Hi guys,

I have had a look through the forums at you guys running TM36-68 carbs on your 351cc kits and was wondering what you’re absolute final mid range settings were.

I’ve just installed the 351cc and have only been on one short ride so it’s still breaking in but the mid range it felt a little on the lean side.

I was running a P6 needle jet with the EBYO1-50 but it didn’t really feel right + I was worried that since I was running this on my stock bore that it might be too lean and I didn’t want to hurt the new bore. I changed it last night to the P8 needle and the standard 9DHZ06-50 needle because Bill had previously told me that he ran his TM36-38 with stock jetting....

Haven’t been for a ride yet with this change so can really comment but just wanted to know what other guys had settled with. Also note that I am at sea level with no air box lid + screen removed and a FMF Q2 exhaust.

The pilot circuit seems fine at 17.5 as I could get the lean and hot stumble so set it half way between the two.

Main jet is the stock 130 jet but I haven’t done any WOT yet so cant comment on this one until I break it in a little more.

 

is sea level in Australia the same as sea level in the states????


HA HA HA HA HA ROTFL I KILL ME!!!!!!!!

 

You found what I found. I think you will find the p8 too rich no matter what.

Stalls with choke on, black soot on fender from exhaust, twist throttle and back off, bike chokes out for an instant.

I went to the p6 with the up grade needle and its a little lean just off idle on #3 (middle) which is where I have it right now. I have been thinking about raising the needle up one, but am too happy with the 57+ mpg every tank. Plenty of power, starts good hot or cold.

With the p6 needle jet and the STOCK needle on #2 from top, it was a little lean. So I picked the needle up ONE notch and it was too rich. Go figure.

I switched to the upgrade needle and have been happy since.

17.5 pilot, 1 1/4 turn on the pilot screw.

130 main could even go to 135 now that I have the lid modified with washers. KDX snorkel, screen removed.

Home modified exhaust.

Acc pump was set for 1/8 throttle to 3/4 throttle. It has adjusted it self to about closed throttle to 3/4 throttle. I am leaving it there. It probably helps the too lean just off idle. When I twist the throttle, SHE GOES!

David

 

Thanks David,

Ill take her for a ride this arvo and see how it runs with the P8 but i think you are probably correct.

One thing I have noticed (or maybe it’s just me) is that the AU bikes tend to need jetting about one step higher than the US bikes. Might be something to do with the different spark advance but I didn’t think that this would make much of a difference.

Cheers
-Neil

 

COuld be your fuel as well. I am told you have a lower octane down under??
is that correct, I think WestOZ said that a while back.

 

Not sure on fuel.... I run a 95 - 98 octaine most of the time... I have a funny feeling that the octaine measurements are different or something.

 

you would be correct.

In the US we use a RON + MON/2 method to determine "octane".

From my understanding of conversion, you would be using mid-high grade (90-93 US) gas.

That really should not have an effect on jetting though. Higher octane really does not make any difference except for knock resistance.

 

ok so I don’t know what I did when i put the P8 and stock needle back in but I couldn’t start the bike. It would turn over but wouldn’t fire. I pulled the plug and it was pretty wet with fuel so not sure what the go is there since I wasn’t using any throttle to try and start it.

Anyway decided to pull the carb and have a look...

Couldn’t find anything wrong but though I would use David's suggestion and go back to the P6 with the rich needle but down one clip. I also readjusted the pump as it was coming on a little late and ending a little early.

Reassembled everything and bang she started up first go. Took it for a ride and its way better now... pulls nicely through the mid range… funny how one clip position makes a difference.

I’m happy with the mid range power now just need to look at the main jet BUT because i am still breaking it in I haven’t done any WOT runs yet. I ordered a 132.5 & 135 main anyway.

I wasn’t overly impressed with the power gain at first but as I play with the jetting and start to break her in i am getting happier and happier.

David have you got any pictures of your air box modified with washers? I was thinking the other day that I could get some spacers under the lid to lift it it to see if this would still give good air flow but reduce some of the noise. is this what you have done?

 

I just put 5/16" (8mm) SAE flat washers in between the lid and box. It only breaks the seal. I even used the stock screws, they are barely long enough. It did seem to help and I hear no more noise than before.

The first time I put the carb on, I took it for a ride with out even hooking up the hose from the air box to the carb. The bike went like a raped ape. Second gear wheelies just by turning the throttle. This is when I realized that air box makes a huge difference. My son says just put on little K&N on it (with NO air box) and forget it. I told him the shock is in the way.

That carb is finicky, but once its dialed in, its a blast.

You could have flooded the bike with the choke, its A LOT of fuel for that bike to fire up. No drilling of the starter jet needed. If my choke would stay at 1/2 when I pull it out, that would be enough to fire up the bike and run it cold.

Now I just pull the choke out, fire it up and let the bike run for less than a minute. I then push it back in . If I don't it starts to "lope" or just plain run too rich until it stalls. I got good at holding the throttle at a fast idle for the first stop sign with no choke. Bike does not stall cold if I keep a little throttle.

Daqvid

I had that carb off MANY times.

David

 

Neil I bought your dyno jets off you on eBay I noticed the 128 was used , I'm having a 300 kit installed at the moment what main should I run I'm in grafton nsw should I use the 128 or the 132. I am also considering the same carb tm 36-68 that you current have is it worth the upgrade and what needle jets combo would you recommend for 300cc in aust sea level.I have power bomb head and fmf q4
Your help would be appreciated