Hello. I have a problem with my TR1 and I need help. When I start my TR1 the engine very quickly increases revs to full throttle. I have to switch the engine off very quickly to prevent it overheating. Throttle and choke cables move freely. When the engine is uncreasing in speed the carb slides do not rise. I stripped the carbs. The carb internals have been cleaned, the jets are clean and the sliders move nicely. I replaced the carbs and if anything the problem is worse, the engine just revs quicker. I suspected air leaks between the carbs and cyclinder heads. I checked the carb manifolds, they look good. I even placed a gasket between the carb manifilds and the cylinder heads in addition to the rubber gasket.. That made no difference.
Is there any diagnostic measure I can take the isolate where the problem lies.
Does nyone have an idea what the problem is?
Thank you in advance for your help.

Hello Jurgen

First - thanks for your help with this.
I have checked the items you mentioned.
1. The cables are free of tension. 2. The throttle is closed on both carbs. 3. If I remove the HT cable from each cylinder in turn. The rear cyclinder runs fine. The front cyclinder coughs and splutters and if I open the throttle it dies. Does this mean it is running too rich? 4. The linkeages between the carbs are free and running smoothly.


Hello Andy

I have cleaned the carbs insode and out. Also the linkages between the carbs are free and appear to be moving correctly.

Hi,
first question: is the throttle cable free of tension? Right placed at the carb and other side?
second question: are the throttles of both carbs closed?
third question: are both cylinders causing this issue? take off the spark plug caps, one by one to see whether is's just one cylinder causing the issue
fourth question: is the linkage connecting front and rear carb (between the carbs) moving free?

maybe this helps,

Jürgen

I have a similar phenomenon when I start the motor rotates normally and calmly.
After about 500 the motor begins to spin faster, without which I give gas. I then cleaned the carburetor from the outside, and all newly oiled.
The small role between the carburetor tends to wear out after many use it slowly and then bit pinched it, so the carburetor for the rear cylinder receives more fuel mixture. It is important to know because the rear is the # 1 cylinder and thus the working cylinder is the only makes everything turn.
Good luck with your search


Andy  ;)

Perhaps the engine gets fuel through the airtube of a gasoline cock? Could happen if the diaphragm of the gasoline cock is damaged. Dismount the airtubes and close the holes, than start. Also the float valve in one of the carbs can be leaky. This would cause the same result.

Olaf

Hi again,
I have a problem to understand what's wrong with your bike - it seems that everything is ok but the issue is still there. I think its worth to check what Olaf mentioned. Another issue from my own history comes to my mind: some years ago I fitted a higher handle bar to the bike. This one was causing the throttle to open when I turned the steering to the left because the throttle cable was too short. Turning the steering to straight closed the throttle. So the question is whether you changed the routing of the throttle cable recently.

Jürgen

All

I would like to thank you for your help with this problem.

I checked everything that was advised. The carbs were stripped again. The throttle cable is not tight and causing the problem. I have discconneted vacuum hoses. The petrol taps have been stripped and new refurn kits fitted. I also found two very small holes in one of the diapragms, I made a temporay repair but it did not change the symptoms. None of this worked.

In the end I purchased two sets of gaskets and jets for the carbs. I also replaced both diaphragms.

I stripped both carbs and installed new jets, gaskets and diapragms. I found nothing wrong during this process. The carbs were clean and no obstructions in the jets.

The carbs are now back on the bike and it works fine.

So, thanks for all the help but I never did find out what caused the problem.

Thank you. Kevin