Qwik Posted April 12 Posted April 12 (edited) Late last year I punched a hole in a piston. Still don’t know why. I Bought a Dale Walker /J&E Holeshot performance 81mm/1216cc kit. This rig is built for long trips. And although I live at altitude. I will be doing a lot of sea level riding. So I want to jet it for sea level. Anybody have a good starting point for this? Edited April 12 by Qwik Quote
Gixer1460 Posted April 12 Posted April 12 You do realise that if you get it 'bob on' for sea level riding, with the added weight / drag / power loss at altitude - you might not get home again? Won't comment on potential jetting as there are far to many variables in play. But that outfit and your situation almost cry out for an EFI conversion - self adjusting for altitude! Quote
DAZ Posted April 12 Posted April 12 I would have thought DW would be able to advise on jetting, he seems to have plenty dyno time ,but as @Gixer1460 the says ideal would be f.i. Possibly using 1250 bandit)/gsx throttle bodies, inlet rubbers and ecu, I think @imago is partway through this conversion on his 1100g but is about to move so it maybe on hold 1 Quote
Qwik Posted April 12 Author Posted April 12 Quote Well the bad news is, DW is currently closed. And may or may not reopen. They are moving all of their shops and home. And he wants to retire he’s 63. I did leave a message for him. He and I speak quite a lot. Now the funny thing, is I’m running a 1200 Bandit motor out to a guy in Oregon. And swapping him for a complete 1250. ECU harness injectors everything. So that might end up happening 1 Quote
Qwik Posted April 12 Author Posted April 12 4 hours ago, Gixer1460 said: You do realise that if you get it 'bob on' for sea level riding, with the added weight / drag / power loss at altitude - you might not get home again? Won't comment on potential jetting as there are far to many variables in play. But that outfit and your situation almost cry out for an EFI conversion - self adjusting for altitude! I would think it would be better to be fat. Then to be Way lean Quote
Upshotknothole Posted April 22 Posted April 22 I'd jet it for where you live and then maybe adjust the mains if you're gonna be going down to sea level. My bikes are jetted for sea level, but an hour away I can be riding at 5K+ feet in the Cascades. You already live higher than I can ride here, highest road near me tops out at 6K'. FI would definitely make it easier to go back and forth without making adjustments. Also some carbs have access bolts on the bottom of the bowls to make swapping main jets easier. Might be worth it to look into some flat slides if you don't want to deal with FI. Also what I usually notice on my bikes when getting to higher elevations is top end power when wide open is where it's most noticeable. There are some really nice long sweepers up in those mountains...if I was cruising along at a normal pace, I doubt I'd notice as much. Play around with it and post up what ends up working for you. Quote
Oilyspanner Posted April 23 Posted April 23 Our engines can run pretty hot when tuned, my solo bike needs to move above 30 mph when it's hot outside (28/82 degrees), else the oil temperature climbs. Pulling a sidecar would produce more heat, high compression pistons produce a lot more heat, so that's why you holed a piston .....forged pistons are tough, so your engine must've been very hot ! Jetting is only one part of the problem/solution. Fitting a fan for slow speed, town environments in the summer would be helpful , dropping the compression would help and make sure you don't have an ignition advancer. Fitting gsxr cams would help reduce cylinder pressure at lower revs, it would reduce torque low down, but would lower engine temperature....but sat in traffic it would still get very hot. Fit an oil temperature gauge, then you'll know when the engine is struggling with heat. 1 Quote
Upshotknothole Posted April 23 Posted April 23 2 minutes ago, Oilyspanner said: Our engines can run pretty hot when tuned, my solo bike needs to move above 30 mph when it's hot outside (28/82 degrees), else the oil temperature climbs. Pulling a sidecar would produce more heat, high compression pistons produce a lot more heat, so that's why you holed a piston .....forged pistons are tough, so your engine must've been very hot ! Jetting is only one part of the problem/solution. Fitting a fan for slow speed, town environments in the summer would be helpful , dropping the compression would help and make sure you don't have an ignition advancer. Fitting gsxr cams would help reduce cylinder pressure at lower revs, it would reduce torque low down, but would lower engine temperature....but sat in traffic it would still get very hot. Fit an oil temperature gauge, then you'll know when the engine is struggling with heat. All good reasons for a top end oil cooler and a fan. Even my 750 suffers in the heat in town during the summer. Quote
Qwik Posted April 23 Author Posted April 23 (edited) 6 minutes ago, Oilyspanner said: Our engines can run pretty hot when tuned, my solo bike needs to move above 30 mph when it's hot outside (28/82 degrees), else the oil temperature climbs. Pulling a sidecar would produce more heat, high compression pistons produce a lot more heat, so that's why you holed a piston .....forged pistons are tough, so your engine must've been very hot ! Jetting is only one part of the problem/solution. Fitting a fan for slow speed, town environments in the summer would be helpful , dropping the compression would help and make sure you don't have an ignition advancer. Fitting gsxr cams would help reduce cylinder pressure at lower revs, it would reduce torque low down, but would lower engine temperature....but sat in traffic it would still get very hot. Fit an oil temperature gauge, then you'll know when the engine is struggling with heat. Good info. Except the fact that it was a bone stock engine. Now it has high compression pistons that are forged. And I was cruising at about 60 mile an hour on the interstate in light traffic When it happened. so I’m genuinely curious on your response to that Edited April 23 by Qwik Quote
Oilyspanner Posted April 23 Posted April 23 Yep, handling heat is always the problem with our engines, tuning, going slow, lugging more weight just make it worse. Like the extra cooler idea combined with a fan, this would help a lot. Quote
Oilyspanner Posted April 23 Posted April 23 High compression is the major producer of heat, even with an otherwise std engine - bandit cams will produce more heat at lower revs, because they've less over lap/cylinder pressure is higher at lower revs. Were the cams dialled in properly ? At 60 the air should offset any slight carburation weakness induced heat. A big bore outfit will need more cooling than a std engine. Quote
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