non vacuum distributor

[rshyndy]

I have seen a few non vacuum dizzys on ebay and am wandering what is the difference.
are the non vac dizzys any better than the vacuum ones.
these are electrronically converted and come with a coil.
but iv read on a few pages that some coils need a ballast bypassed.
bit confused really people. If anyone can shed some light id b very happy.
failing that is it worth just getting a 45quid coil and conversion kit and doing that with my original dizzy......if I can find the thing

[Supercharged Nat]

vacuum advance gives you better economy. on a run (like cruising on a motorway) the throttle is only open a little bit and vacuum in the manifold is high. if the ignition timing is advanced during this time fuel economy is increased. the vacuum advance dizzy allow this to happen.

if removed your economy will suffer. the only reason i think these are removed is for use in race engines or very high performance engines where the timing is so far advanced (lairy cams etc) that anymore from the vac advance and the engine could be damaged (pinking etc).


if an aftermarket coil is fitted and if it requires a full 12v feed (rather than the capris std ballast 9v feed) then the easiest way is to run a fresh switched 12v feed from the ignition barrel OR in the capris loom near the headlight relay there is already what you need- you just need to extend this unused wire to the coil

hope this helps a bit?

[rshyndy]

Yea thats cleared a few things up.thanks for that.
what should my timing be on my engine at the moment.its pretty much a standard motor apart from lightend and balanced crank,con rods and flywheel. And bored to 2.1.
running a standard head at the moment. On the auxilary belt pulley there are notches.some are deeper than others.
what are these notches in relation to degrees btdc?
and what should a standard engine be set at.also il b running just neat unleaded for the rime being.
after a few months il b fitting a lightly ported unleaded head and probably an fr30 cam and r1bike carbs.
then what would my engine timing be roughly.just so I can drive it to the rolling road and get it set up properly.
thanks for clearing up the dizzy question.gonna get an accuspark converted dizzy and coil kit off ebay

[Craigorypeck]

Non vac dissy... from what i remember before megajolt, a hot cam gives minimal vacuum at idle and light throttle so doesn't work that well with a normal dissy. increasing the timing at idle helps it tick over better, (hot cams usually have twin carbs with separate runners and a vac dissy needs a regulated signal which should have a reservoir tapped into each runner for proper signal) A normal dissy that has the timing advanced to say 14 degrees to help a hot cam tick over will have way too much timing up top and will pink heavily.. a purpose built non vac dissy is usually built to spec depending on cam, carbs and CR and will have the centrifugal spring weights modified to have the all in advance of 36 degrees at say 3750rpm and an idle of 14... thats a difference of 22 degrees compared standard which may have 28ish..

if fitting r1 carbs they will have tps and suitable for mapped ignition.. if your not using the tps feature sell them for the 100+ quid you will get and buy some non tps bike carbs for 35 quid. R1 carbs or similar have 38-40mm chokes so get a cam that will make use of the extra air, an fr30 is mild tbh..


Tipsy advice over - HEHE

[rshyndy]

Well its either the fr30 or fr32.was thinking the 30 because of the low down torque factor.
will have a rethink about that. I understand the seperate vacuum take offs from the bike carbs manifold but am unsure about the 'reservoirs'
The carbs will probably be with a tps to allow megajolt in the distant future.
so with a fast cam what is recomended dizzy-wise. If I get an electronic vacuum dizzy will I be getting full advantage of the cam or will my fuel economy suffer badly.
I will be getting it rolling roaded before the bike carbs go on and again after iv fitted them so I know that everything will be right.
but the cam and head will be going on way before the bike carbs and then itl b a long time before magajolt or anything like that.
As long as I can get it running comfortably enough to get to the rr. Then il b happy to let them have a play.but I need to drive it for a while before I let the rr man rev the tits off it because its a fresh build from scratch.

so complicated ha.thanks for the replys. Its slowly making sense to me ha.

[Craigorypeck]

A reservoir is used to give a nice steady regulated signal to the dissy. basically a small box with all the runners piped to it and then a single line to the dissy. I'm currently tapping into my runners to get a signal for my blow off valve and the boost gauge but TBH im just gonna tee them all up as I wouldnt be arsed with the reservoir.
When running my 40s on standard dissy i just removed the vac pipe from dissy, blocked it off and increased the idle timing a bit, think around 10 degrees was as high as it would go as any more had it pinking up top. I was tempted to adjust the dissy by bending the tabs inside via the small access holes on the side to reduce the total advance but as I didnt really know what I was at...... i didnt wanna fuck it up!!! MPG was down without the vac connected but that was also due to the 40s. Vac only helps whilst cruising anyways.
Get it running, watch out for pinking and get it rolling roaded..