Baja Heat 6.5 jackshaft bypass pics

joekd

joekd

Active Member
#1
#1
I finished flipping the clutch and running new chain (5 ft total) to go from the clutch directly to the rear sprocket

Added a chain deflector in the front (don't want a broken chain finding my leg) and modified the rear chain cover by drilling one hole and adding a 2" metal extension (in this picture it only has a 1.25" extension, I have since changed it so the cover sits "level")

I also painted the chain cover with black high heat paint, never liked the look of the chrome piece

Also had to remove the OEM cover over the muffler so the chain deflector would fit

So far have only ridden it around the yard a couple times, low end suffered slightly but it still picks up good and I can already tell top speed will be a lot higher than the OEM 19MPH that I clocked with my GPS





Considering the only $$ I have into this was the new chain (already had the chain deflector, picked it up for the go kart and it was the wrong size so I bought a different one for that) it seems like a good cheap mod

Even with the deflector in place everything still sits closer to the motor then the old plastic cover (which I used to constantly hit with my leg forcing me to stop and reposition it again on the little tabs)
 
joekd

joekd

Active Member
#5
#5
Right now I am still holding onto the OEM parts, if I decide I dont like this setup I am going to put the jackshaft back on and try the 36T rear sprocket I bought from Vipr here on the site
 
joekd

joekd

Active Member
#6
#6
mybiz said:
Looks like he better add a roller guide That a lot of chain that will be flopping up and down
Click to expand...
I have run it for probably about an hour total on jack stands and to be honest, very little chain movement. I adjusted it so there is only about 1/2" and of course the fact that the bike has no rear suspension means no movement between engine and rear.
 
mybiz

mybiz

New Member
#7
#7
chain

joekd said:
I have run it for probably about an hour total on jack stands and to be honest, very little chain movement. I adjusted it so there is only about 1/2" and of course the fact that the bike has no rear suspension means no movement between engine and rear.
Click to expand...
Thats good i was just saying add one for a precautionary so when your way out there away from your tools You wont have to come back to tighten your chain up To me it looks like in time when your chain stretches it will be slapping on the bottom of your frame just an idea:thumbsup:
 
Oldschool

Oldschool

New Member
#8
#8
I have a rebuilt jack shaft for my MB165 that I will list when I buy the TAV 30. It has less than 4 hours on all new bearings and comes with spare sprockets
 
ViperR

ViperR

New Member
#9
#9
Looks good. You'll have to clock it with your GPS and report the speed. I'm wondering if you can re-install the jackshaft plate without the parts except for the stock rubber roller to keep some tension. You'll also be able to use the clutch cover. If the roller doesn't line up, I'm sure you can mod the roller in or out.
 
joekd

joekd

Active Member
#10
#10
ViperR said:
I'm wondering if you can re-install the jackshaft plate without the parts except for the stock rubber roller to keep some tension. You'll also be able to use the clutch cover. If the roller doesn't line up, I'm sure you can mod the roller in or out.
Click to expand...
Cant run the OEM backing plate without losing the chain guard I added

One reason I did this was to LOSE the cover :doah:

joekd said:
Even with the deflector in place everything still sits closer to the motor then the old plastic cover (which I used to constantly hit with my leg forcing me to stop and reposition it again on the little tabs)
Click to expand...
If I decide to stay with this setup and see the chain being a problem I can find a way to add a roller tensioner in the future
 
R

RaWarrior

New Member
#11
#11
Well, ideally your speed should double by eliminating the 2:1 reduction of the jackshaft. If you did 10 before, it should do 38 now, but I kinda doubt it has the power to reach that speed at a 5:1 ratio. You'll also have half the torque at the wheel, so going up hills or loose terrain will be much harder.

Those motors are tough and will hold up to high RPM's, and considering how cheap they are if it wears out a bit sooner it's no big deal. Put a ziptie around the governor spring, very loosely at first. Get a GPS or some other way to measure speed, and slowly tighten it until you reach an ideal top speed. Don't cinch it tight, since that will likely break the plastic governor gear.

