Trek 4500 / GP460 now twin belt jackshaft

[DetonatorTuning]

a few more hours of work this afternoon.

milled the mount flange on my DDM Dominator totally flat for a better seal at the engine port and reworked a previous exspansion chamber support bracket to deal with flange viberation, flex and bolt loosening.

new issue cropping up now that i am using more of the high rpms of the engine. been noticing a sheen of fuel behind and above the carb on the shrouding, no sign of where it comes from when engine is off.

while doing some tuning and using WOT on the bench i found it. these walbro carbs have a overflow/ bypass line out of the carb and back to the tank. while using other configurations i had deleted this line and left it open. since i wasn't using such high rpms nothing ever came out of it.

i had to rig up a catch bottle and replumb a line to it. used one of my old PRIMUS fuel bottles for now but will probably get enough line to make it back up front to the main tank.

not much else, bike is suprisingly smooth considering the jackshaft layout and very quick up to speed now that i'm using less overall reduction and letting it rev the way it wants.

interesting side note of that, while using 18.75-19.27 : 1 ratios i was doing my cruise speed at about 8600 rpm and getting real good mileage. now that i'm using the 20.91 :1 ratio i'm doing my cruise at 11,000rpm. the bike is very strong there, not losing any ground in headwinds or on grades and the mileage has improved like it did when i was using the shifter setup.

lights and all other features are remounted and i'm ready for another week of commuting.

more reports later,
steve

 

[DetonatorTuning]

this piece built right side to cassette drive setup is proving to be a real nice smooth and dependable configuration.

i'm totally sold on the 20.91 : 1 engine ratio. it will pull along at 5mph or take off from there and tear right up to 55mph. the coolest part of the power band is from 20mph to 40mph, in that range with the comp. bump, Dom. pipe and that ratio it just blasts forward. of course it keeps going at the same pace right to 55, but i really don't go there much any more.

great for taking off from a stop, gaining and commanding lane position but you have to really watch cars approaching, they just aren't prepaired for a bike to close on them at that velocity from a short distance.

i'm considering going ahead with the lower leg adjusters. esp. since 5-7 Heaven has described the adjuster he's using for his friction configuration. i can easily rig the same way and all i'll have to change is elongating my lower leg mounting holes. then i can add "L" plates and all-thread like 5-7 and have a real cool feature for ultra fine tuning the chain tension on the lower loop.

steve

 

[DetonatorTuning]

LOL, 130 views since 7-1 and not a single comment.

for those mining the previous ideas and experinces, thanks for the interest and confidence.

for those who have been waiting for me to get it together and post the results of the lower leg adjusters you are about to be rewarded for your patience. in the next couple of days i'll have some pics and a ride report.

this particular rack assembly is morphing and evolving as tweeks become nec. it's finally just about to the place that it could be a repeatable product.

i still hope to convert it to left side twin belt drive, maybe by the end of the yr. LOL

i'm currently doing spacing and alignment work to enclude a freewheel for the hub pulley. if it should happen to all come together we may finally have an all weather, fully adjustable, 8mm pitch cog belt drive rack mount capable of handling 5HP.

thanks for riding along,
steve

 

[Happy Valley]

Sounds good Steve, look forward to your progress.
I'd be happy with an all weather, fully adjustable, 8mm pitch cog belt drive rack mount capable of handling 2hp....so 5 would be a comfortable margin.

 

[fireball_jones]

**** DetonatorTuning, nice ride build. im doing something similar to my folding bike but on the front. but i wanted it as light and simple as possible. can i ask is it up and running? and what have you found most and least sussessful? thanks for the postings

 

[DetonatorTuning]

fireball,

yes sir, the current configuration, jackshaft to the right side cassette single speed is working out fine. there are pics of that manifestation ( no lower leg adjusters ) earlier in this thread.

as to "success" that's kind of a floating concept. i have 3 major build threads here on the forum. in each instance i ended up completely satisfied on an "as is" basis.

my GEBE was a nice light FAST build, didn't like the main mount strap and belts only went 1000 mls. with my engine.

my Staton gear drive was SUPER robust, didn't like the long chain loops or the loss of MPG's.

my "the scooterguy" frame mount / shifter was much better than either of the former and allowed me to easily experiment with final ratios to optimize my engines rpm band.

but i'm on a journey toward the ultimate LWB 26/26 recumbent commuter vehicle, so everything i've done so far has been deliberate R&D toward that end.

this jackshaft rack mount is my solution to and for all the "dilemas" i found in trying to make other stuff do what i wanted rather than what it was offered to do.

quantify "successful" in your eyes and i'll try to answer more directly.

steve

 

[DetonatorTuning]

HV,

i think you'd be very happy indeed.

currently i'm fastening the lower leg mounting bolts in the redrilled fender support holes, above the axle dropouts, on my Trek frame. if other frames don't have those another bracket will have to be added to attach to the seat stays and the support leg length will need to be altered accordingly.

steve

Sounds good Steve, look forward to your progress.
I'd be happy with an all weather, fully adjustable, 8mm pitch cog belt drive rack mount capable of handling 2hp....so 5 would be a comfortable margin.

 

[fireball_jones]

Mr DT, i understand your journey. as i am on a similer expadition. success is im my humble opinion is my/our circumstance if using it makes me/you happy. and allowing me to ride around the world of course..., but everyons differnet.

my "the scooterguy" frame mount / shifter was much better than either of the former and allowed me to easily experiment with final ratios to optimize my engines rpm band.

im glad you have found something you are happy with congradulations to you. and i agree being able to easily experiment is important in further developing the design

 

[DetonatorTuning]

fireball,

just back from your "Brompton" thread, real savy piece of kit that ! congrats yourself.

if i understood what i saw of the main mount hardware, you have a dual purpose "torque strap" that incorporates a bolt that pivots the engine rack to accomplish chain tension.

if you don't mind, i'd like to incorporate that into my assembly.

presently, to change chain tension on the top loop i have to loosen all four locating bolts and add or remove shim washers. easy enough, but tedious, especially in the experimenting stage.

i could instead fix my engine and make the mounting plate pivot as you have, making adjustments from an open topside location. BRILLIIANT

in the belt drive configuration this will make altering the final ratio a snap as well as give easy infinate tensioning.

steve

 

[fireball_jones]

thanks once again for the complement.

feel free to use any of the things ive done in your project. maybe well start a revolution

the bolt pivots the bolt for chain alinment (ie no chain twist.) at the front are two slots which the entire mount slides up or down, which are fixed with the bolt on the side and i havent had any problems coming loose. it took me around ten mins to set of the first time but less than half of that once i had things set up and i shoudn't need to adjust the tension much as the gearbox and chain can stay attached.

the metal strip which is above the brake caliper is not as a "torque strap" which is a good idea, but maybe i misunderstand. if that doenst make sense feel free to tell me.

"i could instead fix my engine and make the mounting plate pivot as you have, making adjustments from an open topside location. BRILLIIANT" agreed i once had a gxh50 and had to always fuss around with the bolts underneath.

thanks