Loncin RE250 6 speed

[AresROC]

Originally Posted by 84convertablegt

Wow nice vid. Can't wait to hear what top speed you can get out of it!

[Merlin]

Originally Posted by 84convertablegt

Yeah. Thats me. Here is the video. Just posted it

Looking at both engines side by side the Hawk looks to be a little taller? Is the new engine shorter? If so how much shorter would you guess it is? I cant remove the valve cover on my bike with out dropping the engine. A shorter engine would help. Thanks.

[84convertablegt]

It is not shorter. Slightly taller actually

[84convertablegt]

Ill say that this setup needs a gearing change. My plan was to have it geared equivalent to how my Hawk was with the stock engine with a 17/45 sprocket setup, which in 520 chain is 13/35. This doesnt work well with the hp/torque curve of the new engine. The Loncin has a much higher torque curve and makes bigger power up around 7-8,000 rpm, unline the stock Hawk around 5k. So like you will see in the video if I shift to 6th gear all the power is gone at lower rpms. Im going to switch to a 40 tooth rear sprocket and see how that works.

[Megadan]

Originally Posted by 84convertablegt

Ill say that this setup needs a gearing change. My plan was to have it geared equivalent to how my Hawk was with the stock engine with a 17/45 sprocket setup, which in 520 chain is 13/35. This doesnt work well with the hp/torque curve of the new engine. The Loncin has a much higher torque curve and makes bigger power up around 7-8,000 rpm, unline the stock Hawk around 5k. So like you will see in the video if I shift to 6th gear all the power is gone at lower rpms. Im going to switch to a 40 tooth rear sprocket and see how that works.

Yep. As I mentioned previously, I wouldn't go smaller than a 37 rear with a 13 front. That combo would gear you in 6th gear like a 5spd with a 13 and a 33. I think a 40 would be just about perfect.

[84convertablegt]

Originally Posted by Megadan

Yep. As I mentioned previously, I wouldn't go smaller than a 37 rear with a 13 front. That combo would gear you in 6th gear like a 5spd with a 13 and a 33. I think a 40 would be just about perfect.

My 40 tooth sprocket should arrive this week. Ill get it installed and try to get in a ride when its decent out. I think I need to bump up to a 115 jet too. May do that as well. Thanks for your reply. So far your advice has been spot on.

[OneLeggedRider]

She is a bit over-geared for sure. Your cheapest/easiest option would be to drop down to a 12 tooth front sprocket. I ran a 12/33 for a long time and was happy with it. And you already know this but after 500 miles that's gonna be a whole different animal as far as power.

It sounds like it's running great but I'm curious about what carb/jetting you're running. Definitely looks like Ohio roads (how bout dem Buckeyes) but down here in southeastern Ohio your either going up or down a steep hill lol.

[OneLeggedRider]

Originally Posted by 84convertablegt

My 40 tooth sprocket should arrive this week. Ill get it installed and try to get in a ride when its decent out. I think I need to bump up to a 115 jet too. May do that as well. Thanks for your reply. So far your advice has been spot on.

Ehh.. with big Dan it's hit or miss. When he's not PMing me for advice on spark plug gap and valve adjustment, he's asking questions about D+D and Magic strategies.

Ofcourse I jest, Dan scrutinizes and thoroughly investigates every aspect of a machine and goes above and beyond to make it better. His only rival is Jerry, who somehow makes amazing innovations on the cheap and is alot more humble than me. Both are amazing assets to our community and extremely helpful.

[JerryHawk250]

I'll have to agree. I think the 40 tooth will put it just about right. Engine just sounds stronger all the way through the rpm's. Those extra rpm's on top end should equal more top end speed. I was looking at this engine more for being able to have it geared for on and off road without having to make changes to sprockets when going from one type of riding to the other. BTW Good video.

[Megadan]

I think the best way I have always judged what sprocket combination to use has always been to look at the RPM at 65mph, which is the most realistic max cruising speed for these bikes.

On the CG engines this was right around 6000-6500rpm, which is why the 17/43 and 17/45 (13/33 and 13/35) worked so well with the lower torque curve of the engine.

A 13/39 on the stock tire would be my go-to as it offers that same 13/33 capability in 6th gear on the 5 speeds in 5th, but the other 5 gears are now 18% lower, giving much better acceleration and off road capability. As Jerry mentioned, that is the real appeal of the 6 gears, to have the best of both worlds.

That 13/35 combo in 6th gear is almost the same final drive as a 17/40 in 5th gear, which is very tall. That puts the rpms in the mid 5000 range.

The 13/40 setup with that 6spd should put the RPMs right around 6800 at 65mph in 6th gear, which should be just about right for a good highway gear with that motor.

[JerryHawk250]

I just realized that I posted this thread about 2 1/2 years ago. It took that long until someone was finally able to get that engine in the US.

84convertablegt, Thanks for posting and videoing the whole install process. This will help other with there install if they decide to do the swap.

Megadan. Please add a link to this thread in you Hawk Resource Guide for future reference.

[Megadan]

Originally Posted by JerryHawk250

Megadan. Please add a link to this thread in you Hawk Resource Guide for future reference.

I plan on it. I want to make an engine Swap and Modification section just for it.

[JerryHawk250]

Originally Posted by Megadan

I plan on it. I want to make an engine Swap and Modification section just for it.

Thanks. This is way too much information to get buried in the forum. Besides we both might need this information in the future. lol

[84convertablegt]

Got the 40 tooth on and took it for a quick night ride. Not enough time and still taking it easy on the new engine but I will make a few premature statements.
1.) 40 tooth rear, 13 tooth front is a good setup for this engine / transmission.
2.) My max speed was still only about 70mph on a slight downhill.
3.)This engine still doesnt have enough power to overcome the drag forces caused by wind once you get above 65mph. Just need more HP. Plain and simple.
4.)This engine is way better than the CG stock vs stock. It pulls way harder all the way through 9500rpms. You can actually do a 0-60 pull on it now.
5.)6th gear is only for cruising on straightaways or downhill at 55mph. Even with the 40 tooth rear it still goes limp in 6th gear. No pulling power. Must downshift to 5th to speed up.
Ill do another video if we have some better weather. Im also going to rejet the carb. Def running lean, especially in the colder air.

[JerryHawk250]

I'm sure it will get better once you get some mile on it. The 6th gear is doing just what it's suppose to do. It's an overdrive gear to cruise at a lower RPM. No different that your car or truck. If you speed up, the car or truck will down shift.