Anyone put bike carbs on a twin-cam?
Discussion
Reading "retro cars" today - spotted the piece about bike carb conversions. The guys they interviewed (Bogg Brothers) built my engine, so I know they're good, but wondering if anyone here has tried it. I'm sick of my webers going off tune all the time (goes like stink for about a fortnight, then gradually fades agan), which bike carbs aren't supposed to do...
(Engine's a Lotus 1558 twin-cam, twin 40 Webers, fast road cams, big valves, etc)
(Engine's a Lotus 1558 twin-cam, twin 40 Webers, fast road cams, big valves, etc)
Retrim, Respray, new adjustables - all adds up, and I hear throttle bodies don't come cheap...
the brothers Bogg will do the full conversion for £500ish.
(and I like to be different, so saying "It's a twin cam with quad carbs" just sounds kind of nice)
edited to add - just spoken to them, and they've done TC's before, from Webers, with apparently dramatic results (1.5 sec quicker hillclimber!) - I'm going for it.
>> Edited by mawds on Monday 15th November 16:32
the brothers Bogg will do the full conversion for £500ish.
(and I like to be different, so saying "It's a twin cam with quad carbs" just sounds kind of nice)
edited to add - just spoken to them, and they've done TC's before, from Webers, with apparently dramatic results (1.5 sec quicker hillclimber!) - I'm going for it.
>> Edited by mawds on Monday 15th November 16:32
Bike bodies onto cars has been done many a time. Not that much more expensive. Say ~£100 for 2003 spec GSXR750 bodies with fuel rail, ~£150 for manifold, you can, depending on application find an ECU for £30 in a scrapyard chipped by chipwizards for example and you are almost running. I've heard it done using a Magneti Marelli ECU from a Pug 405. Indeed, this is the route I'm looking to soon (ish) with perhaps a build-your-own Megasquirt type ECU
Nothing new about using bike carbs on car engines. Using 4 Amals used to be one of the trick things back in the 1960s.
As mentioned earlier though, why not look at using injection with bike throttle bodies?
Or just try and find cause of problem with the Webers. Have run cars in past with twin DCOEs and not had problems with bad running due to them going out of tune, not even with daily driver.
As mentioned earlier though, why not look at using injection with bike throttle bodies?
Or just try and find cause of problem with the Webers. Have run cars in past with twin DCOEs and not had problems with bad running due to them going out of tune, not even with daily driver.
Spoke to my dad today - turns out he used to have four bike carbs on his Rochdale/Austin 7 special in the mid-50s. He wondered why I hadn't done it before! (perhaps if he'd told me...).
As regards the webers - AFAIK they need rebuilding - must be 20 years old at least, and several of the visible gaskets, etc are perishing, if not perished. I realise this would be the cheaper and more sensible option, but I'm rather taken with the idea of the bike carbs now, especially as (although it's been done before), it's a bit different, and should improve the throttle response (if not the overall power), making it (even) more driveable.
As regards the webers - AFAIK they need rebuilding - must be 20 years old at least, and several of the visible gaskets, etc are perishing, if not perished. I realise this would be the cheaper and more sensible option, but I'm rather taken with the idea of the bike carbs now, especially as (although it's been done before), it's a bit different, and should improve the throttle response (if not the overall power), making it (even) more driveable.
Why do the Webers go off? Are they mounted solidly?
As Vizard said, stuff only goes of tune if something wears or physically moves. Sounds like you have a vibration problem.
The bike carb conversion was done by Bill Richards who incidentally is ex-Abingdon Special Tuning. I assume that these bike carbs are pretty much like Amals. Still you will have the problem with getting the jets sorted and accurately set up. 2 custom ground needles for SU's are hard enough. You are looking at getting 4 the same. Here's an idea.
Sort the Webers out!
Or, get a normal Crossflow inlet manifold (I think they are the same) Bugger about with the holes so that it can be mounted upside-down. Get an Eaton M62 blower and ally weld a big flange to the weber mount. Bolt the blower up and make a bottom bracket to hold it steady. Belt the sucker up (I think the pulley is pretty much spot on) have it sucking through a 2.5" SU off a Rolls Royce fire engine. That's what we were going to do with my mates old TVR Vixen (crossflow)
As Vizard said, stuff only goes of tune if something wears or physically moves. Sounds like you have a vibration problem.
The bike carb conversion was done by Bill Richards who incidentally is ex-Abingdon Special Tuning. I assume that these bike carbs are pretty much like Amals. Still you will have the problem with getting the jets sorted and accurately set up. 2 custom ground needles for SU's are hard enough. You are looking at getting 4 the same. Here's an idea.
Sort the Webers out!
Or, get a normal Crossflow inlet manifold (I think they are the same) Bugger about with the holes so that it can be mounted upside-down. Get an Eaton M62 blower and ally weld a big flange to the weber mount. Bolt the blower up and make a bottom bracket to hold it steady. Belt the sucker up (I think the pulley is pretty much spot on) have it sucking through a 2.5" SU off a Rolls Royce fire engine. That's what we were going to do with my mates old TVR Vixen (crossflow)
After spending money to send the compression up, I'm not keen to then fit spacers to bring it down again & fit a supercharger (Vegantune's 200bhp twin-cam turbo conversion had a CR of 8:1 IIRC, mine's currently 11.5:1). I also want to stay NA.
The jetting & setting-up is included in the conversion price, so no problems there. Waiting to see how long the respray will be (to book in) before I get this done finally (ie if the sprayers can start next week, then I'll have that done first).
The jetting & setting-up is included in the conversion price, so no problems there. Waiting to see how long the respray will be (to book in) before I get this done finally (ie if the sprayers can start next week, then I'll have that done first).
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