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Discussion in 'Thumpers' started by MCmad, Jul 14, 2008.
You certainly have some sort of magic. You've gotten more photos out of Rob in one go than his entire total since he's been on the thread. Well done.
Rob, thanks for the photos.
Refresh my memory on one point. On your Green/Yellow bike you are using the CR carbs from Stefan, correct?
Did you ever try that airbox with the standard CV carbs?
The photos illustrate just how many items Suzuki managed to cram into a very small space.
Ray the yellow bike I now am using tm 36 mikuni pumpers.
Before these I used the BST 33,s and no air box at all at that stage the bike was a 750 I lost a little bottom end but gained a bit on the top end as was running a open pro duo and large header pipe the bike went quite well and earnt the name the yella terra .
My belief is to keep the volume between the carbs and the air cleaner the same as the volume and bigger than the bore and stroke ,I used a DR 650 foam filter but ended up taking off the filter skin.
This filter must be be similiar to the air intake of a standard paper job to keep the over all vacume the same, more air at the top end revs won,t bother the 33,s Early in the piece HRT ran a 650 filter in a air box with the whole side cut out so I thought I would try that as a starting point thingy.
Ray if you at at page 940 one of the pic,s I just posted of the blue bike you will see the air box and filter cage but no paper , I made a foam filter to fit inside works ok and not looking for massave amounts of performance I think it is as good as standard job but at least I don,t have to remove a tank to get it out and clean it very versatile .
I'll have new valves (all four) top end gasket set and new piston in few weeks. Piston is 2nd oversize (100) with rings from hessler (like other parts too).
Valves will be third set (when counting originals too) in this engine. Shlould i change valve guides (or how they are called) too? Is there a way to check it easily? i need to take it some shop anyway with cylinder, but it woul be good to have all parts ready.
I start to regret i sold the cylinder head from donor 800 engine
Rockers and cam have been changed some 40 - 50 000 kms ago, seemed not new but ok.
great pics Rob!!
a few of mine with new additions.. quick throttle & aluminum skid plate
Just putting up a quick wanted AD i need the two top 19mm nuts that are on the top of the forks (sr41 sr42 ) mine have been badly rounded ,So if you have a scrap set of forks I"ll buy the top nuts from you .Thanks If someone needs another part we could do a swap !! i have some spares
Just a little tip for you , only use suzuki valve stem seals, the after market ones go hard in no time.
3 sets of valves why , maybe tappet settings could be a little tight, and or runnung a little lean, have a look at the colour of the carbon on the valves may help you determin whats going on.
Jabroka , long time no here since the trip to suthh aaafrica, Its good to have a bit of use full bling , I still like that muffler with the colour co/ordination .
I've used only suzuki valve stem seals and orginal mikuni parts in carbs, learned that hard way...
original valves were replaced when there was some 60 000km in clock, also pistone was replaced by first versize 050 then. I rebuild engine bottom at 85 000 km (if rebember rigt) the top end was like new.
No I have damaged cylinder (heavy oil consumption) and damage in valves. And yes, there were some carburetor problems and some serious overheating while offroading... i was riding too lean.
So i think your dianosis is right.
I'm just wondering how long these valve stems last? Seals for those are easy to change but stem itself reguires some professional help.
Appo ,when I bought my orange bike it was in very poor condition but still was rideable the piston would knock something terrible untill it warmed up I am just giving you an Idea how things were when I got it.
Now it looked like to me the head had never been of it, I did replace the exaust valves only and new stem seals on all 4 valves.
My point is this bike is running with no problems because of other work I did to the motor the valve guides have never been replaced and it has done 142k
If you can feel play in the valve there probably stuffed.
Can anybody remember the odd front wheel bearing size? Some bikes use an identical pair and some (mine included) run a smaller diameter but wider bearing in one side. Last time I made it up from two thin ones. I can't get in the garage to measure it at the moment.
well i finally got around to cutting the side out of a spare filter and seeing if it makes a difference.
after i cut out the triangle, i ran a bead of silastic around the cut edge to make a rounded profile to reduce turbulence.
this mod is worth doing along with 125 mains and richening up the needle.
with the jetting mods and stock filter there was a slight increase in performance but was still flat up top.
after the filter mod, this thing pulls hard all the way to 148k/ph and was still pulling hard but i was running out of road:eek1 this is a definite improvement. i thought the old girl might be getting a bit tired but after today i think she still goes allright
Rob, that yellow bike of yours must be impressive
Gidday Simon, she,s a goer mate, hey there are about 10 or so blokes staying here friday night the 15th to Sun sun the 17th with a ride on the sat 16th remember last year we called it the Turon River Classic .
Are you comin over give us a ring and I will give you the details.
Any of you guys knows if SR43 camshaft will fit into SR42 head and do its job there?
I know the timing and lift is a bit different but other than that?
As far as I know they are identical for fit and use.
The exception is the "A" style cam from the UK that has a bit earlier intake timing than the "B" style from Germany.
I think you get a few more HP with the "A" style. it should be stamped on the cam end where the cam timing marks (that line up with the head casting) are located.