]

Also wanted to add that on one lap during practice I was able to carry enough speed to spin the engine up to 8440 RPM. That seemed a little high from a longevity standpoint but I didn't bother to change it because I didn't have the sprockets to make it happen (although I could have borrowed them) and I knew the brake problem was going to hold me back so I just left it and got off the gas a little early going in the corners during the race. I think I was only spinning it up to about 7900 to 8K during the main and it was loving it. That engine was pulling hard all the way down the straights

 

[Jack]

Dirt or asphalt,you gotta love this those long rods will get you hooked fast. There's one racer who turns his long rod motor up to 9500. You're having fun and that's what counts.

 

[hooser]

We set the gearing to be around 8200-8400 at the end of the straight,

 

[Champion750]

Got the bungs welded on the pipes for the O2 sensor that's used during the dyno run. The shop that I'll be going to is on vacation this week so I should be able to haul the bike down there next week.

Also, does anyone that's following this thread know where I can get a 16 tooth primary output sprocket for a 520 chain?

Thanks

 

[dixieharris]

Heiden tuning have 520 sprockets with correct offset