Monster 695 - Rich One Cylinder, Smoke Exhaust And Very Hot!

Hi! So after some guidance. I’ve been fixing up a monster 695 (2007) which has recently passed its MOT and become an actual motorcycle again. Bikey sat in a garden for 10 years so we’re still uncovering some problems however last night went for a ride to try and build some trust in the machine. Bumbling along when the fuel light came on so started heading for a petrol station. All was going well until the rider behind me and I saw some smoke from the exhaust. We’d just been sat in traffic so things were a bit toasty, but it’s 9degrees Celsius outside so not a hot day. Pulled into the station and put a couple 5 litres in. Smoke isn’t bellowing but if I blip the throttle there’s a definite puff and on idle it looks a little like a bike warming up on a cool day. Hard to tell the colour due to fading light but at a push, I’d guess white to grey. Also noticed smoke coming off the outside of the bike too but I’d just used ACF50 so not surprised. The bike did seem really hot to the feel (and smell) though. The other rider, also a 695 was showing somewhat lower temp on her dash. Rode home... scratched head.

Here’s some considerations:

when I got home I opened the filler cap and noticed a ‘whoosh’ not dissimilar to when your breather gets blocked. Low and behold, possibly due to excess heat, the breather tube had melted shut on the vertical cylinder fins. I’d just replaced the tubes with black vacuum tube so it could be inferior quality but either way, it lead to a vacuum in the tank.

Secondly a few days before all this, I pulled the plugs for inspection and noted that the vert looked good and the horiz looked a bit black. After last nights ride I pulled them again and it looks somewhat blacker. Not noticeably wet, more of a satin finish and doesn’t wipe off. Pic attached for context. Does the other one look lean?

Tested for spark with plug against cylinder and it seems fairly strong.

Put a long screw driver to each injector and the other end in my ear and each has a similar ticking sound on turn over.

Compression test gave good results.

where do I go from here?

my thoughts were initially that the heat was caused by low fuel coupled with melted breather making the fuel pump less efficient leading to a lean condition. Would explain the heat but not the black plug and not the smoke.

second thought was stuck open injector thieving fuel from its counterpart leading to rich in the open one and lean in the normal one. I think the horizontal cylinder gets fed fuel first so that seemed logical but the ticking sound suggests to me that it isn’t stuck open.

bit lost...

 

Forgot to mention that on occasion (3 times maybe) I also experienced a sudden very momentary loss of power which was coupled by what might have been a pop from the intake.

 

Just been out for a ride. Still doing it. Noticed that it only seems to do it when the temp is up to 90+ Celsius. Also seems more prevalent if the bike has idled for a while. Here’s a video. Afterwards I rode home on a dual carriage way so circa 60mph for a couple of minutes and when I got home it wasn’t smoking any more. By the time I’d garaged it it was starting to smoke again.

https://youtu.be/q5JC_zJkO2k

 

Thanks for the reply. I guess parents always worry about the children

Yea, there was another thread about that but in summary it had new belts, filters, oil (twice), plugs. In hindsight I didn’t do the fuel filter because I couldn’t figure out how to do the clips on the hose. In any case I would expect a blocked filter would lead to lean and not rich. Fuel hoses were also replaced and the old fuel was in surprisingly good shape. Nevertheless the old fuel was drained and replaced and it’s had two tanks with injector cleaner. Before starting it was turned over with the starter without fuel/plugs and it was fine at that point but on first start up we found that the horizontal cam was ever so slightly advanced. Not enough to cause contact but it certainly let me know about it. I’d anticipated problems with valve seals as a result but this doesn’t seem like oil to me. More of a fuelling issue.

 

Thanks, appreciate your help. My hope is that won’t be the case (obviously) and that’s based on my belief that the plug is black due to fuel fouling and not oil. It’s hard to tell but everywhere I look describes oil fouling as leaving wet deposits and these are dry, slightly glossy black. I.e. it doesn’t wipe off. Ive swapped three plugs and will see if the other one turns black as a confirmation that it’s that cylinder. I suspect that the vertical cylinder is running quite lean because it feels noticeably hotter and the plug is whiting a bit. As the o2 sensor is downstream from the horizontal, if it’s excess fuel it would make sense that the ECU was trying to combat it by leaning things right? So maybe the vertical cylinder is responding to its instructions and the horizontal one isn’t. I did notice that after my brief ride today that the plug hadn’t darkened since last night so who knows. Sorry for the info dump but I figure if someone can help the more info the better.

 

Sounds logical to me. Thanks

 

So no progress has really been made. I’ve continued to tinker and try to find a solution and ultimately given in and booked in with a specialist. Whilst waiting for the booking I thought I’d treat myself to an inspection camera and had a poke about. Noted this line on the intake side of the casting around the vertical intake valve guide. Not sure if it’s a crack or a casting imperfection or scratch or something. Is this a common place to have a crack?? Note that as this is the vert, it isn’t the one blackening the plugs.

 

Thanks for the reply, could I get an opinion on this too? This is the horizontal piston face with the intake valve recess at the top. I’m a complete novice but this looks to me like the valve has ‘cleaned’ the piston face during contact?? (Top right)

 

Haha yes, you might be right. Bikerchondria. So I’m thinking it may be relevant somehow as when the bike was first started up we found that the horizontal timing pulley was advanced about half a tooth. The adjustable pulley had been adjusted so that even though the pulley marks all lined up, the cam was ever so slightly out. It turned over by hand without noticeable interference but in start up it sounded like hell. I’m wondering whether it’s all linked.

 

Thanks, I was just replying to another comment re-timing. Compression test seems ok. I’ve done it twice and yielded acceptable results.

 

I replaced the fuel lines but nothing in terms of adjusting.

 

yep, that’s the one. I started a new thread thinking it wasn’t related because everything has ‘seemed’ to turn out ok with the timing. It sounded like the interference (if any) was very minor and not likely to have caused any damage.