| Author | Message | ||
     Slaughter |
Out here for 2007 season, we're allowed to convert to chain but not allowed wheel changes. If we put together a group buy, we can probably get a rear adapter made to allow changing to an easily available rear sprocket to allow gear changing. Front cog is going to have to be an over-the-counter sprocket of some sort. Who's in? PM me if you would be interested. We have a half dozen racers who will commit and I'm feeling the temperature of the water here. | ||
| Ezblast |
What are we looking at price wise? GT - JBOTDS! EZ  | ||
| Slaughter |
I have to get some estimates... it's a chicken-and-egg question. I'm telling the machine shops we're talking a half dozen. Be really cool if Steve Mackay could do it - since he has a Blast himself. It looks like a rear sprocket adapter - either a plate + spacers to offset the sprocket to line up with the front sprocket. I've got a local riding buddy looking at it as a garage project but hey... we'll see. I am thinking that $200 is more likely for the rear adapter hardware... hoping for $100 but we're probably only talking 6 commitments. You're on your own for a rear sprocket (stock item) and a front sprocket (probably old stock Sportster) I'll stay in touch - this is just day one after they announced the rule changes yesterday. I'd bet there'd be a street rider or two who might want one - especially if they can always go back to the belt. Personally, the belt is almost hassle free. Still looking at chain sizes. 520 is easy to get sprockets for - but it's capable of 3 times the power the little Blast beastie can dream of. Lighter chain would be more appropriate but it's going to be harder to find a front sprocket... so 520 might be it. | ||
| Ezblast |
Yes it might be a nice addition to the Black bike - lol GT - JBOTDS! EZ | ||
| Xgecko |
hummmm make things difficult why don't you  | ||
| Gearheaderiko |
Yeah, my research tells me the 520 is the way to go. However, I dont see any need or have any desire to convert a Blast to chain drive (even the raceBlast). I see the only benefit as for gear changes. BUT if the conversion is just to adapt a Sportster/Big Twin/Buell sprocket OR belt pulley to the Blast wheel, then I'd be really tempted. Actually, it seems (if I remember correctly) that the Speedway bikes use 520 chains and their sprockets are available big enough just to drill the Blast mounting holes in. And there are regular inquiries about a chain conversion at the various Blast forums. | ||
| Swampy |
2 Please | ||
| Slaughter |
We're going to have to gear these little beasties DOWN for racing the streets of Willow. We're going to figure out how best to get it done and since we're ALL cheap bastids here, we want it GOOD but we want it CHEAP. I've put feelers out but I figure that the B-last for racing could use the same chain as a 125 GP bike since they have nearly the same HP (though the uneven pulses of the Blast would snap a chain before long) - but a street bike could use the much heavier 520. I figure if 180HP club racers are running 520's - you might be able to throw a lighter chain on the blast - though a 520 would probably outlive all of us and NEVER stretch. (Erik - bring your buddy back out who was thinking of racing his VF500 in Vintage! I can put him in touch with Tony Digati who raced the one we now own for a few seasons) | ||
| Ezblast |
Erik - where you talking about the Jawa sprockets? GT - JBOTDS! EZ | ||
| Slaughter |
I haven't found enough info out there to see if somebody is already building a kit - so that's what I'm going to do more of today. We're talking like 10 sets (Glendale HD/Buell and I can split up-front costs) This is NOT going to be a way to make money, but a way for our fellow racers to get one CHEAP. If we get more of our street buddies in the loop, it'll be cheaper yet. If any of you can post links to anybody offering a conversion kit, please post up. I don't need to "reinvent the wheel!" | ||
| Slaughter |
I have approached a couple sponsors here about having them machined by the way. | ||
| Mmelvis |
Are we talking a complete kit, sprockets, chains and the works ? | ||
| Slaughter |
No - it'll just be the parts that would require machining with a parts list of the "jewelry" required to complete the kit. We're ALL cheap bastiges here and a complete kit is probably going to cost more than just the parts you can't easily do yourselves. I'm going to attack the problem with a tape measure, calipers and micrometer tonight to see where we can actually put the bits and pieces. Should make a go/no-go decision by end of week this week. | ||
| Ezblast |
The Jawa sprockets are big there should be others also - you could drill and adapt those with spacers - I think from looking at them. GT - JBOTDS! EZ (Message edited by ezblast on December 19, 2006) | ||
| Jprovo |
I would make it fit CR250 Sprockets. Slaughter, any ideas on how to tension the chain? Spring loaded idler? | ||
| Ezblast |
