AAOK Blog - Vintage Harley Davidson Restoration

inch/mm Conversion Chart

Monday, May 4, 2020 12:57:48 PM America/Denver

INCHES		METRIC	INCHES		METRIC	INCHES		METRIC
FRACTIONAL	DECIMAL	mm	FRACTIONAL	DECIMAL	mm	FRACTIONAL	DECIMAL	mm
.	0.0039	0.1000	.	0.5512	14.0000	.	1.8898	48.0000
.	0.0079	0.2000	9/16	0.5625	14.2875	.	1.9291	49.0000
.	0.0118	0.3000	.	0.5709	14.5000	.	1.9685	50.0000
1/64	0.0156	0.3969	37/64	0.5781	14.6844	2	2.0000	50.8000
.	0.0157	0.4000	.	0.5906	15.0000	.	2.0079	51.0000
.	0.0197	0.5000	19/32	0.5938	15.0813	.	2.0472	52.0000
.	0.0236	0.6000	39/64	0.6094	15.4781	.	2.0866	53.0000
.	0.0276	0.7000	.	0.6102	15.5000	.	2.1260	54.0000
1/32	0.0313	0.7938	5/8	0.6250	15.8750	.	2.1654	55.0000
.	0.0315	0.8000	.	0.6299	16.0000	.	2.2047	56.0000
.	0.0354	0.9000	41/64	0.6406	16.2719	.	2.2441	57.0000
.	0.0394	1.0000	.	0.6496	16.5000	2 1/4	2.2500	57.1500
.	0.0433	1.1000	21/32	0.6563	16.6688	.	2.2835	58.0000
3/64	0.0469	1.1906	.	0.6693	17.0000	.	2.3228	59.0000
.	0.0472	1.2000	43/64	0.6719	17.0656	.	2.3622	60.0000
.	0.0512	1.3000	11/16	0.6875	17.4625	.	2.4016	61.0000
.	0.0551	1.4000	.	0.6890	17.5000	.	2.4409	62.0000
.	0.0591	1.5000	45/64	0.7031	17.8594	.	2.4803	63.0000
1/16	0.0625	1.5875	.	0.7087	18.0000	2 1/2	2.5000	63.5000
.	0.0630	1.6000	23/32	0.7188	18.2563	.	2.5197	64.0000
.	0.0669	1.7000	.	0.7283	18.5000	.	2.5591	65.0000
.	0.0709	1.8000	47/64	0.7344	18.6531	.	2.5984	66.0000
.	0.0748	1.9000	.	0.7480	19.0000	.	2.6378	67.0000
5/64	0.0781	1.9844	3/4	0.7500	19.0500	.	2.6772	68.0000
.	0.0787	2.0000	49/64	0.7656	19.4469	.	2.7165	69.0000
.	0.0827	2.1000	.	0.7677	19.5000	2 3/4	2.7500	69.8500
.	0.0866	2.2000	25/32	0.7813	19.8438	.	2.7559	70.0000
.	0.0906	2.3000	.	0.7874	20.0000	.	2.7953	71.0000
3/32	0.0938	2.3813	51/64	0.7969	20.2406	.	2.8346	72.0000
.	0.0945	2.4000	.	0.8071	20.5000	.	2.8740	73.0000
.	0.0984	2.5000	13/16	0.8125	20.6375	.	2.9134	74.0000
7/64	0.1094	2.7781	.	0.8268	21.0000	.	2.9528	75.0000
.	0.1181	3.0000	53/64	0.8281	21.0344	.	2.9921	76.0000
1/8	0.1250	3.1750	27/32	0.8438	21.4313	3	3.0000	76.2000
.	0.1378	3.5000	.	0.8465	21.5000	.	3.0315	77.0000
9/64	0.1406	3.5719	55/64	0.8594	21.8281	.	3.0709	78.0000
5/32	0.1563	3.9688	.	0.8661	22.0000	.	3.1102	79.0000
.	0.1575	4.0000	7/8	0.8750	22.2250	.	3.1496	80.0000
11/64	0.1719	4.3656	.	0.8858	22.5000	.	3.1890	81.0000
.	0.1772	4.5000	57/64	0.8906	22.6219	.	3.2283	82.0000
3/16	0.1875	4.7625	.	0.9055	23.0000	.	3.2677	83.0000
.	0.1969	5.0000	29/32	0.9063	23.0188	.	3.3071	84.0000
13/64	0.2031	5.1594	59/64	0.9219	23.4156	.	3.3465	85.0000
.	0.2165	5.5000	.	0.9252	23.5000	.	3.3858	86.0000
7/32	0.2188	5.5563	15/16	0.9375	23.8125	.	3.4252	87.0000
15/64	0.2344	5.9531	.	0.9449	24.0000	.	3.4646	88.0000
.	0.2362	6.0000	61/64	0.9531	24.2094	3 1/2	3.5000	88.9000
1/4	0.2500	6.3500	.	0.9646	24.5000	.	3.5039	89.0000
.	0.2559	6.5000	31/32	0.9688	24.6063	.	3.5433	90.0000
17/64	0.2656	6.7469	.	0.9843	25.0000	.	3.5827	91.0000
.	0.2756	7.0000	63/64	0.9844	25.0031	.	3.6220	92.0000
9/32	0.2813	7.1438	1	1.0000	25.4000	.	3.6614	93.0000
.	0.2953	7.5000	.	1.0039	25.5000	.	3.7008	94.0000
19/64	0.2969	7.5406	.	1.0236	26.0000	.	3.7402	95.0000
5/16	0.3125	7.9375	.	1.0433	26.5000	.	3.7795	96.0000
.	0.3150	8.0000	.	1.0630	27.0000	.	3.8189	97.0000
21/64	0.3281	8.3344	.	1.0827	27.5000	.	3.8583	98.0000
.	0.3346	8.5000	.	1.1024	28.0000	.	3.8976	99.0000
11/32	0.3438	8.7313	.	1.1220	28.5000	.	3.9370	100.0000
.	0.3543	9.0000	.	1.1417	29.0000	4	4.0000	101.6000
23/64	0.3594	9.1281	.	1.1614	29.5000	.	4.3307	110.0000
.	0.3740	9.5000	.	1.1811	30.0000	4 1/2	4.5000	114.3000
3/8	0.3750	9.5250	.	1.2205	31.0000	.	4.7244	120.0000
25/64	0.3906	9.9219	1 1/4	1.2500	31.7500	5	5.0000	127.0000
.	0.3937	10.0000	.	1.2598	32.0000	.	5.1181	130.0000
13/32	0.4063	10.3188	.	1.2992	33.0000	.	5.5118	140.0000
.	0.4134	10.5000	.	1.3386	34.0000	.	5.9055	150.0000
27/64	0.4219	10.7156	.	1.3780	35.0000	6	6.0000	152.4000
.	0.4331	11.0000	.	1.4173	36.0000	.	6.2992	160.0000
7/16	0.4375	11.1125	.	1.4567	37.0000	.	6.6929	170.0000
.	0.4528	11.5000	.	1.4961	38.0000	.	7.0866	180.0000
29/64	0.4531	11.5094	1 1/2	1.5000	38.1000	.	7.4803	190.0000
15/32	0.4688	11.9063	.	1.5354	39.0000	.	7.8740	200.0000
.	0.4724	12.0000	.	1.5748	40.0000	8	8.0000	203.2000
31/64	0.4844	12.3031	.	1.6142	41.0000	.	9.8425	250.0000
.	0.4921	12.5000	.	1.6535	42.0000	10	10.0000	254.0000
1/2	0.5000	12.7000	.	1.6929	43.0000	20	20.0000	508.0000
.	0.5118	13.0000	.	1.7323	44.0000	30	30.0000	762.0000
33/64	0.5156	13.0969	1 3/4	1.7500	44.4500	40	40.0000	1016.0000
17/32	0.5313	13.4938	.	1.7717	45.0000	60	60.0000	1524.0000
.	0.5315	13.5000	.	1.8110	46.0000	80	80.0000	2032.0000
35/64	0.5469	13.8906	.	1.8504	47.0000	100	100.0000	2540.0000

