KLR riders out there

**cooneyr** · 5th July 2009, 10:49

I'm not sure where the fuel taps are on Woddys new tank but if they are in the obvious location at the lowest point in the tank I reckon you are up for a fuel pump. There is no vacuum in the fuel lines, purely gravity feed to the carbies. Problem with fuel pumps is that you need to make sure they don't generate too much pressure or they overwhelm the float needle i.e. overfill the float bowl and flood the bike.

The other thing is if you are running an electric pump you really want a solid state one rather than one with contact points. The @'s all eventually need new pumps cause the contacts pit and die. The common electric options used for the @ and KTM 950's are Facet 40105, Facet 40171 (same as the 40105 but with check valves so no need to turn of fuel tap), and Carter (NAPA P74021). No idea what they cost and my 950 got a new factory pump put in at is last service so hopefully wont have to worry about this for some time (last one did 50k km). A non electric option is the Mikuni vacuum pump that the S10's run.

Cheers R

**warewolf** · 5th July 2009, 11:02

Originally Posted by Padmei

if it's lower than carb as with IMS tank will the vacuum be enough to draw it thru or is a fuel pump needed? What probs would that create?

Probably need a fuel pump. No big drama, the 640A runs one as the carb is up near the middle of the tank. It's just a simple Mikuni one runs off intake vacuum, set up with excessive flow and high waste IIRC, so it copes with various combinations of intake vacuum vs fuel flow (edit: and probably not to overwhelm the float needle).

Originally Posted by Woodman

turn your tank into the airbox and visa versa. airbox size is important to a degree at slower speeds, but bikes still run fine with trumpets.

Mid- and high-range engine speeds I thought? ie when you have significant air flow. Air box creates resonance, akin to a two-stroke expansion chamber - amongst other things like swirl etc.

Probably more significant on multi-cylinder high-revving engines. A few years ago motogp bikes and road sports bikes were chasing bigger and bigger airboxes; much was made of this in the media. Balances the pulses between the cylinders (per exhaust plumbing for decades) and they were talking about a big "air spring" effect with the inertia of the flow and treating the airbox as a big reservoir of controlled air. Dunno what the story is now - have been too busy riding dirty bikes to be interested in the latest poofteenth of performance gain on sports bikes - but they are putting trumpets inside the airbox... having your cake and eating it, too.

That's not to say it isn't important on our singles. There's a fair bit of debate and confusion about snorkel in/out and performance airbox sidecover yes/no for the LC4; the dyno-proven camp was saying "keep the snorkel" and DIYers were saying "take it out". The latest info says that the pre-'03 (aka low-flow) head needs the snorkel in per the dyno, and the post-'03 High Flow head needs the snorkel out.

Almost all dyno testing I recall - especially that by exhaust builders who are trying everything to maximise the gains from their stuff - shows little or no mods to the airbox is best, for mildly tweaked bikes of course. Often opening the airbox results in mid-range losses, with the commensurate steep climb in power back up to the standard level when revving past the hole. Seat-of-the-pants tuners feel this steepness and mistakenly believe they've made massive gains to the top end by "removing that restrictive airbox". Way out of date seventies thinking, that.

**Box'a'bits** · 5th July 2009, 11:14

On the Gilera, the fuel system runs a vaccum fuel pump set up to pump too much fuel. The fuel goes from the backbone mounted tank, up to a much smaller tank set at a level above the carb, which allows a gravity feed. That smaller tank also has a run off back to the main tank, to avoid any pressurisation impact.

Steve.

**Woodman** · 5th July 2009, 21:46

Took the bike for a short run today, (can't say where exactly as the location is subject to a current tagorama ) with lots of mud and rocks and river crossings. Anyway it seems pretty good and possibly a bit wider where my knees usually go, but this could be that i was wearing mx boots with a thicker sole than my ususal road boots.

Put about 15 litres in and the bike seems way more stable than usual due I think to the fuel sitting way lower. I don't think it is my imagination or a case of farkle justification , it really did feel more stable and a couple of times when I thought she was going down it seemed to right itself. Once going up a very steep hill that had to be aborted and turning back down I lost me footing a bit and it didn't topple over as expected. Could also be the lost weight going from metal to plastic.

**marks** · 7th July 2009, 08:58

Have any of you KLR'istas regreased your steering head bearings?

is there any drama involved?

I've got the fork legs out of mine at the moment and was wondering if I should do it will its in bits (bike is 9 months old and has 18K)

cheers

Mark

**Eddieb** · 7th July 2009, 16:52

**warewolf** · 7th July 2009, 17:01

Originally Posted by marks

Have any of you KLR'istas regreased your steering head bearings?

Can't answer specifically for KLRs but yes it is a good idea, especially when you have the fork legs out already.

The biggest pain is usually man-handling the top clamp if you leave the handlebars connected.

**Woodman** · 7th July 2009, 17:05

The other day when I was fitting me new tank and was wondering where to put the vent I noticed that the top nut on the steering head was loose, in fact it was so loose the only thing stopping it coming off was the handlebars. I tightened it up and the front doesn't seem to shimmy now under brakes.

**pete376403** · 7th July 2009, 18:57

Originally Posted by marks

Have any of you KLR'istas regreased your steering head bearings?

is there any drama involved?

I've got the fork legs out of mine at the moment and was wondering if I should do it will its in bits (bike is 9 months old and has 18K)

cheers

Mark

Its ok but it can be awkward if you have the bike on the sidestand (really should have put it up n the axle stands and used a block under the engine). Dropping the forks down was easy, getting them back in was a bit messy. The bearings were quite dry, reason I noticed that was the rust streaks on the front guard

**marks** · 7th July 2009, 21:51

As I have a center stand and can support the handle bars from the carport roof it should be 'do-able' so I'll give it a go on Saturday.

Thanks for the answers.

**warewolf** · 7th July 2009, 23:30

Go under the head stock of the frame, not the handlebars. The handlebars have to come off, separated from the top triple clamp or not.

I'm sure you would have figured that out.

**marks** · 11th July 2009, 16:26

steering head bearings all cleaned and greased (were a tiny bit loose)
sparkly new set of 606's fitted
new fork oil and intimininimanaminator thingys fitted

what a difference the intiminy thingys make (thanks oh nordick one for the write up that made me try them)

the klr had horrendous fork dive under brakes - its simply gone. Front has firmed up a bit - don't think I'll need spacers or stronger springs now. Be interesting to see what its like off road.

all ready for mmmm

roll on Friday the 24th

**NordieBoy** · 11th July 2009, 21:57

Originally Posted by marks

steering head bearings all cleaned and greased (were a tiny bit loose)
sparkly new set of 606's fitted
new fork oil and intimininimanaminator thingys fitted

what a difference the intiminy thingys make (thanks oh nordick one for the write up that made me try them)

the klr had horrendous fork dive under brakes - its simply gone. Front has firmed up a bit - don't think I'll need spacers or stronger springs now. Be interesting to see what its like off road.

Finally put the Eibach springs in the front today with 10mm of preload. Will see how they compare tomorrow.