[KarthikK]

I didn't find any other related thread so started a new one. As the title suggests, the problem I am facing is a stuttering thunderbird twinspark at 1500-1800 rpm. Let me elaborate a little on the problem - I never had this issue until yesterday evening. This happens only in the first and second gear for some strange reason. When stationary, I engage first gear and release the clutch and accelerate simultaneously (as usual) but when the tacho hits 1500 rpm, the engine seems to stutter a bit. The stutter feels exactly like how a bike behaves when the fuel supply is drying up. When the rpm crosses 1800, engine resumes normal acceleration. Same issue occurs with second gear as well.

For the record, I got my T-Bird serviced 2 weeks back. I haven't yet taken it to the RE service centre to look at this problem, since I needed the bike today and tomorrow. What do enfield gurus here think the problem could be? Any help would be appreciated

Additional details -
- 2008 model, done 5400km on odo, last serviced when odo was at 5100km.
- I do not shift at half clutch. Also, clutch is fully released when this problem occurs

[adrian]

Hi KarthikK, First things first : I am not a bullet guru

Is your bike showing problems between the said rpms when revving in neutral as well?

[bradhey]

@ KarthikK: These RPMs are very close to idling RPMs. You can check your Spark plug and clean it, Secondly, you can have your Carburetor overhauled and cleaned. I am not aware if these new carbs have a separate pilot jet circuit or not...but it could very much be a case of your slow idling circuit not funtioning correctly.....!!

[bblost]

Check if the rubber connectors between the airfilter to carb and the carb to the engine disturbed?

[KarthikK]

Thanks all for your suggestions. I will check what bblost and bradhey suggested. @Adrian - no it does not happen in neutral gear. Idling is set to 1100rpm

Meanwhile, noticed a few more symptoms of the problem while using the bike yesterday. I will post them here anyway, in case it helps someone else :-

- The stuttering seems to occur only in the first 5-6kms after the bike is started up. Once engine is warmed up nicely, problem disappears. Any thoughts on how this happens?
- The problem occurs in all the gears now, but the jerk is most noticeable in the first and second gears.

I'll update the thread after I check the carb and rubber connectors

[adrian]

@KarthikK : Looks like a carb issue as bradhey said. Get it serviced and tuned ASAP and it seems like your bike is running rich and that is why the engine runs smooth after it has heated up.
Regards Adrian

[dhanushs]

Karthikk, I think its a spark plug issue.

If not, check the A/F ratio and tune if necessary. How is the FE?.

[bblost]

Its not easy to service a CV carb.

Also check if the air filter is dry.

[vivekchugh]

Friends,

I recently bought a new RE TBTS a couple of months ago and after the first service and 700 kms done on the odometer, I took it for a long ride (450 kms) from Goa to Hampi and back. I didn't ride beyond the stipulated 70 kmph except for 2 or 3 occasions where I touched 80 kmph.

During the trip I found that the TBTS started making a very loud thumping (like farting) noise. And it just seems to grow louder by the day.

This came as a surprise as the new REs don't normally have a thumping noise. This is abnormally loud to the point where it scares people on the road.

Would anyone know what is likely to be the problem?

Vivek

[Randhawa]

I think your issue is with the carburetor (too rich or lean) or you have a leak some where in the exhaust. Whats the mileage you are getting and does it hesitates during acceleration? Does it makes the noise while acceleration or deceleration ?

[ArizonaJim]

Well, if I heard a RE approaching and it was making a far**ng sound I might be scared too. At least, I would try to stay upwind of it.

Seriously, if your TB has a rubber intake between the carburetor and the cylinder or a rubber tube between the carburetor and the air cleaner you might want to check them to see if one of them has developed a crack.

With the engine running try holding the back of your hand close to where the exhaust exits from the engines head. (Of course I don' have to tell you not to burn yourself.)
If you feel a "puffing" blast of warm/hot air you've found the source of your flatulence.

[Karlitoz]

Point #1 Did you get you batteries replaced recently ?
Check Air filter and spark plugs for any blackouts.
Also check if the spark plug is a bit oily or is it just blacked out ?

[jeeva]

Originally Posted by KarthikK

- The stuttering seems to occur only in the first 5-6kms after the bike is started up. Once engine is warmed up nicely, problem disappears. Any thoughts on how this happens?
- The problem occurs in all the gears now, but the jerk is most noticeable in the first and second gears.

Feels like its an issue with the current. Check the Rectifier-Regulator (RR) unit and the spark plug(s) gap.

[simplynitin]

I have the same problem with my TBTS. I got the bike serviced in August 2011 and undertook a Bangalore - Coorg - Bangalore trip couple of weeks later. The problem surfaced after this trip. Although its very intermittent and doesn't always happen even after a cold start. My first impression was that it was an air filter issue. As I will be giving the bike for servicing in first week of November(a long trip coming up in Dec), I didn't investigate the issue further.

Another small but very irritating issue I am facing is with the front brake cable. TBTS has a kind of rubber loop attached to the front mud guard through which the cable passes. My problem is that cable sometimes comes in contact with the front tyre. The front tyre has got a nice big ring where the cable comes in contact. I have tied the cable to the outside part of the loop to create as much distance as possible between tyre and cable. No luck. Anyone has any ideas/jugaads/workarounds?
The cable isn't too loose either.