http://www.ablproducts.com/ What year spread for the CR250? GT - JBOTDS! EZ | ||
| Slaughter |
Slaughter, any ideas on how to tension the chain? Spring loaded idler? I was going to look at changing chain length by adding/removing links - instead of putting in an axle slider and idler. Don't think there's anywhere near the swingarm travel to require an idler. Changing out chain links is pretty simple. It will make things more pricey with a slider/adjuster. Since I'm not racing a Blast, I can't test any of this. Probably talking a 415 chain, not a 520. 520 would be better for street but the 415 would be better for racing. I'll be putting a 415 on the 660 Blast going into the XB chassis - it works for the 125GP guys and they're making more HP than some of the Blasts (43HP in the TZ125) (Message edited by slaughter on December 19, 2006) | ||
| Swampy |
There are some ideas out there for the XB chain drives and different idler setups. | ||
| Woody1911a1 |
if you don't need an idler with a belt on a blast , why would you need one with a chain ? second question , the only reason i'd go to a chain is to lower the gear ratio , is a readily available smaller front sprocket available ? i cant imagine using a larger than blast rear . | ||
| Swampy |
The two reasons to go to the chain would be easy gear changes and not being stranded! | ||
| Jprovo |
A slider/adjuster is out for the Blast, because the rules specifically state that swingarms must be stock... I would stick with a 520 chain unless you can find a good source of cheap 420 front sprocket. You can find a 520, 23 tooth countershaft sprocket for $33. | ||
| Slaughter |
Cheaper IS better and the 520 chain fighting only 50 HP will outlive all of us. The rules state stock swingarm but they will allow slider adjustment but Larry will have to approve on a case-by-case basis so if somebody re-interprets just exactly WHAT a chain adjuster is, he better be prepared to get bounced the first tech inspection. We're looking also at dished sprockets for the rear. Kinda fun to fantasize - but we'll see how it all shakes out when we actually sketch out how we're going to cut metal Realized I have no dog in this fight, if it takes more than a couple hours of my time, I'm not going to mess with it. Gotta take some flowers to Steveb's wife. She's recovering from surgery last Friday. 'Nite all | ||
| Woody1911a1 |
Jprovo or anyone , how does the diameter of a 23t compare to the diameter of the stock front on a blast . sorry just mentally trying to figure out the gearing . chit the rear sprocket on a blast is almost as big as the rim ! has anyone done any research on the gearing or know how any of the heavily modded blasts were done ? differrent primaries , gearboxes ? my personal interest would be in gearing it down a bunch as an around town screamer. | ||
| Blake |
HP likely governs chain durability concerns; might it be wise to also consider the effects on teh chain of peak torque/chain loading? Dropping the clutch with a big ol' flywheel spun up to 5 grand and/or an agressive hamhanded traction-breaking downshift may result in peak chain loads that exceed what a 180 LB 125GP bike produces. | ||
| Blake |
Steve, Thank you for contacting sponsors for this. They absolutely deserve the first shot at helping with the Blast chain conversion. | ||
| Slaughter |
Yeah - Blake - there is some inspiration. Obviously the delivered cost is going to be more if they're only going to machine one set at a time so I'm hoping to guarantee at least 6-10. Without naming names, we DO have a sponsor with in-house machine shop - but we'll have to see. On chain size, the realistic choice would be the 520 because nobody would choose a 415 for the street knowing they'd be replacing it every month or two. Plus, we're not finding ANY countershaft sprockets for the smaller chain (surprise!) | ||
| Swampy |
Any thought on making a belt that would last? Maybe go to a full sized one? | ||
| Woody1911a1 |
ok , so no-one in this discussion is asking about gearing ? you know you cant just buy whatever front and rear sprocket off the shelf and bolt them on and expect them to work . right ? saw this about changing primary gearing http://www.badweatherbikers.com/buell/messages/327 77/247617.html?1166742245 not sure if it's applicable to a blast . | ||
| Swampy |
Thats a good question, then it would just be a matter of making what we already have on the outside to last longer.... | ||
| Slaughter |
For racing the smaller tracks, we need to gear down a little lower. We're not concerned about the things lasting longer. The 520 chain would probably last forever but because it's so huge for these little motors, might not make too much sense for a streetbike. 415 chain might work better for racing but would probably have to be replaced monthly on a bike used on the street for daily commute. 520 can probably find a good primary sprocket - but that is my assumption. I'm still behind schedule on looking at the problem. Busy week at work here trying NOT to have to come in next week! |
