Welp I decided I am not going to go for 50 anymore. The couple times today I hit 44 was just too much. So I am going to slap back on the 36T for the time being when I feel like doing that. Get me back a little bit more low end.
High Performance Wally World Cruiser?
- Thread starter YesImLDS
- Start date
Good call, low 40mph is a good speed for most bicycles that are good shape and put together right.
low to mid 40's is my aim for all my bikes now, I've done the 50+mph and it was a little unnerving, it was fun but the thought of how lightweight the axles and other parts are on a bicycle are, kinda got me thinking about all the potential failures that could happen and be a very big deal at 50mph.
Even at 40mph a major failure would be a horrible accident but 40mph is much more stable and easier to control than 50mph, that 10mph makes a really big difference.
Cruising in the mid to upper 30's with the right gearing and a well balance engine is ideal in my opinion, and then having the capability to hit 40-43mph if needed on the flat is just a nice bonus for the areas you may ride in from time to time that have a 40mph speed limit.
If I were to ever build another bike that I was wanting to run 50mph, I'd use the mag wheels that have the good high speed bearings, or Id be using the best worksman wheels and I'd be doing some gusseting in key areas of a good frame and any other bracing I thought was vital to having a very strong set up.
I agree on going above 40mph.. it's fun and all but you'll reach a point where the bars will begin to flutter and that's where you need to back off, you can get a few more mph safely by adding in a steering stabilizer but finding one that works for a decent price can be a challenge. I know I'd much rather be using a 20mm axle and cartridge bearings up front for more rigidity like in the better downhill forks but those are very pricy and can easily cost what you already got invested in that bike or more. The other scary factor is the type of tires you can get for your bike and their availability... I've had a cheap Huffy mountainbike over 50mph from pedal power and a steep downhill section of pavement on my way to work, that was fun but with no helmet and the bars fluttering like crazy it became more of a "how fast can you go and still hold the bke steady" than the "how fast can you go" thing. I know a few more tricks by correcting the rake and trail angles that'll make a bike super stable but either way, if you crash at those speeds it's not gonna feel good, that's for sure.
enginewise, I'm thinking the restricting factor after the porting is done and the exhaust is opened up enough to flow really well is the stock NT carb needs to be replaced simply because even tho it's been a proven performer, there's only so much air it can pull in at only 14.5mm. An 18mm Mikuni would definitely help get you a few more mph on top but these aren't always the easiest things to tune since you need to jet up to compensate for the larger air volume at high rpm and also to make them responsive enough at low rpm cruising can become chalenging... that's why a lot of people recommend the VM18 carb tho because it has enough size but it's still fairly small and easy to tune, the larger 21mm carbs become a real pain to tune but will offer the best top end power. If your bike feels like it hit a wall just over the 40mph mark and it doesn't matter which sprocket you're using it could be the carb that's restricting it from going faster if the exhaust and the porting is all already done good, it could also be that there's not enough torque left to turn the 36 tooth to get it faster so the top speed is almost the same compared to a 44 so going with something in the 38 to 42 tooth range might bump it up just a bit more.
enginewise, I'm thinking the restricting factor after the porting is done and the exhaust is opened up enough to flow really well is the stock NT carb needs to be replaced simply because even tho it's been a proven performer, there's only so much air it can pull in at only 14.5mm. An 18mm Mikuni would definitely help get you a few more mph on top but these aren't always the easiest things to tune since you need to jet up to compensate for the larger air volume at high rpm and also to make them responsive enough at low rpm cruising can become chalenging... that's why a lot of people recommend the VM18 carb tho because it has enough size but it's still fairly small and easy to tune, the larger 21mm carbs become a real pain to tune but will offer the best top end power. If your bike feels like it hit a wall just over the 40mph mark and it doesn't matter which sprocket you're using it could be the carb that's restricting it from going faster if the exhaust and the porting is all already done good, it could also be that there's not enough torque left to turn the 36 tooth to get it faster so the top speed is almost the same compared to a 44 so going with something in the 38 to 42 tooth range might bump it up just a bit more.
The NT speed carb is good for just a tad extra flow, not much but it is a little larger, I've seen close to 50mph on a slight delcining road running the NT speed carb on one of my bikes, but only 46mph on the flat with a 34T sprocket.
I've got a 20mm Mikuni Im gonna tinker with eventually when I have the time, may be a pain in the neck to get tuned right but Im gonna see what I can do with it.
most builds will do all they're capable of with an NT or NT Speed carb but a well tuned bigger carb can for sure be a benefit on an engine that can handle it and is balanced well enough to get i to those higher rpms.
I've got a 20mm Mikuni Im gonna tinker with eventually when I have the time, may be a pain in the neck to get tuned right but Im gonna see what I can do with it.
most builds will do all they're capable of with an NT or NT Speed carb but a well tuned bigger carb can for sure be a benefit on an engine that can handle it and is balanced well enough to get i to those higher rpms.
