Glens Hybrid dreambike

[Glen]

first race day every is over and im still smiling ear to ear

still lost every race but the bike went fantastic. the performance is easily on par with all the euros out there (i chased a ZPF powered banshee and GRC RR down the straight and was dead even on them) and the T43s clinged on all day, i only crashed 3 times because i dived over the ripple strip and lowsided it cause i didnt hang off the bike enough.

having a quick look over the bike its all still intact. top end was running strong so the jetting seems good and all the rest. amazingly after eating 3 sets of clutch shoes i finally got it hooking up good. you have to set them to engage MUCH earlier then i thought..

only problem that is still there is the very low speed bogging (occasionally) and it doesnt return to idle very fast at all it takes a heck of a long time. so i might fiddle with the mixture screw.

also found the foot peg brackets are total Shyte on the dreambikes after i shattered off 3 sets so ill have to CNC some up from Bisalloy steel and get some metal meathooks off *shudder* PBU. i wasnt leaning off the bike enough in the early races and busted off the pegs when they dug into the ground. and in the final i lost a peg all together and did the whole race with my foot on the stubby bolt XD

gearing is way too short at 7-68. its peaking out about 20m into the straight.. so ill have to chuck it down to 7-65 or 66. the Bzm powered blata was running 7-64 and it was the most unbelievably fast thing ive ever seen

so yeasss im very eager to get out and practice my turns. i need to scrub 4 seconds off my laps times to be up with the front runners hahah but i can definitely see where those 4 will come from!

time to start looking at the full bzm motor now me thinks.. 8 petal reeds.. gold crank... excellent.

[mac90]

to sort out the low end bogging you could try lowering it 1 jet size or buying a set of jet drills & lowering it by .05 or whatever the jet drills allow & keeping a eye on the plug

im unsure if the bzm has a fine ajustment on the needle to fine tune the mix, ?

i do know of jap race carbs with after market needle kits, had different length & tapered needles for extra fine tuning but it sounds like u got it sorted out

as for the bike taking longer to idle down, this could be a sign of a ritch mix (do the bzm carbs have a idle jet + main ?) or a tight cable even good quality cables will be stiff if kinked or routed so they bind

this is where electronic mixture tuning equipment is gonna come in handy & the tacho & digital vernias to fine tune the clutch $

we dont see much of the good engines down this way, the best iv seen here was a stock b1 rep from toowoomba pocketracing when he imported a container load

[Glen]

yeah the bzm carb is just a dellorto, it has the idle mixture and speed + the needle. i tried all needle settings before so i think i need to try a different needle all together idle jet is a 50.

just stripped the bike down and no cracks in the frame so good stuff! only problem has been one rear sprocket bolts a bit looser so i tightened that up with a bit of loctite.

also going to remake my exhaust mount using a rubber spacer instead of a metal one to stop the vibrations. theres a fair few coming from it.

plug looks okay. coffee colour on one side and a teeny bit sooty on the other. but that maybe from the non stop idling and testing from before..

so yeass all good! VEEERY HAPPY

anyone know a good cheap tach? i looked for some tiny tachs but couldnt find any sub $150. and i might as well get a gp chrono for $180 at that money

[Glen]

well heres the plug - a little lean but thats cause i was running 30:1 oil and fuel so ill knock that up to 50:1 to richen the mix some. else ill try a 104 jet.



also started work on porting out my 620 cases for the monster motor i have in the works for it.

but a bit more of a practical mod is the footpegs. i snapped 3 sets on the race day because i kept digging them into the ground when i crashed so i replaced the cruddy cast aluminium ones with some meaty 10mm steel. these should be bomb proof.

because the rear foot guard is removed it lets you put the rear of your foot on the swingarm which i find much more comfortable and natural. im gunna get them cnc cut from aluminium soon if anyones interested.

gotta grind out some more metal from behind the bolts. made them a bit too big.





going to indy on thursday as well to put in a ton of laps and really learn to hang off the bike. should be fun. hope to see all the nsw people here there!

[greeny]

plug is almost perfect. I would say running 45-50:1 will get it back within the conservative range. What fuel are you running? Does your club allow ELF or AVGAS? This will make any Dets softer, reducing the chance of holing a piston. The plug doesn't look white and flaky, and looks almost ideal from the pic. But without a DET counter you will never know...

[greeny]

Be careful with steel pegs, you may end up breaking the frame. I havn't broken a support yet, but was also considering billet ones so i could make them adjustable. Maybe it is the meathooks causing them to break?

[greeny]

The returning to idle problems may be caused by an air leak somewhere. Most likely it is the throttle cable or slide sticking. An airleak may explain your plug, and the over revving.

The bogging down will almost certainly be needle. May need to go back and forth a notch (start richer just in case) to find out whether it is flooding when you get off the throttle.

Gearing: smaller front spockets chew power because the chain has to go through a far tighter turn each revolution. Try and get the equivalent gearing using an 8T front. e.g 8-72 is pretty much equal to 7-64, but is far easier on the chain and crank shaft. It is free HP.

Cheers

[Glen]

definitely not an air leak as ive put the whole motor through a leakdown tester when i built it, but the plug i think was okay as well.

the pegs break because they are cast shit :P i broke the first set across where the peg mounts on (the thinnest bit) and then got another pair with stock pegs and it broke even worse. just cant afford to replace them at $40 a pair. and with a single m6 bolt going through the pegs to hold them on hopefully thatll shear off first before the frame

as for the needle im waiting for my new needles to come. ive tried all positions and havent gotten decent results yet. it does change. but no perfect. gunna play with the idle mix anyway for the slow return to idle. i think thats what it is.

will see how it goes none the less

[mac90]

plug looks pretty good may look a little dry & light from the gearing issue & peaking out 2 soon 2 long down the straight ?

id go a 40:1 mix if your gonna change the plug isnt over oily & im one that would rather that bit extra lube than not enough,
especially with the money spent on a quality engine

some of your after market octane boosters for older cars like STP will bring BP ultimate fuel up a point or so & may help if you cant use avgas or other race fuel

[greeny]

$40 a pair??? Have a look at maylands, much better value. Didn't think of that. Upper cylinder lubricant is a real good if you cant use leaded fuels. You just add a drop or two in each tank of fuel, it acts like lead and softens DETS and lowers the flash point just a touch. Good idea Mac