Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Race Job Progress

Race Job Progress

Post Mon Jun 06, 2011 12:38 am

Posts: 1654
I don't know what the correct condensers for your mag might be, but I do know from experience that Lucas condensers in particular are noriously fallible, and the AM ones available these days aren't much better. I usually fit external condensers wired from the cut-out terminal so that when ( not if ) the internal ones fail, the extarnal one takes the load and when THAT one fails, it is a quick swap
Shoot, a man could have a good weekend in Dallas with all that stuff...

Post Mon Jun 06, 2011 3:19 am

Posts: 575
Location: devon,england
hunt dont appear to sell a 'racing' application, condenser . only a high performance one.
morris sell to types. p6 is for normal avg rpm ,and p6r for continuos high rpm racing only.
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years

Post Mon Jun 06, 2011 7:12 am

Posts: 199
Location: Cedar Springs Mi USA


Of course it is impossible for anyone who hasn't had his hands on your bike to properly troubleshoot it, but, I think you need fuel. Your early posts make it sound like you need a bigger main jet, (not main nozzle work) You should be starting with the size that comes stock in an M-74B carb (whatever that is). It may be a touch rich, but it's where you want to start. AHRMA rules will allow an Amal carb or Dellorto if you can scrounge one up to try, and can make an adapter plate for the intake. Judging from how your bike will start good, I wouldn't worry about the mag for now.

Hope you get it running.....we would like to see you there.


Post Fri Jun 10, 2011 9:08 pm

Posts: 123
Location: OH,USA
Hi Bob
I have had the condenser in the Hunt mag fail and am not impressed with the quality of the points also.
I replaced the bad one with a Blue Streak part and don't have the part number but I use them in the 12 volt HD.
I will try out the Morris race condenser also.
The Linkert carbs can be some what tricky to get the heigh speed mixture just right with good throttle response.
We make the main jets from the appropriate size allen cap screw drilled to different sizes.I run the main jet as a safety anti burn a hole in the piston feature so don't want to give that up.I do tuning runes and make one small adjustments at a time and keep a record of your changes so you can zero in on the correct mix.
Also I have tuned on a dyno with AFR and that was super easy but I can't afford to do that except the one time with a new engine configuration to get best timing and mixture.
Something I would like to do is make an AFR gauge to mount at tuning time and then remove for vintage racing.

Post Mon Aug 08, 2011 6:35 am

Posts: 42
A little update.
The bike is running well now, although I haven't had a chance to ride it.
Back story: I messed around & messed around trying to get it to run - tried different jetting, two different carburetors (a CV & a flat slide), poked & prodded, rechecked this, reset that & basically just got frustrated. Also, every time I checked the timing it was out a fair bit. I finally concluded that I was the world's worst mechanic & I didn't even know which end of the screwdriver to hold when I was pounding the pipe wrench. I gave up & took the bike to a local expert on old H-D's & asked him to make it run. Well, long story short, he found that the #2 cam gear was slipping on the shaft & letting the timer gear get out of time with the cam. So every time I timed the mag, as soon as the engine started, the gear would slip, timing would go way retarded & the bike wouldn't run. No one's fault - just a freaky oddball failure that no one anticipated.
So now it's running pretty good. I haven't ridden it yet, but the mechanic did & he says it goes like stink.
One other related issue that I've learned something about in all this: The M-74B nozzle will NOT work in the M-53. The reason is that the M-74B nozzle is much longer than the M-53 nozzle & when you put the longer nozzle in the M-53 the bottom of the nozzle blocks off the main jet opening, where it goes into the center bore where the nozzle lives. The reason the M-53 nozzle is shorter is because it seats against a shoulder that is machined into the carb body, at the top of the nozzle bore. The M-74B nozzle goes up higher & seats against the bottom of the annular groove in the venturi, quite a bit higher than the feature on the M-53.
Unfortunately, I have not been able to do much more lately because I've travelling a lot for work, but my plan is to make the race at Gingerman at the end of August. Keep your fingers crossed...

Post Sun Aug 14, 2011 7:59 am

Posts: 123
Location: OH,USA
your local expert sounds like he is worth his salt,great to hear that you guys sorted it out.You should be able to tune it now that the timing is not giving you fits. Good luck with your race.What sanctioning body is your race in Gingerman?

Post Tue Aug 16, 2011 4:47 pm

Posts: 42
Yeah, Zooma, he does know what he's doing. When I was asking around trying to find someone to help me out on it, everyone kept saying, "I'd recommend you go talk to xxxx." He's well known around here & really does know his stuff. (I dunno what the rules are for naming names on this board & I'm too lazy to go re-read the rules, so I won't name him) The only reason I had been asking around for other sources was that he's always pretty busy. That's usually a good sign - if the shop has got a bunch of old scoots lined up waiting for work, the reason may be that the guy on the business end of the wrench is well qualified & sought after. That's the case here.
Anyway, the club I'm racing with is AHRMA (they're just a non-profit club, so I think that it's legal to name them (?))


Return to 45 Flatties