Possible Surging Fix

ApexGT · Nov 4, 2010

Hi all, I know a lot of you are having surging issues like me with my 2006 Gen.II, mine started in Aug.'10, the classic 2000-3500

rpm range intermittent stumble, synced the TB's,still there, then it really looked like the TPS but it checked out good.

Then I checked and cleaned all but 2 of the grounding spiders and every other wiring plug connecter I could get at.

I started to change the plugs today and found a failed #4 plug cap,when I accidently pulled on the plug wire where it

goes in the cap ,it pulled out, they are actually screwed in and shouldn't pull out, I found a ton of corrosion in the wire end

of the cap and then noticed the screw in fitting in the plug cap broken off in the plug wire.

I just ordered a new plug cap (full list $68.00) OUCH !! My dealer in Sault Mi. is great, gave me a great discount.

most online dealers will sell them for about $50.00 I'll get the new plug cap on Nov. 9th and post the results, I love my FJR but this

problem is driving me nuts !!! If this is the fix, I'll be one happy rider. (crossed fingers)

Slappy · Nov 5, 2010

Actually Apex they are suppose to pull out. I broke a plug cap trying to remove it while it was still very warm. The plug cap is nothing more than a donkey **** with a cap on top. The wires are hard wired into the coils which are elsewhere. The $68 just pays for the donkey **** and cap not new wires. New wires are part of the coils and they are going to run around $100 each coil.

BritFJR · Nov 5, 2010

I had the same surging and rough acceleration and tried the cleaning connectors route with no success.

I looked at FredW's posts on the his TBS syncing method and it prompted me to adopt his 'balancing the cylinders' with each other when doing the TBS. The tank is up already to do the TBS so why not adjust the three other screws to balance the cylinders. Made sense to me.

The following method does work and made my FJR silky smoooooth and the surging's gone away big time!

FJR1300 Throttle Body Sychronisation

Run Engine to warm up to 2-3bars.

1. Connect the vacuum gauge as normal for a TBS to the four take-off points.

2. With a flat bladed screwdriver - screw in the four throttle body screws gently to lightly close/seat them, also turn the engine idle screw (at the rh side of the tank) a couple of turns clockwise.

3. Start the engine and adjust idle screw to obtain 1000rpm.

4. Locate the Butterfly Throttle Plate adjustment screws (crosshead screws) there is one for cylinders 1&2 another for cylinders 3&4 and a third to adjust cylinders 1&2 to cylinders 3&4). FredW's posts pictures showing their location.

Using cylinder 3 as the reference adjust cylinder 4 to 3, then cylinder 1 to 2 and finally the third screw to balanced 1&2 to 3&4.

The engine will need to be stopped and started a few times to open the throttle, as the third screw to adjust 1&2 to balance with 3&4 is only accessible with the throttle held open (it

rotates round into view on the throttle cable linkage). During this procedure the idle screw may need to be re-adjusted adjusted to maintain

1000rpm idle speed.

5. When everything is giving near level readings across all cylinders use the flat blade screwdriver again and open each of the TB Air Screws (previously closed in step 2) on all Cylinders out 1 & 1/4 turns and start the engine again. You will need to ramp down the idle screw to lower the revs to a 1000 - 1100rpm idle.

Take a look at the vacuum gauge levels and tweak the TB air screws as required to level things off again. Rev the engine a few times and make any fine adjustments needed to obtain a

good balance (-+10mm Hg). (you won't have to adjust them much from their 1&1/4 turns)

All Done.

ApexGT · Nov 13, 2010

new spark plug cap/boot has solved the issue.

Anyone having stumbling issues,try unscrewing your plug wires from the caps and check

for corrosion and broken off screw connectors in the cap