Performance Ideas

Abramelin · 02-13-2020, 04:49 PM

First off huge thanks to the individuals on here who have worked towards getting more out of their cg250 I picked up a lot from you all so

. This is my first post but I have been lurking for the last 6 months or so, picked up my hawk a few months back and have been planning out mods. Intake mod, vm26 carb, 14t front (not going for top speed) are done. WGK camshaft gets ordered tomorrow after I get paid, when that goes in I will dimple and port the head as well as deck off 1.3mm and maybe a thinner homemade head gasket (running 93 with a booster or going to e85). But it seems, that is about as far as anyone has taken it. Before I continue this rambling let me first say I am not considering costs of part/mods v.s the cost of the bike, or shortening the life of the engine. I am simply contemplating how far this platform can be taken as I cant help myself. First thought is lightened valves, yes this will without a question increase maintenance. But with the ease of work and low cost of parts why not at least discuss it. It seems some have gone hollowed stem (more costly unless you have a capable drill/equipment) while some examples I have seen are dimpled on the rounded portion above where contact on the cylinder head is made (yes this is more so an air movement mod). Next thought lightened flywheel, this seems to be a go to mod for a lot of the other small engine platforms. As there is not one commercially available *yet*. I figure lightening the stock one (outside of areas needed for stator) either through cnc or simply drilling the back area in a proportional manner to ensure balance should create an increase in response. As previously mentioned I am considering switching over to e85 (tested each time for purity, not allowed to sit extended periods of time, carb replaced/rebuilt as needed and up jetted). Power gains on this are as with any NA e85 application, questionable but the cooling effects are not. These engine are clearly loosing efficiency to heat, running e85 would theoretically correct this to an extent and net power just from less energy wasted converting to heat. Also there are several examples of performance gains on small engines from e85 that can be found online. Next is forced induction either the amr300 roots style super charger or the VZ21 turbo, though the supercharger would be easier to tune. The turbo install is several degrees easier than the process of adding a crank pulley, clearancing the amr, pulley alignment, draw through cutout etc etc etc. I would like to also mention I think I have found a company who is producing the 300cc jug and piston for this engine, that was made by (CCW I think) originally but cannot seem to get solid answers as to if it direct fit or requires modification. As I would assume, but google translate only goes so far, yes I know they had heating issues, but if I am running E85 that should be far less of an issue. I look forward to others thoughts and input

02-13-2020, 04:49 PM	#1
Abramelin Join Date: Jan 2020 Location: South Texas Posts: 15	Performance Ideas First off huge thanks to the individuals on here who have worked towards getting more out of their cg250 I picked up a lot from you all so . This is my first post but I have been lurking for the last 6 months or so, picked up my hawk a few months back and have been planning out mods. Intake mod, vm26 carb, 14t front (not going for top speed) are done. WGK camshaft gets ordered tomorrow after I get paid, when that goes in I will dimple and port the head as well as deck off 1.3mm and maybe a thinner homemade head gasket (running 93 with a booster or going to e85). But it seems, that is about as far as anyone has taken it. Before I continue this rambling let me first say I am not considering costs of part/mods v.s the cost of the bike, or shortening the life of the engine. I am simply contemplating how far this platform can be taken as I cant help myself. First thought is lightened valves, yes this will without a question increase maintenance. But with the ease of work and low cost of parts why not at least discuss it. It seems some have gone hollowed stem (more costly unless you have a capable drill/equipment) while some examples I have seen are dimpled on the rounded portion above where contact on the cylinder head is made (yes this is more so an air movement mod). Next thought lightened flywheel, this seems to be a go to mod for a lot of the other small engine platforms. As there is not one commercially available yet. I figure lightening the stock one (outside of areas needed for stator) either through cnc or simply drilling the back area in a proportional manner to ensure balance should create an increase in response. As previously mentioned I am considering switching over to e85 (tested each time for purity, not allowed to sit extended periods of time, carb replaced/rebuilt as needed and up jetted). Power gains on this are as with any NA e85 application, questionable but the cooling effects are not. These engine are clearly loosing efficiency to heat, running e85 would theoretically correct this to an extent and net power just from less energy wasted converting to heat. Also there are several examples of performance gains on small engines from e85 that can be found online. Next is forced induction either the amr300 roots style super charger or the VZ21 turbo, though the supercharger would be easier to tune. The turbo install is several degrees easier than the process of adding a crank pulley, clearancing the amr, pulley alignment, draw through cutout etc etc etc. I would like to also mention I think I have found a company who is producing the 300cc jug and piston for this engine, that was made by (CCW I think) originally but cannot seem to get solid answers as to if it direct fit or requires modification. As I would assume, but google translate only goes so far, yes I know they had heating issues, but if I am running E85 that should be far less of an issue. I look forward to others thoughts and input
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