Just took her on a run and it seems like when it hits the high rpm. Around 8k rpm it just sounds like it wants to self implode. On the other side I hit 43mph with the 36T before I backed off because like I said it wanted to implode it sounded like. It sounded like when a car hits vvt or vtec on hondas where it gets more air and hits a different exhaust tone. Really weird. need to check the exhaust for leaks. I haven't really found much oil anywhere except one weird spot on the expansion chamber itself... Sounds like a super leaking exhaust, but only at those rpms.
Other than that she is a nice cruiser at 20mph which is all I really do in these towns. The exhaust is kind of loud now that it's gutted, but it does the job alright at low speed. Sounds like a dirt bike. Need to get an exhaust clip on my go pro.
Other than that she is a nice cruiser at 20mph which is all I really do in these towns. The exhaust is kind of loud now that it's gutted, but it does the job alright at low speed. Sounds like a dirt bike. Need to get an exhaust clip on my go pro.
I was able to get rid of the chain tensioner with the 36T which I REALLY happy about. Thing was ugly and probably took a hair of power out with the extra friction and crappy bearing that wouldn't spin worth a crap either.
Fatty pipe exhaust video after being gutted, this was also at idle. The lowest I could get it while keeping it running.
https://www.youtube.com/watch?v=BF6O_q-czdY
https://www.youtube.com/watch?v=BF6O_q-czdY
sounds good, I hear a tad bit of 4 stroking in there but that is normal.
If the power is good and you can cruise at 20s-30s and up to low 40s if needed, that is an ideal set up in my opinion.... congratulations on the nice running build and yes it is so nice ot to need a idler/tensioner for the drive chain.
wish we lived closer, if so we'd have to hit the road for a nice long cruise, get some bugs in the teeth and wind them 2 smomers up a little.....
Haha well there is a midwest meet in the planning stages you oughta join us up here! I'll have my dax motor on here by then. That balanced lower should be pretty nice for some higher revs. This one hit 43 on flat, but like I said sounded like it wanted to explode so I backed off. Wasn't even tucking in! So it's got a little more in it for sure.
Also found a couple pin hole exhaust leaks, but nothing major and will be fixed next time I have access to the welder. Might even up the exhaust piping on a section of it so I don't have that little section of 3/4" piping. Might go from a 1" header to the 7/8" exhaust piping that leads to the fatty pipe.
If I wsnt a full time working fella that would be fun, I do good to have time to get out of my local county most of the time unfortunately.
Hoping the dax GT5 lower will deliver, just be sure to shave deck height on jug for best ompressjon and squish clearance, I think that is a huge key for getting the GT5 lowers to perform at there best when all else is right, need to get good compression to go along with all the other improvements.
Hoping the dax GT5 lower will deliver, just be sure to shave deck height on jug for best ompressjon and squish clearance, I think that is a huge key for getting the GT5 lowers to perform at there best when all else is right, need to get good compression to go along with all the other improvements.
Well do. Actually calculated out the compression on my PK80 and it's at 11.5:1 at the moment. Hoping to keep the GT5 bottom end at about the same. Going to order the jug and piston sometime next month as ya know taxes. Gotta save up another $600 and then pay the man.
sounds good...
yeah I know what ya mean, that organization that basically ended America as free country, better known as the IRS.
Glad to here of your success.
Bike sounds good, reminds me of my old Rm 125 A....
Have fun and be safe...
Bike sounds good, reminds me of my old Rm 125 A....
Have fun and be safe...
whats with this video, bad audio, no text in the post to tell for sure what its about or why it was even put in this thread.....lol
if you wanted us to hear your bike, do the vid outside and get the carb set right so it will idle is my advice since this vid doesnt say much other than bad audio, kickstand not correct length and engine not running right.
Id say get all this stuff right and then post the video in the right section with some info on the purpose of it...
Peace, Map
Was thinking with this nice weather that I'd go on a ride. What the heck a flat?
No idea what happened.
Kind of weird cause I found this sticker today on the ground...
No idea what happened.
Kind of weird cause I found this sticker today on the ground...
I use the heavy thorn resistant tubes in all my bike tires, and I use a small fine tround file to debur the wheels where the valve stem goes through, use the wide rim strips and I never have issues with flats even though I do most all my riding on rough country dirt roads.
We gotta take our tires and tubes seriouse in rural West Central Texas, everything we have here will, stick you, sting you or bite you, the dirt roads are littered with fencing nails, pieces of barbed wire, baling wire, glass, cactus thorns etc.
Put you some heavy tubes in those tires and be sure not to pinch them when putting tire back on wheel and you have way less issues with flats and much less chance for a blow out also.
We gotta take our tires and tubes seriouse in rural West Central Texas, everything we have here will, stick you, sting you or bite you, the dirt roads are littered with fencing nails, pieces of barbed wire, baling wire, glass, cactus thorns etc.
Put you some heavy tubes in those tires and be sure not to pinch them when putting tire back on wheel and you have way less issues with flats and much less chance for a blow out also.