JH or JDH twin cam?

[Eric]

Inside 2cam

Hello,
You can see inside a twocammer at this adress :
http://www.harley-memories.com/harle...res/index.html

[silentgreyfello]

Originally posted by Tommo
some of Harleys cylinders were made with the Ricardo style combustion chamber cast into them and once again look up from the bottom and you should see the chamber sloping down towards the valve chamber

The chamber does slope gradually towards the valve chamber. It is not an insert, as i.e. Ricci chip. It is cast into the cylinder.

I didn't notice before because of all of the grease, but each cylinder has a casting number on it on the flange. They are facing each other and I couln't read it until I pulled the front cylinder.

Front: 1-24B-H-D (or 1-24R-H-D)
Rear: 1-24C-H-D

[silentgreyfello]

Bore at the bottom looks to be 3.352 +/-. I would assume it started life at 3-5/16 (61ci). Piston is alloy, slightly domed.

I couldn't measure the stroke as the rear cylinder/piston are in a liplock. I'll dump a bit of oil in there to try to free it up.

[Tommo]

We all get to the edge of our knowledge at some time or other and I feel I'm very close to going into that dangerous area right now.
There are people out there that know this subject a lot better than I do but they do not appear to be contributing.
Steve Raffills here in NZ is one such person and I will try and get him to post a reply on the subject for you.
I reckon you have a pair of factory racing 61 cu in "Chicago" cylinders. The crankcase may or may-not be the correct timing side one that left the factory with those cylinders but would certainly not be out of place if used to rebuild the engine.
Whether or not the drive side JD crankcase is appropiate to the rebuild is beyond my knowledge and if I was in your situation I would be consulting with Steve.
Leave things with me for a few days and I'll talk to him. He may wish to contact you direct and not via this forum.
Regards, Tommo

[silentgreyfello]

Thanks Tommo... any help would be appreciated. My email address is in my profile. Thanks again!

[Tommo]

I've asked Paul to post for me the 1928 Parts Book Supplement that covers any parts that are used on the JDH.
Any part listed in this list is for the JDH only and differ from parts used on the J and JD models.
The opening paragraph, under the heading "Parts used on 1928 H Models", is very revealing and must be read and considered very carefully.
I have had many a heated discussion with regard to the narrower tanks used on these models. Some experts vow and declare that these tanks were a racing only item but have no answer when I produce this list.
Have a read and let me know what you think.

Tommo

[silentgreyfello]

Thanks again, Tommo! I just ran across Daniel Statnekov's website on 2-cammers and other racing bikes. Well worth the read!

http://www.statnekov.com/motorcycles/2camfurther.html

http://www.statnekov.com/motorcycles

[silentgreyfello]

here is another link:

http://www.statnekov.com/motorcycles/26-2camrteng.html

and a picture of his 26 two cam:

[AdminGuy]

PG1 from Tommo.

Ok, here you go guys. I just split the scan into 2 pgs.

[AdminGuy]

pg2 from Tommo.

I had my hands on a 1929 JD engine and frame yesterday. A fellow club member is restoring it. All this talk is getting me interested in such things now. Esp after seeing and touching one for real. So I'm really getting into this now. And to top it off my buddie w/ the 29 is an Indian guy!!!! GO figure.

[silentgreyfello]

Thanks to all who have contributed!!!

Anybody have a LH case for an FH model (factory racing motor)???

I emailed Daniel Statnekov with photos.... here is his response:

"I think what you have is a 1928 or '29 FH 2-cam motor with some sort of "J" model left hand case that was added when the original left case broke. I'd leave it as it is unless you can find an FH left hand case which would be very very hard to do. If you wanted to make the motor more aligned with it's original configuration you could extend the engine case through bolt tunnels on the left side to conform to those on the remaining FH case. The same is true of the little tabs. Sorry I can't say for sure what engines used those, race or otherwise, but Fred Lange has been researching this and could probably give you a clear answer to that feature. If you decide to reconfigure the left case, the number boss should be milled away completed as the original FH motors did not have a boss. The numbers were stamped directly into the case itself. If it was me, I'd leave the engine blank since you don't know what number it originally had. I'm not sure about your cylinders but they're either Ricardo cylinders as were supplied originally on the FH race motor or they are the tapered fin cylinders that were made for production models to emulate the race configuration and supplied on the 61 inch production 2-cams. That's about all I can add. Still, you've a great motor there and I wish you good luck with your project. Do you know what you're going to build with it?

[Tommo]

I've talked to Steve but I don't know if he'll respond or not, he reckons he's not very good with computors. We'll see.
He did say that there were very few 61 cu in twin cam racing motors or road motors for that matter and a 61 cu in twin cam would be a lot rarer than a 74.
Remember it will be a JH or FH as a 61.
I thought that Daniel or one of the others could help and Steve and I are pretty sure those are racing cylinders you have.
By the way Steve is in the process of producing exact replicas of those crankcases at this very minute and although I haven't asked him I feel sure you could get a drive side case from him.

Hope this helps, Tommo

[sveger]

Tapered cylinder 61" twincam IOE

Hi folks,
Interesting to read this info regarding Silentgreyfellows 61 racing twincam-motor, lucky fellow.
I have mentioned this before on this board with no response, but I try again:
Here in Scandinavia there are a couple of these race twincam-motors with the exact same apperance, tapered 61 cylinders etc. The odd about these tough is they have production numbers telling they where made in the thirties. This means that Harley continued to make the IOE Twin-cam racing engines long after the IOE had officially ended. One of these motors are here in Norway, I will try to get the exact engine number and a photo to post the next time I go visit its owner. Is there anything like this "down under"? or in the US.
I mentioned the Norwegian thirties Twin cam motor a couple of years back for Mr. Statnekov and he responded he had never heard of any like this before.
Sverre