Hi everyone I am having a problem with this carb and cannot get past it, the carb is a VM36 and supplied by Phil Pearson Jnr to the previous owner the problem I am getting is firstly the float keeps sticking and secondly it will only run and rev on choke, the carb has been in a sonic cleaner twice the pilot jet has been replaced and was not blocked or worn anyway bigger pilot jets have been tried but it runs worse with those, this was only done because I could not think of another solution and just do not know what to try next suggestions please
Maybe contact Pearson?
Number one gotcha...?
The choke is On when the plunger is pulled out.
Normal running is when the plunger is pressed In.
Choke on is when lever that operates the plunger is down and choke off when it is up
have you looked at needle, valve and seat? the right needle can make all the difference
is it a mikuni mikuni or the american copy (cant remember what theyre called). the yankie ones arent finished as well so i'd check for bad cleaning up on the bowl.
look up motocarb.com they are brilliant
should have said motocarb recommends a VM38. might be a /4 but i'm not sure about that
Have you tried a larger Main Jet..? The sizes are different to Amal, so you need to experiment. I found that a good way of carb tuning was to partially cover the inlet with a thumb, if it went faster you needed a bigger jet. ( Obviously running with no air filter.)
Honestly I have given up and sent the carb back to Allen's Performance for them to sort out but many thanks for your reply
i would have said the right meedle was imperayive but its all academic now
As far as I know the carb was running correctly as the milometer was zeroed when it was rebuilt and it now has 384 miles on it but it has gone back to Allens performance for thorough ivestigation and I have asked them to give me a list of the spec and sizes of everything
That's why I love Amals... ;)
Exactly what do you mean with float sticking? Is fuel dripping?
Has it correct fuel level in the float bowl?
Have a couple of bikes with VM carbs, Velocette, Honda and Suzukis. All running great.
Yes but not all the time just when it feels like it and yes I have changed the fuel cut off valve for a new one and it still does it when it wants
VM's are brilliant. they have to be set up right and its a bit of a faff. once they are though you'll never looh back
Hi,
I have a Mikuni on an A65 and when it was new the fuel would come out of the overflow tubes when the fuel was left on. Not every time but annoyingly frequent. I think in the booklet that came with the carb it did imply that the float needle is not meant to act as 'fuel tap' and that the fuel should be turned off when not in use. Turning off the fuel at the same time as stopping then engine solved the problem.
However over time, if I leave the fuel on, there does not seem to be a problem any more.
Dave.
No help at all on your mikuni but Why . My db500 , totally rebuilt with pearson internals , runs perfectly on an amal gp . Starts first or second kick , ticks over good , and pulls like a train .
the needle 'seated' over time? what is youre set'up? what size? vm38/4? what slider? jetting? i lurve mukinis. all my harleys run on them
Quote from: ducati2242 on 12 Nov, 2024, 08:18 No help at all on your mikuni but Why . My db500 , totally rebuilt with pearson internals , runs perfectly on an amal gp . Starts first or second kick , ticks over good , and pulls like a train .
I have the original GP for the bike and I spoke with Burlen's about re conditioning it is very worn even from first glance and Burlens priced a replacement that will do the job but is not correct at over a grand and said a correct one is no longer available so that will not be happening
Quote from: chrisf-1 on 12 Nov, 2024, 10:11 Quote from: ducati2242 on 12 Nov, 2024, 08:18 No help at all on your mikuni but Why . My db500 , totally rebuilt with pearson internals , runs perfectly on an amal gp . Starts first or second kick , ticks over good , and pulls like a train .
I have the original GP for the bike and I spoke with Burlen's about re conditioning it is very worn even from first glance and Burlens priced a replacement that will do the job but is not correct at over a grand and said a correct one is no longer available so that will not be happening
I hit lucky and got mine from a genuine seller on ebay for £360 took a bit of set up and afew different slides and experimental holes drilled in said slides but i have it almost perfect now . sometimes stalls on tickover but i dont want to try to up the revs from the 800 i have it at now as it may go all wrong .
If only
heres a useful little nic nak to help tune it...if you can find one
just bought one from Ghost bikes what have I got to lose £11.00 delivered
does help . gives you an inkling of whats to be done
I've got a couple of Amal 1036 set up for a DBD 😉. I am using one on my 600.
Also have a 930 on my 500 (but also have a 10TT9 for that). They are simple and work well with decent slides and correct jets. Not as flash as the GP or as sophisticated as the Mikuni.