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Intake port opinions.

General engine tech -- Drag Racing to Circle Track

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PackardV8
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Re: Intake port opinions.

Post by PackardV8 » Wed Sep 04, 2019 8:16 pm

Only slightly off topic, but the '65 BSA Lightning was the fastest/quickest/most unreliable machine of its day. I never lost a race to a Triumph or a Harley unless the Beezer blew, which it did early and often. After I gave up on it, the problem was reportedly a wrongly designed breaker point cam.
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pcnsd
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Re: Intake port opinions.

Post by pcnsd » Wed Sep 04, 2019 9:47 pm

PackardV8 wrote:
Wed Sep 04, 2019 8:16 pm
Only slightly off topic, but the '65 BSA Lightning was the fastest/quickest/most unreliable machine of its day. I never lost a race to a Triumph or a Harley unless the Beezer blew, which it did early and often. After I gave up on it, the problem was reportedly a wrongly designed breaker point cam.
I have seen point bounce make other machines unstable/unreliable at highish rpm, but what could you do in the time before CDI?
- Paul

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Re: Intake port opinions.

Post by ole4 » Wed Sep 04, 2019 10:32 pm

The 1965 BSA's had multiple issues. The maverick spark issue was caused by the change in 1965 from 6 volts to 12. The lucas breaker cam was the same 6 volt cam used in 63/64 and it was causing spark not only when the points opened but also when they closed, they changed the dwell for 66 and fixed the issue. In addition from 1963 till 1965 they used a ball bearing on the drive side and a bush on the timing side, the ball bearing was used to locate the crank and give the correct amount of endfloat to the crank. The ball bearing worked OK for the engines in 63 and 64 but when the 65's came out there were two high performance models which had the compression increased to 10.5:1 the spitfire mk 2 special which also had two amal GP carbs with a remote floatbowl and that is the one that hot rod had to 125MPH (don't know how accurate there claim was) and also the hornet scrambler. The hornet had a et ignition and did not suffer the blowups the spitfires had due to the spark issue, The lightening which was the same engine just with 9:1 compression and amal monoblocks did not blow up as frequently. The ball bearings had a high failure rate in the bikes that were driven hard. In 1966 they went to a roller bearing on the drive side to handle the loads and that failure was fixed but now they had to control end float with a thrust washer next to the timing side bushing and as it wore it caused the bush to fail and the left side rod to seize on the crank due to oil starvation. My two 65 hornets.
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Re: Intake port opinions.

Post by Truckedup » Thu Sep 05, 2019 6:16 am

PackardV8 wrote:
Wed Sep 04, 2019 8:16 pm
Only slightly off topic, but the '65 BSA Lightning was the fastest/quickest/most unreliable machine of its day. I never lost a race to a Triumph or a Harley unless the Beezer blew, which it did early and often. After I gave up on it, the problem was reportedly a wrongly designed breaker point cam.
Yes, the design of the points cam allowed a"'phantom" spark that caused pre ignition....Triumphs were not faster than BSA's but they blew up a less, you know, can't win unless you cross the finish line...
In land speed racing Triumphs hold most of the 650 pushrod class records. A guy I know runs several BSA's.Him and his partner are bike mechanics and own a dyno.. He a has a 650 bike running a turbo in partially streamlines class that has set several records in the 160 mph range...As expected he has had more than a few engine failures.He also runs a modified production 650 in the same class as me but can't catch me or the other Triumph that squeaked by me to take the record.
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire

Diodedog
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Re: Intake port opinions.

Post by Diodedog » Fri Sep 06, 2019 3:42 pm

How did Borris Murray keep his engines together. https://www.cycledrag.com/the-greatest- ... f-all-time

Truckedup
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Re: Intake port opinions.

Post by Truckedup » Sat Sep 07, 2019 6:18 am

Diodedog wrote:
Fri Sep 06, 2019 3:42 pm
How did Borris Murray keep his engines together. https://www.cycledrag.com/the-greatest- ... f-all-time
Murray and the few others running nitro fuel Triumphs made about 100 hp or so per engine...Far as I know Murray used had stock 1950's crankcases, stock crankshafts, rods and after market Chatman 750 cylinders...Most likley engine internals were replaced frequently..Murray was the last of the one speed drag bikes that smoked the tire nearly the whole 1/4 mile ..Alp Racing 650 N/A naked frame Triumph has run 175 mph at Bonneville on 98 % nitro...He uses aftermarket cases , barrels and rods but stock crankshaft...He claims near 150 hp although others claim it closer to 125....
Around 1970 the first ever naked frame bike over 200 MPH at Bonneville was a dual engine Royal Enfield. A few runs later a dual engine Triumph went 1 mph faster..The nest year was a 200 MPH naked frame Sportster...I find it amazing they went so fast on such crude equipment compared to today bikes that run just a little faster..Rules by 1970 required feet and hands on the controls at all times so they was none of that lying naked on the bike like the famous Rollie Free 150 mph Vincent photo.. It's implied that the Vincent was stock but it was far from that and running fuel class..
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire

RCJ
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Re: Intake port opinions.

Post by RCJ » Sat Sep 07, 2019 8:19 am

I googled Rollie Free.That is a picture of a guy that was ''All in''. It's like the story of the ham and egg breakfast.The chicken is participating ,but the pig is all in.

Truckedup
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Re: Intake port opinions.

Post by Truckedup » Sat Sep 07, 2019 8:48 am

This is my dual engine 650 Triumph land speed racer I built a few years ago using a 65 year old lathe and hand help tools...two mildly 1956 Triumph crankcases, late 60's cylinders and heads. The engines are somewhat mild, 100 hp rwhp total on a Superflow dyno...Harley 5 speed and clutch and I retained the Harley electric started so the rider just pushes a button,..It ran two runs at 145 mph to check handling and so on at the 1-1/2 standing start track in Loring Maine...But it had persistant flooding with one the carbs...We didn't race it last, too busy with other stuff..
Yes that's me................

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Full chain drive..

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Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire

Diodedog
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Re: Intake port opinions.

Post by Diodedog » Sun Sep 08, 2019 2:12 am

Very nice Mr Truckedup, I got your attention with the Boris link. Sonny Routt was popular with the Triumphs also http://showandgo.blogspot.com/2009/09/s ... -drag.html.

Geoff2
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Re: Intake port opinions.

Post by Geoff2 » Sun Sep 08, 2019 6:34 am

A mate of mine built a double Triumph, using 650 engines, around 1969-70. This was in Sydney, Australia. The rear engine was a unit construction engine, front engine was pre unit. I am going from memory now, he lengthened the standard Triumph frame about 15". The bike was street registered. I rode it for about 30 min & couldn't wait to hand it back.... handling left a lot to be desired.

I remember he tried to contact people like Murray & Routt in the US because he wasn't sure about phasing the engines, whether to have both in sync or one engine 180* out.

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