Hello All

I am suffering from what we call in the UK 'the Corona virus effect'. We are in lock down and I have run out of jobs. Really I have done all the jobs I have wanted to do and am now doing the jobs I have been putting off.

One of my engine mounting bolts has broken off. It is the one that sits through the left hand foot rest plate, just behind the main drive sprocket. The end 10mm of the bolt has broken off and I need to drill and tap the hole. I have started to strip the bike and have two questions:

1. Do I really have to take the engine out? It looks like it. I could use a long drill to remove most of the broken off bolt but I don't have a tap long enough to go through the engine casing.

2. What thread is this bolt? It is a M10 bolt but the thread is finer than a standard 10mm bolt. I have a set of metric taps and the 10mm tap I have is a courser pitch than the bolt. I hope that makes sense?

If anyone knows an easy way to do this please advise.

Thank you
Kevin

Hi Kevin,
if you want to do a proper Job you have to take out the lower frame.
However, is the rest of the bolt still in the nut? When this happened to me first time, I was able to remove the small rest with a thin long screw driver turning it clockwise to the rear open end, and the thread was clean so I just had to replace the bolt.
Thread is M10 x 1,25, as all M10 bolts at the TR1.

Jürgen

I once removed the broken off tip of the bolt by putting a piece of 10mm tube into the hole and then drilling with a long 8mm drill through the tube into the bolt-tip. As i hoped the drill got stuck within the tip and screwed it through so that it fell off under the engine. The thread was still good and i just had to mount a new bolt. A friend made it for me at work.

Hi Kevin,
I‘m riding my TR without that bolt for about 10 years.
I think you can ignore it.
greets babsch

Hi Kevin,
i know some people ride witout that bolt a long time.
I would fix it. Especially when the Bike is on the Mainstand, with some luggage, and when the Rider sits on it to start, (i often saw that),
the lower swingarm frame / the bolts are really stressed.
I took off the lower (swingarm-bearing) frame piece, and put some heli-coil repair threads (10x1,25) into all 3 bores.
Engine - with some piece of wood underneath- and mainframe /rearframe don´t have to be removed, only the Swingarm and the lower frame
Hope to see you this year,
Ali

Hello All

I have been riding without the bolt for three years so thought it was time I fixed it. Anyway with the Coronavirus about I have nothing better to do!!

I tried George's method of using a little tube and an 8mm drill bit. It would have saved me a lot of time if it worked but it didn't. The bolt end was very tight in its hole.

So I had to remove the lower frame. I have a small hydraulic bike lift which works very well. I could see I had drilled part way through the bolt but it was tight in the hole. The bolt goes through the hole and leaves about 5mm the other side. I was able to put a pair of mole grips on the bolt and wind it through. I didn't have to drill and tap it.

I am now cleaning things up and assembling again.

Thank you all for the advice. Please see photo's. (Sorry they are out of focus but you will get the idea.)

Kevin

It's all done. Thank you for your help.

Kevin

Hi.. I have two of these TR1 and both came with the bolt broken.
Its caused by the drive chain being too tight when set by the book.
I set the chain adjustment off the stands loaded with rider and luggage.

Hello

That fits. Prior to the bolt breaking I had to replace the chain. The symptoms were that when  the rear wheel was rotated it tightened and went slack as it went around. Brian New, a friend of mine, said that's a sure sign of the chain being stretched. I replaced the chain and the problem went away. Thank you Brian.

He didn't tell me the bolt was likely to break!!

Regards
Kevin