Can you read my plugs

[monkfish]

Been for a couple of test rides on my 4Lo this week ,12 miles each, as full on as traffic conditions would let me. The first run whent well after I got it started, turned out to be the old float bowl problem , but it did run ok. 4000-7000 as flat as ****, too flat in my opinion, 7000-red line in all gears great ;D. Held 9000 rpm in 6th with an indicated 95 mph. Didnt do a plug chop but looking after the ride the RH cylinder plug lookeed very lean and the LH plug very rich.
I swaped the bowles over and went for a 2nd run. It started first kick and The flat spot seemed to have moved to 4500-6500 and although the band was narrower it seemed a little worse, infact it wont pull through it in 4th, 5th,6th and has a right struggle in 3rd. It will now wheelie on the throttle in 1st but the power is done by 9000rpm. This time with the same plugs the LH plug looked a tad richer and the LH a tad leaner, see the pix.. The 1st run was done on 230 mains and the 2nd on 240. . I believe the carbs to be set up as good as I can get em, clean, and I have great fuel flow to each. I am thinking air leak or reeds at the moment but any imput would be great

[mellow]

I can read them m8.................NGK B9ES


Sorry ;D

shouldnt they be BR9ES

[monkfish]

Id expect nothing less off you ;D ;D ;D
Had em of Norbo along with new caps, so i guess the caps have resistors in em doin away with the need for resistor plugs

[Norbo]

Only Valves need resister plugs, so they are correct mate as they are .
As Garry says on everything elce.
One flote bolle with have a small holl in the bottle . if you look at both of them you will clrarly see one has and one does not . The one that has must go on the choke carb.
Are your needles bent at all . cracks in reed rubbers ? Bent the ballance tube a lottle and look at the rubber around them is it cracked

[monkfish]

Thanks for the advice lads. So far i can say that the carbs are ballanced with the lolly sticks, I think the needles are the same but I cant remember checkin them so I will look for clip position and straightness. Ive not fitted a carb kit so I cant tell you if crapster has been used or not but I am aware of the hatred that everyone has for these kits. float bowles are the correct way round. There is no obviouse signs of wear in the carbs. The barrels are both marked 4Lo 1, I did a quick test for crank twistage using 2 screwdrivers down the plug holes wich looked fine, think i will do it again just to be sure.
I tink I will strip the carbs again and check the inlets and reeds then look at the timing although I havent got the tools or ther knowledge to do that yet ;D
Im off to stafford now but I will try n do a couple of hours later
Keep ya posted. Cheers
Andy

[bare]

I would think a Dial gauge and a degree wheel is necessary to check for crank twist.
Reeds: the Best street use reeds you can use on that engine, ...without... serious/skilled porting having been done, are the Yama 1986 YZ125 oem Fiberglass reeds.. Cheapish too and all you need do is snip off the 3rd reed for a direct fit on the 4lo reed block.
The midrange will be noticeably better and the top end will improve as well... recomended.
I suspect your carbs are knackered.. a complete strip/clean/ refit is the first step to solving the problem IMO.

[monkfish]

Finally got into the garage tonight and found that on the rich cylinder the needle clip is on #1, whilst on the lean side the clip is on #2. Mmmmm looks like someone has been tryin to correct this lopsided runner with some needle clip tomfoolery . reed rubbers look fine. I'll go back now and inspect the reeds although tbh I wouldnt know the difference between a good un and a bad un

[monkfish]

I have stripped the intakes side down to the reeds and all of this seemed very well sealed down so i am confident in saying that its not a leaking problem.
The reeds themselves arnt fully closed but are showing about a 1mm gap, is this right?? other wise they are not cracked or showing any need to replace
The reed stops are spread a little different. I measure 28mm across them on the rich cylinder and 30mm on the lean. The 28mm fits in the block without touching the sides however the 30mm has to be helped in so to speak as it does make contact before the reed block is fully seated. Will this effect anything??
I hve stripped and cleaned the choke carb again and am happy with it not showing any grate signs of wear but I think I will get new carb kits just incase crapster has been used in the past
Andy

[monkfish]

They are fibre reeds Gaz. I figure the stops shouldnt touch the sides of the inlet manifold, or should they??

[monkfish]

Got carb kits of norbo today and it apears to be runnin a bit better now....well almost. The flat spot is now between 4 and 5000rpm and although I've not done a chop yet the differential in smoke output from the pipes has grately reduced,but the rich side is still a little smokeyer.
The problem I have now is that it is cutting out intermitently at 8000+ rpm. Feels like a breakdown of an electrical component. Any suggestions as to what I shold look at next
Cheers Andy