Starting to get grumpy

[nismo]

Help! Just spent a small fortune on getting the mighty Thunderace back on the road, massive service etc and still having problems. At low revs (3k and under) and when the engine isn't under load it sounds like she is only running on 3 cylinders. Open it up when riding and seems fine once it gets above 3k ish. Also doesn't like ticking over without a little bit of choke. Any ideas? Starting to loose my patience with it now

[Teego]

Help! Just spent a small fortune on getting the mighty Thunderace back on the road, massive service etc and still having problems. At low revs (3k and under) and when the engine isn't under load it sounds like she is only running on 3 cylinders. Open it up when riding and seems fine once it gets above 3k ish. Also doesn't like ticking over without a little bit of choke. Any ideas? Starting to loose my patience with it now

Toobs or pilot screw?

[nismo]

Maybe, problem is I don't really know where to start now. Have had the bike in pieces that many times over the past few weeks changing this, putting new that on it I'm getting really pissed off with it, just want to get out riding. It may well end up in the classifieds section at this rate

[Stig]

Mine went like that after being stood for some time. Pilot jets were blocked. Roadrunner & Nuggitt came to assist and we stripped everything out one at a time, blew thro with air line and carb cleaner

[nismo]

Well just tried starting it, always used to start on the first push of the button, bit of a struggle this time but got her going then noticed a slight blue smoke out of the exhaust

[Teego]

Reason I said pilot screw is I had a similar problem in France. On the open road the bike was perfect and ran with the Blades and R1s.
In town it ran rough like a super tuned two stroke in traffic.
Took it to a Yam workshop. Checked and changed plugs (which were crap anyway). That didn't sort it. Then another techie came over and fiddled under the carbs. The outside right pilot screw had gone AWOL.
On the road five minutes later.

[nismo]

Yes, will check that, thanks. It has been stood for about 2 years so anything is possible!

Now this is where it gets weird....

Changed the oil (again) as the sight glass was changing its opinion constantly and I let my mate's retard girlfriend fill it first time round. Got just over 3 1/2 litres out of it instead of 3, so might have been the cause of the smoke. Fired her up after the oil change, struggled to start, but when it caught it was perfect. Smooth, not missing and even ticked over happily at 1000 rpm with no choke for about 6 or 7 mins, then the revs dropped and it cut out. Checked oil and coolant, no wvidence of head gasket failure.

[Stig]

Could it be running rich? Ideal for when the engines cold but then too much once warm, hence cuts out warm but starts without choke

[nismo]

Am thinking carbs too. Think the oil was just a distraction

[nugget]

You say its been stood 2 years? Has it been stood with old petrol in the carbs for 2 years. If so I think its time the carbs could do with a good clean out. If and when you do its worth putting in some new emulsion tubes while your in there. They do make a big difference to the running of it.

[Tipper2]

Have you checked the carb inlet rubbers? Could be drawing air if they're perished.

[Jay762]

second look at carbs for blocked pilot jets or carb inlet rubbers letting air in - when you have it idling spray brake cleaner around the rubbers 1 at a time - if the revs rise that one is sucking in air

[nismo]

Looking pretty unanimous that carbs are the culprit! Will see if I can get it in somewhere - carbs are a dark art!!

[nugget]

Which Shire are you from in the UK nismo?

[nismo]

Cheshire these days, just by Cheshire Oaks. Well, on the rare occasion work lets me go home