Search found 794 matches

by barryh
Tue Nov 04, 2025 5:49 pm
Forum: Post 1970 Airheads
Topic: E5/E10 Petrol
Replies: 11
Views: 9757

Re: E5/E10 Petrol

In the UK the petrol blend changes 4 times per year broadly with each season. The cold weather blends have more volatile components to aid starting but lower caloric value per litre. The difference in calorific value is small and similar to the 1.6% difference between E5 and E10. The biggest impact ...
by barryh
Mon Nov 03, 2025 11:27 am
Forum: Post 1970 Airheads
Topic: E5/E10 Petrol
Replies: 11
Views: 9757

Re: E5/E10 Petrol

I've not seen anything like a 10% difference in fuel consumption between E5 and E10. Based on the caloric value of the two fuels it should only be approx.1.6% although there are some other subtle things going on besides the caloric value change which may alter that figure slightly. Based on Calorifi...
by barryh
Mon Nov 03, 2025 4:11 am
Forum: Post 1970 Airheads
Topic: Rattling Bing Flat Tops
Replies: 1
Views: 720

Re: Rattling Bing Flat Tops

Flat tops don't have a guide sleeve like the dome top Bings, instead the slide has to be a reasonably good fit in it's bore but not too tight otherwise it wouldn't fall under it's own weight and there are no springs on a flat top to help it. I've never had that problem with my flat tops or heard any...
by barryh
Thu Oct 30, 2025 5:04 am
Forum: Post 1970 Airheads
Topic: Couple issues, maybe normal
Replies: 8
Views: 1852

Re: Couple issues, maybe normal

Worn bearings or something. Assuming the speedo works proving the cable drive is ok, then the usual cause of the odometer not working is a gear wheel slipping on it's shaft. It's a common enough fault and has been discussed on various airhead forums. Mine only slipped when it got hot due to differe...
by barryh
Sun Oct 19, 2025 5:42 pm
Forum: Post 1970 Airheads
Topic: Got a "tiny" charging problem...
Replies: 28
Views: 7232

Re: Got a "tiny" charging problem...

The stator won't produce any output until you get some current flowing through the rotor. It sounds like that isn't happening initially because of a break in the wiring somewhere. It might help to break things down into sections. For example, using the diagram above take a temporary feed from the ba...
by barryh
Sun Oct 19, 2025 10:17 am
Forum: Post 1970 Airheads
Topic: Got a "tiny" charging problem...
Replies: 28
Views: 7232

Re: Got a "tiny" charging problem...

Am I correct in saying that I should be able to measure AC voltage with a multi-meter from the 3-wire output on the bottom right of the stator casing, with - engine running - the said 3 wires unplugged from the stator casing - all other wires untouched - probes on only 2 separate spades Cause I'm c...
by barryh
Tue Oct 07, 2025 5:12 am
Forum: Post 1970 Airheads
Topic: R75/5 Fork Oil Level and Amount??
Replies: 4
Views: 8587

Re: R75/5 Fork Oil Level and Amount??

Different forks but the same principle of using oil level to tune the forks should apply. R45/R65 forks as well as having a fixed volume of 190cc also have a recommended level of 20mm - 50mm above the damper piston top. That difference allows for some tuning of the air spring effect. The 20mm level ...
by barryh
Mon Sep 29, 2025 3:36 am
Forum: Post 1970 Airheads
Topic: 1978 R100RS Engine Noise
Replies: 5
Views: 8861

Re: 1978 R100RS Engine Noise

Even an engine that does does have pinging would never exhibit it when the bike is stationary on the stand. The engine has to be under substantial load. With no load the engine will rev right up with just a fraction of throttle and that won't produce sufficient compression in the cylinders to promot...
by barryh
Sun Sep 28, 2025 4:19 pm
Forum: Post 1970 Airheads
Topic: E5/E10 Petrol
Replies: 11
Views: 9757

Re: E5/E10 Petrol

Are there different burn rates of the flame front with E5 vs E10? Or volatility of the fuel? Could something like that contribute to better running? Kurt I doubt there are significant burn rate or volatility differences for E5 and E10 but it might depend where you are located. In the UK E5 is 98 Ro...
by barryh
Sun Sep 28, 2025 5:16 am
Forum: Post 1970 Airheads
Topic: E5/E10 Petrol
Replies: 11
Views: 9757

Re: E5/E10 Petrol

I didn't notice any difference in running moving from E5 to E10 although it must have weakened the mixture by a few percent.

I'll find out what it's done to fuel hoses and O rings in the carbs at the next overhaul. I've already had the bowls off and seen nothing untoward.