Sudden excessive exhaust smoke

[gladders]

A steady ride to the Oil Can Café for breakfast on Sunday, then up over Woodhead and Glossop and through Buxton ending up in Matlock today with no issues(about 80 miles), parked up for an hour to look at bikes and have some chips. Set off from Matlock and straight away lots more exhaust smoke from the bike, no noticeable loss in performance and felt to be running ok on the 20 miles home, noticed when I got home lots of oil residue from the exhaust on the shocks and rear mudguard/light areas including a few heavy spots.

Pump arm lock nut and adjuster are still tight, any advice/thoughts please before I start stripping things down
Cheers
Gladders

[teazer]

Could be a failed crank seal allowing gearbox oil to be sucked in, so check the transmission oil level first. If a crank seal did fail you should find oil around the oil pump from the breather tower.

Equally likely is a failed oil feed check valve on one cylinder. That could allow oil to seep into the bottom end and would take a while to burn off.

I would do a compression test and leakdown test which means taking pipes and carbs off so it's a PIA, but if it's something serious, you already got it half way stripped.

[gladders]

Could be a failed crank seal allowing gearbox oil to be sucked in, so check the transmission oil level first. If a crank seal did fail you should find oil around the oil pump from the breather tower.

Equally likely is a failed oil feed check valve on one cylinder. That could allow oil to seep into the bottom end and would take a while to burn off.

I would do a compression test and leakdown test which means taking pipes and carbs off so it's a PIA, but if it's something serious, you already got it half way stripped.

Hi Teazer

Cheers for the reply

Gearbox oil level has dropped but no oil around the oil pump, removed SRIS valves both outers check valves work but thick crappy oil coming out of the casing, centre check valve failed but oil coming out is much cleaner/thinner, looking inside the exhaust ports and exhaust pipes both the outers are wet with oily residue the centre one is coloured but much drier and looks more normal

What is a leak down test?
Cheers
Gladders

[teazer]

a moderate amount of black oil in each crankcase is normal. A larger quantity of clean oil suggests that a check valve in the oil feed "octopus" might not be closing. The simple way most of us check those is to to remove the pump and all the feed banjo bolts to get the octopus out. Fill all the lines with oil and hang it up to see if oil drips out of one or more of the lines. If it leaks badly, GTReiner sells ball and spring kits and the check valve assembly can be replaced with one form a Kawasaki triple.

Leakdown test is where you block off the inlet and exhaust and add pressure to one cylinder at a time to determine whether it holds pressure. I use https://www.revzilla.com/product_images ... 50x750.jpg but you can make a simple one form hardware store parts. there's a couple of videos on youtube. Do not exceed 10psi though or you will blow the seals.

[GTNelly]

I had a similar problem on start up and found that the fuel tap was leaking fuel into the carbs and engine.
This caused a lot of smoke on start up which then cleared after a few miles
This modern fuel (ethonal) eats the o-rings causing fuel tap failure
Ended up buying a new OEM fuel tap and problem sorted
Only found the problem when I took the exhausts off and found one full of fuel!!
Should also say that that exhaust (RHS) was a more wet as well!

[gladders]

I had a similar problem on start up and found that the fuel tap was leaking fuel into the carbs and engine.
This caused a lot of smoke on start up which then cleared after a few miles
This modern fuel (ethonal) eats the o-rings causing fuel tap failure
Ended up buying a new OEM fuel tap and problem sorted
Only found the problem when I took the exhausts off and found one full of fuel!!
Should also say that that exhaust (RHS) was a more wet as well!

Hi GTNelly
Thanks for the reply, fuel tap is working ok, bike was still smoking like a tramp steamer for the whole 20 miles home
Cheers
Gladders