With the jackshaft, I would do 31 with the stock 6.5 clone and the partially ziptied gov spring. Never had any issue with the motor, still runs great, and I would run it at that speed for 10-15 min at a time. One of my friends totally removed the governor, essentially said "f it", and just ran the motor WOT with no governor whatsoever. He was doing like 42 with stock gearing, but the motor quickly lost compression and was running like crap within about 2 weeks.
 
Oldschool

Oldschool

New Member
#12
#12
3 things affect the effective life of an engine in my experience.

Lubrication.
Dirt.
And high rpm oppperation.

Oil is easy use good oil.....
Dirt is easy change oil and filters often.....

High RPM is complicated:
In order to make power in a small displacement engine they have to rev free and high. Wear increases exponentialy with high speed and the friction created. Better oil helps but idealy you want to keep your revs down to manageable levels so you don't stress and wear things out. The stock jack shaft or any combination of singkle ratios is not going to help you unless you decided where is the best range for your type of riding without over reving or lugging the engine.
 
R

RaWarrior

New Member
#13
#13
Maybe more time will tell, but the original clone for me was really friggen tough. I finally calculated out that 31-32 mph with the stock tire size and ratio was about 5700 RPM from the stock motor. No billet rod, no flat piston, no stiffer valve springs. I did think there was a bit of valve float if you held it WOT going down a hill, but on flats it sounded more or less happy.

Plus, mine went WOT, full speed into bodies of water that it probably shouldn't have, deep enough to reach the carb and hydrolock the motor. The first time it happened I thought for sure the motor was done, but I just pulled the plug, pulled it over a few times, drained the carb bowl, and it re-started on the FIRST PULL, and idled happily. That proceeded to happen again at least 3 more times last summer. I changed the oil after it hydrolocked, but I used the cheapest oil I could find, no-name ND30 from the dollar store.

Several times I'd have to remove the sheet metal because the fan blades were totally clogged up with mud/grass/crap, so ya, I put this thing through deep stuff.

I was not kind to the motor, and other than the side cover gasket springing a leak mid-summer, I had zero issues with it. I'm thinking now it's going to get mounted on the back of a formerly electric powered scooter, since it still starts first pull and runs great.
 
Oldschool

Oldschool

New Member
#14
#14
I bet you weren't running it wide open for very long however were you.

A short sprint down the trails is not the same as full bore and pushing hard for top speed on flat paved surface or across a sand pit all day.

Mine gets a carbon run every now and then. I ran mine today up too 4700 rpm on a flat dry road for 4 good runs today as I adjusted my carb and tried some new jets. But out on the trails I can't drive it like that at 25 mph on a rough trail it would throw me lol.

If you have had that bike as wet as you say strip your jack shaft and repack your bearings. Same for your wheel bearings, Mine on a 2008 bike were completely finnished after 1 season of hard running in the woods.

Any engine you can keep running in its recomended rpm range will run a long time. Me I generaly stay between 2500 and 4000 rpm and I don't need to go WOT to stay there. The Big hills and deap sand well that may require some push. Next upgrades will allow for some safer and harder push.....
My bones however are not as strong as the bike :scooter:
 
8

845mx5

New Member
#15
#15
looks good. hope the acceleration and torque didnt suffer too much. Also it doesnt look like you removed the muffler cover like you said. Nice job
 
joekd

joekd

Active Member
#16
#16
It did suffer very badly, I ended up going back to the jacksharft in like 2 weeks

I have a smaller rear sprocket that I will be installing very soon to hopefully give me a good balance between top speed and acceleration
 
U

ultravista

New Member
#19
#19
RaWarrior said:
Put a ziptie around the governor spring, very loosely at first. Get a GPS or some other way to measure speed, and slowly tighten it until you reach an ideal top speed. Don't cinch it tight, since that will likely break the plastic governor gear.
Click to expand...
Would you mind explaining this in greater detail?
 
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