R-27 with broken timing chain; can I replace without pulling the motor ?

[Grant R26]

Last evening I was cruising in low 4th gear and suddenly nothing. Engine entirely dead yet electronics still live and operative

I find now that the engine turns over but the valves are not moving so clearly the cam shaft is not rotating. Looks like my timing chain is broken

It is a low mileage motor but since I got it, it has had a noisy rattle to the front of the engine. I assumed that was part of the charm of the engine. My R 26 has an entirely different tone to it.

In retrospect, looks like the chain was on the way out.

So, should be no problem getting a new chain from Vech at Benchmark plus whatever else he deems needed for this job.

My shop manual only shows the replacement procedure on the workbench but I don't want to go to that extreme if I can help it

Can I do the replacement job with the engine still in the frame ?

Has anyone out there tried this ?

Thanks for the help

Grant in Toronto

[Grant R26]

All's well that ends well

My R27 is back running beautifully again and the engine sounds smooth and reliable

The master link gave out. The 50 year old original timing chain looked perfect but I replaced it. total cost $55 with the chain tensioner.

But some work involved in removing the engine, installation and reassembly. Runs beautifully now except I still have some fast idle issues

Once the engine is hot, it idles fast. Turn off ignition and immediately restart and idle is still fast so don't think it is an advance weights or timing issue.

I'm convinced my throttle slide is sticking when the carb gets hot.

If anybody has any experience with this on a basic r26 or r27 Bing carb, I would be grateful for input

Elsewhere in the forum I've put in a request for anybody with experience with Blitz Bing carb replica...but no luck on a response there.

Apparently there used to be a guy up here in Canada who machined and installed new sleeves on these older Bings but no more. the only advice that Vech could give me was either get used to it...or upgrade to a type 53 Bing. I have a Type 53 on one of my R26 bikes and it is trouble free but want to keep things "original" if I can

Bing no longer sells the throttle slide for the R27 carb. No problem getting the jets, float and needles but not the slide.

I'm contemplating 1000 grit and power buffing the throttle slide in the hope that I can buff off whatever high spot is hanging up on the cylinder wall of the carb...

Any ideas or advice anybody ??

Thanks

Grant

[Grant R26]

Correction !!

Re the last few lines in my comments immediately above;

I was speaking to the incredible guys at Bing today...and they do indeed have the Bing throttle slides again for the R 26 and R27 Bing carbs.

Apparently they managed to get them made again. this is great news as all of mine were showing some wear.

Bing is great to deal with and if you dont already have a Bing carb manual, get one. they are cheap and very thorough.

Grant in Toronto

[c.d.iesel]

yea - and you didn't want to emory the slide as ANY metal removal
just makes the clearance greater and your increasing the 'wear'
and poor metered air flow. So order a new slide, and needle while your at it.
Look closly and see wear on the needle lower end where most of the
wear occurs as it scrapes the needle jet. Order a new needle jet also.
All these tiny details equal better adjustments, better power, smoother
running, better MPG's. Happer motor

so your racing idle may also be a throttle cable without enough
freeplay when OFF?, or a poor slide return spring?, a binding slide
spring? order a new slide spring - why not?

if your slide is sticking up due to poor spring, or to tight
throttle cable, then your timing advance will also open and advance
adding to the high idle.
When all the parts are replaced in the carb that are worn,
try to keep the idle speed low while adjusting the idle mixture
for best, smoothest tick-over.
You ignition timing should be set correctly
FIRST before any carb adjustments!

you'll be amazed at how easliy it will start once all the correct
adjustments are made to valve clearance, timing, jetting,
float level, idle speed & mixture.