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Posted in Tech Articles By - AAOK

Tire Pressure Service Shop Dope November 1, 1946

Tuesday, November 3, 2015 11:00:20 AM America/Denver

Service Shop Dope

No. 252 November 1, 1946

Tires Wheels Speed

When a racing motorcycle or car Is being groomed for an event on road or track, just as close attention is given to perfect condition of wheels and tires as to engine tuning for maximum performance. Wheel bearings are checked, wheels and tires are checked for out-of-true sideways, eccentricity, out-of-round, and out-of-balance. Careful attention is given to anything found not just right. If a tire tread is found worn irregular to an appreciable degree, tires are transposed or a new tire installed. Inflation pressure is carefully adjusted to the poundage known to be right for weight of vehicle and nature of event.

Harley Davidson Model Numbers

Tuesday, November 3, 2015 10:43:53 AM America/Denver

The model number is in effect the motor number of a bike. The motor number is stamped on the left crankcase. The numerals of the motor number preceding the letters indicate the year. The letters indicate the size and type of the motor.

For example:

41EL2037 would be a 1941 model with a 61 OHV motor.
38U1863 would be a 1938 model with a 74 SV motor.

Glossary of Terminology

Tuesday, November 3, 2015 10:28:49 AM America/Denver

BT: Big Twin
Flathead: A type of engine with Side Valves.
Knucklehead: A type of engine with Over Head Valves.
OHV: Over Head Valve
SV: Side Valve