Hello,
I've just finished this bike build. You can see the build thread here:
(won't let me post the link to a popular engine kit forum.. username beginner01... weak....)
Funny thing is, most times I search on google for an engine/driveline answer, I end up lurking here. :thumbsup:
Setup:
1980 Chicago Schwinn, stretched, 1998 Briggs & Stratton 3.5hp, Tecumseh H35 intake and carburetor with adjustable jets (Thanks Restorekid), air filter fell off somewhere, water heater pipe header with a slapped-together muffler, which, compared to the straight heater pipe, robs a LOT of power.
Gearing: TAV2 ebay knockoff, 6" driven, 10:23 to jackshaft, 12:44 final drive. 26" rear wheel. Direct drive total ratio 8.43, 33mph at 3600rpm (calculated).
Weight: I'm 170, and the bike is probably around 55lbs, so something like 225lbs.
Tire pressure: 45psi.
Problems:
1. not enough power.
2. CVT not shifting into overdrive.
Power: Engine was been ported/polished, eyebrows cut, head shaved .015". The valves need lapping and it probably has zero valve lash. I'm going to fix this today or tomorrow, soon as I get a valve lapping kit.
The engine will NOT rev higher than 3000-something under load. But it does rev until the valves float without a load.
CVT: The cvt will shift into approximately direct drive, but no higher. The red spring is set to the middle position and I don't have the tools to take that C-clip off to change it.
Climbing a steep hill made the belt smoke at 5mph, after having climbed 100ft up. I shut it down, and afterwards did not do any hill climbing except at the end of my first ride- it did make it to the top albeit slowly.
Is there some exhaust I can fit to my 3.5hp? All those briggs headers on ebay, will they bolt right up to the 3.5? And what is the deal with mufflers? RLV, or universal briggs type, and can I still use the water heater pipe with it? When it was just the straight pipe, it had a good bit more power, accelerated quick and the CVT seemed to shift higher (top speed was slightly highbut due to some bolts coming loose on my first ride I did not get to hill-test it.
Also.. I've come to the conclusion I need to install a tougher driver spring, so that it lets the engine rev a bit higher before engaging and shifting. But I can't find ANY info or springs for sale. Would it be beneficial to just drill a couple of .25" holes in the weights?
I've just finished this bike build. You can see the build thread here:
(won't let me post the link to a popular engine kit forum.. username beginner01... weak....)
Funny thing is, most times I search on google for an engine/driveline answer, I end up lurking here. :thumbsup:
Setup:
1980 Chicago Schwinn, stretched, 1998 Briggs & Stratton 3.5hp, Tecumseh H35 intake and carburetor with adjustable jets (Thanks Restorekid), air filter fell off somewhere, water heater pipe header with a slapped-together muffler, which, compared to the straight heater pipe, robs a LOT of power.
Gearing: TAV2 ebay knockoff, 6" driven, 10:23 to jackshaft, 12:44 final drive. 26" rear wheel. Direct drive total ratio 8.43, 33mph at 3600rpm (calculated).
Weight: I'm 170, and the bike is probably around 55lbs, so something like 225lbs.
Tire pressure: 45psi.
Problems:
1. not enough power.
2. CVT not shifting into overdrive.
Power: Engine was been ported/polished, eyebrows cut, head shaved .015". The valves need lapping and it probably has zero valve lash. I'm going to fix this today or tomorrow, soon as I get a valve lapping kit.
The engine will NOT rev higher than 3000-something under load. But it does rev until the valves float without a load.
CVT: The cvt will shift into approximately direct drive, but no higher. The red spring is set to the middle position and I don't have the tools to take that C-clip off to change it.
Climbing a steep hill made the belt smoke at 5mph, after having climbed 100ft up. I shut it down, and afterwards did not do any hill climbing except at the end of my first ride- it did make it to the top albeit slowly.
Is there some exhaust I can fit to my 3.5hp? All those briggs headers on ebay, will they bolt right up to the 3.5? And what is the deal with mufflers? RLV, or universal briggs type, and can I still use the water heater pipe with it? When it was just the straight pipe, it had a good bit more power, accelerated quick and the CVT seemed to shift higher (top speed was slightly highbut due to some bolts coming loose on my first ride I did not get to hill-test it.
Also.. I've come to the conclusion I need to install a tougher driver spring, so that it lets the engine rev a bit higher before engaging and shifting. But I can't find ANY info or springs for sale. Would it be beneficial to just drill a couple of .25" holes in the weights?
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